Air France Jet Crash

DaivdBender

You have probally all heard about the Air France jet crashing in the Alantic.

Reports so far have suggested that lighting was the cause of failure.

Now I believe Commericial Air Crafts are struck by lightning at least once a year. Lightning is suppose to pass around the exterior of the plane causing only small distrubance.

From what I have read though lightning strikes can cause structural damage and electro-magnetic interference.

So the question is how safe are commercial jets against lighting strikes ?

How accurate are our models for predicting damage on a plane from lighting strikes ?

russ_watters

Welcome to PF!

I was wondering when someone would post about this incident and I'm glad you did it in engineering instead of general discussion! Correct, and since the initial reports, most news sources I've seen have backed off that speculation, noting that airplanes are designed to withstand lightning. The easy answer is that they are very safe, but nothing can be completely safe. More specific, I can't be because I don't have a lot of specific knowledge of the testing and modeling of this. We have plenty of members with more specific knowledge of this subject than me, though, who I'm sure will weigh in...

DaivdBender

Thanks for the response.

I just read that "The head of communication at Air France said the plane, an Airbus A330, had probably been struck by lightning" so i'm not too sure what the deal is.

If it had been struck by lightning I wonder how it damaged the plane?

If the report was false then I guess it could be almost anything. Have to wait until the black box is found.

FredGarvin

A lot of work and certification testing goes into an aircraft and its engines. A proper ground path between major components is a mandatory design feature. We just finished lightning strike testing on one of our engines.

That being said, there is no way to ever predict the worst case scenario when it comes to mother nature.

Personally, I don't buy the lightning strike theory. It may have had a contributing factor, but I doubt it was the main factor. Unfortunately, it looks like we may never know.

Astronuc

Here is some information on the research of lightning and aircraft interaction.

http://www.sae.org/aeromag/features/aircraftlightning/

http://oea.larc.nasa.gov/PAIS/Concep...lightning.html
I've seen a video of some of these experiments, but I can't find it on the internet.


Lightning might have been a factor. There is some speculation that aircraft with composite material might be more vulnerable to lightning strikes - but as of now, that's speculation.


Commercial aircraft have lightning wicks (basically lightning rods) or protusions with which to facilitate the conduction current in a more controlled process.

Lightning Strikes Airplane [Boeing 747] During Takeoff
http://www.youtube.com/watch?v=eX6Xk0DRVvE


As Fred mentioned, it will be difficult to find in the mid Atlantic. The craft seems to have gone missing somewhere near the mid-Atlantic Ridge.
http://news.yahoo.com/s/ap/brazil_plane

Borek

So far they have not even approximately located the plane.

Anybody knows what is a range of underwater locator beacons?

Obviously the range will depend on the equipment used for detection so there can be no easy answer to that...

Astronuc

Update: Some possible aircraft debris found along path of AF447.

http://news.yahoo.com/s/ap/20090602/...a/brazil_plane

DaveC426913

Did I not hear in the report that the plane sent out a warning complaint of electrical problems shortly prior to radio silence? Presumably the lightning fried some critical navigation or flight component(s).

DaivdBender

Thanks for the information. A very good read.

russ_watters

It also reported a cabin pressure loss, so I was thinking about it from the other direction: that wind shear had caused a structural failure, leading to both the cabin pressure loss and electrical failures. But I haven't seen it reported what order the failures were reported in.

My gut reaction to the early news reports was to think about the last time this many people died in a plane crash: in 2001, when wake turbulence and possible pilot or computer overcorrection tore the tail off an A300 over New York. http://en.wikipedia.org/wiki/America...nes_Flight_587

We certainly can't rule out lightning completely, but it would be an exceedingly rare failure. Lightning hasn't taken down a commercial airliner in more thana 40 years and an average, every airliner is hit by lightning once a year, so there have been millions of lightning strikes since then.

DaveC426913

IIRC, often air accidents are a conflagration of events. Lightning in conjunction with some other element(s), such as the age of the plane may be the cause. I heard early reports mentioning how old the plane was, though I think they said it was only 4 years or something.

Phrak

I don't suggest this as the most plausible, or even likely cause, but not beyond some consideration. It's not unheard of that ball lightning can enter an aircraft.

http://www.straightdope.com/columns/...g-really-exist

Phrak

Here is a weather analysis in the vicinity of AF447.

http://www.weathergraphics.com/tim/af447/

Wikipedia has the most comprehensive ACARS (Aircraft Communications Addressing and Reporting System) transission sequence I've seen so far. ACARS is the autonomous data broadcaste system the A330 utilized to report fault conditions directly prior to it's demise. It's about four screens down under "Incident".

Borek

Can't find it - can you please give more detailed pointers?

Borg

And, there is already a Wikipedia page for this flight as well.

http://en.wikipedia.org/wiki/Air_France_Flight_447

LURCH

Could have been positive lightning (BIG maybe).

Vals509

it was shown on the news that half an hour after last contact, weather satellites recorded extreme weather near where the plane was. could bad weather have crippled the plane.

also just as a guess. could the plane have suffered engine failure while in the storm. after all, there were electrical problems and i think the engines provide some power and also the engines i believe maintained presurisation and it is thought that there was a cabin loss of pressure