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Old 20th February 2013 | 16:45
  #51 (permalink)  
PJ2
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Joined: Mar 2003
: ATPL
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From: BC
Dozy, noske;

Concerning the MD83 Stabilizer accident there is a decent NTSB animation of the THS installation here.

I think a reversal of the hinge-point and the jackscrew mechanism arrangements, (hinge point forward, jackscrew aft),would permit a certain weather-cocking as per noske's comments, (or possibly flutter), but I think Dozy is correct in observing that making room for such an arrangement would be challenging, (though not impossible, given some of the variations of airplane designs extant!).

The design, (single jackscrew, aft hinge), is industry-proven as are the outcomes of not following established maintenance schedules and procedures. Frankly I don't think there is much to learn here except the obvious.

Regarding the flight crew there is no direct instruction to attempt to move a jammed stabilizer but nor in the manuals I have for the DC9 & DC8 are there procedures for handling a jammed stabilizer in cruise. Perhaps those flying the MD80 can comment.

David36 mentioned in post #8 the DC10/MD11 as having two jackscrews, I assume as an example of redundancy and mentioned the L1011 as having a "hydraulic" THS. There would be no jackscrew for the THS on the L1011 as the entire stabilizer moved, serving as both "elevators" and a "THS".

Last edited by PJ2; 20th February 2013 at 16:53.
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