Category: Uncategorized

Mountain Flying

PLANNING AND PREPARATION

1. Met – As the site is likely to be remote from an airfield with the associated met facilities, the pilot will be required to interpolate the information provided in the synoptic charts, TAFs and METARS.
2. However, it must be noted that hills and mountainous terrain can create their own micro climates in which the weather may deteriorate rapidly.
3. Wind speed and direction is influenced by the terrain and special attention should be paid to identifying the local wind conditions, especially for any sign of up-draughts and down-draughts.
4. Clouds can form quickly on both hill tops and valley bottoms and pilots must learn to recognize the clues to weather given by cloud formations such as lenticular and rotor clouds.
5. Aircraft – Take-off mass, center of gravity (CG), and performance calculations will be required for the arrival and departure from a landing site (LS), especially if there is a difference in elevation and cargo or passengers are been picked up or dropped off.
6. It is essential to calculate the density altitude (DA) at which the aircraft will be operating as this will have an effect on aircraft performance; higher density altitudes can reduce the power margin dramatically.
7. The Rotorcraft Flight Manual (RFM) will indicate the relevant power margins, hover in ground effect and hover out of ground effect ceilings, minimum and maximum speed and pitch settings.
8. Helicopters operating at a high DA will generally be flown at higher pitch settings and therefore higher angles of attack. This will result in reduced control response consequently flying with reduced margins with regards to the dangers of retreating blade stall, vortex ring and Loss of Tail rotor Effectiveness (LTE).
9. ATC – Whilst any airfield information and NOTAMs for en-route/diversion/departure airfields will be available through the normal channels, information on LSs may need further research and landing permission.
10. Radio communication in mountainous terrain may be difficult and/or intermittent and therefore consideration should be given to establishing a flight following system. Always file a flight plan whenever operating over inhospitable terrain or notify somebody of your intended route and operating area.
11. Exercises – A flight (regardless of an intended landing) into hilly and mountainous terrain will require the pilot to be proficient at the skills associated with off-airfield landing techniques, advanced transitions, limited power and out of wind operations. Knowledge of the special techniques for operating / transiting / landing in valleys, bowls, ridges and pinnacles outlined in this document is essential.

12. Duties – Although the flight can be conducted as a single pilot operation by a pilot experienced in hilly and mountainous terrain operations, it is strongly recommended for the inexperienced pilot to initially undertake dual training and wherever possible fly with a second crew member. This is especially important as the pilot may encounter negative physiological and psychological effects he has not encountered before, e.g.:
13. Hypoxia – a lack of oxygen, which is difficult to identify in oneself and can lead to over confidence and a lack of judgment.
14. Spatial Disorientation – being surrounded by high mountains and flying over deep valleys can disorientate a pilot.
15. Visual Illusions – lack of horizon, false horizon, white out and grey out, lack of depth perception which can lead to disorientation.
16. Apprehension – nervousness due to lack of experience in the environment can lead to nervousness indecision and over-controlling.
17. Fatigue – mountain flying can be very mentally and physically tiring.

Note 1: Survival equipment and or emergency supplies should be carried when flying over inhospitable terrain in the event of a precautionary or forced landing. Consideration should be given to a means of communication, water, warm clothes, fire-making, a means of attracting a search aircraft. It should not be assumed that a stranded aircraft and crew will be quickly or easily located.

Note 2: Be aware that a GPS is merely an aid to and not a replacement for your navigation skills. A route indicated by the GPS might be inappropriate in hilly or mountainous terrain as the GPS does not recognise areas of turbulence or an appropriate flight path.

Weather

18. An awareness of the wind speed and direction is critical in the hills and mountainous terrain because it follows the surface. If the ground rises, the wind flows upward on a slope and it is referred to as the ‘windward’ side.
19. If the ground slopes away from the wind direction, the wind flows downwards and is referred to as the ‘leeward’ side.
20. When wind flows over smooth hills and mountains it tends to flow smoothly. When it flows over a cliff it tends to tumble over the edge in a turbulent manner. When it is forced through a gap i.e. along a valley then the speed is increased due to the Venturi effect.
21. On a windward slope turbulence rarely exists and the resulting up-draughts can be beneficial in producing lift and therefore requiring less power to manoeuvre. As a result the windward slope with up-draughts is preferable to operate in whenever possible.
22. On a leeward slope there is generally turbulence and down-draughts that can make flight hazardous and should be avoided.
23. The area where the up-draught turns to a down-draught is referred to as the ‘demarcation line’. The demarcation line between up-draughting and down-draughting air will, typically, become steeper and move towards the windward edge of the feature as wind speed increases.
24. When flying along a valley it is preferable to fly closer to the windward slope to take advantage of the up-draughts, rather than down the centre of the valley. The leeward slope should be avoided because of down-draughts and potential loss of lift.
25. The Venturi effect in valleys can cause a significant increase in wind speed possibly doubling the normal wind speed. This phenomenon is also accompanied by a decrease in pressure, which can cause the altimeter to over read the altitude at which the aircraft is flying.

26. Estimating the local wind speed and direction in hilly and mountainous terrain is difficult, however is essential and can be achieved by using the following techniques:

• Smoke
• Wind farms
• Wind lanes on lakes (smooth surface on the up-wind side of the lake and waves on the down-wind side)
• Vegetation, long grass, tree movement
• Cloud movement
• Fly a 360° turn around a ground reference at a safe height whilst maintaining a constant angle of bank and speed. The resultant drift will indicate the wind direction and strength.
• Comparing groundspeed to airspeed, visually over the ground or by use of GPS.

27. Clouds and Mountain Wave

Mountain Waves are defined as oscillations to the lee side (downwind) of a mountain caused by the disturbance in the horizontal air flow caused by the high ground. The wavelength and amplitude of the oscillations depends on many factors including the height of the high ground above the surrounding terrain, the wind speed, and the instability of the atmosphere. Formation of mountain waves can occur in the following conditions:

1. Wind direction within 30 degrees of the perpendicular to the ridge of high ground and no change in direction with height.
2. Wind speeds at the crest of the ridge in excess of 15 kts, increasing with height.
3. Stable air above the crest of the ridge with less stable air above and below that stable layer.

Vertical currents within the oscillations can reach 2,000 ft/min. The combination of these strong vertical currents and surface friction may cause ‘rotors’ to form beneath the mountain waves, resulting in severe turbulence.

28. Mountain Waves are associated with severe turbulence, strong vertical currents, and icing. The vertical currents in the waves can cause significant fluctuations in airspeed potentially leading, in extremes, to loss of control.
29. Loss of Control can also occur near to the ground prior to landing or after take-off with a risk of terrain contact or a hard landing if crew corrective response to a down-draught is not prompt.
30. Severe icing can be experienced within the clouds associated with the wave peaks. Local knowledge of the conditions which tend to cause the formation of mountain waves enables forecasting of potential wave propagation.
31. Lenticular Clouds (lens shaped clouds) can form in the crest of the mountain waves if the air is moist. Roll Clouds can also occur in the rotors below the waves if the air is moist. These clouds are a good indication of the presence of mountain waves but, if the air is dry, then there may not be any cloud to see.

Cloud formations

Föhn Effect

 

32. Föhn Effect is a warm dry wind that blows down the lee side of a mountain. When a large air mass is forced up and over a mountain range (Orographic Lift), clouds and precipitation form as the air rises and cools adiabatically. When the air mass reaches the top of the mountain it has lost a significant amount of its water content and so has a much lower dew point. As the air then begins to descend down the lee slope of the mountain, and the air pressure increases, it warms adiabatically. The resultant wind is dry and warm giving clear conditions at airfields on the lee side of the mountain range. As well as creating a warmer climate, these dry winds can be a cause of wild fires during the summer months which may affect flying operations.
33. Another effect is that a pilot approaching from the leeward side of a mountain can only see the silhouette of the top of a cloud, but he cannot see the full extent of the cloud on the windward side.

¹ 1. Air cools at 3ºC / 1000 ft until saturated, then cools at 1.5ºC / 1000 ft1 until the top of the mountain is reached

2. Precipitation removes moisture from the air
3. Air warms, quickly becoming unsaturated, at rate of 3ºC / 1000 ft
4. Air on leeward of mountain is drier than the windward side and has a lower dew point +16ºC +13ºC +10ºC +7ºC +5.5ºC +7ºC +8.5ºC +13ºC

Cumulonimbus Cloud

 

Cumulonimbus clouds and other clouds of vertical development typically produce heavy rain and thunderstorms, especially when the air is forced up due to Orographic Lifting. The cumulonimbus convection currents produce strong and unpredictable winds particularly up-draughts and down-draughts which are extremely dangerous and aircraft should avoid flying in the vicinity of a cumulonimbus cloud.

Turbulence

 

34. In mountainous areas turbulence is often encountered. This can either be mechanical turbulence (due to the friction of the air over uneven ground at low levels), or thermal turbulence (due an air temperature instability at mid-levels). Turbulence affects the behavior of the aircraft in flight and increases the threat of retreating blade stall, vortex ring and LTE as the ground and air speed fluctuates. For helicopters equipped with teetering rotor systems there is the additional danger of main rotor mast bumping and rotor / tail strike.

Severity of turbulence:

• Light turbulence: is the least severe, with slight, erratic changes in attitude and/or altitude.
• Moderate turbulence: is similar to light turbulence, but of greater intensity – variations in speed as well as altitude and attitude may occur but the aircraft remains in control all the time.
• Severe turbulence: is characterised by large, abrupt changes in attitude and altitude with large variations in airspeed. There may be brief periods where effective control of the aircraft is impossible. Loose objects may move around the cabin and damage to aircraft structures may occur.
• Extreme turbulence: is capable of causing structural damage and resulting directly in prolonged, possible terminal loss of control of the aircraft.

Turbulence can be experienced anywhere and without warning, therefore it should always be anticipated, especially in hilly and mountainous terrain. Pilots should always be prepared for turbulence by keeping a positive grip on the flying controls and reducing the airspeed to the recommended RFM ‘turbulent airspeed’.

Solar Heating, Anabatic and Katabatic Winds

 

35. In days with no or little winds, orographic up-draughts or down-draughts are not very significant; therefore the effect of heating the ground by the sun can produce an inversion with associated up-draughts on the sun-side and down-draughts on the shadow-side of a mountain.
36. The same effect can be experience by day and night. During the day, the air heated by the ground creates an ascending air mass (anabatic wind). This breeze can be apparent from about a half hour after sunrise. At night, the air close to ground cools creating a down-draught (katabatic wind). This night breeze can start an hour before sunset and can continue throughout the night.

Note: where there is rising air, there will also be descending air!

Snow

37. Snow is particularly hazardous, especially when encountered in mountainous terrain. Flight in falling snow with the associated threat of icing and DVE shall be avoided. In snow covered areas it is advisable to wear appropriate eye protection as glare makes it difficult to assess speed, terrain, wind and height.
38. Due to recirculation and ‘white out’ landing on snow in mountainous terrain is extremely hazardous. Therefore this should only be undertaken by pilots using the zero speed/zero rate of descent landing technique who have conducted appropriate training!

FLYING TECHNIQUES

 

Speed Management

39. Maintaining an appropriate airspeed can be very challenging in mountainous terrain. Pilots need to be aware of the speed limitations from the RFM especially in relation to turbulence speed and VNE. It is advisable to maintain Vy whenever possible, thereby allowing maximum power margin for maneuvering.

Attitude Management

 

40. When operating in hills or mountains the ‘real’ horizon can be difficult to identify from the slopes of the surrounding terrain. When this happens, vertical and horizontal references can be lost and it is difficult to establish whether the aircraft is climbing, descending or is in straight and level flight. Frequent reference to the aircraft altimeter, ASI, VSI and attitude indicator should be made.

Height Management

41. If the aircraft encounters a wind-shear or a severe down-draught and it is not possible to maintain height using power, the pilot should turn toward a clear area, adopt wings level, set maximum power and the pitch attitude for Vy in order to maintain or achieve a safe flight condition.

Transit Flying

40. When flying through hilly or mountainous terrain, the route should be planned taking the local meteorological conditions into account avoiding adverse weather as described earlier. When crossing mountains, especially in strong winds, you should clear the top of the mountain by at least 500 ft. If you are unable to achieve a safe clearance, consider an alternative route or a diversion.
41. When crossing a range of hills or mountains with cloud on the top, it is better to approach parallel to the top of the range in order to see the extent of the cloud. If the cloud cover appears to be extensive beyond the high ground, consider an alternative route or a diversion.
42. If flying along a valley it is preferable to fly closer to the windward slope rather than along the center of the valley. The leeward slope should be avoided for transiting because of down-draughts and potential loss of lift. If it is necessary to fly on the leeward side, it is advisable to fly at Vy in order to optimise the power margin.
43. Special consideration should be given to the threat of power/cable car wires, logging wires etc. which are often strung across valleys sometimes without any notice to pilots.
44. The escape route when flying along a valley is normally to perform a 180° turn. Therefore if continued flight along the valley is deemed inappropriate, e.g. due to low clouds, DVE or obstacles, an early decision to turn back is essential to ensure a successful turn.

Landing Site Recce, Circuit and Approach

45. Before landing at any remote site a recce has to take place to identify the wind speed and direction, obstacles, an approach/departure path, potential escape routes and to assess the elevation and suitability of the LS.

Approach to a Ridge or Pinnacle

46.The absence of obstacles and the opportunities for an ‘escape route’ make ridges and pinnacles a good choice for a landing site. However, as previously described, these sites are often affected by a turbulent rising and descending airflow over the top, the demarcation line has to be identified.

47. A normal circuit should be flown above the elevation of the LS. For the final approach, if possible, rather than flying directly into wind towards the feature, the final approach may be flown at an offset angle (up to 45°) and out of wind to keep the aircraft out of the descending air and allow an escape route away from the feature. If there is little or no wind, the approach angle can be normal, however, it is essential to avoid reducing the speed too early and loose translational lift before gaining ground effect. If the wind is moderate or strong, an approach with a normal to steep angle can be flown as the wind will maintain translational lift until entering in ground effect (avoiding flight through turbulent areas upwind of the LS).
48. To maintain a constant angle approach the ‘backdrop technique’ can be employed by choosing an additional reference beyond the LS. If on the final approach the reference point appears to go UP or DOWN, in relation to the LS it indicates an overshoot or undershoot situation and should be corrected (see below)
49. The escape route for an approach to a ridge or a pinnacle should be a planned turn away from the feature, which should not require abrupt or excessive manoeuvring, into an obstacle free area previously identified during the recce phase.

Take-off from Ridge or Pinnacle

50. The take-off from a ridge or pinnacle uses the same technique. Where possible the takeoff point should be an area closest to the windward edge of the feature to utilise the up-draught. In the hover and prior to transition, a power check should take place to ensure there is a sufficient power available for a transition away from the LS.
51. Wherever possible a normal transition should be performed gaining forward speed whilst maintaining sufficient height to clear any obstacle until Vy is achieved. If obstacles are present, consideration should be given to performing either a vertical climb prior to transition, or using the appropriate aircraft elevated heli-pad technique.

52.On transition to the climb frequent reference should be made to instruments especially the ASI, VSI, altimeter and the power being used. It can be hazardous to attempt to ‘fly down the hill’ and this should not normally be considered as an appropriate take off path.

If it is not possible to land back on the feature, an escape route should be planned to fly the aircraft into a clear area.

Bowl Approaches and Departures

53. A ‘bowl’ is where mountains surround a confined area (often formed by a small lake or stream) with an open access on one side of it into a valley. The surrounding ‘walls’ can be steep and high with limited escape options and therefore this technique requires a high degree of skill and should only be undertaken by a proficient pilot.
54. An approach can normally be made by entering the bowl, flying around the sides of the bowl and then making a descending approach into wind to a flat area close to the exit to the bowl.
55. An orbital recce is normally flown around the inside of the bowl, entering from the open area, initially as high as possible and as close as safely possible to the sides of the bowl.
56. Vy is recommended to ensure maximum power margin and the power required to main level flight should be constantly monitored in order to identify areas of up-draughts and down-draughts.

57. The aircraft may then depart the bowl through the open area flying over the proposed LS. If necessary, further lower recces can be conducted until a safe orbit can be achieved at which a final descending approach can be made.
58. The landing is similar to that employed for the pinnacle and ridge. The take-off, ideally, is to exit into a clear area through the open access. However, it may be necessary to climb within the bowl in order to achieve the required obstacle clearance.
59. The escape route once inside a bowl would normally to fly the aircraft away from the bowl walls, initially towards to center of the bowl and then exit through the open area. Once flying inside the bowl there are few outside references, it is therefore essential that frequent references are made to the relevant aircraft instruments.

THREAT AND ERROR MANAGEMENT

 

60. Before undertaking flight in hilly or mountainous terrain a risk analysis should be conducted in which the Threats, Errors and Undesired Aircraft States are identified and Managed with the appropriate mitigating actions.
61. A Threat is defined as an, event or errors which occur beyond the influence of the flight crew, increase operational complexity and which have to be managed to maintain safety margins.
62. Errors are defined as actions or inactions by the flight crew that lead to deviations from organisational or flight crew intentions or expectations.
63. Undesired Aircraft States are defined as flight crew induced aircraft positions or speed deviations, misapplication of flight controls or incorrect system configuration, associated with a reduction in safety margins.

Example:

Threat: Turbulence, wind-shear, up- and down-draughts

Error: Flying at inappropriate speeds

Undesired aircraft state: Retreating blade stall, LTE, Vortex Ring, mast bumping, momentary loss of control

Mitigating Action: Fly at appropriate turbulence speed / Vy

SUMMARY

62. If you wish to ensure a safe and enjoyable flight in, around, or over hills or mountains, you must develop the skills, collect the knowledge and appreciate the factors involved. Above all, know your own limitations and those of the aircraft and stick to them.

When conducting operations in hilly or mountainous terrain consider the following:

• Be aware of aircraft performance and limitations
• File a flight plan or notify someone of your intentions.
• Study the navigational charts carefully – do not rely on GPS
• Get up to date weather information for a go no-go decision
• Don’t go when winds are stronger than 25 knots.
• Fly at a safe altitude
• Be aware of the wind direction and speed
• Monitor for sign of change in weather
• Be aware of the psychological and physiological effects of mountain flying
• Always plan an escape route
• Be aware of wind-shear and recovery actions to be taken

Before undertaking flight in hilly or mountainous terrain receive appropriate training from a qualified flight instructor who is experienced in mountain flying techniques.

A Checklist for Circumstances Not Covered by Procedures

• Remain calm and do not rush:
• Fly the aircraft.
• Maintain controlled flight — attitude, speed, altitude.
• Avoid terrain.
• Vacate bad weather.
• Check fuel.
• Talk with your crew and with ATC.
• Manage the immediate threat.

DECIDE Model

• D – Detect. Gather all facts and information about the event — what still works and what does not.
• E- Estimate. Assess and form an understanding of the situation.
• Have you seen something similar?
• Consider possible solutions.
• C –Choose– Choose the safest practical solution.
• I- Identify -the actions necessary to carry out the safest option.
• Have you done this before?
• What are the expected outcomes?
• D – Do. Act by carrying out the safest option.
• E –Evaluate. Evaluate the changes due to the action.
• Reassess the situation.
• Revise the plan if necessary.
• Review the situation.
• Return to the emergency checklist.

DADA Model.

• D- DETECT. See, hear or feel cues Instrument displays Pattern recognition.
• A-ASSESS. Compare with something familiar. Form a mental model. Pattern match.
• D –DECIDE. Evaluate the relative importance of the information.
• Review patterns and mental models.
• Identify suitable action — a pattern or mental model.
• A -ACT -Monitor Review the situation. Plan ahead.

Golden Rules in Aviation 

During an abnormal condition or an emergency condition PF/PM task sharing should be adapted to the situation (in accordance with the aircraft operating manual or quick reference handbook.

Golden Rule 1-Aviate.

The PF must fly the aircraft (pitch attitude, thrust sideslip, heading) to stabilize the aircraft’s pitch attitude, bank angle, vertical flight path and horizontal flight path.

The   PM must back up the PF (by monitoring and making call outs till aircraft stabilised).

Golden Rule 2-Navigate.

Upon the PF’s command, the PM should restore the desired mode for lateral navigation and/or vertical navigation (selected mode or FMS lateral navigation), being aware of terrain and altitude.

Know where you are.

Know where you should be.

Know where the terrain and obstacles are.

Golden Rule 3-Communicate.

After the aircraft is stabilized and the abnormal condition or emergency condition has been identified, the PF should inform air traffic control (ATC) of the situation and of his/her intentions.

Golden Rule 4-Manage.

The next priority is management of the aircraft systems and performance of the applicable abnormal procedures or emergency procedures.

 Latest Update Related to GPS Aided Geo Augmented Navigation System (GAGAN).

The DGCA certificate issued to Airports Authority of India (AAI) for Indian Satellite-based navigation GAGAN system earlier on April 21, 2015, for a five-year period is about to lapse on April 21, 2020. Has the certificate been renewed by AAI yet or has Covid-19 delayed the same? Let’s understand why the DGCA certificate is important and what will happen if the certificate expires?

The Air Navigation Services provider certificate issued by the Director-General of Civil Aviation (DGCA) to Airports Authority of India (AAI) certifying the GPS-Aided GEO Augmented Navigation (GAGAN) system for a period of 60 months (five years) from the date of issue being April 21, 2015 is about to lapse soon.

The certificate authorizing the holder AAI, to provide the facility to operate as navigational aids to support air traffic services for all users on equal terms and conditions is on the verge of expiry. This certificate will be suspended, modified or withdrawn in case of any violations of the provisions of the Aircraft Act, 1934 and the Aircraft rules, 1937.

In 2019, the ministry of Civil aviation postponed the requirement for aircraft registered in India to be equipped with GPS Aided Geo Augmented Navigation system (GAGAN) compatible avionics from January 2019 mandated earlier to June 30, 2020. “All the aircraft being imported for registration on or after 30.06.2020 shall be required to be suitably equipped with GAGAN equipment,” the public notice published by the Director General of Civil Aviation (DGCA) said.

What is GAGAN and how does it help?

GAGAN stands for GPS Aided GEO Augmented Navigation system. It is a system of satellites and ground stations that provides GPS signals to provide better position accuracy. GAGAN is a Space-Based Augmentation System (SBAS) jointly developed by ISRO and AAI to provide the best possible navigational services over Indian FIR (Flight Information Region) with the capability of expanding to neighbouring FIRs.

With the certification of GAGAN for approach and landing operations (APV 1) on 21st April 2015, India has become the third country in the world to have such capabilities. GAGAN is the first system in the world to have implemented in the equatorial Ionosphere region. The GAGAN system is designed to help pilots navigate successfully under all-weather conditions by the accuracy of up to three meters, this capability would enable aircraft landing even on tough terrain and extreme weather. It will allow an aircraft to reduce fuel burn by flying on a specific path on straight routes and between two three-dimensional defined points.

To provide better position accuracy, the GAGAN system corrects itself for GPS signal errors caused by ionosphere disturbances, timing and satellite orbit errors and also it provides vital information regarding the health of each satellite. The GAGAN system offers services to aviation, railways signalling, location-based services, scientific research for atmospheric studies, mobile and tourism.

As mentioned on the portal, currently two GEOs simultaneously transmit the GAGAN signal in space. The footprint of GAGAN GEO expands from Africa to Australia. The system has the capability to serve 45 reference stations for expansion to neighbouring countries.

GAGAN’s civil aeronautical navigation signal is consistent with the International Civil Aviation Organization (ICAO) Standards and Recommended Practices (SARPs) as established by the Global Navigation Satellite System (GNSS) Panel.

What will happen if the DGCA certificate expires?

The Director-General of Civil Aviation (DGCA) formed a Technical Review Team (TRT) to examine specific safety-related artefacts and hazard records and to provide recommendations for resolving any observed issues. Initially, the DGCA certified GAGAN for en route operations (RNP 0.1) on December 30, 2013, and subsequently on April 21, 2015, for precision approach services (APV 1). APV1-certified GAGAN signals are being broadcast since May 19, 2015, according to the website.

If the DGCA certification expires, amid the coronavirus outbreak exemptions from the aviation controller can be availed by AAI. However, without accurate GPS signalling provided by GAGAN system, it will be difficult for pilots to take off flights on rough terrain and bad weather conditions.

 

 

 

 

VISUAL ILLUSIONS

Illusions occur when conditions modify the pilot’s perception of the environment relative to his or her expectations possibly resulting in spatial disorientation or landing errors.

Visual Landing at night presents greater risk because of fewer references and because of illusions or SD.

Factors Affecting Visual Illusions.

Runway environment–

Runway dimensions.

Runway slope.

Terrain drop off at the approach end of runway.

Approach lighting and runway lighting.

Runway condition.

Weather Conditions–

Cloud Ceiling.

Visibility.

Obstruction to vision.

Visual Illusions (VI).

VI most critical when transitioning from IMC and instrument reference to VMC and visual reference.

VI affect situational awareness (SA) particularly while on base leg and during final approach.

VI usually induce crew inputs that cause the ac to deviate from vertical or horizontal flight path.

VI can affect the decision process of when and how rapidly to descend from MDA/H.

• Uphill slope of Runway or Helipad gives illusion of being too high.
• Downhill slope of Runway or Helipad gives illusion of being too low.

©      A wide or short runway creates an impression of being

             too low.

• A narrow or long RW creates an impression of too high.
• Approach, RW including touch down zone lighting affect depth perception depending on light intensity, day or night conditions and weather conditions.
• Bright lights create impression of being closer to the RW.
• Low intensity Lts –farther away from the RW.
• Nonstandard lts modify the pilots perception.
• If RW lighting partially visible-on base leg or circling approach, RW may appear farther away.
• Flying in haze creates the impression that RW is farther away inducing a tendency to shallow glide path and land long.
• In light rain, the RW may appear indistinct because of the rain halo effect increasing risk of misperception of vertical/horizontal deviation.
• Heavy rain affects depth perception and distance perception.
• Rain on wind shield creates refraction effect that causes crew to believe the ac too high.
• Day light, rain reduces intensity of lights resulting in impression of being further away.
• Night time rain increases the apparent brilliance of the ALS making RW appear close.
• When breaking out at both min ceiling and visibility minimum, the slant Vis may not be sufficient for crew to see farther bars of VASI/PAPI thus reducing visual clues.
• In cross wind, RW light and environment will appear at an angle to ac heading, resist the tendency to align with center line.
• A wet RW, reflects very little light, affecting depth perceptions, impression of ac farther away, resulting late flare and hard landing.

CONSEQUENCES OF VI

• Unconscious modification of ac trajectory to maintain a constant perception of visual reference.
• Natural tendency to descend below glide slope or path, inability to judge the proper flare point because of restricted visual references (hard landings before reaching touch down point).
• Inadequate reference to instruments to support visual segments.
• Failure to detect the deterioration of visual references.
• Failure to monitor the instruments and the flight path because both pilots are involved in the identification of visual references.

 

Guard Against Adverse Effects of Visual Illusions

• Flight Crew should be aware of:-
• Weather factors.
• Surrounding Terrain and obstacles.
• Assess the airport environment, airport and RW hazards.
• Adhere to defined PF/PNF task sharing after transition to visual flying.
• PF to monitor outside visual reference while referring to instrument references to support and monitor flt path.
• Monitoring by PNF of head down references while PF Flies.

 

 

 

SPATIAL  DISORIENTATION

Number of accidents have occurred around the world due to Spatial Disorientation.

Tests conducted with qualified instrument pilots indicate that it can take as much as 35 seconds to establish full control by instruments after the loss of visual reference with the surface.

Five most common illusions reported were:

60 percent had a sensation that one wing was low although wings were level.

45 percent had, on levelling after banking, tended to bank in opposite direction.

39 percent had felt as if straight and level when in a turn.

34 percent had become confused in attempting to mix “Contact” and instrument cues.

29 percent had, after recovery from steep climbing turn, felt to be turning in opposite direction,

Surface references and the natural horizon may at times become obscured, although visibility may be above visual flight rule minimums.

Lack of natural horizon or surface reference is common on overwater flights, at night, and especially at night in extremely sparsely populated areas, or in low visibility conditions.

A sloping cloud formation.

An obscured horizon.

A “White-out” condition caused by fog, haze, or falling snow blending with the snow-covered earth surface.

A dark scene spread with ground lights and stars.

And certain geometric patterns of ground lights can provide inaccurate visual information for aligning the aircraft correctly with the actual horizon.

Other factors which contribute to disorientation are:

Reflections from outside lights.

Sunlight shining through clouds.

Reflected light from the anti-collision rotating beacon, Flashing Lights, Nav Lights and Rotor Tip Lights.

All these factors may obscure outside references leading to a disoriented pilot who may place the aircraft in a dangerous attitude as a consequence of sensory illusions.

VESTIBULAR ASPECTS OF SPATIAL ORIENTATION:

The inner ear contains the vestibular system, which is also known as the organ of equilibrium.

About the size of a pencil eraser, the vestibular system contains two distinct structures:

The semi-circular canals, which detect changes in angular acceleration.

And the otolith organs (the utricle and the saccule), which detect changes in linear acceleration and gravity.

Both the semi-circular canals and the otolith organs provide information to the brain regarding our body’s position and movement.

A connection between the vestibular system and the eyes helps to maintain balance and keep the eyes focused on an object while the head is moving or while the body is rotating.

THE SEMICIRCULAR CANALS.

The semi-circular canals are three half-circular, interconnected tubes located inside each ear that are the equivalent of three gyroscopes located in three planes perpendicular (at right angles) to each other.

Each plane corresponds to the rolling, pitching, or yawing motions of an aircraft.

Each canal is filled with a fluid called endolymph and contains a motion sensor with little hairs whose ends are embedded in a gelatinous structure called the cupula.

The cupula and the hairs move as the fluid moves inside the canal in response to an angular acceleration.

The movement of the hairs is similar to the movement of seaweed caused by ocean currents or that of wheat fields moved by wind gusts.

When the head is still and the airplane is straight and level, the fluid in the canals does not move and the hairs stand straight up, indicating to the brain that there is no rotational acceleration (a turn).

If you turn either your aircraft or your head, the canal moves with your head, but the fluid inside does not move because of its inertia.

As the canal moves, the hairs inside also move with it and are bent in the opposite direction of the acceleration by the stationary fluid.

This hair movement sends a signal to the brain to indicate that the head has turned.

The problem starts when you continue turning your aircraft at a constant rate (as in a coordinated turn) for more than 20 seconds.

In this kind of turn, the fluid inside the canal starts moving initially, and then friction causes it to catch up with the walls of the rotating canal.

When this happens, the hairs inside the canal will return to their straight up position, sending an erroneous signal to the brain that the turn has stopped– when, in fact, the turn continues.

If you then start rolling out of the turn to go back to level flight, the fluid inside the canal will continue to move (because of its inertia), and the hairs will now move in the opposite direction .

Sending an erroneous signal to the brain indicating that you are turning in the opposite direction, when in fact, you are actually slowing down from the original turn.

VESTIBULAR ILLUSIONS (SOMATOGYRAL – Semi-circular Canals)

Illusions involving the semi-circular canals of the vestibular system occur primarily under conditions of unreliable or unavailable external visual references and result in false sensations of rotation.

These include the:

Leans.

The Graveyard Spin and Spiral.

The Coriolis Illusion.

The Leans is the most common illusion during flight and is caused by a sudden return to level flight following a gradual and prolonged turn that went unnoticed by the pilot.

The reason a pilot can be unaware of such a gradual turn is that human exposure to a rotational acceleration of 2 degrees per second or lower is below the detection threshold of the semi-circular canals.

Levelling the wings after such a turn may cause an illusion that the aircraft is banking in the opposite direction.

In response to such an illusion, a pilot may lean in the direction of the original turn in a corrective attempt to regain the perception of a correct vertical posture.

The Graveyard Spiral is more common than the Graveyard Spin, and it is associated with a return to level flight following an intentional or unintentional prolonged bank turn.

For example, a pilot who enters a banking turn to the left will initially have a sensation of a turn in the same direction. If the left turn continues (~20 seconds or more), the pilot will experience the sensation that the airplane is no longer turning to the left.

At this point, if the pilot attempts to level the wings this action will produce a sensation that the airplane is turning and banking in the opposite direction (to the right).

If the pilot believes the illusion of a right turn (which can be very compelling), he/she will re-enter the original left turn in an attempt to counteract the sensation of a right turn.

Unfortunately, while this is happening, the airplane is still turning to the left and losing altitude.

Pulling the control yoke/stick and applying power while turning would not be a good idea–because it would only make the left turn tighter.

If the pilot fails to recognize the illusion and does not level the wings, the airplane will continue turning left and losing altitude until it impacts the ground.

The Coriolis Illusion involves the simultaneous stimulation of two semi-circular canals and is associated with a sudden tilting (forward or backwards) of the pilot’s head while the aircraft is turning.

This can occur when you tilt you head down (to look at an approach chart or to write a note on your knee pad).

Or tilt it up (to look at an overhead instrument or switch) or tilt it sideways.

This produces an almost unbearable sensation that the aircraft is rolling, pitching, and yawing all at the same time, which can be compared with the sensation of rolling down on a hillside.

This illusion can make the pilot quickly become disoriented and lose control of the aircraft.

Non-adherence to standard operating procedures (SOPs).

The captain, as PF, did not follow standard procedures, resulting in:

A higher than standard speed for start of descent and initial approach.

A non-stabilized approach.

The low-altitude orbit as a nonstandard manoeuvre to the runway.

The incorrectly performed go-around.

The first officer did not object or call the captain’s attention to his non adherence to the procedure.

The controller allowed a shortcut — a 360-degree turn above the airport — and did not follow the procedure for the path leading to a stabilized approach from the final fix.

During go-around, the crew apparently experienced spatial disorientation, which may have caused the captain to wrongly think the airplane was pitching up.

Despite the GPWS warnings, the crew did not adequately respond.

Analysis of the cockpit voice recorder (CVR) data showed the crew did not perform as a team, due to inadequate training in crew resource management (CRM), SOPs, controlled flight into terrain (CFIT) and GPWS.

Somatogyral/ Somatogravic illusions.

During the approach in night conditions, the crew had on one side a very bright view of the airport and a landmass and on the other side a completely dark area over the water.

Focusing on the visual approach, the crew may have lost visual cues and may have experienced visual illusions and disorientation when initiating the tight 360- degree turn over water, after the non-stabilized approach.

The first officer, as pilot not flying (PNF), was not monitoring his instruments and did not use proper CRM techniques to gain the captain’s attention.

In addition, TOGA provides constant acceleration.

In the absence of visual cues such as the horizon, this constant longitudinal acceleration fooled the captain’s vestibular system into interpreting this as horizontal flight at constant speed.

Prevention Strategies.

Lines of Defence.

The first precaution to avoid an accident is to not put oneself in a nonstandard situation.

The resulting situation may not appear to be risky at the beginning, but, as we know, accidents often result from multiple contributing factors.

Allowing the situation to develop in the first place generates unnecessary risks.

Further, the quality of the approach briefing helps to focus on the following:

Ensuring that one crewmember maintains visual contact with the runway lights.

Task sharing and workload management between the crewmembers.

Effective coordination with the ATC.

Being prepared for a go-around.

Remembering the consequences of visual illusions when there is a mismatch between the real world and what is sensed.

Maintaining continuous instrument monitoring to counter the onset of vestibular system illusions.

When realizing that situational awareness is lost:

Applying strict SOPs such as precise go-around procedures with task sharing.

Callouts.

Go-around altitudes.

Speeds, headings and minimum safe altitudes.

This is the principal reason for approved SOPs.

Adherence to SOPs.

Adequate CRM training helps to achieve an effective balance among crewmembers.

Emphasis on cross-checking and clear task sharing provides a basis for sound attitudes.

In our example, the first officer’s task was to monitor the instruments to effectively and adequately inform his captain.

The captain’s role in relation to his first officer was to encourage him to speak.

Quality of briefings:

Operational procedures require a go-around to be flown at constant speed and without any acceleration with one flap retraction.

The acceleration and clean up should be done at a higher altitude.

This is to ensure that a correct go-around is performed and associated procedures follow.

In general, there are no go-around procedures that require a sustained turn because, from a human factors point of view, crews might suffer Somatogyral (Coriolis) disorientation as well as Somatogravic (false climb) disorientation.

Avoiding shortcuts and strict adherence to procedures help to avoid creating risky situations.

Improved training in CRM and visual illusions.

Training to prevent Somatogravic illusion is almost impossible, but information and sensitization can help pilots recognize its onset and prepare to face it.

The only known way to regain proper orientation is to focus on the airplane’s instruments to rebuild a correct mental image of the situation.

The pilot should understand the elements contributing to spatial disorientation so as to prevent loss of aircraft control if these conditions are inadvertently encountered.

The following are certain basic steps which should assist materially in preventing spatial disorientation.

Before flying in less than 5 Kms visibility, obtain training and maintain proficiency in airplane control by reference to instruments.

When flying at night or in reduced visibility, use the flight instruments.

If intending to fly at night, maintain night-flight currency. Include cross country and local operations at different airports.

If only Visual Flight Rules-qualified, do not attempt visual flight when there is a possibility of getting trapped in deteriorating weather.

If you experience a vestibular illusion during flight, trust your instruments and disregard your sensory perceptions.

Study and become familiar with unique geographical conditions in areas proposing to operate.

Check weather forecasts before departure, en route, and at destination.

Be alert for weather deterioration.

Do not attempt visual flight rule flight when there is a possibility of encountering deteriorating weather.

Discipline helps: adherence to SOPs helps improve safety.

In the absence of visual cues, referring to the instruments to get a correct mental image and continuous instrument monitoring may help to counter vestibular disorientation.

Rely on instrument indications unless the natural horizon or surface reference is clearly visible.

Adequate crew communication is a critical contributing factor to risk reduction as well as effective coordination with ATC.

Remain prepared for a go-around while remaining aware of possible visual illusions.

 

 

 

 

Controlled Flight into Terrain (CFIT)

When an airworthy aircraft or helicopter under the command of a qualified pilot is inadvertently or without prior knowledge is flown into terrain, water or obstructions, is called CFIT. Most of the CFIT accidents are fatal and almost always a pilot error.

 CFIT mostly occurs when visual cues are lost due to flying during night or into clouds, fog or poor visibility conditions. Under such conditions, Pilots may get spatially disorientated, loose Situational Awareness and meets with CFIT accidents. In addition visual illusions, also add to the CFIT accident statistics.
CFIT is more likely to occur over water, hilly areas, long stretches of forested or desert terrain and Night due to lack of prominent visual cues.

Most of the CFIT accidents occur during final approach and landing or during take-off and initial climb. However, Number of Aircraft/Helicopter accidents have occurred during cruise or manoeuvring flight.

Causes of CFIT

Lack of:-

• Proper Flight Planning, Preparations.
• Adequate weather briefing, knowledge and intelligent monitoring of weather.
• Proper analysis of terrain with particular emphasis on Minimum Enroute Altitude, Minimum Safe or Sector Altitude, Minimum off route altitude (MORA),Grid MORA, Minimum Descent Altitude, obstructions around runways, helipads, towers, pylons, power, Cable Car/ trolley cables particularly in the mountains.
• Knowledge about SOP’s, Check List, Procedures, Approach, Enroute, Let down Charts , Weather Radar, GPS, Flight Management System, Automatic Flight Control System, Automation, Electronic Flight Instrumentation System, ILS, VOR,EGPWS,DME.
• Knowledge about Spatial Disorientation, Visual Illusions.
• Situational Awareness- Horizontal, Vertical and overall.
• Correct Altimeter Settings and Cross Check between PF and PM.
• Adequate CRM and Proper Communication.
• Compliance with SOP’s, Rules, Regulations.

Lack of proper configuration and verification of the flight management computer for the profile approach.

Inadequate Vertical Mode Selections of the Aircraft Flight Control System (AFCS).

Inadequate or delayed response to the Warning Alerts of EGPWS/Terrain Awareness and Warning System.

Inadequate or delayed Missed Approach and Go around Flight Path.

Lateral and/or vertical deviation from intended flight path.

Loss of terrain separation.

Low Energy State during Approach / Unstable Approach.

Inadequate Response to Wind Sheer Warning.

Continued approach, when below DA (H) or MDA (H), after loss of visual references.

Unstable approach and Failure to Go Around in time.

Late or inadequate response to MSAW warning.

Lack of effective flight path control during go-around.

Failure to follow published missed-approach procedure.

Inadequate fuel management.

Fatigue and Stress.

Interruptions / Distractions.

Overconfidence, Complacency, Macho Attitude.

VIP, Commercial, Peer and Self Imposed Pressures.

Lack of effective and result oriented Simulator Training, Flight and Ground Training, CRM, All Weather Operations.

Inadequate supervision, lack of monitoring by the Senior Management and Accountable Managers.

Hazardous Attitudes like Ante Authority, Invulnerability, Impulsiveness, Macho and Resignation.

Lack of currency in hands on flying, instrument flying.

Lack of communication, Proper Pre Flight Briefing, Pre Descent, Approach Briefing and Debriefing.

Lack of teamwork and synergy.

Distraction/ loss of Attention.

Poorly developed and outdated Procedures, SOP’s.

Poor Decision Making, Delayed Decision, Fixation, Distraction.

Not knowing or not following the Golden Rule in Aviation which is Aviate-Navigate-Communicate.

Human performance limitations and deficiencies.

Cockpit Gradient/Authority Gradient/Power Distance which takes away the ability of the Co Pilot or First Officer to Speak up or correct the Captain when he is doing something wrong. Lack of assertiveness by the Co Pilot or First Officer.

Single Pilot aircraft or Helicopters are more susceptible to CFIT.

Duck under Syndrome or Scud Running.

Flying visually in IMC conditions or mixing instrument flying and visual flying.

Exceeding the laid down limitations.

Misunderstanding or misinterpretation of ATC instructions or blindly following ATC instructions.

Automated “MINIMUM” alert not activated. 

Inadequate response to the EGPWS alert.

EGPWS software was not updated.

Stabilized criteria is not respected.

Failed to monitor the aircraft’s altitude during the approach.

The relevant weather was not provided to the flight crew.

Delayed decision to execute missed approach when unstable approach or unable to see visual reference below MDA(H).

For helicopter pilots, reluctance to land at suitable place if unable to continue flight due weather.

 

Prevention of CFIT Accidents.

Planning, preparation for the flight needs to be thorough.

Obtain proper Met Briefing, forecast and interpret the weather to see how it will impact on your Flight.

Be knowledgeable about the hazards of flying during pre-monsoon (Norwesters or Kal Baisakhi), Monsoons, Foggy   Winter Months, Wind Shear, Western Disturbances, Cyclones, Tsunami etc.

Improve your knowledge about the weather and how to interpret the weather from the various websites like IMD, Acu Weather, Sky Met and Meteo Earth Etc.

Make good use of the information available from METARS, ATIS, about the weather, runway conditions and act accordingly in time. Respect the Weather and do not press on in adverse weather.

ATC, Met and Company dispatch, must ensure that updated weather information are provided to the Pilots.

Thorough knowledge of Terrain, highest obstructions, Minimum Enroute altitude, Minimum Sector or Safe Altitude, Minimum Off route Altitude, obstructions in the approach path to the Runway or the Helipad and obstructions around the Airport, Helipads. Hilly reason may have Chair Car trolley cables or power cables, communication cables, transmission towers. Knowledge of these and good look out while flying in the hills particularly for helicopter pilots who fly along the valleys at low levels.

Captain, Co Pilot or First Officer should be having good knowledge about the Aircraft, Helicopter, its systems, Avionics, Nav Aids, approach and let down charts, Jepson charts, Weather Radar, Flight Management System, Automatic Flight Control System, SOP’s, Rules, Regulations, Spatial disorientation, Visual Illusions, Situational awareness, recovery from unusual attitudes, recovery from wind shear, stable approach, missed approach procedure, Take off and Go Around Mode switch, SIDS and STAR’s, ILS, Non Precision CDFA approaches.

Carry our proper risk assessment of the flight in coordination with the other crew, taking all the factors into consideration and decide on minimums for the flight which should be respected.

Undertake comprehensive pre-flight, pre decent and Approach briefing of the crew covering the aspects about weather, terrain, obstructions, type of approach, runway condition, winds and division of duties and responsibilities between Captain and Co Pilot or First Officer.

Follow the SOP meticulously. If you feel that SOP is not properly drafted and may compromise safety, it should be reviewed, updated and approved.

Always keep in mind the Golden Rule in Aviation-Aviate-Navigate-Communicate and make sure that at least one Pilot is flying all the time.

Beware of overconfidence, complacency, distraction, Fixation, lack of attention which may lead to loss of situational awareness.

Be Situationally Aware particularly Horizontal and Vertical situational awareness at all times.

Know your capabilities and limitations.

Be very careful in entering data into computers, FMS, AFCS, GPS etc  and selection of correct frequencies must be ensured and cross checked.

Correct Altimeter setting must be entered and ensure cross check and call outs between Captain and Co Pilot and with radio Altimeter. Knowledge of the altitudes for changing from QNH to QNE and vice versa is essential.

Remain current with hands on flying, instrument flying and be knowledgeable to recover from unusual attitudes, wind shear.

Take timely decision to execute missed approach and diversion. No questions will be asked by DGCA, ATC or Operator if pilots execute missed approach or divert due unstable approach or weather conditions (DGCA CAR on ALL Weather Operations).

Helicopter pilots should not hesitate to land at a suitable place if unable to continue the flight due weather (DGCA, ASC 09/2013).

Do not descend in IMC conditions or under cast conditions unless sure of the terrain or following established procedures under radar surveillance.

Do not carry out spiral descent or descend through hole since it may lead to special disorientation. Descend in a race course pattern if required.

Do not succumb to commercial, on time performance, VIP, passenger, peer or self-imposed pressures to undertake flight in the face of adverse weather conditions. Always take a professional well considered decision.

Get Homitis, get thereitis and mind set should be kept under check and no chances should be taken with the safety of the aircraft, crew and passengers.

Do not follow ATC instructions blindly and be situationally aware. If the ATC gives you a radial to fly which is taking you into weather, tell ATC unable and ask for another radial. If ATC gives you altitude to climb or decent which may put you in conflict with other traffic or with your minimum safe altitude, advise the ATC accordingly. Listen out the ATC instructions carefully and don’t hesitate to verify if in doubt.

Keep open atmosphere in the cockpit where crew members are free to give inputs, particularly related to safety of the aircraft/helicopter without any hesitation, fear, apprehension, snubbing or reprisals.

The Co Pilot/First Officer should be given freedom to be assertive and encouraged by Captain to correct or caution the Captain and even take over control if the Captain continues the approach in spite of the approach being unstable or without sighting the runway or any of the runway clues at MDA (H).

Do not undertake the Flight if you are stressed, fatigued or unwell. Be very careful while taking flight during Window of Circadian Low and be aware of Human Performance Limitations.

No decision should be taken if it is influenced by hazardous attitudes like Ante Authority, Impulsivity, Invulnerability, Macho or Resignation.

Operators and Pilots also must ensure to conduct a proper pre-flight planning session and familiarize themselves with the terrain that may surround them during their flight, as terrain familiarization is critical to safe visual operations, in particular at night

CDFA techniques contribute to a stabilized approach. Hence, the operators should develop procedures and train pilots to fly a stabilized CDFA.

Effective crew coordination and crew performance, and in general CRM principles and behaviours can reduce pilots’ workload and decrease the probability of human errors.

Enhancing pilot performance and complacency, both in normal and abnormal circumstances, will empower pilots to intervene, with greater confidence and competence, to prevent any environmental threats and hazards that could lead to high-risk outcomes.  Operators must ensure that their training programs robustly address potential deficiencies, environmental, technical/non-technical factors such as human factors, air carrier’s SOPs.

Encourage operators to review their procedures for responding to alerts on final approach to ensure that these procedures are sufficient to enable pilots to avoid impact with terrain or obstacles in such situations.

Operators should always ensure that their EGPWS software is update to date.

Pilots’ knowledge of aircraft systems, aircraft performance and normal/abnormal procedures is vital to ensure that they do not find themselves in unexpected situations from which they cannot immediately recover.

Pilots must also be keenly aware of the risks of CFIT, the circumstances in which those risks are greatest and the best strategies for maintaining an accurate picture of their horizontal and vertical situation.

Pilots’ competence in recognizing and responding to potential CFIT must be realistically trained and tested in recurrent simulator training sessions, using examples from operational experience.

Analysis of the causes of CFIT accidents should be included in the training courses to help pilots to understand their own limitations and recognize when an undesirable situation is developing.

Learn an escape manoeuvre and techniques designed to enhance the possibility of survival.

Improved monitoring and cross-checking are methods that can prevent many of the accidents

Good CRM behaviour and Pilot Monitoring can help to mitigate CFIT accidents.

Operational procedures can also provide CFIT risk mitigations by avoiding non-precision approaches especially in high risk destinations or adopting risk reducing strategies such as CDFA or PBN approaches.

Pilot in command should be aware of the risks involved when transitioning from visual to instrument or from instrument to visual procedures on take-off or landing.

Helicopter pilots are more likely to get into CFIT conditions since they fly at low levels in hostile terrain. In addition to adverse weather conditions, environmental factors such as time of day, minimal light, shadows, darkness, sun glare, cockpit blind spots, fatigue, or other such factors may result in the pilot losing situational awareness and hitting an obstacle or impacting the ground.

Even if a Pilot is aware of the obstructions and environmental factors, He/She may not be able to see the danger in time or may see the danger but fail to react in time to avoid collision.

Flying in the hills along the valleys can result in a CFIT accident if a power line or cable is strung between the hills. Flying up a box canyon and not being able to fly up and out of it before impacting terrain. Flying over rising terrain that exceeds an aircraft’s/helicopters ability or performance to climb away from the terrain.

Pilots should be aware about the adverse effects of high density altitude which may lead to low reserve of power with consequent large radius of turn, at high altitudes. Under such conditions, manoeuvring the helicopter in narrow valleys may lead to collision with terrain.

Helicopter pilots, particularly, must be fully prepared, knowledgeable about the weather, environmental factors, terrain, obstructions, and adverse effects of high density altitude on performance, performance limitation of the helicopter, disorientation, snow blindness, icing and strong vertical and horizontal wind shear etc. Remember mountain flying in adverse weather conditions is a deadly situation.

Never take chances with weather particularly in the hills, high seas and night.

 

Analysis of number of accidents/serious incidents have highlighted following issues related to safety and for prevention of CFIT accidents.

Situational Awareness has been found deficient in number of accidents analysed. It is recommended that operators increase training on maintaining situational awareness at all times, especially when close to the ground, and provide pilots with appropriate language and procedures to communicate, and respond to, positional concerns without delay.

Procedural non-compliance is a common factor in CFIT accidents. It is recommended that operators promote and enforce a culture of universal compliance with policies and procedures, unless unusual circumstances directly affecting safety dictates otherwise. Such situations also need to be trained.

Emergency checklists are essential tools that flight crews use to respond to serious and time-critical situations. The lists must be well designed and clear; and adherence to these lists must be trained.

SOPs for communication between pilots on approach frequently give no special authority for the pilot not flying to command a go-around, and this is of particular concern when the pilot not flying, is the more junior crew member. It is recommended that operators devise and implement Policies to allow the “Emergency authority” for pilots not in command to take control in emergency situation, should be encouraged and enforced.

Most terrain awareness systems currently available are incompatible with VFR operations in mountainous terrain.

Nuisance’ warnings have the potential to exacerbate CFIT risk. The crew members should be advised not to isolate audio warnings.  It is recommended that regulatory authorities and operators interact with system manufacturers to review the warning logic to ensure that the frequency of nuisance warnings is minimized, without unduly compromising the systems terrain awareness and warning capabilities.

‘Nuisance’ warnings can also be inherent in the design of approach procedures, especially those using satellite based guidance to provide instrument approaches in challenging terrain.

Safety Management System (SMS), enhanced CRM, strict adherence to SOPs and result oriented Ground training need continued emphasis.

Unclear approach templates may cause pilots to deviate from them or misinterpret them hence taking them close to unsafe areas especially if the airport is near mountainous regions. This is exacerbated especially if pilots are unfamiliar and are operating into the airport in a night time environment. Operators and pilots must ensure that they carry the most up-to-date flight instrument charts so that they fly the correct instrument charts and do not fly into terrain mistakenly.

An unstable approach also has been found to be a factor contributing to CFIT accidents. Unstable approaches increase the possibility of diverting a flight crew’s attention away from the approach procedure to regain better control of the airplane. Operators must require their pilots to fly a stabilized approach and to always make timely decision to go-around from an unstable approach.

It is evident that most of the CFIT accidents result from a pilot’s breakdown in situational awareness (SA) instead of aircraft malfunction or a fire. SA refers to the accurate perception by flight crew of the factors and conditions currently affecting the safe operation of the aircraft, and their vertical and/or horizontal position awareness in relation to the ground, water, or obstacles. The data shows that 49 percent of CFIT accidents had vertical, lateral or speed deviations as a contributing factor to CFIT accidents.

Situational awareness can be enhanced through proper flight planning, preparation, knowledge about aircraft, systems, on board equipment, procedures, alertness and vigilance particularly during critical phases of the flight and good CRM. More reliable warnings of possible terrain conflicts through EGPWS that is equipped with accurate navigation systems like global positioning system (GPS) for both navigation and terrain surveillance can improve situational awareness.

Flight crew non-compliance with established procedures was a contributing factor in 23 percent of CFIT accidents. Poor CRM was also a frequent contributing factor.

Pilot Performance remains a major factor in CFIT accidents; despite the efforts to mitigate risk, handling and/or inappropriate actions by flight crew continue to be weak area..

Training, whether it is academic or simulator training, should allow pilots to experience realistic situations that require timely decisions and correct responses. Simulator training should also be given to provide pilots the opportunity to practice CFIT prevention strategies, including the escape manoeuvring. Training should be given to pilots during initial, transition and recurrent training.

Data collection and analysis can provide information of threats, hazards and identify potential weaknesses of an operator.

Collection and sharing of flight data in order to identify hazards ahead of time and mitigate those risks that can lead to an accident is another important element for continued improvement in CFIT accidents.

The best potential source of operational data is the operators’ own Flight Data Monitoring (FDM), Flight Data Analysis (FDA), or Flight Operations Quality Assurance (FOQA) programs.

The aim should be to improve safety through an analysis of information downloaded from an aircraft’s on-board computer at the end of every flight. This information can be used to identify trends and discover issues that might develop into a serious safety problem.

The routine download and analysis of recorded flight data has been used by operators for many years as a tool to identify potential hazards in flight operations, evaluate the operational environment, validate operating criteria, set and measure safety performance targets, monitor SOP compliance and measure training effectiveness.

In non-routine circumstances, when an incident occurs the data can be used to debrief the pilots involved and inform management. In a de-identified format the incident data can also be used to reinforce training programs, raising awareness amongst the pilot group as a whole.

Revise the minimum operational performance standards to improve the effectiveness of terrain awareness and warning systems when an airplane is configured for landing and near the airport, including when the airplane is descending at a high rate and there is rising terrain near the airport. 

All operators of airplanes equipped with the automated “minimums” alert should brief crew members to activate it.

For those airplanes not equipped with an automated “minimums” alert, it is advised that all operators of airplanes equipped with terrain awareness and warning systems (TAWS) to activate the TAWS 500-ft voice callout or similar alert. 

Human, Procedural, Technological. The available human mitigations involve improving and maintaining pilots’ knowledge, their awareness and their competence, and each of these can be achieved by a comprehensive training program embracing classroom, simulator and flight training.

With realistic training, flight crew will be well prepared to:

Know the hazards of flying close to terrain.

Recognize the symptoms of spatial disorientation.

Recognize the factors that may lead to CFIT accidents.

Know the mitigation strategies that will ensure a safe flight.

 

The Safety management systems (SMS) must incorporate management procedures to constantly review and assess the CFIT risk exposure to the operation in order to ensure that the risk is as low as reasonably practicable (ALARP) and tolerable.

Technologies have also been developed to mitigate the risk of a CFIT accident. There are a variety of technologies available but the most considerable one is TAWS/EGPWS; this technology can be used with a terrain map database via GPS to provide the pilots with a more reliable source of data.

Unfortunately, many pilots falsely believe that there is sufficient time to react once an EGPWS alert is sounded. In order to be effective, it is essential that the aircraft system hardware and firmware are correctly maintained and that the software database is properly updated.

Vertical situation displays in the cockpit are becoming more common and these provide pilots with an easy to assimilate picture of the terrain profile ahead of the aircraft, together with its projected vertical flight path.

Operators must ensure that the latest modifications are incorporated in their TAWS/EGPWS computer and with GPS providing aircraft position data directly to the computer. These provide earlier warning times and minimize unwanted alerts and warnings.

Furthermore, appropriate TAWS/EGPWS response procedures by the operators should be established for the flight crew in accordance to the aircraft type performance capability. These procedures should include and encourage pilots that “warnings” should be followed without hesitation as soon as a triggered.

DGCA should promote development and use of a low cost terrain clearance and/or a look ahead devices particularly for helicopters who operate at low levels close to the terrain, obstructions.

Supervision and monitoring of flying operations by Accountable Managers, Chief Operations Officers, Chief Pilots  of aircraft and helicopters particularly  belonging to NSOP, State Govt and Private operator’s needs to be improved.

Effective implementation of SMS which improve Company Safety culture, must be ensured.

The senior management, Accountable Managers, Chief Operating Officers and Chief Pilots must proactively identify hazards related to operations during adverse weather conditions (Pre Monsoon, Summer Season, Monsoon Season, Winter Season) and operations to and from airports, helipads which are known to be difficult and challenging. Standard procedures should be introduced to brief the pilots about the hazards and precautions they need to take to operate safely. Operations Staff and Chief of Flight Safety should be fully involved and remain extra alert and vigilant during marginal weather conditions to provide necessary and accurate weather related information, support and guidance to pilots.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

New Delhi: With the domestic flights resuming operations from Monday, the Central government on Sunday decided to restart regional air connectivity services under the UDAN scheme on select routes and with conditions. The central government said that the services will be started as per the modalities set by the Ministry of Civil Aviation.
Issuing an order, the Central government said that all the operational routes in priority areas which include the northeastern region, hill states and islands are permitted to resume operations.
The order further stated that all operational helicopter routes are permitted to resume operations. All operational routes with no viability gap funding (VGF) are permitted as well. Also Read – Heartbreaking Pictures Show Lions Starving In Sudan Zoo, Spark Online Campaign to Save Them.
The Ministry of Civil Aviation said that all operational routes up to 500 km stage length are permitted to resume operations. “And selected airline operators (SAOs) are allowed to operationalise awarded routes under UDAN, including seaplanes on the permitted routes,” it said.
“If willing to operate without VGF support, SAOs may operate Tourism RCS routes (T-RCS) or RCS routes with stage length more than 500 km in areas other than Priority Areas. However, other incentives for the respective routes as per the scheme document would continue to be available for the contract period,” the order said.

Amphan damages aircraft and two hangars

Structures that collapsed were unauthorised: Airport director

At least two hangars of Air India at the Calcutta airport collapsed, one plane was smashed and portions of the terminal’s roof were blown away during Wednesday’s storm.

Airport officials said hangars 16 and 17 collapsed because of the cyclone and a four-seater Cessna aircraft, which was parked in hangar 16, was damaged after the structure crashed on it.

A 42 seater ATR- 42, which was parked inside hangar 17, was brought out by the airline authorities and parked outside, just as many Calcutta’s were taking out their cars from flooded garages.

“That was the reason why the aircraft did not suffer any damage even though hangar 17 had collapsed,” an airport official said.

However, the nose of the aircraft turned 180 degrees because of the strong winds, the official said.

“The two hangars that collapsed were more than 50 years old and owned by Air India. We had asked them to remove the hangars several times because those were unauthorised constructions but they have not done so,” said airport director Kaushik Bhattacharya.

“The aircraft that got damaged was parked by a private aviation company. For the last two years we have been asking the company in vain to remove the aircraft.”

Air India officials could not be reached. Phones of at least two officials were unavailable through the day.

Bigger aircraft are parked on the tarmac in the open. Officials said that earlier 52 aircraft used to be parked at the airport overnight. Now, the count has come down to 42 because of the lockdown.

In several parts of the terminal, roof made of corrugated sheets was blown away.

Officials said the roof had three layers of corrugated sheet and insulation. As the top layer was removed, there was a huge amount of water seepage, flooding parts of the terminal.

“The roof will be repaired quickly,” said the airport director.

Portions of the airport’s tarmac were flooded. “The main inundation was on the Kaikhali side. We were trying to pump the water out but were unable to do so because the adjoining areas were waterlogged,” the airport director said.

The airport was closed till 5am on Thursday. An official said the airport finally became operational at noon with the take-off of a Spice jet flight to Delhi.

A flight from Russia had arrived at 2.30 on Thursday to evacuate 103 Russian nationals who were stuck because of the lockdown.

According to airport sources there was a delay in starting flight operations because several branches of trees had fallen on the tarmac and portions of the runaway, which needed to be cleaned.