Air France Jet Missing Off Brazil Coast

[MrRiplEy[H]]

One thing seems to be totally overlooked in this discussion: lightning strike as claimed by Air France.

Here's a major downfall of composites - they're vulnerable to lightning damage where metal will conduct the current away. It's possible a lightning hit caused a catastrophic failure of some composite part as has happened to some composite helicopter blades previously.

[Die Hard]

Seems rather low for an inter-continental flight. Well, then I guess they could have run into some clouds.

35k is th A330's rated cruise altitude. I don't know what its ceiling is, probably in the 40's.

[Die Hard]

One thing seems to be totally overlooked in this discussion: lightning strike as claimed by Air France.

Here's a major downfall of composites - they're vulnerable to lightning damage where metal will conduct the current away. It's possible a lightning hit caused a catastrophic failure of some composite part as has happened to some composite helicopter blades previously.

While it is true that the metal fuselage protects the occupants from lightning it is a popular myth that aircraft don't take damage from lightning strikes. They do, and a number of fatal accidents are attributed to lightning strikes.



For example lightning strike caused this Asiana Airlines' A321 nose cone to fall off.

[Denholm]

Is the plane itself struck or does the plane happen to just inadvertently fly into a lightning strike? It doesn't make sense to me that an aircraft with no physical connection to the ground can be struck by lightning seeking the easiest route to the ground.

[jdbecks]

I was on a plane flying from rome to pisa and the plane got struck by lightning..it made a big bang and flash..everything was ok  

i was flying in a fokker 50 or 100.

[Wolfala]

One thing seems to be totally overlooked in this discussion: lightning strike as claimed by Air France.

Here's a major downfall of composites - they're vulnerable to lightning damage where metal will conduct the current away. It's possible a lightning hit caused a catastrophic failure of some composite part as has happened to some composite helicopter blades previously.

I own a Cirrus SR-20 which is 95% composite minus the control surfaces.

An SR-22 was struck by lightening sitting on the ramp in IER (Natchitoches, LA). I have the photos somewhere. There were hundreds of little holes blown out of the skin and a few large areas of damage under the wire mesh. It was ugly. I have no idea if or how it was repaired and what the final outcome was. It looked like the structure was compromised significantly, but without a full inspection there would be no way to know for sure.

I was struck in my Twin Beech right on the nose of the airplane. I was an impressive experience. The bolt looked to be about a foot in diameter and the impact point was only about 8 feet in front of our noses. It was LOUD, too. There was about a four inch diameter burn spot on the radome and we could find no other damage at all. It seems as though the voltage just ran over the surface and discharged out the static wicks.

[humble]

That is not a design flaw. The aircraft was certified as safe to fly; in other words the sensitivity of the rudder controls were not deemed unsafe, and thus the plane was designed within the safety regulations governing commercial flight. If the pilot had just stomped on one pedal the rudder and vertstab was designed to take it. What it wasn't designed to take was the alternating stomping on both pedals; something few, if any, airliners are designed to tolerate. While the A300-600 had lighter and more sensitive rudder controls than other similar airliners they still required a 35 lbs force for maximum deflection; that's not a hair trigger by anyones standard.

This is not entirely true, AA and the pilots association contend (and are still litigating) that the root cause is a design flaw.

[Angus]

35k is th A330's rated cruise altitude. I don't know what its ceiling is, probably in the 40's.

My first Airbus flight was on the leg London - Munchen with Lufthansa back in 1993. We cruised at 39K. Was one of the best airline flights I ever had. The aircraft had a very good ROC and was quite stable. I think the alt was because of bad weather by the way. After all, it was December.

Anyway, if I understand the theories on the composites, - could it be that the airbus would catch a lightning worse than a metal airframe due to the lack of "skin"? I have no idea really, but neither do I have much ideas about thunderstorms above 39K...

I did get hit by a lightning once, - well it hit the car I was driving. Wham-Bang, and a flash and that was it. No damage visible.
It was a Volvo

[OOZ662]

Is the plane itself struck or does the plane happen to just inadvertently fly into a lightning strike? It doesn't make sense to me that an aircraft with no physical connection to the ground can be struck by lightning seeking the easiest route to the ground.

I figure it still has to do with resistance. Lightning is just waiting to happen until it can get enough push to make it through the air to the ground. Although the plane doesn't make the trip to the ground immediate like a big ol' wire would, the metal is much less resistant than air and will make the path "shorter." If the lightning is just about ready to strike and the plane flies under it, bang.

[humble]

Skuzzy, "consumer grade" is a relative term. I'm using it in the context of a customer originated purchase decision matrix that balances percieved cost/benefit vs the more absolute performance regardless of cost we see in military development. While the military doesnt have an endless budget and airlines wont intentionally buy "less safe" airframes the reality is that all modern planes (not just Airbus) are effected. The end result is planes designed to maximize revenue and be "good enough".

I can find only one case of a turbulence induced crash in the last 30 yrs (I may very well have missed one){Polkovo 612}. The plane in question was forced over its designed alt limit and apparently entered a flat spin. Numerous distress calls were picked up as the pilots fought for control all the way down.

The lack of any distress signals indicates a sudden and catastrophic failure vs a prolonged attempt to regain control. AF is the source for the order of the automated signals received that indicated AP disconnect and a change in the planes flight logic. From the query I posted on Pprune it appears that the airbus is designed to eliminate fail safes...so a change in "logic" would disable restrictions designed to protect the plane in normal flight to give the pilot more authority over inputs. I have no idea how this interfaces with the ADIRU and how it effected the Quantus flight (and others). I do know that the 612 plane (Tu-154) was largely intact. Just looking at 747's I can find 4 accounts of turbulence severe enough to kill one or more passengers and cause upset severe enough to literally flip the plane on its back in at least one instance. Other instances of upset at cruise due to mechanical failure (china air 006 comes to mind) show a history of planes able to survive severe stress in flight. Another instance is an El Al 747-200 (ferry no pax) that lost #3 pylon engine in flight...which hit #4 which also separated and took off the leading wing edge. The plane almost made it back to point of origin before crashing on final.

I recognize the reality of unforeseeable events and "acts of god". However the reality that its now acceptable engineering for a plane to fail completely in normal use is appalling.

[straffo]

This is not entirely true, AA and the pilots association contend (and are still litigating) that the root cause is a design flaw.

As the alternative would be training flaw ... what else can they say ?

One thing seems to be totally overlooked in this discussion: lightning strike as claimed by Air France.

Here's a major downfall of composites - they're vulnerable to lightning damage where metal will conduct the current away. It's possible a lightning hit caused a catastrophic failure of some composite part as has happened to some composite helicopter blades previously.

I remember reading somewhere that some metal in the composites just to handle that.

[Die Hard]

This is not entirely true, AA and the pilots association contend (and are still litigating) that the root cause is a design flaw.

Again, what flaw? The aircraft was certified, and do you consider 34 lbs of force to be excessively light for full rudder deflection?

[OOZ662]

I'm sure every aircraft that's crashed in service was certified.

[Die Hard]

I'm sure every aircraft that's crashed in service was certified.

True, and the NTSB did not fault Airbus in this incident. It was clearly pilot error.

[jdbecks]

I did get hit by a lightning once, - well it hit the car I was driving. Wham-Bang, and a flash and that was it. No damage visible.
It was a Volvo

I heard they will use volvos to replace the abrhams tank