On 21 Nov 2010, a Boeing 737-700 being operated by Arik Air on a non revenue positioning flight from Southend to Lagos with only the two pilots on board carried out a successful take off in daylight and normal ground visibility from runway 06 but became airborne only just before the end of the runway.
An Investigation into this Serious Incident was carried out by the UK AAIB with the assistance of the Operator, who provided Flight Data Recorder (FDR) data and crew reports, and Boeing. It was established that both pilots were qualified aircraft commanders with the one in the right hand seat designated as PF.
It was found that a reduced thrust had been used for the take off which had been commenced from the displaced landing threshold rather than using the available full runway length. This had the effect of reducing the full length Takeoff Run Available (TORA) of 4785 feet by 600 feet. After becoming airborne, it was found from Flight Data Recorder (FDR) data that the aircraft had crossed the end of the paved surface used at a height of 150 feet with the landing gear retracting and a rate of climb of 2590fpm.
It was found that the crew had initially programmed the aircraft FMC for a maximum thrust takeoff from Runway 24 but during the taxi out, ATC had changed the runway in use to Runway 06. The FMC had then been re-programmed for a reduced thrust take off but an incorrect ‘assumed’ temperature of 50° rather than the correct 29° had been entered, resulting in too great a thrust reduction for the available runway length. It was established that the flight was behind the intended schedule due primarily to the aircraft commander arriving late at the airport and that a time pressure was perceived which may have led to the rushed re-programming of the FMC after the runway change. The assumed temperature used was one which would have been typical for the longer runways in Africa where the Operator and the incident crew were based and where most operations were conducted.
It was concluded that although the take off performed had been compliant with the 35 foot screen height requirement when crossing the upwind end of the runway, “had an engine failed at or close to V1, the aircraft may not have stopped before the end of the runway if a rejected take off had been attempted or become airborne before the end of it had the take off been continued. The consequences of an overrun from the runway involved were noted as potentially serious with an “arrester bank” 85 feet from the end of the paved surface, a main railway line 145 feet beyond that and housing estates thereafter. For the case of a decision to reject the take off just before V1, it was calculated that even with maximum braking and maximum reverse thrust, the aircraft would have overrun the end of the runway at a speed of approximately 60 knots and would have needed a further 656 feet of paved surface before coming to a stop.
The Final Report of the Investigation was published on 6 October 2011. In view of appropriate Safety Action taken by the Operator, no Safety Recommendations were made.