Gonzalo
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LH A330 With Undetected Tail Strike Flew ORD-MUC

Fri Mar 08, 2013 3:34 pm

A LH Airbus 330 took off from ORD and suffered substantial damage after a tail strike while rotating. However the tail strike was not noticed and the flight continued to MUC at FL 370.
Although the flight landed safely in MUC and there were not a single problem along the flight, I think is a little worrying that this aircraft crossed the Atlantic Ocean with a potential explosive decompression ( the pressure bulkhead was not damaged, if so, the story will be different ).

In the recent thread about the UA 739 Tail Strike at ORD the subject of tail strike warnings in the cockpit was discussed, and IIRC some aircraft models had this kind of warnings.... I guess the A330 don't.

Does anyone have some more info or pics of the damaged aircraft ?

http://www.avherald.com/h?article=45edb5ae&opt=0


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Semaex
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Fri Mar 08, 2013 9:46 pm

I wonder how the tailstrike was unnoticed yet the news made it to the german BFU, Avherald and here too.

I'm not doubting the event at all, I would've just thought that a tailstrike would be quite noisy in the cabin making a very destiguishable sound that the FAs would have reported to the pilots who might have overheard it in such a stressful moment as Takeoff....
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Stitch
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Fri Mar 08, 2013 10:07 pm

Quoting Semaex (Reply 1):
I wonder how the tailstrike was unnoticed yet the news made it to the german BFU, Avherald and here too.

I would guess once the plane landed at MUC, ground crew noticed the damage at the gate.

That being said, I do agree with you that there could be such damage without anyone aboard the plane hearing or feeling anything.
 
TC957
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Fri Mar 08, 2013 10:27 pm

I find this quite incredible that no crew noticed anything. Surely the higher than normal angle of take-off should have triggered an alert to experienced crew that a tailstrike at least could have happened.
And why is there no audible warning in the cockpit that alerts crew when the take-off angle becomes be so severe so as to cause a tailstrike ?
 
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Stitch
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Fri Mar 08, 2013 10:41 pm

Quoting TC957 (Reply 3):
I find this quite incredible that no crew noticed anything. Surely the higher than normal angle of take-off should have triggered an alert to experienced crew that a tailstrike at least could have happened.

An AC 330-343 departing Frankfurt for Montreal in 2002 had a tail-strike that was undetected by the flight crew, but was caught by a cabin crew member. The cause was a too-low V1 speed that was not caught by either crew member:

http://www.tsb.gc.ca/eng/rapports-re...viation/2002/a02f0069/a02f0069.asp



Quoting TC957 (Reply 3):
And why is there no audible warning in the cockpit that alerts crew when the take-off angle becomes be so severe so as to cause a tail-strike?

The A340-600 has a TAIL STRIKE ECAM warning. I don't know if this is present on the A330 family.

[Edited 2013-03-08 14:42:38]
 
roseflyer
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Fri Mar 08, 2013 10:56 pm

Quoting Gonzalo (Thread starter):

In the recent thread about the UA 739 Tail Strike at ORD the subject of tail strike warnings in the cockpit was discussed, and IIRC some aircraft models had this kind of warnings.... I guess the A330 don't.

Usually only stretched airplanes have tail strike warning systems and tail skid. The probability of a tail strike on an A330 is low, so I guess that is why it doesn't have a tail skid or tail strike warning. The A340-600 does, and so does the 777.
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roseflyer
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Fri Mar 08, 2013 11:17 pm

Quoting TC957 (Reply 3):
I find this quite incredible that no crew noticed anything. Surely the higher than normal angle of take-off should have triggered an alert to experienced crew that a tailstrike at least could have happened.
And why is there no audible warning in the cockpit that alerts crew when the take-off angle becomes be so severe so as to cause a tailstrike ?

First off, there would never be an audible warning in the cockpit for a tail strike. The FARs only allow audible warnings are only used when immediate action is required by the pilots. It is limited only to safety problems that require action of the pilots (usually within 15 seconds). You don’t want warnings going off right at rotation when crew workload is high.

Secondly, the software should make it so that a tail strike is impossible. The A330 has rotation protection that should prevent tail strikes. (this isn’t an A vs B control theory argument since the 777 has the same rotation protection software logic limits too).

A warning message alerting the crew is more likely. I don’t know the A330 system well, but in the 777 it is on EICAS. Airplanes that are prone to tail strikes typically have a tail skid which is a shock absorber (sometimes one position, sometimes deployable 2 position) to protect the airplane. On the 777, there is a tail strike detection system that detects a scrape. It prohibits the cabin from pressurizing, so the plane must do an air turn back and inspect for damage. I assume the A340-600 system is similar. However, Airbus likely decided that the possibility of a tail strike on the A330 is low since the body is short enough and the software should prevent it. However we know that even with such protections, occasionally one does happen.

As far as detecting tail strikes, they happen all the time on 737-900s. That airplane is very susceptible. There’s a two position tail skid on the 900ER with the shock absorber, but no tail strike indication. The airplane has flown many flights with the crew never knowing. If the shock absorber does its job, there is little chance of an impact great enough to do damage to the pressure vessel without the crew noticing.
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rfields5421
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Fri Mar 08, 2013 11:27 pm

Quoting Semaex (Reply 1):
I would've just thought that a tailstrike would be quite noisy in the cabin
Quoting Stitch (Reply 2):
I do agree with you that there could be such damage without anyone aboard the plane hearing or feeling anything.

I've seen two different types tail strike occur - both with B747 early aircraft on Guam. I was hanging out on the mid-field US Navy fire truck with some friends both times.

The first was very obvious and noticeable to the crew and the tower. The aircraft over rotated sharply and struck the ground with sparks, smoke and a visible shudder in the aircraft in bright daylight. The crew radioed the tower that something had happened, but none of their instruments and indicators a problem. The tower told them that the tail had struck, and they returned for an examination. After flying in tech types, the plane was eventually flown empty at low altitude back to Japan for repairs.

The second was almost undetectable. A seemingly normal rotation, no sparks or smoke seen. But my buddy asked the tower if he could make a runway inspection because he though the tail might have struck. He found what he though was new scrape mark on the runway. It was discussed with the tower, and the crew. Because no one could confirm the tail had actually struck the runway, the plane continued on to Haneda.

The plane was observed on taxi-in at Haneda to have very visible damage. They had to replace a substantial amount of metal, and the plane was out of service for almost three weeks for repairs and inspections.

Some tail strikes are simply undetectable in the cabin, or by outside observers, but they can still create a lot of damage.

Quoting Gonzalo (Thread starter):
I think is a little worrying that this aircraft crossed the Atlantic Ocean with a potential explosive decompression ( the pressure bulkhead was not damaged, if so, the story will be different ).

A tail strike which could damage the pressure bulkhead will be very noticable to everyone on the aircraft, especially the flight crew. It takes several Gs of impact force to damage those bulkheads.
 
BEG2IAH
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Sat Mar 09, 2013 5:04 am

Quoting rfields5421 (Reply 7):
Some tail strikes are simply undetectable in the cabin, or by outside observers, but they can still create a lot of damage.

Thanks for this great post.
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CamiloA380
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Sat Mar 09, 2013 8:25 am

Quoting Gonzalo (Thread starter):
In the recent thread about the UA 739 Tail Strike at ORD the subject of tail strike warnings in the cockpit was discussed, and IIRC some aircraft models had this kind of warnings.... I guess the A330 don't.

IIRC, the PLI (Pitch Limit Indicator) which was firstly introduced in the A346 for obvious reasons, is also available in the A330.

It's basically a V in your attitude indicator that activates at 400ftRA. Exceed that limit below 14ftRA you get an aural warning "Pitch, Pitch"

Again, this is from memory. 
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Apprentice
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Sat Mar 09, 2013 8:58 am

Quoting Roseflyer (Reply 6):

12 years ago, in my initial training in Germany, I was told that there is not Tail Strike msg nor tail skid on A330 since a TS was imposible due to envelope protections, since I'm a believer, I didn't expect one in my walk-arounds, till today.
It's unbelivable that FAs seated for TO in doors 4 RH & 4 LH did not feel the noise and scratch vib associated.
Since there is not tail skid, at least some skin area should be damaged. No much damage tolerance in the skin.
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71Zulu
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Sat Mar 09, 2013 10:51 am

Quoting rfields5421 (Reply 7):
A tail strike which could damage the pressure bulkhead will be very noticable to everyone on the aircraft, especially the flight crew. It takes several Gs of impact force to damage those bulkheads.

Well the cockpit crew missed this one. Even after being notified of a possible strike by the cabin crew, they continued the flight with a damaged aft rear bulkhead. AA B738.

http://avherald.com/h?article=43cbc4f9&opt=0
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Semaex
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Sat Mar 09, 2013 12:47 pm

Quoting Roseflyer (Reply 6):
However, Airbus likely decided that the possibility of a tail strike on the A330 is low since the body is short enough and the software should prevent it. However we know that even with such protections, occasionally one does happen.

Typical example of a Confirmation Bias. "Hey this plane cannot do a tailstrike because the envelope protects it. It is so good, it doesn't even need a Tailstrike warning." Should be brought up in the next ICAO Annex 8 meeting...
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Gonzalo
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Sat Mar 09, 2013 6:06 pm

Quoting 71Zulu (Reply 11):
they continued the flight with a damaged aft rear bulkhead. AA B738.

And they were flying Los Angeles - Toronto... a long flight of 4+ hours, with the aft pressure bulkhead damaged....the cockpit crew that ignored the warnings from the cabin crew members should be punished, they put in danger their aircraft and everybody on board.... Does anyone know if this crew was sanctioned ??

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Gonzalo
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Mon Mar 11, 2013 1:42 pm

The AvH report was updated today, adding the word "structural" between substantial / damage. This makes the issue of how this was not detected by the cabin crew in the aft section more puzzling, since this basically eliminates the chance of the strike being "just a few sparks upon rotation"... I guess you need a hard hit with some G forces to cause what is now described as "substantial structural damage"...

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coachclass
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Mon Mar 11, 2013 3:29 pm

Quoting Apprentice (Reply 10):
It's unbelivable that FAs seated for TO in doors 4 RH & 4 LH did not feel the noise and scratch vib associated.

Is it possible that the "culture" of LH is such that you don't challenge the captain or call attention to his short comings? I understand that at some Asian airlines this is a major problem, even for the co-pilot.
 
wilco737
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Mon Mar 11, 2013 3:34 pm

Quoting CoachClass (Reply 15):
Is it possible that the "culture" of LH is such that you don't challenge the captain or call attention to his short comings? I understand that at some Asian airlines this is a major problem, even for the co-pilot.

Oh no, far from that. At LH ALL F/A's are instructed to report everything to the cockpit, no matter how small and unimportant it may sound.

And I made the experiance on most flights that they call for minor things and let us know and never heard one say after the flight: "I wanted to call you, but thought it wasn't important."

The atmosphere between cockpit crew and cabin crew is very relaxed (not too relaxed of course), but the youngest F/A can easily tell the captain that something smells or looks weird in the cabin and nobody will be mad at her if it is nothing.

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CCA
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Tue Mar 12, 2013 1:58 pm

Just to let you know Boeing is removing the tail skid and all associated components from the 77W as of yesterday.

Line number 1166 will be the first to roll out without it.

The A/C will get an enhanced tail strike protection system encorporated into the primary flight control computers which negates the current mechanical tail skid.

Current 77Ws can be modded to remove the tail skid to save weight.

[Edited 2013-03-12 07:00:06]
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Gonzalo
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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Tue Mar 12, 2013 2:59 pm

Quoting CCA (Reply 17):
Just to let you know Boeing is removing the tail skid and all associated components from the 77W as of yesterday.

Line number 1166 will be the first to roll out without it.

The A/C will get an enhanced tail strike protection system encorporated into the primary flight control computers which negates the current mechanical tail skid.

Current 77Ws can be modded to remove the tail skid to save weight.

Interesting news.... although a little tinted with overconfidence in the software.... I mean, yes, the computer glitch events are extremely rare, but not unheard of...

BTW, how much weight are they reducing after the tail skid and associated components removal ? I doubt it will be more than a 200 pounds ?

Thanks ....

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RE: LH A330 With Undetected Tail Strike Flew ORD-MUC

Wed Mar 13, 2013 7:14 am

320lbs saving, so not a small amount by any means, especially for 100,000 plus hours of flying.
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