Etihad A332 at Abu Dhabi on Jan 30th 2012, rejected takeoff due to false line up

Last Update: July 18, 2016 / 15:44:40 GMT/Zulu time

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Photo of Etihad Airways A6-EYE, Airbus A330-200 — Etihad Airways A6-EYE, Airbus A330-200 (Photo credit: Faisal Akram Ether / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Jan 30, 2012

Classification
Incident

Cause
Rejected takeoff

Airline
Etihad Airways

Flight number
EY-45

Departure
Abu Dhabi, United Arab Emirates

Destination
Dublin, Ireland

Aircraft Registration
A6-EYE

Aircraft Type
Airbus A330-200

ICAO Type Designator
A332

Airport
Abu Dhabi International Airport, Abu Dhabi

Airport ICAO Code
OMAA

An Etihad Airways Airbus A330-200, registration A6-EYE performing flight EY-45 from Abu Dhabi (United Arab Emirates) to Dublin (Ireland) with 216 passengers and 13 crew, was accelerating for takeoff on runway 31L in low visibility conditions with the runway visual range (RVR) reported between 150 and 200 meters (490-660 feet), when the crew rejected takeoff at low speed due to burst nose wheel tyres as result of impact with runway edge lights and stopped. The aircraft was towed to the apron.

The runway needed to be closed for 5:50 hours until the debris from 11 runway edge lights and burst tyres was removed and the runway lights were repaired. Airport operation basically came to a halt for about 4 hours because operation on the northern runway 31R requires 550 meters RVR.

The aircraft reached Dublin with a delay of 12.5 hours.

The airport confirmed an incident involving an Etihad aircraft, which closed runway 31L due to damaged runway edge lights, at 03:19L (23:19Z Jan 29th).

On Mar 19th 2012 the United Arab Emirates' General Civil Aviation Authority (GCAA) released their preliminary report stating the aircraft had been cleared to line up on runway 31L in low visibility and darkness, the crew was following the yellow taxi line normally illuminated by about 30 green taxi center line lights along the 222 meters past the red stop bar. The crew however reported they could not see those green lights after the stop bar. After following the yellow line for about 157 meters the crew turned left off the taxi line and actually aligned with the left hand runway edge lights instead of the runway center line lights. Shortly after the takeoff run was initiated, the nose gear went over 11 runway edge lights with the left main gear about 4.9 meters to the left of the left runway edge, the crew felt the resulting bumps were more intense and the time interval unfamiliar and rejected takeoff for that reason. The aircraft reached a maximum speed of 83 knots and came to a stop on the left runway edge line.

After holding there for about 2 minutes the crew taxied the aircraft onto the runway center line in order to vacate the runway however received an ECAM message "TIRE LO PR" due to the left hand nose wheel being punctured as result of impact with the runway edge lights. The aircraft stopped on the runway center line, the crew requested being towed to the apron.

11 runway edge lights were destroyed due to impact with the nose gear of the aircraft.

The left hand nose wheel tyre was punctured, seven main wheels were found with glass pieces embedded in the wheels requiring replacement of the wheels. The right hand nose wheel was also replaced due to the load as result of impact with the edge lights.

The crew comprised the captain (38, ATPL, 9,663 hours total experience, 4,408 hours on type) and the first officer (47, ATPL, 6,173 hours total, 399 hours on type).

On Jul 18th 2016 the GCAA released their final report concluding the probable cause of the incident was:

The Air Accident Investigation Sector determines that the cause of aligning the Aircraft with the left hand edge of runway 31L instead of the runway centerline was the loss of situation awareness by the crew. The root cause of the loss of situation awareness was not determined.

With respect to the taxi lead in lights the GCAA analysed:

The evidence gathered from the Airfield Lighting Control and Monitoring System (ALCMS) history report indicated that the stop bar and sensors at taxiway Echo 15 and runway 31L were functioning and recording between the time the Aircraft crossed the stop bar and the time the Aircraft came to a complete stop after the takeoff was rejected. The report did not include any logs of malfunctions and revealed that all associated lights were functioning normally.

However, there was no recording of the actual switch positions, nor which mode the ATCO had used to manage the aerodrome lighting, nor there was a regulatory requirement that this information be recorded. Having a record of the actual switch positions, or the mode selected by the ATCO to operate the stop bar, either manually or automatically, would have assisted the Investigation in verifying the ATCO’s actual selections.

If an automatic/timed operation was selected, the taxiway green lead-in lights would not remain ON throughout the Aircraft taxiing. As per the automatic/timed operation, when an aircraft passes the second sensor (17/7), the stop bar will automatically come ON and the green taxiway lead-in lights to the runway will go OFF. The lead-in lights on the runway itself remain ON at all times. Such a change of lighting conditions would have been recorded in the ALCMS history report, which was not the case, indicating that there was no change in the lighting system. Therefore, the ATCO had selected the ALCMS to ‘manual’ mode, in which case the taxiway lead-in lights remained ON as the Aircraft taxied onto the runway.

The GCAA analysed with respect to the sequence of events in the cockpit:

After the Aircraft passed the stop bar, and based on the Aircraft’s average speed, the Investigation calculated that at approximately 70m, after crossing the stop bar, the Commander said that “He could not see.” The Investigation believes that when the Commander expressed that, he was, most likely, referring to the green taxiway lead-in lights and other lights in the vicinity. At that time, he had, most likely, lost external visual cues that could have assisted him in taxiing the Aircraft into the correct take-off position. The Investigation could not determine why the crew could not see the external visual cues.

At the same time, the Commander asked the copilot to request the tower ATCO to switch on the runway lights. Immediately after, the tower ATCO called to provide the take-off clearance. The copilot read back the clearance, but he did not request the ATCO to turn ON the runway lights, and the Commander did not repeat his request. The Investigation believes that when this happened the two pilots, most likely, saw an external reference, which was the first light of the left hand runway edge lights. Probably, both of them believed that this was the runway centerline and followed it. That is why there was no challenge of each other’s decision
The Commander continued to taxi and turned the Aircraft to the left of the taxiway centerline and followed the runway left hand edge lights. It is most likely that he believed that following the only visible light was the safest option, not knowing that the Aircraft was away from the actual runway centerline.

When the Aircraft lined up, the copilot stated that “The centerline lights supposed to have more space than that [silence of two seconds] No?” and the Commander explicitly commented on the number of lights visible as being two. The Commander said: “I see only two lights.”, but neither of the other pilots who were in the cockpit effectively challenged their statements to confirm whether they were at their intended position. They could have verified their position by comparing the location of identifiable features to the best of their ability. Identifiable means would had been other lights left and right and runway markings in the Aircraft vicinity.

There was a significant difference in the spacing between the runway edge lights, which are 60 m apart, and the spacing between the runway centerline lights which were 15 m apart.

In the case of the runway centerline lights, with the RVR of 175m and the knowledge of the light spacing, the flight crew should have been able to see about 11 lights. Therefore, applying their knowledge and experience of airfield lighting and markings should have allowed them to confirm the Aircraft position.

Two visible lights on the runway centerline equate to a 30 m RVR, because of their 15 m spacing. If the Aircraft had been located over the runway centerline lights this would equate to a 45 m RVR. This was an indication to alert the crew that the RVR was well below the minimum required for departure.

...

Confirmation biases contribute to personal beliefs and can maintain or strengthen beliefs in the face of contrary evidence13. It is the tendency to attend only to evidence that supports the default hypothesis, which is natural but can result in flawed analysis. The Incident flight crewmembers allowed themselves only to take into account the facts that were compatible with what they believed. Therefore, their situational awareness was influenced. Situational awareness involves appreciating what all the crewmembers need to know. To a crewmember, situational awareness is knowing the status of the aircraft in relationship to external cues.

...

The Incident crew regained their situational awareness after the rejected takeoff.

After the Aircraft had impacted nine left hand runway edge lights, the Commander rejected the takeoff. The Aircraft continued to impact two additional lights before becoming to a complete stop on the runway edge. The Commander’s decision to reject the takeoff was based on the unusual sound and thumps coming from the nose landing gear wheels. The Investigation believes that the thumps were a good triggering event that caused the crew to reject the takeoff. Without the thumps, and if the takeoff had continued, it may have resulted in severe consequences.

Metars:
OMAA 300600Z 17003KT 140V200 5000 2000NE BR NSC 16/15 Q1020 A3014 BECMG 7000
OMAA 300505Z 18003KT 0300 R13R/P2000U R31L/0400N R13L/P2000N R31R/0700V1600U FGBKN005 13/13 Q1020 A3012 BECMG 3000 HZ
OMAA 300500Z 17003KT 130V190 1500 0600S R13R/P2000D R31L/0550N R13L/P2000N R31R/0600VP2000D BCFG SCT005 13/13 Q1020 A3012 BECMG 3000 HZ
OMAA 300439Z 16003KT 1500 0600S R13R/P2000U R31L/0800U R13L/P2000D R31R/P2000U BCFG SCT005 12/12 Q1019 A3011 BECMG 3000 HZ
OMAA 300400Z 18003KT 0300 R13R/1000N R31L/0175V0325N R13L/0325D R31R/0225N FG BKN005 12/11 Q1019 A3009 BECMG 3000 HZ
OMAA 300309Z 17002KT 0200 R13R/0175N R31L/0325N R13L/0750V1300U R31R/0225N FG BKN005 12/12 Q1018 A3007 BECMG 3000 HZ
OMAA 300300Z 16002KT 0500 R13R/P2000N R31L/0450N R13L/0650D R31R/0275N FG FEW005 12/12 Q1018 A3007 BECMG 3000
OMAA 300225Z 17003KT 0500 R13R/P2000U R31L/0325N R13L/0500V1000U R31R/0325N FG FEW005 12/12 Q1018 A3007 NOSIG
OMAA 300200Z 14002KT 0200 R13R/0275N R31L/0250N R13L/0350N R31R/0550N FG BKN001 12/12 Q1017 A3005 NOSIG
OMAA 300100Z 11003KT 0150 R13R/0175N R31L/0225N R13L/0350N R31R/0275N FG OVC001 13/13 Q1017 A3003 NOSIG
OMAA 300000Z 12004KT 0150 R13R/0175N R31L/0200N R13L/0200N R31R/0200N FG BKN001 13/13 Q1016 A3002 NOSIG
OMAA 292300Z 13003KT 090V180 0100 R13R/0175V0350N R31L/0150N R13L/0275VP2000U R31R/0450D FG BKN001 13/13 Q1016 A3002 NOSIG
OMAA 292200Z 35002KT 0100 R13R/0300N R31L/0150N R13L/0225V0550D R31R/0800U FG FEW008 15/14 Q1016 A3002 NOSIG
OMAA 292114Z 35002KT 1000 0400NE R13R/0200V0600D R31L/0450D R13L/P2000N R31R/P2000N BCFG FEW008 16/15 Q1016 A3002 BECMG 0200 FG
OMAA 292114Z 35002KT 1000 0400/ R13R/0200V0600D R31L/0450D R13L/P2000N R31R/P2000N BCFG FEW008 16/15 Q1016 A3002 BECMG 0200 FG
OMAA 292121Z 34003KT 0200 R13R/0150D R31L/0225D R13L/P2000D R31R/P2000N FG SCT005 16/15 Q1016 A3002 NOSIG
OMAA 292100Z 32003KT 2500 1000NE R13R/0250D R31L/1700U R13L/P2000N R31R/0250D BR FEW008 17/15 Q1017 A3003 TEMPO 1000

Relevant NOTAM:
A0031/12 - REF UAE AIP OMAA AD 2.20.1.5 MNM RVR REQUIRED TO READ 550M INSTEAD OF 50M. H24, 22 JAN 10:00 2012 UNTIL 23 APR 12:30 2012 ESTIMATED. CREATED: 22 JAN 10:08 2012