Diatribe 188 July 09
1
Diatribe 188
Planely disastrous. Did Computer Failure Bring Down Air France 447?
Speculation abounds following a plane crash. Mechanical flaws, terrorism, pilot error, and
weather are the usual suspects. But in the tech age, where even your toaster is digital, IT
systems must be added to the list. In the Air France disaster, there's a particularly urgent
need for government authorities to eye the aircraft's on-board computer system as a possible
culprit.
That’s a quote from a US blog dealing with the recent crash of a an Air France 447,
an Airbus 330 on June 3, off the coast of Mexico. 228 souls, men, women and children,
passengers and crew, perished, and no-one survived. At the time, the aircraft was largely
under the control of ADIRU, an electronic inertial reference system which interacts with
the auto-pilot
By way of contrast, earlier, on Jan.15th, another Airbus, at that time a 320, ditched in
New York’s Hudson river after birds hit both engines which died, and nobody was even
injured let alone lost. Control of that plane was manual, having not yet reached an altitude
where the computers take over, in the hands of Capt. “Sully” Sullenberger, a former U.S.
Air Force fighter pilot, former safety chairman of the Air Line Pilots Association, scholarly
author on aviation safety, graduate of the U.S. Air Force Academy, and recently appointed
Visiting Scholar at the University of California, Berkeley. Sullenberger was ably
assisted by a crew who not only carefully instructed the passengers on what to do, but
safely guided them to their rescuers who had been summoned by radio. Sullenberger,
after executing a perfect “landing” on the river, topped his performance by twice walking
the length of the half-submerged aircraft to make sure that all passengers were out.
The majority of the blogs relating to the Mexican disaster were clearly lodged by industry
representatives, insisted that at this time it was not yet possible to draw any conclusion
regarding the latest event. From this they also decided that currently nothing can
be done about it. If I were an intending passenger on an Airbus, I would not be likely to
agree with their suggestion, so much the more so as there were accidents with our very
own Airbuses too.
One which reached prominence happened to a Qantas Airbus 330. Last year it
started porpoising wildly while at cruising altitude, from memory somewhere over Western
Australia. 51 passengers were injured, with damage ranging from broken bones to
spinal trauma.
The accident report issued by the Australian Transport Safety Bureau tells us: About
two minutes after the initial fault, the air data inertial reference unit (ADIRU) generated
very high, random and incorrect values for the aircraft’s angle of attack.
Apart from this near crash, there were other warnings. Also last year, the US Federal
Aviation Administration issued an airworthiness directive warning airlines about an “unsafe
condition” associated with ADIRUs aboard Airbus 319, 320 and 321 models. The
directive warned that the equipment was sending out bogus navigational fault warnings
that could “result in loss of one source of critical altitude and airspeed data and reduce
the ability of the air crew to control the airplane”. Earlier direct transmissions to Paris
from the craft had indicated danger signals from the ADIRU system. Indeed, later evidence
showed that the crew had actually attempted to turn the plane back before the
crash.
Diatribe 188 July 09
2
In 1990, while the Australian Hawke “Labor” government conspired with the tycoon
Peter Abeles to lock out the experienced pilots of this country who were, amongst other
things, demanding a say in air safety, I happened to be travelling to Sydney on unavoidable
business sitting next to one of the locked-out captains who told me then about the
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