BRITAIN:The pilots of the British Airways (BA) aircraft that crash-landed at Heathrow on Thursday received no warning that the aircraft was losing power because of a problem with the alarm systems, a source has said.
Because there was no signal from the Boeing 777's automatic warning system, the pilots did not realise anything was wrong until they approached the runway and noticed the aircraft was losing speed more rapidly than normal.
The aircraft "fell out of the sky" just three metres (10ft) from the ground after stalling as it came in to land. The first details of the pilots' battle to land the jet safely emerged as the Air Accidents Investigation Branch (AAIB) said the two engines on flight BA038 "did not respond" to a demand for increased thrust about 3.2km (two miles) from the runway, when the aircraft was about 152m (500ft) above the ground.
All 136 passengers and 16 crew had a miraculous escape after the aircraft skidded 122m (400ft) along the Heathrow turf.
The fact that the pilots, Capt Peter Burkill and senior first officer, John Coward, did not receive an automated warning of the drop in engine power will cause concern about the safety of systems on the 777 of which more than 600 are in service. Although all commercial aircraft have programmed "inhibitions" on certain warnings so that the crew are not distracted by unnecessary alarms during take-off and landing, the alarm should have been triggered when the engines failed.
Specialists from the AAIB will look at whether the Boeing 777's inhibition threshold is set too high and does not alert pilots to engine problems if they are below a certain height.
A key instrument, the engine pressure ratio gauge, which tells the crew how much power is available, had failed. The pilots tried to coax more power from the 777, but it did not respond, according to an aviation source.
Realising every ounce of lift would be needed to nurse the aircraft over Heathrow's perimeter fence, Mr Coward, who was at the controls, dropped the nose to maintain speed.
As he approached the fence, he lifted the nose, wringing the last reserves of energy from the jet. It then narrowly missed a guidance beacon before stalling about three metres from the ground.
"It just fell out of the sky from a few feet," said the source. "It was the skill of the crew that kept those 136 people alive."
The jet's auxiliary power unit, which is rarely used in flight, was still running when the aircraft was on the ground, indicating that main power had been lost on the approach. Investigators also found the jet's thrust controls were on their maximum setting.
Greeted by rapturous applause at a press conference yesterday, Capt Burkill paid tribute to his crew and confirmed it was his co-pilot who landed the aircraft. He said Mr Coward had done "the most remarkable job" of bringing the jet and passengers to safety.
A BA spokesman said the company would await the findings of the investigation. Boeing said it was "working with the AAIB to support the investigation".