Control disagreement causes excessive G-forces | FerrariChat

Control disagreement causes excessive G-forces

Discussion in 'Aviation Chat' started by CarterHendricks, Jun 16, 2016.

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  1. CarterHendricks

    CarterHendricks Rookie

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    #1 CarterHendricks, Jun 16, 2016
    I found this long update in yesterday's Aviation Herald fascinating:

    Accident: Virgin Australia AT72 near Sydney on Feb 20th 2014, control disagreement causing excessive G-forces injures cabin crew and pitch controls disconnect

    "The ATSB reported the initial examination results as: the first officer used pitch trim to bring the nose up, however, the airspeed increased again and both first officer and captain pulled the yoke. When the vertical load increased through +1.8G the first officer began to push the yoke, the differential forces applied to the left and right yoke were sufficient to generate the pitch disconnect.

    The ATSB reported: "The aircraft manufacturer inspected the aircraft and found broken carbon plies, cracked joint sealant, and deformation in and around the area where the horizontal stabiliser attaches to the vertical stabiliser (Figures 2 and 3). There was also some minor damage to the rudder. The damage was assessed as being consistent with an overstress condition. Subject to further assessment and non-destructive testing, the aircraft manufacturer recommended replacement of the horizontal stabiliser, elevators, and vertical stabiliser."

    On Jun 15th 2016 the ATSB released another interim report indicating they became seriously concerned that an untimely disconnect between left and right hand controls might create substantial damage before the crew is able to react. The interim report therefore releases a first finding (emphasis by ATSB):

    Inadvertent application of opposing pitch control inputs by flight crew can activate the pitch uncoupling mechanism which, in certain high-energy situations, can result in catastrophic damage to the aircraft structure before crews are able to react. [Safety issue]"
     
  2. tazandjan

    tazandjan Three Time F1 World Champ
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    #2 tazandjan, Jun 17, 2016
    Whatever happened to the old shake the stick and saying "you have the airplane"? Fighting each other for control with one pulling and one pushing has to be rough on the aircraft. Sounds like a real lack of crew coordination. You sometimes hear of a student pilot freezing the controls and causing problems, but that should not happen with two pros flying the aircraft.
     
  3. RWP137

    RWP137 Formula 3

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    #3 RWP137, Jun 17, 2016
    That looks like it was a few flights away from a total disaster.
     
  4. Hannibal308

    Hannibal308 F1 Veteran
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    #4 Hannibal308, Jun 23, 2016
    Basically, a total cluster f in crew coordination caused them to break the plane...nice work!
     
  5. Wade

    Wade Three Time F1 World Champ
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    #5 Wade, Jun 23, 2016
    I recall a similar incident years ago from the TAC Attack magazine; T-38, student pilot up front, loss of cockpit communication during loss of aircraft control, both pilots fighting over the stick inputs (unaware of the other), ejection sequence initiated, loss of aircraft.
     
  6. Hannibal308

    Hannibal308 F1 Veteran
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    #6 Hannibal308, Jun 23, 2016
    I would love to see that MIB report. T-38 student pilots are way far along in their training and positive transfer of aircraft control under lost comm is briefed for every flight (mandatory) and is, in fact, practiced routinely throughout pilot training with IPs regularly "taking" the jet by a small (or sometimes large) shake of the stick when ATC or someone else is yapping too much to allow anyone to hear the words "I have the aircraft." It happens so often that it's basically operant conditioning. That mishap, if in the sixties maybe, could have been a genesis for our current procedures, which is why it's interesting to me.

    It could have been a perfect storm moment...ATC yapping, heavyweight no flap landing at the beginning of the flight, Saudi student up front, inexperienced IP in the pit, and behind the power curve in the transition from short final to flare...
     

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