Boeing again - Alan Irwin and Helios 522

[TheGreenGoblin]

https://www.theguardian.com/world/2020/ ... p-a-switch

[Boac]

Amazing this has popped up again. The crew failed to do proper pre-flight checks which would have picked up the mis-setting and did not carry out correct after takeoff checks which would have picked up THAT omission.

[TheGreenGoblin]

Amazing this has popped up again. The crew failed to do proper pre-flight checks which would have picked up the mis-setting and did not carry out correct after takeoff checks which would have picked up THAT omission.

Irwin specifically asked the Captain to check that the switch was set to Auto. It was a travesty of justice that he was hounded the way he was.

Boeing were definitely also party to blame...

But the causes of the crash were more complicated. Since 1994, there had been a history of incidents involving a confusing alert system on Boeing 737s. A warning horn on the plane would sound for two very different reasons: problems with the takeoff configuration (incorrect positioning of wing flaps, for example) or as an altitude warning – a loss of pressure that leads to less oxygen on the plane. Boeing had been alerted to this as a safety concern – most recently by the director of Nasa’s Aviation Safety Reporting System (ASRS), the year before the crash.

For Irwin, this design flaw was crucial. “The crew have to take some responsibility, because at the end of the day they are in command of the airplane,” he says. “But if Boeing had listened to previous concerns, the crash wouldn’t have happened.”

When Stephen Preston appeared before the Greek courts on Boeing’s behalf, on 20 and 21 February 2008, he gave a slew of reasons why the crash had been caused by human error: one third of Helios employees were seasonal and “many did not have Greek or English as a mother tongue”; Helios engineers “failed to use common sense… by leaving the pressure system selector in manual”; the pilots were “low standard” and their “inability to work together” was “well documented”, owing in part to the East German captain’s “authoritarian nature”.

According to Preston, the pilots “failed to react correctly” to the altitude warning alarm. “It appears [the first officer] reacted to what he took as a takeoff configuration warning signal, despite the fact that the plane was flying at 12,000ft.” This mix-up, he suggested, was so ridiculous as to be almost farcical. He pointed out that Boeing 737s had flown safely for decades and that, in millions of flights, “the Helios accident was the one and only accident in which pressure problems were not understood or were not put right”. But this downplayed a number of near misses and a string of complaints about the warning system.

When asked by the judge, Preston acknowledged that Boeing had been informed of six “air pressure instances” before the Helios crash. On 15 February 2001, a Boeing 737 on a flight from Kristiansund to Oslo in Norway was climbing above 10,000ft when the captain and first officer were surprised to hear the warning horn. Neither associated it with a pressurisation problem. Knowing that takeoff configuration couldn’t be the cause, they assumed that the problem was the horn itself and switched it off, only realising their mistake when the oxygen masks dropped in the cabin. A further four serious pressurisation incidents, all involving confusion over the warning horn on Boeing 737s, were reported to the Irish air accident investigation unit between 2000 and 2005. In 2004, the director of Nasa’s ASRS had brought the same safety concern to Boeing’s attention. Accident investigators had identified 10 incident reports on Nasa’s database over the previous decade, in which flight crews admitted to having, at least momentarily, misinterpreted a warning horn.