4 ms·

Just to add, here’s a forum discussion from 5 years about about aircraft cracks in general. People are saying they are common in all aircraft even during manufa

by wil421 7y ago

Just to add, here’s a forum discussion from 5 years about about aircraft cracks in general. People are saying they are common in all aircraft even during manufacturing. https://www.airliners.net/forum/viewtopic.php?t=773937 https://www.airliners.net/forum/viewtopic.php?t=773937

vultour 7y ago
Except this is not about cracks in the airframe but in a component that is certified for significantly more cycles than when the cracks are being found. If these were benign FAA wouldn’t have released an AD to inspect and repair them.
- wil421 7y ago
  I believe it was 27,000 vs the 30,000 Boeing stated. How long is 3,000 landings in days/years? The FAA is going to be investigating Boeing for everything minor and major if they want to gain a fraction of the credibility they lost.
  - msbarnett 7y ago
    > I believe it was 27,000 vs the 30,000 Boeing stated. How long is 3,000 landings in days/years? Boeing's originally stated lifetime was 90,000. After the initial discovery of the unexpected cracking, the FAA ordered an inspection of all pickle forks with more than 30,000 cycles within 7 days -- this is probably the source of your confusion. The "youngest" cracked pickle forks discovered so far was on a plane with 27,000 cycles, which is to say 63,000 cycles early (not 3,000 early) with respect to what Boeing rated it for.
    - wil421 7y ago
      Makes sense thanks for the clarification. That’s a hell of a lot more and very concerning.
  - notfromhere 7y ago
    As the comment below states, the difference is 27,000 vs 63,000. For more context, the pickle fork holds up the wings, so if those fail you are SOL
  - manicdee 7y ago
    The 27k vs 30k number is Qantas claiming they don’t need to inspect their planes yet because their planes still have 300 cycles to go. Inspection costs money. It might only take an hour to perform the inspection but that plane will be out of service for days.
msbarnett 7y ago
The issue here isn’t about airframe cracking in general, which is fairly normal and expected in the lifetime of the plane, but cracking in the “pickle fork” in particular— which is abnormal, as these are not normally expected to crack during the plane’s lifetime according to Boeing’s own modelling and expectations — engineers had rated these at 90,000 cycles, the effective lifetime of the craft. This appears to indicate (yet another) QC and manufacturing deficiency (Boeing already is dealing with other such issues with the 787 and KC-46). The claim by OP that this is normal because aluminum cracking is normal is really wide of the facts. This part was engineered to withstand the forces it experiences for a certain timespan, and the fact that some now appear to be failing in less than one-third of the lifespan the materials engineers expected it to calls into question whether Boeing or a subcontractor is failing to engineer these components to spec.

by wil421 7y ago

vultour 7y ago

Except this is not about cracks in the airframe but in a component that is certified for significantly more cycles than when the cracks are being found. If these were benign FAA wouldn’t have released an AD to inspect and repair them.

wil421 7y ago
I believe it was 27,000 vs the 30,000 Boeing stated. How long is 3,000 landings in days/years? The FAA is going to be investigating Boeing for everything minor and major if they want to gain a fraction of the credibility they lost.
- msbarnett 7y ago
  > I believe it was 27,000 vs the 30,000 Boeing stated. How long is 3,000 landings in days/years? Boeing's originally stated lifetime was 90,000. After the initial discovery of the unexpected cracking, the FAA ordered an inspection of all pickle forks with more than 30,000 cycles within 7 days -- this is probably the source of your confusion. The "youngest" cracked pickle forks discovered so far was on a plane with 27,000 cycles, which is to say 63,000 cycles early (not 3,000 early) with respect to what Boeing rated it for.
  - wil421 7y ago
    Makes sense thanks for the clarification. That’s a hell of a lot more and very concerning.
- notfromhere 7y ago
  As the comment below states, the difference is 27,000 vs 63,000. For more context, the pickle fork holds up the wings, so if those fail you are SOL
- manicdee 7y ago
  The 27k vs 30k number is Qantas claiming they don’t need to inspect their planes yet because their planes still have 300 cycles to go. Inspection costs money. It might only take an hour to perform the inspection but that plane will be out of service for days.

msbarnett 7y ago

The issue here isn’t about airframe cracking in general, which is fairly normal and expected in the lifetime of the plane, but cracking in the “pickle fork” in particular— which is abnormal, as these are not normally expected to crack during the plane’s lifetime according to Boeing’s own modelling and expectations — engineers had rated these at 90,000 cycles, the effective lifetime of the craft. This appears to indicate (yet another) QC and manufacturing deficiency (Boeing already is dealing with other such issues with the 787 and KC-46). The claim by OP that this is normal because aluminum cracking is normal is really wide of the facts. This part was engineered to withstand the forces it experiences for a certain timespan, and the fact that some now appear to be failing in less than one-third of the lifespan the materials engineers expected it to calls into question whether Boeing or a subcontractor is failing to engineer these components to spec.