Prop falls off Cessna 172

Discussion in 'OFF-Topic / Misc.' started by beaupower32, Feb 3, 2012.

  1. beaupower32

    beaupower32 Well-Known Member

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  2. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    I saw this the other day. More than likely several of the prop bolts failed. You're supposed to NDI them everytime the prop comes off and they should be replacd at prop overhaul. 172B, hmmmm........
     
  3. beaupower32

    beaupower32 Well-Known Member

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    Looks like the bolts sheared clean off I would probably replace every time the prop came off. But then again I dont know much about Cessna Maintenance.
     
  4. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    The MM calls for NDI only at removal, replacement at overhaul. Those bolts are pretty pricey. There is always a tendency to over torque them, so this would be an end result.
     
  5. beaupower32

    beaupower32 Well-Known Member

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    Intresting.
     
  6. ccheese

    ccheese Member In Perpetuity
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    I would tend to agree with Joe... Over torquing them was probably the problem.

    Or.... maybe they were all put on finger tight and not torqued at all !

    Only the NTSB knows for sure....

    Charles
     
  7. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    That happened in Mexico - I wonder if their aviation authority was even notified.

    Under torque would also cause them to fail. If I remember correctly the bolts go into a backing plate then are safety wired at the hub along the bolt head. I believe another configuration uses self locking nuts.
     
  8. vikingBerserker

    vikingBerserker Well-Known Member

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    Wow, that was impressive!
     
  9. evangilder

    evangilder "Shooter"
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    Someone in the aircraft had an angel on their shoulder.
     
  10. bobbysocks

    bobbysocks Well-Known Member

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    bet you it shook like a mother right before that prop flew off!!!
     
  11. GrauGeist

    GrauGeist Well-Known Member

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    It'll be interesting to see what the cause was, but I'm going to make a guess here that the bolts were over-torqued and failed.

    Had they been loose, there may have been warning signs, such as excessive vibration (and possibly chatter) as well as visible signs of imminent failure (the dust...look for the dust) whereas over-torqued hardware can fail (but not always) internally (where the shoulder meets the threads) and be overlooked during a visual inspection.

    Either way, that pilot did a great job keeping his head during the whole ordeal
     
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