BillLumbergh
Veteran
[SPAN class=headline][A href=http://biz.yahoo.com/djus/021029/0528000318_1.html][FONT size=2]Flight 587 Probe Focusing On What Made Tail Fall Off[/FONT][/A][/SPAN]
Flight 587 Probe Focusing On What Made Tail Fall Off
- Thread starter BillLumbergh
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ac500,
I hope this information helps. This was taken from the transcripts that were read by NTSB IIC no the 587 investigation.
NTSB recommendations
The Board has issued two recommendations to the FAA so far during this investigation. These two were considered so important that we could not wait until the conclusion of the investigation.
The two safety recommendations address the fact that many pilot training programs do not include information about the structural certification requirements for the rudder and vertical stabilizer on transport-category airplanes. Significantly, full rudder inputs even at speeds below the design maneuvering speed, may result in structural loads that exceed certification requirements. However, pilots may have the impression that the rudder limiter systems which limit rudder travel as airspeed increases to prevent a single full rudder input from overloading the structure, also prevent cyclic full rudder deflections from damaging the structure. This is not true. The structural certification requirements for transport-category airplanes do not take such maneuvers into account; therefore, such cyclic rudder inputs, even when a rudder limiter is in effect, can produce loads higher than those required for certification and that may exceed the structural capabilities of the aircraft.
Staff is continuing to evaluate whether the pilots caused the rudder to move or determine if a rudder system anomaly could have contributed to the movement. Regardless, staff believes that the rudder movement resulted in most, if not all, of the loads imposed on the vertical stabilizer.
Because of the lack of understanding of the certification requirements of the vertical stabilizer, the Board asked the FAA to require the manufacturers and operators to ensure that pilot training programs: (1) explain the structural certification requirements for the rudder and vertical stabilizer; (2) explain that a full or nearly full rudder deflection in one direction followed by a full or nearly full rudder deflection in the opposite direction can result in potentially dangerous loads on the vertical stabilizer, and (3) explain that, on some aircraft, as speed increases, the maximum available rudder deflection can be obtained with comparatively light pedal forces and small pedal deflections.
I hope this information helps. This was taken from the transcripts that were read by NTSB IIC no the 587 investigation.
NTSB recommendations
The Board has issued two recommendations to the FAA so far during this investigation. These two were considered so important that we could not wait until the conclusion of the investigation.
The two safety recommendations address the fact that many pilot training programs do not include information about the structural certification requirements for the rudder and vertical stabilizer on transport-category airplanes. Significantly, full rudder inputs even at speeds below the design maneuvering speed, may result in structural loads that exceed certification requirements. However, pilots may have the impression that the rudder limiter systems which limit rudder travel as airspeed increases to prevent a single full rudder input from overloading the structure, also prevent cyclic full rudder deflections from damaging the structure. This is not true. The structural certification requirements for transport-category airplanes do not take such maneuvers into account; therefore, such cyclic rudder inputs, even when a rudder limiter is in effect, can produce loads higher than those required for certification and that may exceed the structural capabilities of the aircraft.
Staff is continuing to evaluate whether the pilots caused the rudder to move or determine if a rudder system anomaly could have contributed to the movement. Regardless, staff believes that the rudder movement resulted in most, if not all, of the loads imposed on the vertical stabilizer.
Because of the lack of understanding of the certification requirements of the vertical stabilizer, the Board asked the FAA to require the manufacturers and operators to ensure that pilot training programs: (1) explain the structural certification requirements for the rudder and vertical stabilizer; (2) explain that a full or nearly full rudder deflection in one direction followed by a full or nearly full rudder deflection in the opposite direction can result in potentially dangerous loads on the vertical stabilizer, and (3) explain that, on some aircraft, as speed increases, the maximum available rudder deflection can be obtained with comparatively light pedal forces and small pedal deflections.
RDU Jetblast
Veteran
I'm ignorant in this matter. I'm not a pilot but I have argued to family and friends that a tail just should not fall off. If I were in that pilot's seat and did not get the expected response from the rudder, I would certainly try pushing harder. If I still got nothing, I would certainly try going the other way.
Again, I'm ignorant here, but could that wake turbulence have been severe vibrations from a tail loosening before coming off? Is this the first guy to rip a tail off in the history of aviation? Help me understand this.
Again, I'm ignorant here, but could that wake turbulence have been severe vibrations from a tail loosening before coming off? Is this the first guy to rip a tail off in the history of aviation? Help me understand this.
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