Belgique
19th Sep 2002, 16:10
Can anyone help me out here? (ratbags remain in limbo pls). Seems to be (prima facie) yet another case for CCTV inside and outside.
Request Received
Request for comment
I am hoping they will adress the unresolved issue of no feedback and not tell me they're using stronger attachment fittings. The seminal issue here is absence of feedback. Shades of departing vertical fins, what?
Here is an Aviation Safety Reporting System (ASRS) report on an incident involving an A319 in which the flight crew was not aware of vibration or flutter. If memory serves, the A319 followed the A320 and therefore is a FBW aircraft. At any rate, I'd appreciate any comments/insights you or your colleagues might have. I'd like to present this case in the next issue. If a response could be generated in the next 5-6 days, I can run it in our Sept. 30 issue. The acronym RVDT seems to translate variously to Rate variable displacement transducer or Rotary Variable Differential Transformers (or any permutation thereof). LVDT is Linear Variable..... Someone's getting confused by their own acronyms.
Much appreciated, J
ASRS report:
On aircraft twice in two weeks. The left aileron panel between aileron and rear spar broke causing major damage in both incidents (there is an AD note pertaining to this problem). I bring this incident up to reflect on how it was discovered. Both of these incidents were reported by passengers. The cockpit crew neither felt nor observed anything amiss with the aircraft. Had this not been a 'fly by wire' aircraft, a vibration would have been felt on the control wheel and reported, thus minimizing the damage and increasing the safety factor. However, because of the 'fly by wire', the computers compensated for the flutter and vibration that occurred, and did it so well the cockpit crew knew nothing about what was happening to their aircraft. There would be no warning until a complete failure occurred and then a possible catastrophic event could occur I believe this could be prevented if we were to reprogram the onboard computers utilizing the existing RVDT's that report to the onboard computers. When the computers sense abnormal movement or vibration, a warning would be sent to the cockpit. I believe this would bring the situation to the attention of the crew and it would then be checked out and repaired before the damage would reach a major stage. At present there's no telling what the preamble symptom to failure time was.
Callback conversation with reporter revealed the following information: The reporter stated this airplane XYZ had two reports of passengers observing the left aileron to wing upper panel vibrating and fluttering which incurred damage to the aileron and panel was cracked. The reporter stated the carrier had three other events of this panel vibration or flutter on other airplanes in this fleet. The reporter said an airworthiness directive has been issued by the FAA to install heavier nut plates and fasteners on the panel. The reporter stated the flight-crews were unaware of the vibration as no feedback was felt in the controls - and no flight control warning was annunciated. The reporter said it may be possible to modify the flight control units to trigger a flight control warning when a control surface or fairing panel is fluttering or vibrating.
Request Received
Request for comment
I am hoping they will adress the unresolved issue of no feedback and not tell me they're using stronger attachment fittings. The seminal issue here is absence of feedback. Shades of departing vertical fins, what?
Here is an Aviation Safety Reporting System (ASRS) report on an incident involving an A319 in which the flight crew was not aware of vibration or flutter. If memory serves, the A319 followed the A320 and therefore is a FBW aircraft. At any rate, I'd appreciate any comments/insights you or your colleagues might have. I'd like to present this case in the next issue. If a response could be generated in the next 5-6 days, I can run it in our Sept. 30 issue. The acronym RVDT seems to translate variously to Rate variable displacement transducer or Rotary Variable Differential Transformers (or any permutation thereof). LVDT is Linear Variable..... Someone's getting confused by their own acronyms.
Much appreciated, J
ASRS report:
On aircraft twice in two weeks. The left aileron panel between aileron and rear spar broke causing major damage in both incidents (there is an AD note pertaining to this problem). I bring this incident up to reflect on how it was discovered. Both of these incidents were reported by passengers. The cockpit crew neither felt nor observed anything amiss with the aircraft. Had this not been a 'fly by wire' aircraft, a vibration would have been felt on the control wheel and reported, thus minimizing the damage and increasing the safety factor. However, because of the 'fly by wire', the computers compensated for the flutter and vibration that occurred, and did it so well the cockpit crew knew nothing about what was happening to their aircraft. There would be no warning until a complete failure occurred and then a possible catastrophic event could occur I believe this could be prevented if we were to reprogram the onboard computers utilizing the existing RVDT's that report to the onboard computers. When the computers sense abnormal movement or vibration, a warning would be sent to the cockpit. I believe this would bring the situation to the attention of the crew and it would then be checked out and repaired before the damage would reach a major stage. At present there's no telling what the preamble symptom to failure time was.
Callback conversation with reporter revealed the following information: The reporter stated this airplane XYZ had two reports of passengers observing the left aileron to wing upper panel vibrating and fluttering which incurred damage to the aileron and panel was cracked. The reporter stated the carrier had three other events of this panel vibration or flutter on other airplanes in this fleet. The reporter said an airworthiness directive has been issued by the FAA to install heavier nut plates and fasteners on the panel. The reporter stated the flight-crews were unaware of the vibration as no feedback was felt in the controls - and no flight control warning was annunciated. The reporter said it may be possible to modify the flight control units to trigger a flight control warning when a control surface or fairing panel is fluttering or vibrating.