France sends nuclear sub to hunt for jet wreckage

[babylonsister]

France sends nuclear sub to hunt for jet wreckage

Manslaughter case opened into death of French citizens onboard Flight 447
Last Updated: Friday, June 5, 2009


The French navy is dispatching a nuclear submarine to join the search effort for the wreckage of an Air France passenger jet that crashed into the Atlantic Ocean, the country's defence minister said Friday.


The nuclear submarine Emeraude is seen here in an undated file photo provided by the French Ministry of Defence. (ECPAD/French Ministry of Defence)

Defence Minister Herve Morin said the submarine Emeraude is equipped with surveillance equipment that could help find Air France Flight 447's data recorders. It is expected to arrive by next week in the area where search crews have been concentrating their efforts.

Earlier in the day, French officials said search planes have not yet been able to confirm that any debris spotted in the Atlantic Ocean belongs to the jet and urged searchers to be "extremely prudent" in identifying any wreckage.

No evidence has yet been retrieved from the Airbus A330 that disappeared off radar screens between eastern Brazil and western Africa, said French Transportation Minister Dominique Bussereau.

The flight was en route from Rio de Janeiro to Paris with 216 passengers and 12 crew on board when it flew through stormy weather and disappeared.

more...

http://www.cbc.ca/world/story/2009/06/05/air-france-search-debris-black-box469.html

[AzNick]

1. Manslaughter, hmm?

Maybe there's more to it, and someone placed a bomb on board, and they are simply not reporting it.

[babylonsister]

2. There were indications on board that something was wrong with

the speed the plane was going. My maintenance guy here just tried to explain it, thinking something called a pitot tube might have iced up because the systems failed.
I don't think anyone knows. Since the debris field they thought was the plane isn't, I think they're starting from scratch.

[Thothmes]

3. Think that is "pitot" tube.

It is used to measure aircraft air speed.

[babylonsister]

4. I'm sure you're right. He didn't spell it for me! nt

[backscatter712]

5. I've been hearing that theory from a few places.

If a pitot tube sensor malfunctioned, then the airspeed indicator would be reading wrong. Engines on modern airliners are very powerful, because you want to do tricks like have a two-engined airliner make it off the runway on takeoff even after a birdstrike disabled one engine.

So if the airspeed indicator is reading radically low, then the pilot or autopilot could have compensated by increasing the throttle. Go fast enough, and you can literally rip the plane apart, and yes, the engines are powerful enough to do that.

Or if the malfunction went the other way, the airspeed indicator was reading fast, the pilot or autopilot throttles down, and if it throttles down enough, the plane stalls, or stops flying and flutters out of the sky like a giant leaf, which again, exposes the plane to aerodynamic forces which are hard on it.

Right now, Air France is replacing pitot tube sensors and airspeed indicator instruments on its aircraft and retraining its pilots on what to do if the airspeed indicator is wrong (if trained right, they should notice that one of the THREE airspeed indicators on the aircraft is reading wrong, and take appropriate action to deal with it.)

Yeah, if this theory is true, what we have is a pilot training issue.

[AzNick]

6. So it would be design error again?

I am not a pilot but used to know French pilots, both airliner and fighter pilots.

When that Airbus crashed while performing tricks with passengers at an air show, they blamed the pilot.

According to these friends, the system was programmed to prevent certain maneuvers, like push down and all the way up to prevent stress on the wings. The system would instead put the plan in less sharp curve.

The pilot was apparently not well trained and when he performed a trick where he flew towards the ground then pulled all the way back on the yoke, the computer instead decided to not allow the recovery and the plane crashed.

Another issue occurred when an Airbus disintegrated over New York/New Jersey due to foreman at Toulouse refusing to discard a cracked tail piece and instead having it mended, which ended up causing the tail to rupture.

I forgot when these incidents took place, but Airbus needs to put it together real quick if they don't want to lose their reputation of safety (it's not like Boeing is any safer).

[backscatter712]

8. Very likely.

I suppose that to know for sure, we'd need to look at the black boxes, if they can be recovered...

But yeah, with computerized aircraft control systems, the usual rule with computers applies: Garbage in, garbage out.

Bad airspeed data in, bad control surface movements and throttle settings out...

[babylonsister]

7. Could easily be an issue with the systems. My DH came up

with the scenario that both pilots could have been registering different speeds on their indicators, so they'd have to make a decision amid a raging storm. Make the wrong decision, and poof.

I wouldn't be too hasty blaming this on pilot error. The sad thing is, we may never know where they crashed, much less what happened.

[strategery blunder]

9. I would think that Airbus would've learned their lesson from Boeing here.

The 757 had an EXCELLENT safety record up until a Bergenair 757 pitot tube getting jammed by nest-building insects.

Aircraft took off with a jammed pitot tube. Airspeed indicators disagreed with each other and gave conflicting data.

Crew received conflicting data indicating they were going too fast and too slow at the same time. Autopilot fought the pilots' throttle inputs for a while before giving up and disengaging. Eventually the aircraft stalled out.

As a result of the Bergenair crash, 757s were reprogrammed to include an "IAS DISAGREE" indicator to alert the pilots to this exact problem and pilots received training in how to proceed. IAS=indicated airspeed.

If Airbus did not take notice of this and failed to realize that something similar could happen to ITS aircraft, and that failure is found to have contributed to the cause of the crash, I will be none too pleased with Airbus. If the crash was due to a pitot tube problem (what jammed it, ice or insect nests, is irrelevant), the crash was probably entirely preventable. :( :( :(