Airframe testing

[TeeVee]

so, as i flew through some turbulence that knocked a FA around a bit the other day, the thought popped into my head, "how do manufacturers test airframes for turbulence/stress resistance?" years ago i saw a video about how boeing bent the wing of a 747 some ridiculous amount. but what i wanna know is if there are test done on the complete structure and if so how.

[brianw999]

Airframes are stress tested in a static rig designed to take various parts up to a required load standard to ensure non break-up. This link shows how bombardier are doing it for the new C series.... http://www.reinforcedplastics.com/vi...rame-underway/

[3WE]

...and has there ever been an in-flight structural break up of a modern airliner with turbulence as a primary cause?

I can think of lots of pressurization cycle fatigue stuff (Comet, Hawaii, JAL aft dome) and cargo doors and even AA-587...

And, lots of wind shear crashes, but I can't think of any instance where an airiner was downed by in-flight turbulence/structural failure.

[brianw999]

The only inflight break up that I can think of that is anywhere near airliner size and anything like turbulence caused is the horrendous wings detachment suffered by a C130 water bomber some time ago.
Short clip from YouTube ...... http://youtu.be/-A4QZAxrb28

May they rest in peace. Brave souls simply trying to help and save others.

[HalcyonDays]

BOAC 707 Japan 1966

[3WE]

The only inflight break up that I can think of that is anywhere near airliner size and anything like turbulence caused is the horrendous wings detachment suffered by a C130 water bomber some time ago.
Short clip from YouTube ...... http://youtu.be/-A4QZAxrb28

May they rest in peace. Brave souls simply trying to help and save others.

I don't know that I'd call turbulence the primary cause as much as pulling hard up with a heavy load...and wasn't aircraft age part of this one too?

[TeeVee]

thanks for the responses. i was aware that no in-flight break-ups had occurred as a result of turb, i was just wondering how they simulated it

[3WE]

thanks for the responses. i was aware that no in-flight break-ups had occurred as a result of turb, i was just wondering how they simulated it

Big time computer modeling.

I'm thinking you are hinting that there's more than stressing the hell out of the wing.

The irony/paradox/whatever you want to call it is sometimes interesting in that if the plane is more lightly loaded.

Hey, the plane's light, less stress on the wings, life is good.

But ligher load means you can pull more G's but your engines aren't any lighter and then maybe your engine mounts get over stressed.

[TeeVee]

Big time computer modeling.

I'm thinking you are hinting that there's more than stressing the hell out of the wing.

The irony/paradox/whatever you want to call it is sometimes interesting in that if the plane is more lightly loaded.

Hey, the plane's light, less stress on the wings, life is good.

But ligher load means you can pull more G's but your engines aren't any lighter and then maybe your engine mounts get over stressed.

well computer modeling would depend on certain absolutes, such as the absolute strength/quality of the materials used. maybe not so much in aviation, but there have plenty of instances where the assumed quality wasn't quite what it was supposed to be.

a while back, i read a piece about non-approved parts and spares being used in aviation. i think it was bolts. they had nowhere near the specified strength and were some cheap chinese knock offs.

[Evan]

thanks for the responses. i was aware that no in-flight break-ups had occurred as a result of turb, i was just wondering how they simulated it

BOAC flt 911 (call it the other 911). Broke up due to extreme turbulence over Mt Fuji. The fin seperated from the fuselage (yes, it also happens to Boeings), perhaps due to pilot using excessive rudder inputs, causing a flat spin and break up in flight.

[Gabriel]

BOAC flt 911 (call it the other 911). Broke up due to extreme turbulence over Mt Fuji. The fin seperated from the fuselage (yes, it also happens to Boeings), perhaps due to pilot using excessive rudder inputs, causing a flat spin and break up in flight.

So.... there was turbulence, the pilot used (abused) the rudder, the fin was overloaded and separated from the fuselage, the airplane entered a flat spin, it got overloaded again, and it broke up in flight.... And it broke up due to turbulence?

"¿¡Dónde estará ahora mi sobrino Yogurtu Ngue, quien tuvo que huir precipitadamente de la aldea por culpa de la escasez de rinocerontes!?"

[BoeingBobby]

So.... there was turbulence, the pilot used (abused) the rudder, the fin was overloaded and separated from the fuselage, the airplane entered a flat spin, it got overloaded again, and it broke up in flight.... And it broke up due to turbulence?

"¿¡Dónde estará ahora mi sobrino Yogurtu Ngue, quien tuvo que huir precipitadamente de la aldea por culpa de la escasez de rinocerontes!?"

Gabriel, Your new signature has me wondering? Does your nephew require numerous rhino's to be present?

[UncleFire]

As a child I remember flying from the US to Italy on a trip with my parents. We hit some turbulence along the way and the wings were flopping around like they were rubber. They didn't just flap like a birds wings but some parts went up while others (at the same time went down).

My point is it seems the deflection isn't uniform along with wing.

The static tests I've seen are pretty much: secure the fuselage and left the crap out of the wings at the ends until they break. IIRC I think the deflection on the 777 was something like 20+ feet. Video below shows it broke at 154% of design strength.

http://www.youtube.com/watch?v=Ai2HmvAXcU0

Although turbulence (IMO) is kinda different in that it isn't constant slow deflection but could be quick spikey deflection. I doubt they can test, but history shows that unless you do some really odd stuff it won't break up.

[Gabriel]

Gabriel, Your new signature has me wondering? Does your nephew require numerous rhino's to be present?

Oh, it's not my signature. It's part of my post. And a very relevant (albeit ironic) one.

[3WE]

BOAC flt 911 ...perhaps due to pilot using excessive rudder inputs, causing a flat spin and break up in flight.

Do you have any source whatsoever to support excessive rudder inputs?

I didn't see any mention of that.

I'm thinking you have just achieved the ultimate level of sit on your ass ignorant judgementalism and a cheap attempt at trolling

Do the words "extreme turbulence" mean anything to you, or do you think a tailless aircraft might enter a flat spin on its own?...never mind, you just read the manuals, type on Jetphotos.net and never make mistakes.