Julian Bray writes: We are happy to run this item from The Daily Record, you will recall we reported on the original incident last December, but now the official AAIB report has come out. Fresh eyes can look at it, and from a media perspective.
Due to my often repeated public position on the need for urgent real time live reporting of cockpit data and conversations, I'm happy to let others give their view. It is also refreshing to have an alternative non jargon view on the narrative.
Leaving out the tabloid lexicon, the media report is factual, highly detailed and highlights a continuing problem with computer aided flying "fly by wire."
Pilot training needs to be intensified to concentrate on non autopilot manipulation of the controls, whatever the additional commercial cost.
The drama occurred on December 14 as the Loganair flight from Aberdeen approached its destination at Sumburgh airport, Shetland, at night.By Jeremy Armstrong The Daily Record Scotland
Passengers on the island-hopping Saab 2000 sat in terror as the plane ignored the crew’s commands to climb - and instead sent itself into a nosedive.
The plane, which had been struck by lightning, fell to just 1100 ft before its captain wrestled back control and applied full power.
The drama occurred on December 14 as the Loganair flight from Aberdeen approached its destination at Sumburgh airport, Shetland, at night.
Moments later a ball of lightning appeared in the cockpit and a bolt struck the nose, travelling the full length of the plane before leaving at the tail.
As the co-pilot declared a mayday, the pilot tried to gain height - but every move was countered by the autopilot. The more aggressive his movements on the control column, the less effect it seemed to have.
When it reached 4000ft, the plane suddenly pitched nose down and started falling out of the sky at 9500ft a minute - giving the crew barely 20 seconds to act before crashing into the icy North Sea.
At 1100ft, as ‘Pull up!’ alarms sounded in the cabin, the captain applied full power and the aircraft finally started to climb. The plane diverted to Aberdeen where it landed safely and shaken passengers disembarked.
A report into the near-disaster by the Air Accident Investigation Branch said the crew may have thought the lighting strike had disabled the autopilot because it had knocked out some of the other controls.
In fact, it was still operating and trying to adjust and fly at the level it has been instructed. Only when the computers became overloaded with faulty data during the plunge did it disengage itself and give the pilot seconds to save the flight.
The AAIB report said: “Although the pilots’ actions suggested that they were under the impression the autopilot had disengaged at the moment of the lightning strike, recorded data showed that it had remained engaged.
“The pilots’ nose-up pitch inputs were countered by the autopilot pitch trim function, which made a prolonged nose-down pitch trim input in an attempt to maintain its altitude tracking function until it disengaged. This accounted for the perception that the control response was not normal.”
It added: “As the aircraft reached 4,000ft, the pitch attitude tended towards nose-down and a descent began. Invalid data from one of the air data computers then caused the autopilot to disengage. The pitch trim was, by this time, almost fully nose-down, and the aircraft continued to pitch nose-down and descend.
“The peak rate of descent was 9,500 feet per minute.”
The report says no technical problems were fund with the plane, which is now back in service, and pilot training now included simulations of this incident.
The AAIB probe is also continuing looking at crew training, autopilot design and any ‘human factors’.
JULIAN BRAY ++44(0)1733 345581, Journalist, Broadcaster, Aviation Security & Operations Expert, Travel / Cruise Industry, EQUITY, NUJ, Broadcast COOBE ISDN ++44 (0)1733 345020 (DUAL CODEC) SKYPE: JULIAN.BRAY.UK e&oe Cell: 07944 217476 or iPhone 0743 530 3145 #VENDOR 10476453 http://feeds.feedburner.com/BraysDuckhouseBlog