Heathrow crash plane had low fuel pressure

12.5.2008     (Metro)

The plane that crash-landed at Heathrow last winter had low fuel pressure at
the inlet to the fuel pumps, an accident report claimed yesterday.

heathrow crash

The crashed plane at Heathrow

The British Airways Boeing 777 came down before the runway because the engines
lacked power.   The onboard computers detected the reduced fuel flow between the
tanks and the high-pressure pumps and instructed the metering valve to open fully,
according to the interim accident report.

‘The fuel metering valve responded to this command and opened fully but with
no appreciable change in the fuel flow to either engine,’ revealed the Air Accidents
Investigation Branch.

There was no evidence of aircraft or engine control system malfunction nor of
a birdstrike or engine icing.

It is the fourth report the AAIB has made into the incident and was published
‘in view of the sustained interest within the aviation industry and among the
travelling public’.

‘The focus of the investigation continues to be the fuel system of both the aircraft
and the engines, to understand why neither engine responded to the demanded increase
in power,’ the AAIB revealed.

‘Extensive full-scale engine testing has been conducted at the Rolls-Royce factory
in Derby and fuel system testing is ongoing at the Boeing firm in Seattle.’    
All 16 crew and 136 passengers survived the January 17 crash.


Heathrow crash plane had low fuel pressure

UK Airport News

Heathrow crash landing ‘could have been caused by cold weather’


Extreme temperatures caused by cold weather over Russia could explain a British
Airways Boeing 777 crash landed at Heathrow in January, flight investigators have said in a preliminary report. Fresh tests
are being carried out by both at Rolls Royce’s engine plant at Derby and the Boeing’s
factory in Seattle to recreate what happened on the flight from Beijing to test
the theory.

One passenger suffered serious injuries and 12 others on board British Airways
Flight 38 were slightly hurt when the jet failed to reach the runway on January
17. The plane was wrecked beyond repair. In its latest report on the incident,
the Air Accidents Investigation Branch has focused on the ‘region of particularly
cold air’ between the Urals and Eastern Scandinavia. It found that temperatures
plummeted to -76C, far lower than would have been expected.

Experts are now examining whether this could have led to a thickening of the
fuel, which led to neither engine receiving the necessary power during the final
stages of its descent into Heathrow. They suspect that the plane’s fuel flow became
restricted somewhere between the engines and the fuel tanks.

The investigation has homed in on fuel flow as the key issue that led to the
crash landing after the AAIB ruled a number of theories that had been floated
in recent months including bird strike and ice in the engine. Its experts have
also discounted electromagnetic interference from jamming devices which were claimed
to have been used to protect the Gordon Brown’s motorcade as he arrived at Heathrow.

The experts have also established that the fuel used on the aircraft was of high
quality. While the average freezing temperature of aviation fuel is -47C, tests
on what was on this flight showed that it did not turn to ice until -57C. Tests
also found that the fuel temperature throughout the flight never dropped below
-34C. But even though the fuel did not turn to ice it could have thickened to
an unusual extent, which could have restricted the flow.

A spokesman for Rolls-Royce, which made the plane’s engines, declined to comment.
Spokesmen for Boeing and British Airways also declined to comment, citing company
policies against making public statements before investigators have concluded
their work. However, David Learmount, operations and safety editor at Flight International,
was critical of the update. He said: ‘This report takes us absolutely nowhere,
I think they still have no idea.