G-YMMM was executing British Airways Flight 38 Beijing-London Heathrow on 17 January 2008 when it crash landed just short of the runway at its destination airport. Several people were injured but there were no fatalities.
The UK Air Accident Investigation Branch (AAIB) has now released its final report on the accident.
The 777 was 720 feet above ground level (AGL) on final approach to Heathrow runway 27L when an un-commanded power reduction occurred first in the right then 7 seconds later in the left Trent 800 engine. The resulting loss of airspeed caused the aircraft to touch down prematurely and skidding on the grassy surface, it came to a stop near the threshold of the runway.
The cause was identified as ice in the fuel system which impeded fuel flow to both engines.
As evidenced by the accident photos, the fuselage remained relatively intact, an important factor that explains why there were no fatalities.
However, even more important was the supreme airmanship of the flight crew. In the few seconds available to save the day, the captain decided to reduce the flap setting… this goes against all standard procedures but then there were no procedures ever developed for the kind of predicament they were in! This lengthened the glide by 160 feet or so, enabling them to clear the ILS aerial and make a smoother touch-down. Pilots we have spoken to were unanimous in saying that “not everyone would have thought of reducing the flap setting”. Boeing did a series of tests after the accident and none of the test pilots could extend the glide any further than the flight crew managed that fateful day!
Interestingly, many pilots after the accident said that raising the flaps was the wrong thing to do. Luckily, the captain of G-YMMM did not think so!
You can download the full AAIB report here.
Download the LHR Tower radar images and ATC radiotelephony exchange here.