Computer Error Caused Qantas Jet Mishap

highways sends word that preliminary investigations into a Qantas Airbus A330 mishap where 51 passengers were injured has concluded that it was due to the Air Data Inertial Reference System feeding incorrect information into the flight control system — not interference from passenger electronics, as Qantas had initially claimed. Quoting from the ABC report: "Authorities have blamed a faulty onboard computer system for last week's mid-flight incident on a Qantas flight to Perth. The Australian Transport Safety Bureau said incorrect information from the faulty computer triggered a series of alarms and then prompted the Airbus A330's flight control computers to put the jet into a 197-meter nosedive ... The plane was cruising at 37,000 feet when a fault in the air data inertial reference system caused the autopilot to disconnect. But even with the autopilot off, the plane's flight control computers still command key controls in order to protect the jet from dangerous conditions, such as stalling, the ATSB said."

uhh huhs

I'm sure this comes as no surprise to the /. community. Nice to see the truth actually did surface though.

Re:Don't forget the spin

So what if they do make such claims?

If all it takes is a kid with a gameboy to bring down the Airbus then their entire fleet should be grounded.

The aircraft systems design would be completely unsafe as there are far more powerful transmitters in any urban area.

No, in truth, Airbus planes would be raining from the skys if it were indeed susceptible to such interference. It would have never been certified.

But more important, why did the controls not respond to the pilots? Why would the computers be programmed to prevent a Stall in an *diving* aircraft?

Re:Don't forget the spin

If the pilots lost consciousness they would lose control of the aircraft and may slump on to the controls and put the plane into an unsafe course.

The computers put the plane INTO a dive to prevent a stall they *thought* was taking place.

In this case the pilots attempted to abort the 'safety' maneuver but the computer decided that the pilots through incompetence or perhaps incapacitation did not actually intend to kill all aboard and took the action it thought was necessary.

Re:Don't forget the spin

I'm sorry Dave, I'm afraid I can't do that...

Re:Don't forget the spin

RTFA. The computer was being fed random and wildly varying attitude inputs. It first pitched up, then dived, presumable responding to different random attitude inputs.

Regarding the earlier point: ATC people say they regularly hear the distinctive "ditda ditda" of an active cellphone on their channel because the pilots haven't turned off their own cellphones. So (a) active cellphones are failing to crash planes, even on presumably the most sensitive part of the craft, the flight deck, and (b) pilots know it and don't care.

Questions:

From TFA:

"About two minutes after the initial fault, (the air data inertial reference unit) generated very high, random and incorrect values for the aircraft's angle of attack," the ATSB said in a statement.

Correct me if I'm wrong but don't most modern aircraft have an inertial navigation system and a seperate angle of attack transmitter protruding from the plane? Why no redundancy?

The incident was the fourth involving Qantas planes in two-and-a-half months[read TFA for the other 3 incidents]...

The plane's French-based manufacturer has issued an advisory on the problem and will also issue special operational engineering bulletins to airlines that fly A330s and A340s fitted with the same air data computer, the ATSB said.

Does Qantas' aircraft maintenance suck or does Airbus' quality control suck? Do both suck?

Finally, shame on the PR guys for blaming passenger electronics. Maybe it's a feature, not a bug...in case any government decides that they want to make another 9/11 ;)

Re:Questions:

They never did, the initial reports that they were looking at laptop was a mistake by the journalist. Qantas said they were looking at the onboard computers (ie. the computer that was flying the plane) and the journalist thought computers that were on board (ie. the laptops that passengers were using).

Re:Questions:

The real reason:

"It looks like you are trying to fly a commercial airliner. Would you like me to:
a) Make an announcement to passengers
b) Call the stewardess for some more coffee
c) Compensate for the incredibly high angle of attack"

Re:Questions:

Umm... the attitude sensor was a Northrop Grumman part, used in some Airbus models (2 A330 models, and A340) and "some other non-Airbus" aircraft. So it doesn't sound like an Airbus problem - it may even also be a Boeing problem! And it sounds like a software problem, not a Queerarse maintenance issue, for once! But what happened to quadruplex-redundant FBW - are only the flight control computers truly quadruplex redundant? It sounds like a single point of failure in a design which should have considerable redundancy. Jim

Re:Questions:

Qantas. Not Quantas.

Queensland And Northern Territory Aerial Services.

Re:Questions:

Why no redundancy?

Exactly my thought.

IANAE, but the Wikipedia says An ADIRU acts as a "single, fault tolerant" source for both pilots of an aircraft., and there are 3 ADIRUs.

From TFA,

faulty computer triggered a series of alarms and then prompted the Airbus A330's flight control computers to put the jet into a 197-metre nosedive.

I wonder whether the control computers are programmed to take decision to nosedive just like that OR consult other ADIRUs OR alarm the crew before taking that kind of decision.

Having worked for nuclear installations where I designed automations for, which always demanded to have 2 out of 3 voting redundancy and a careful fault tree analysis making sure no single point of failure would lead to any kind of disaster, I feel the control computer might have been taking decision without consulting other ADIRUs OR all 3 ADIRUs went bad at the same time. And both cases look very scary.

Just my thoughts.

Re:Questions:

Qantas HAD an excellent reputation for safety, but that is surely history now. What was it about 6-12 months ago they moved all of their international flights maintainance offshore. Qantas engineers went on strike etc. Lo and behold yet another outsourcing operation is falling flat on its face, unfortunately this time it could come at the expense of lives.

I'd be staying well away from Qantas international flights until they sort their shit out.

Re:Questions:

If Qantas cuts the costs of maintenance to such a degree that fatalities are not only likely, but inevitable, can anyone actually be charged with murder?

Re:Questions:

Correct - the Habsheim crash was caused by pilot stupidity in that he was both below the visible height of surrounding obstacles, and had brought the throttles back to idle. Engines take some time to come back from idle to 'take off - go around' thrust (TOGA), and he applied that thrust far too late.

Maybe they should have...

...tried turning it off and then on again.

Been there, done that

put the jet into a 197-meter nosedive.

I've been in nose dives before.. it's awesome fun. Everyone is screaming and the assholes who refuse to keep their seatbelt fastened while seated quickly learn the *reason* why they request you to do this.

People pay good money for this experience [gozerog.com], and with a little malfunction or two they give it to you for free. When you throw in the fact that you could very well be experiencing the last few minutes of your short pathetic little life - you can't get a better adrenaline rush.

Re:Been there, done that

I was thinking the same, "that will teach them to buckle up".

I do feel bad for those buckled in who got hit by the assholes flying through the cabin though. Also for the poor smuck on the toilet.

Re:Been there, done that

Also for the poor smuck on the toilet.

He must have been shitting himself...

Re:Been there, done that

Cheapest way to experience zero G? Go along to your nearest glider/sailplane club and have a trial lesson. If you ask nicely, some of instructors will give you an aerobatic flight (loops, wing-overs, stalls, but not spins).

If the cable breaks during a winch launch, at a couple of hundred feet, you go zero g in order to recover. The motto is that if the mud (on the floor) floats around your face then you got it about right, whereas if it plasters itself on the canopy then you were too enthusiastic.

Before you go solo (which you can do at age 16/15/14 depending on where you live) you have to be able to repeatedly demonstrate that you can recover from cable breaks and also from a spin started at 1000ft in which you are descending at 100ft/s.

Not an experience you will forget.

oblig star trek blahblah

SOOOOO.... you are saying the inertial dampeners were offline?

Not an isolated incident

This isn't an isolated incident. Although I think the string of technical incidents suffered by Qantas isn't a coincidence either. "A global alert was issued in 2005 after a Malaysia Airlines Boeing 777 en-route to Kuala Lumpur from Perth experienced similar problems. Investigators found a software glitch in a unit made by the same US manufacturer as the one in the Qantas plane combined with a mechanical problem." http://www.australianit.news.com.au/story/0,24897,24499849-15306,00.html [news.com.au]

Quantas' claims

From the summary: "not interference from passenger electronics, as Qantas had initially claimed"

Care to show me where Quantas claimed that? It seems to be all the rage to say that Quantas are shifting the blame, but so far I've seen nothing at all to indicate that was the case. What I *have* seen was a statement from Quantas saying they were investigating passenger electronics as a possible cause. Now I know it doesn't make such good news, but I'm afraid there's a world of difference between being investigating something and trying to place the blame on it. Unfortunately that's a distinction that appears to be lost on the crowd...

DO178B

For those that are interested in coding/test methodologies, the FAA created a system called "DO178B" which defined as set of software assurance standards for aircraft. (Note, it's not coding standards, it's assurance standards)

Wiki link: http://en.wikipedia.org/wiki/DO-178B [wikipedia.org]

It set different standards for different types of code. The movies would be Class E, a non-critical nav system maybe C or D, FCS probably A. But even then, the code can be made modular to decrease the assurance level required. For instance, an artificial horizon needs to work, right? But you normally have more than one in a cockpit. If one goes bad, you can use the other, not catastrophic. But the key is the pilot(s) need to recognize that it's busted. What if one froze in place in flight during landing? The pilot might follow it and go ka-boom.
So by itself, an electronic artificial horizon would require level A ($$$) software so that it 'never' fails. This is very very expensive (for level A the post-compiler machine code must be analyzed for possible compiler issues, and MC/DC http://en.wikipedia.org/wiki/Modified_Condition/Decision_Coverage [wikipedia.org] coverage)
So instead, they write it to a lower level, and then create a small set of code that cross-checks everything and kills off any horizon that's malfunctioning by placing a big "X" (or whatever) on the screen instead. Lower risk and greatly reduced cost.

Re:well duh

I think you missed his point. It isn't the airlines that banned those things, it is unrelated but authoritative departments of government which did.

The blame for what you mention rest with agencies other then the airlines.

Re:Thanks, I'll pass on that flight...

Thanks, I'll pass on that flight ... until you get all the bugs worked out of those systems

It's interesting the way people rationalize things isn't it?

Statistically, you are far more likely to die in a car on the way to work than you are in a commercial passenger aircraft. Statistically, the computer system in a commercial passenger aircraft is far less likely to fsck things up than a human pilot (although that's saying nothing about the _size_ of the fsckup, should one occur...)

I drive around 600km a week in my car. A lot of that is spent at 110km/hour on a freeway, and at 100km/hour along some reasonably windy and hilly roads. I often think about the ways that such an activity could end rather badly for me, but it doesn't worry me greatly.

In about a week though I'm going to be getting onto an airplane for the first time in about 28 years, and the thought of it has me a little nervous - far more so than driving a car which is, statistically speaking, far more dangerous.

A car crash here in Australia will often make the news, possibly only locally unless more than a few people lost their lives. A plane crash of any reasonable size will make the news world wide, and will probably continue to do so for weeks after the event. The Quantas Airbus 'mishap' didn't kill anyone, and the majority of the passengers have probably mostly healed whatever injuries they did sustain by now, and yet here in Australia the incident still makes the news daily. The logical part of your brain should tell you that that is a comforting thing - it's so unusual that it is still newsworthy a week later. The less logical parts of your brain though are constantly reminded that while safe, air travel is not 100% safe.

For me I think the difference is the time I will have to contemplate things should something go wrong. In a car, the time between the realization of error (mine or someone elses) and things ending badly is going to be measured in seconds. In an airplane, the time between when I realize that things are not as they should be and the time when I won't be thinking anymore could be measured in minutes. That is a pretty chilling thought for me...