Boeing simulation ignored Chinook's Fadec system
A House of Lords committee investigating the crash of Chinook ZD576 on the Mull of Kintyre has found that a Boeing simulation of...
The disclosure came as the committee considered a possible anomaly in the speed of the Chinook's rotors just before the helicopter crashed in June 1994, killing all on board, including 25 senior police and intelligence personnel.
Computer Weekly and Channel Four News have highlighted doubts over the cause of the crash, particularly in the light of the aircraft's history of problems involving its Fadec computer system.
In extreme cases, the Fadec could cause the Chinook's jet engines to surge suddenly, making it difficult to control the helicopter.
Last week a House of Lords committee held its final hearing into whether two air marshals were justified in finding the two pilots of Chinook ZD576 grossly negligent.
Tony Cable, chief technical investigator into the crash, was asked about Boeing's simulation of ZD576's final moments, in which the company had assessed the Chinook's rotor speed as nearly 10% below the expected norm.
Cable said the Boeing simulation "did not accurately model the Fadec".
Instead the Boeing model included only a "simple engine governor for each engine, which could have quite different characteristics, in small areas, from the Fadec".
Cable was satisfied with the results of the simulation. He said all simulations were "never going to be fully representative".
But Lord Tombs, a member of the committee with an aeronautical engineering background, found this "very unsatisfactory".
He said, "That's the whole point of the Chinook Mk2 - that it has an automatic engine power control."
The committee is due to publish its findings by the end of January 2002.
