B744, Johannesburg South Africa, 2009

B744, Johannesburg South Africa, 2009

Summary

On 11 May 2009, a British Airways Boeing 747-400 departing Johannesburg came close to stalling following a stall protection system activation during night rotation which continued until landing gear retraction despite immediate appropriate crew response. Subsequent investigation found that loss of lift on rotation had resulted from the unanticipated effect of a design modification in respect of thrust reverser unlocked signals with the aircraft in  ground status. The Investigation found that the potential effects of this on the transition from  ground to  air status including the lower stalling angle of attack in ground effect had not been foreseen.

Description

On 11 May 2009, a Boeing 747-400 being operated by British Airways on a scheduled passenger flight from Johannesburg to London Heathrow experienced a stall protection system activation at rotation during a night departure in Visual Meteorological Conditions (VMC) which continued for a short time after the aircraft became airborne. A loss of lift was apparent and the flying characteristics of the aircraft were abnormal. Rate of climb was reduced by the PF, the First Officer, which resulted in stick shaker activation becoming intermittent. Then, shortly after the landing gear had been selected up, stick shaker activations ceased altogether and normal flying characteristics were restored. Being unsure of what had caused the event, but suspecting some sort of problem with both No 2 and No 3 engines, the flight crew declared a ‘PAN’ to ATC and decided to return to the airport of departure where, after fuel dumping, an uneventful landing was made about two hours after departure. None of the 283 occupants was injured and the aircraft was undamaged.

The full content of this page is available to registered users only.
Please Log in or Register

SKYbrary Partners:

Safety knowledge contributed by: