ACCIDENT ANALYSIS-B-737-800-04 SEP 17- COCHIN
Sequence of Events and
Observations by Investigating Team
B 737-800
aircraft was involved in an occurrence on 04-09-2017 at 2112, UTC (05-09-2017
at 0242 IST) at Cochin Airport while operating Flight from Abu Dhabi to Cochin.
Captain -59
Years old, highly experienced with almost 14500 Hrs. of Flying including 4176
Hrs. on Type.
Co Pilot- 28
Years Old, Total Flying experience 1429 Hrs. and 1139 hours on B 737-800.
There were
102 passengers and 06 Crew (02 Cockpit Crew & 04 Cabin Crew) on board the aircraft.
Both PIC and Co-pilot
were operating first time together for Cochin- Abu Dhabi- Cochin flight. The
PIC was based at Delhi and Co-Pilot was based at Cochin by the Air India
Express.
The flight
took off from Abu Dhabi at 1644 UTC and landed at Cochin at 2107 UTC.
The aircraft
was given landing clearance by ATC at 210324 UTC informing “landing surface
wet, Runway 27 cleared to land, wind 050 degree 03 knots.”
As per
METAR, at 2100 UTC the visibility was 4000 meters which reduced to 3000 meters
at 2130 UTC.
ATC informed
crew before landing regarding rains and runway surface as wet.
At 210715
UTC aircraft landed, and at 210741 UTC ATC informed aircraft to “vacate via
convenient right”.
Since
the aircraft touched runway late at approx. 4900 feet from the beginning of
Runway 27 near taxiway C3 and vacated via C2 instead of usual C3 exit due to
delayed touchdown.
After
landing the aircraft vacated runway from C2 and was given taxi clearance to bay
23L via C-F-L and hold short of Taxiway Lima due another aircraft taxing out
from bay 20.
As per CVR,
while taxiing, co –pilot informed PIC about passing taxiway “E” and next is
“F”.
Also, co-pilot requested PIC who was at controls, to go slow as
runway markings were not visible and advised to call follow me jeep.
Co-pilot informed PIC
that she cannot see any markings.
However,
there was no response from PIC.
The aircraft after crossing
abeam taxiway E on taxiway C made a premature left turn 90 m before Taxiway F.
Aircraft entered
in Open Rain Water Drain, (3-meter-wide having depth of 1.7 meter on Taxiway
side) running parallel to Taxiway “C” , situated
at a shortest distance of 43.55 meters from centerline of Taxiway “C”.
PIC applied throttle three times for aircraft to come out of the
drain, in spite of the fact that Co Pilot advised Captain not to do so. The
aircraft didn’t come out of drain and remained stuck into the drain.
Both engines
and rear belly of the aircraft became the weight bearing member and Main
Landing Gear (MLG) were freely suspended in the drain.
Follow me
Jeep reached at the accident site at 2117 UTC and first
fire fighting vehicles reached aircraft at 2137 UTC.
Passengers
were evacuated using step ladder from L1 door at 2150 UTC and last passenger
deplaned at 2155 UTC.
Three (03)
persons on board the aircraft received minor injuries.
There was no
fire.
The aircraft
received major Structural damage including damage to Nose Landing Gear (NLG),
Engine inlet Cowls, Fan Cowls, Engine Strut, lower skin etc.
Findings and Recommendations by
Investigation Team.
As
per PIC’s statement, he reached hotel late in the previous night while
operating flight Cochin- Dubai-Cochin and was not able to sleep before the
flight and was fatigued at the time of landing at Cochin. In CVR, there is noise of PIC
yawning in the flight.
He also mentioned that
Fatigue, poor weather and confusing taxi track appearance contributed to
incorrect judgment of initiating the turn short of the link “F”.
As per co-pilot’s
statement, when PIC turned aircraft left prematurely, she was adjusting her
wipers and spectacles to see clearly.
PIC was found BA +ve on 17.08.2007
and 09.01.2016.The license of PIC was suspended by DGCA for 3 Months from
09.01.2016.
The Tower Controller
was handling three aircraft at the time of the accident and fourth joined after
five minutes.
The tower controller
failed to maintain two way eye contact i.e. surveillance over the subject aircraft
and lost situational awareness.
There was blatant use
of Non Standard ICAO language as well as Non Standard Phraseology and local
language among invariably all the Units i.e. Tower, Approach, Area, SMC, Alpha,
CIAL Tower Coordinator in Tower, Operational Vehicles etc.
WSO was on ATC Channel till
2125 UTC and made a logbook entry regarding the accident at the same time i.e.
2125 UTC and didn’t reach the tower till 2130 UTC.
As per Alpha’s
statement, WSO was in Tower. But after corroboration from ATC log books and ATC
tape transcripts, it was found that WSO was on Channel at ASR till 2125 and at
the same time i.e. 2125, WSO made a detailed log in WSO’s log book about the
accident.
It means WSO has not reached
Tower before 2140 and by this time, the Controller had briefed the relieving
Controller and handed over watch at time 2130 UTC.
The markings at Taxiway
C were repainted in March 2017 and Markings on Taxiway F were repainted in July
2017.
However as per CVR tape
transcript, the taxiway marking were not visible.
The DGCA
team also found on 05-09-2017 that Taxiway C Centerline Marking was not
visible.
As per records submitted by ATC, a few other
aircraft also reported that Taxiway Marking were barely visible during the month of April, May and June 2017.
The Taxiway C was
equipped with blue Taxi way edge lights. Alternate Taxiway C blue lights and Taxiway Sign Board
lights were on at the time of accident.
However,
there were no Taxiway center lights.
Taxiway edge lights are
spaced 60 feet apart. At the time of taxiing, one circuit of taxi lights was working
and alternate blue lights was glowing.
CCTV camera
recordings shows that the taxiway blue lights were ON and Green leading lights to the taxi track link
(Taxiway F) were ON with Low intensity when aircraft was taxiing.
After the accident the
intensity of Green leading lights was increased by ATC.
Cochin Airport is equipped with CAT-I
Approach CAT I lighting system.
Alternate Taxiway C
blue lights were “ON” at the time of accident. There was no request received
from crew to ATC to switch “ON” all Taxiway lights or increase the intensity of
the lights.
Taxiway sign lights were on at the
time of accident.
The Retro reflective
Markers / Delineation Markers were not installed at drains at Cochin.
Taxiway Edge Lights — “Sea Of Blue”
Effect
As per ICAO
the Aerodrome Design Manual (Part IV) para 9.2, the concentration of taxiway
edge lights in the operational area often results in a confusing mass of blue
lights commonly referred to as a “sea of blue”.
In some
cases, this can result in pilots finding it difficult to correctly identify the
taxiway boundaries.
This problem
particularly occurs in complex taxiway layouts with small radius curves.
This problem
can be removed by the use of taxiway center line lights, thereby eliminating
the need to install edge lights in much of the taxiway system.
Edge lights
are normally still installed on curved portions of taxiways, at taxiway
intersections and at taxiway/runway intersections.
At Cochin
Airport when the aircraft moved forward from the eastern end of the taxiway
towards exit F, the pilots must’ve been seeing clearly the taxiway stretching
ahead.
The thick
yellow line marking and the center-line of the taxiway too must’ve been
visible, due to the edge lighting.
A little farther ahead on the right, there
were five links-taxiways perpendicular to the taxiway that connect the taxiway
with aprons.
These links
-denoted by Roman alphabets G, F, E, B & A- too had blue edge lights.
When any
aircraft initiates the 90 degree turn to enter the link-taxiway, the glow of
the blue lights fitted along the edges of the five parallel exit paths can
together appear as a huge, rectangular illuminated surface. This optical
illusion is the Sea of Blue Effect.
It occurs
because blue light that travels as shorter, smaller waves gets scattered more
than other colors.
The light
thus scattered from the edges of the five link-taxiways spaced just 125m apart can
easily overlap, hiding the open land between them. So the chances are abundant
for the pilot either to totally miss the actual exit that got submerged in the
‘blue sea’ or to confuse between the exit (link-taxiway) and the area between
the link-taxiways.
In rains
& night, the
concentration of taxiway edge lights called “sea of blue” may result causing
the pilot either to miss the actual exit that got submerged in the ‘blue sea’
or to confuse between the exit (link-taxiway) and the area between the
link-taxiways.
As it was
raining, there are chances that the pilot may have been influenced by “blue sea
effect” resulting in missing the actual exit.
WOCL.
The accident occurred
at 2112 UTC (0242 IST) which is in the window of circadian low (WOCL) cycle
RVR equipment/ SMR-Not
installed at Cochin Airport.
The drains
may be properly illuminated and the obstructions to be indicated.
CIAL may
also explore the possibility of installing the center line lights for taxiway C
for better visibility.
Analysis by Aviation Safety
Management Society of India-Lessons Learnt
Main Cause of Accident.
In the
considered opinion of ASMSI professionals, this accident occurred due to poor
CRM and Fatigue factor of the Captain.
Contributory Factors.
- Adverse Weather, Wet Runway Conditions, in
addition to the existence of only alternate Taxi lights on low intensity
resulted into poor visibility conditions and inability of the pilots to see
clearly, the Taxi center Line and other Markings. - Operation
during Window of Circadian Low. - Sea
of Blue Effect. - Absence
of any light markings to caution the pilots about the presence of the drain. - Possibly,
complacency on the part of the Captain leading to loss of situational awareness.
The Inquiry team seem to have not deliberated enough on the
point as to why a highly qualified and experienced Captain, turned 90 meters
before the turning towards foxtrot Taxi Track, without confirming the correct
place to turn. It can only happen if the pilot is fatigued, stressed and under
tension due to fear of loss of professional reputation.
No questions seem to have been asked to the captain, as to
why he failed to respond, to the cautions by the Co Pilot, when she repeatedly
told the Captain that visibility is poor and she is unable to see the Taxi
Track markings and advised the Captain to go slow and ask for Follow Me Jeep.
It is indeed intriguing that the Captain opened throttle
three times in spite of the caution by Co Pilot, to move his aircraft forward
when the aircraft was on its belly in the drain. The complete perspective of
the Captain and Co Pilot related to the ground from the cockpit, would have
changed, when the aircraft came to rest, on its engines and belly. How come the
pilots did not realise this major change in perspective.
The
touchdown of the aircraft 4900 feet, after the beginning of the Runway, goes to
show that the pilot was fatigued, due to which he was not situationally aware.
The failure of the pilot to respond to the cautions by the Co Pilot, also
points to either the arrogance of the Captain by virtue of large Power Distance
or uncertain, confused and fatigued state of mind.
CRM -Power Distance.
- There appeared to be serious lack of
CRM (communication, leadership, team work and
synergy) between Captain and Co Pilot. - There was vast gap between the Age
(Capt. 59 Years, Co Pilot 28 Years, Experience (Capt. 14500 Hrs, Co Pilot 1500
Hrs) and Status (Capt. Very Senior Commander, Co Pilot Very Junior) of the
Pilots. Thus, there was large Power Distance between Captain and Co Pilot by
virtue of the vast difference in the age, experience and status. - The large power distance takes away
the ability of the Co Pilot to Speak up, give flight and safety related inputs
to the Captain, to advise the Captain if he is going wrong or committing errors
and to be assertive. - Crew pairing is an important part of
CRM. The Captain and Co Pilot were flying together for the first time and the
large Power distance between the Pilots played a major role towards causation
of this serious occurrence. In addition, Male and Female Crew composition can
lead to lack of synergy which may affect the safety of the flight. - Although in this accident, Co Pilot
appeared to be alert and kept advising the captain correctly but the Capt.
failed to pay any heed to the Co Pilot due to, may be his ego, overconfidence,
arrogance and complacency which unfortunately comes in most Pilots with age,
experience, seniority and status(Power Distance). - Due to Power Distance, the Co Pilot
was not assertive enough for which, of course, she can’t be blamed since majority
of Co Pilots are not able to speak up to
the Captain which is a shortcoming in the CRM Training, with consequent
compromise on Safety. - The Captain ignored the inputs from
the Co Pilot where she clearly stated repeatedly that please Taxi slowly since
she is not able to see the center line markings, advised the Captain to ask for Follow Me Jeep and not
to open throttle when the pilot was trying
to take out the aircraft from the drain. It appears that the Pilot was not
aware that the aircraft was in the drain.
Fatigue Factor
- As per the statement of the Captain, he had not slept well and was
obviously sleepy (yawning in the Cockpit).Long flight in the night, adverse
weather and operations during WOCL added to the fatigue factor of the Captain,
particularly since he was already suffering from lack of sleep. Fatigue leads
to increased reaction
time, reduced attentiveness, impaired memory and withdrawn mood. The very late
touchdown i.e. 4900 ft. ahead from the beginning of the runway, lack of
response to the inputs from the Co Pilot, turning 90 Meters before the correct
turning point, failure to realise that the aircraft has got into the drain and opening
throttle to move the aircraft forward three times shows that the Pilot was
terribly fatigued, stressed and confused.
Situational Awareness.
- The situational awareness displayed
by the pilots appears to be poor. They were high and fast on approach due to
which they landed after 4900 ft. from the beginning of the runway. Why they
landed after 4900 ft. has not been deliberated by the Investigation Team. - Co
Pilot appeared to be better situationally aware then the Captain while taxiing.
If the Co Pilot could not see the center line markings due to rain, then Capt.
also must have not been able to see the center line. However, the Captain
failed to make any comments whether he can see the center line or not, in
response to the Co Pilot who has been saying repeatedly that she can’t see the
center line. - When
the Co Pilot as well as the Captain were not able to see the Center line
marking, why they did not request ATC to increase the intensity of lights to
high and also to switch on all the Taxi lights? - Pilots
had not realized that the Taxi Lights were on low intensity and only alternate
lights were on and the fact that increase in the intensity of lights would have
helped them to see better. - The
Captain turned 90 meters short of the Foxtrot Taxi Track without seeing/being sure,
consulting or taking any help from the Co Pilot (who of course stated that when
the pilot turned, she was cleaning her spectacle and adjusting wind screen
wipers). Turning without seeing and not being sure, is strange and irrational
act on the part of the Pilot. - The
action of the pilot to open throttle three times in attempts to come out of the
drain in spite of the advice of the Co Pilot not to open throttle, is
intriguing to say the least, since the action of the pilot to open throttle to
move his aircraft forward when the aircraft was stuck in the drain, and the
engines were resting on ground, could have resulted in catastrophic
consequences. - It
appears that the Pilot was under the impression that he has encountered
something minor which is affecting the forward movement of Aircraft and it can be
overcome by opening throttle, least realizing that his aircraft was in a drain
3 meters wide and 1.7 meters deep. Surely, the pilots must have heard the thud
and felt something very unusual when the aircraft nose wheel got into the drain,
collapsed and the aircraft came to rest on its engines and belly with wheels
dangling in the drain. The Pilot appears to have not paid any attention to the
unusual occurrence. It is indicative of very high levels of fatigue/stress of
the Captain who was unable to understand and cope with the situation. - The
pilots seemed to have no knowledge about the existence of the drain parallel to
the Taxi track. There were no caution lights to indicate the presence of the
drain. - The
ATC had no clue about the position of the aircraft after it landed and was
confused about the communication between the Pilots and ATC. - The
ATC controller failed to activate the Airport Emergency Services in time even
after knowing that the aircraft has got into ditch. - The
delay of almost 25 mts by the Fire tenders to reach the aircraft after the
accident had taken place, can be attributed to the lack of correct information
from the Pilots to ATC,lack of situational Awareness by the ATC controller and consequent
delay in activating the emergency and fire services. - The
ATC Controller should have known that the taxi center line markings may not be
visible to the pilots particularly in rain. (It must have been in the knowledge
of the controllers that the taxi center line markings may not be visible since
they have been receiving inputs from number of aircrafts during past months
about the inability to see the center line marking. The ATC should have
cautioned the pilots and switched on all the Taxi Lights on high intensity. - ATC
Controller should have known that the aircraft is landing in rain, in the night
and during WOCL, after a long flight. Hence, he should have been more alert,
vigilant and situationally aware. The ATC controller at that time was busy
handling four aircraft and obviously was overloaded with work. The WSO should
have been more involved in supervision and monitoring of the aircraft movement
during this critical period of the operations. - The Controller increased the intensity of Taxi lights after the accident
which served no purpose towards prevention of the accident. If he had been
situationally aware, he would have switched on all the Taxi Lights and
increased the intensity of lights before the aircraft landed.
Aircraft
Operator.
- The
Operator’s Supervisors seem to have paid no attention to the issue of large
Power Distance between the Captain and Co Pilot and the fact that the pilots
were operating flight together for the first time. - There
appears to be inadequate emphasis on the problems associated with large Power
Distance between Crew Members during the conduct of CRM Training by the
Operator. - The
lack of knowledge of the Pilots about the Sea of Blue Effect is evident in this
accident. - The
Station Manager/ Duty Officer/Dispatcher at Cochin did not seem to be aware about
the problem related to sighting of the center line marking in rain by the
Pilots. Even if they were aware, they did nothing about it.
Airport Operator.
- Subsequent
to painting of the Charlie Taxi Track Center line in the Month of Mar, number
of Pilots had communicated to the ATC about their inability to see the Taxi
Center line, possibly due to its fading. The Foxtrot Taxi Track Center line was
painted in the month of Jul. During the months of Jul, Aug and partly September,
Cochin experiences heavy rains which would obviously degrade the painting of
the center line. Airport Operator did not appreciate this important factor and
no efforts were made to inspect the Taxi center line marking to confirm if they
are visible or not. The quality of paint and painting standards also appear to
be suspect. - The
Monsoons in the area of Cochin are quite heavy and Airport Operator should have
taken adverse effects of Monsoon on the condition of painting of the center
line into consideration. The condition of the Center Line markings should have
been observed by the Safety Department of the Airport. - The
reflective markers were not available to indicate the presence and boundary of
the drain at Cochin. It reflects poorly on the knowledge, involvement,
supervision and proactive hazard identification of the Safety Department of the
Airport. - It
is not known whether proper Internal, DGCA or Third Party Audit were conducted
of the Cochin Airport. If conducted then how come such glaring issues were not highlighted. - It
is assumed that effective system of Hazard identification, reporting and
addressing hazards before they turn into accidents, incidents have not been
given due attention by the concerned officials. - There
were no SOP’s for switching on all the taxi lights to full brightness in the
night particularly during poor visibility and rain which was the condition, in
this case. - The concerned officials were not aware of the problems associated with
Sea of Blue Effect and suitable measures to eliminate or minimise these effects.
As such, no SOP was issued for ATC controller to caution Pilots about the likelihood
of Sea of Blue Effect.
Lessons Learnt.
- Proper
Crew Pairing keeping in mind the Power Distance, interpersonal relations, team
work and synergy, is of paramount importance for the conduct of safe
operations. - The
aspect of two pilots flying together for the first time during expected adverse
conditions like bad weather, long flight in the night during WOCL period,
should be kept in mind by the Supervisors and adequate briefing of these
aspects should be ensured. - Power
Distance has led to large number of accident, incidents. This aspect should be
emphasized particularly during CRM and SMS Training. - Need
for open atmosphere in the cockpit, effective communication, team work and
synergy are essential for safety and efficiency of Operations. - There
is no place for arrogance, overconfidence and complacency among pilots
regardless of their experience, age, seniority and status. - Inputs
from the Co Pilot should not be ignored by the Captain and the Co Pilot need be
more assertive if there is no response from the Captain to the repeated inputs
from the Co Pilot. - It
is essential for the Cockpit crew to be situationally aware at all times
and they should not hesitate to inform
ATC if they are facing any problem related to the safety of the flight or
unable to see the markings, Centre line or any other issues. They should not
feel that the Controller will think poorly of them if they ask for some help. ATC
will always be willing to help and respond to the Pilots request promptly. - Pilots
should not hesitate to ask for Follow me Jeep, increase in the brightness of
lights and switching on all lights and any other related assistance as and when
required. - Airport
Safety Department should be Proactive in identification of Hazards, addressing
and eliminate them before they lead to accident/incident. The lack of
visibility of the center line marking, problem associated with Sea of Blue
Effect and absence of the reflective markers to indicate the presence of drain,
should have been identified and action could have been taken to address these
issues if the supervisors had ensured the Proactive identification of Hazards. - The
WSO should be more involved in supervising and monitoring the Operations
especially during adverse weather and WOCL period. - The
fatigue factor, work load and level of the alertness of the ATC controller in
the early morning hours during adverse weather conditions, should be kept in mind
by the WSO/supervisory staff and accordingly level of supervision should be
enhanced. - The
Airport Manager of the operator should be more involved, interact with the ATC
and Safety Department to become aware of
the grey areas related to safety of the aircraft and bring the same to
the notice of the pilots so that the pilots are better situationally aware. - The
Operator should be accommodative of the request of the pilots if they inform
the management that due to lack of sleep, fatigue and likely risk of compromise
on safety, when operating in the WOCL, under fatigue conditions, they should
not be detailed for the flight. - The
Pilots should also not hesitate to inform the Management that they are unable
to undertake the flight due to any reasons, which can compromise safety. The
Pilots will be encouraged to approach the Management if Management is known to
consider the Pilots request favorably without any prejudice.
- The
knowledge about Sea of Blue Effect should be imparted to the Pilots and ATC
Controllers during recurrent training. The airports which are known to have
conditions conducive to Sea of Blue Effect must be identified and the details
should be circulated to all the operators to brief their pilots about it.
- The
conduct of the Internal and DGCA Audit should be taken seriously. Third Party
Audits are known to be very effective in identifying the hazards and the
Airport Operators should not shy away from Third Party Audit.
- The
Senior Management of the Aircraft and Airport Operator should pay special
attention to Safety and Safety Management System (SMS). - There
should be accountability of the Accountable Manager to DGCA to ensure sincere
implementation of SMS, addressing all safety related issues and promotion of
safety in his organization.
- The
time taken by the Inquiry team to complete the inquiry should not exceed three
months in such accidents.
- There
should be a system by which the lessons learnt from Accidents, Incidents can be
disseminated to all the Pilots and Aircraft, Helicopter and Airport Operators.
- The
Follow Up action on the Recommendations of the Investigation Team should be
implemented in a time bound manner and DGCA may consider sharing the completion
of implementation of the recommendations with concerned stakeholders.
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