AT72, Karup Denmark, 2016
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|On 25 January 2016, an ATR 72-200 crew departing from and very familiar with Karup aligned their aircraft with the runway edge lights instead of the lit runway centreline and began take-off, only realising their error when they collided with part of the arrester wire installation at the side of the runway after which the take-off was rejected. The Investigation attributed the error primarily to the failure of the pilots to give sufficient priority to ensuring adequate positional awareness and given the familiarity of both pilots with the aerodrome noted that complacency had probably been a contributor factor.|
|Actual or Potential
|Human Factors, Runway Excursion|
|Flight Conditions||On Ground - Low Visibility|
|Type of Flight||Public Transport (Passenger)|
|Intended Destination||Copenhagen Airport, Kastrup|
|Take off Commenced||Yes|
|Flight Phase||Take Off|
|Location - Airport|
|Tag(s)||Copilot less than 500 hours on Type,|
Dark Night VMC
Ineffective Monitoring - PIC as PF
|Tag(s)||Misaligned take off|
|Damage or injury||Yes|
|Causal Factor Group(s)|
On 25 January 2016, an ATR 72-200 (OY-LHA) being operated by an unidentified airline on a scheduled domestic passenger flight from Karup to Copenhagen rejected its night take off in fog from the 2,929 metre-long runway 27L when the crew realised that they had aligned the aircraft with the right hand runway edge lights instead of the runway centreline lights. There were no injuries to the 69 occupants but minor damage was caused to the aircraft and six runway edge lights and two obstacle lights on a military arrestor cable mechanism at the side of the runway were destroyed.
An Investigation was carried out by the Aviation Unit of the Danish Accident Investigation Board. The SSFDR and SSCVR were removed and their data were successfully downloaded and a recording of Karup TWR voice communications was also available.
It was found that the 38 year-old Captain, who had been PF for the take-off had accumulated 3,514 total flying hours including 1,134 hours on type and that the 35 year-old First Officer had accumulated 1,530 total flying hours including 390 hours on type. Both pilots were “very familiar” with the joint military/civil use aerodrome at Karup and were “often scheduled to fly the domestic route from Karup to Copenhagen”.
It was established that the aircraft had taxied south from the departure parking position at the joint military/civil aerodrome passing the threshold of runway 27R before reaching the holding point for runway 27L and reporting there to TWR, who then cleared the aircraft for take-off with the RVR given as 1,700 metres for the first third and 1,600 metres at the midpoint with fog being reported in the current METAR. The TWR controller requested and received confirmation from the aircraft crew that the brightness of the runway lights was "about right”. The Captain had begun taxiing onto the runway without following the unlit lead-on line which would have taken the aircraft onto the centreline and instead made a “sharp right turn” to line up on what he thought was the lit runway 27L centreline but was an alignment of the aircraft with the lights marking the northern edge of the runway. As this positioning was taking place, the First Officer was reading the 13 challenge and response items on the ‘Before Takeoff Checklist’ that included a “runway heading and GPS alignment check” which “was performed without remarks”. Whilst slowly taxiing on the runway prior to the displaced landing threshold, the aircraft nose landing gear then hit a (red) runway right hand edge light but this was not noticed and the Captain began to advance the power levers to the take-off position which was confirmed set 7 seconds later. As the aircraft gathered speed, the crew reported having heard “a thumping noise from the nose gear” and in response, the Captain had “re-aligned the nose gear slightly to the left to prevent the nose gear hitting what the flight crew thought were the recessed runway centre line lights”. Only when the aircraft approached a military arrester cable mechanism located to the right-hand side of the runway did the Captain realise that the aircraft was lined up on the runway edge lights instead of the runway centreline lights and 20 seconds after beginning to set take-off power, he rejected the take-off and simultaneously manoeuvred the aircraft onto the runway centreline. TWR were advised and it was decided that the aircraft should be taxied back to the apron. The ground track followed by the aircraft is shown on the illustration below.
Inspection of the aircraft disclosed damage to the taxi lights mounted on the Nose Landing Gear, and to both right hand nose landing gear doors, two of the blades on the left hand propeller, the lower fuselage skin in front of the air conditioning ground connection panel and to the Nose and Right Main landing gear tyres.
It was noted that Karup is a joint civil/military aerodrome owned by the Danish Air Force which manages and maintains “all aerodrome ground installations” except the civil terminal building. No evidence of any relevant deficiencies in the aerodrome lighting or marking was found.
In analysing the evidence, it was also considered that:
- Although the prevailing visibility was reduced, it had been well above the threshold for which the procedures required by “Low Visibility Operations” would have been necessary. However, “the reduced visibility in combination with a dark night operation most likely impaired flight crew visual acuity”.
- Although the flight crew had been following an FTL-compliant and undemanding duty roster, use of a “generic fatigue evaluation tool” indicated that both pilots may have been fatigued on the morning of the occurrence with the Captain possibly suffering from “accumulated fatigue” and the First Officer from “acute fatigue”.
- Given the familiarity of both pilots with operations at Karup and the routine nature of the morning flight to Copenhagen, “mental expectations might unknowingly have overshadowed the external information flow and inadvertently lowered the vigilance and the positional awareness of the flight crew (and) that the combination of routine, familiarity and flight crew fatigue might have provoked flight crew complacency”.
- The additional width of pavement beyond the unmarked edge of the designated runway width and the continuous movement of the aircraft prior to the setting of take-off power in partial darkness and reduced visibility were capable of “provoking a visual and mental illusion of having lined up the aircraft on the centreline”.
- The ‘Runway Heading and GPS Check’ included in the Operators ‘Before Take Off Checklist’ appeared to be a system check rather than a runway environmental check which “did not encourage the First Officer to respond or challenge the call out of the commander” and as a result, when the flight crew looked outside after it, “the external visual references fulfilled their mental expectations and they therefore initiated the take-off roll”.
- The absence of lighting on the lead on taxi line which led from the dark area at the end of the perimeter taxiway to the runway centre and the fact that the centreline lighting only began at the displaced landing threshold may have contributed to the misalignment given that “essential flight crew tasks apparently suppressed the effect of the available cues”.
- There was no evidence to suggest that any aspect of the runway 27L lighting system had contributed directly to the sequence of events.
The Investigation identified a number of previous similar events in which aircraft had begun - and in some cases completed - night take-offs when inadvertently aligned with the runway edge lights instead of the runway centreline lights. These included:
- a Gulfstream III at Biggin Hill UK in 2014,
- an Airbus A330-200 at Abu Dhabi in 2012,
- a Bombardier Challenger at Dubai in 2011,
- an Airbus A320 at Las Vegas in 2006,
- an ATR72 at Dresden in 2002.
A 2009 review of ‘Factors influencing misaligned take-off occurrences at night’ carried out by the by the Australian Transport Safety Bureau was also noted by the Investigation as listing a series of factors sometimes found in runway edge take-offs which included some of those associated with the event under investigation.
The Investigation identified a combination of environmental, operational, and human Causal Factors which had contributed to the sequence of events as follows:
- Dark night operation.
- Reduced visibility.
- The runway and taxiway environment, including the extension of the runway 27L pavement width beyond the designated runway width, the absence of runway shoulder markings, the absence of taxiway centreline lighting and the marking of a displaced (landing) threshold.
- The divided attention of the Flight Crew unintentionally provoked by the before take-off procedures and checks.
- Flight crew fatigue.
Safety Action taken by the Aircraft Operator as a result of the event and known to the Investigation included reducing the number of items in the ‘Before Take Off Checklist’ and the addition of a positive identification of aircraft position to be confirmed by both pilots in the ‘Runway and Position Check’.
The Investigation concluded that a reduction in the risk of a night take off being attempted when misaligned with the edge of a runway could be achieved if runway edge lights could be directly identified as such by pilots without reference to other lights and noted that the UK AAIB had issued such a Safety Recommendation to ICAO as a result of their Investigation of the misaligned take off attempt by a Gulfstream III at Biggin Hill in 2014 referred to above and decided to reproduce this Recommendation and the initial ICAO response to it rather than issue a further equivalent Recommendation. This earlier UK Safety Recommendation was reproduced as issued as follows:
- that the International Civil Aviation Organisation initiate the process to develop within Annex 14 Volume 1, ‘Aerodrome Design and Operations’, a standard for runway edge lights that would allow pilots to identify them specifically, without reference to other lights or other airfield features. [2015-038]
The Final Report of the Investigation was published on 24 August 2016. No new Safety Recommendations were issued.