[NSRCA-discussion] 747 Snap Entry?

[Martin X. Moleski, SJ]

Gerald Gallagher wrote:

> I was a pilot with TWA & knew the captain that is accused of this, also a
> TWA Pilot. To this day he denies this ever happened & so do the 2 other crew
> members that were flying that 727. The loss of altitude was, according to
> the three crewmembers aboard was clear air turbulence. I believe the pilot,
> but I am prejudiced. 

The pilot in question was Harvey "Hoot" Gibson (not the astronaut
with the same nickname).

There isn't anything in the NTSB report about "clear air turbulence."
The crew claimed that the extension of the leading edge flap #7
was a mechanical failure.  The NTSB found no evidence of that,
although they did note seven failures like that in their report.
Everybody agrees that it was the asymmetrical extension of the
#7 flap that caused the roll to the right; they disagree about
how it got that way.

Crew: it just happened.

NTSB: the crew was trying to extend the flaps 2 degrees to improve
cruise performance; the leading-edge slats dropped; when the pilot
tried to retract them, the #7 slat hung up and caused the rest of
the troubles.

"It has been reported that the older 727 Captains would pop the circuit breaker 
for the leading edge slats and drop the flaps 2 degrees.  In the 727 the flaps 
extend rearward and do not start to drop down at flaps 2 degrees.  This 
increases the wing area with no added drag letting the pilot cruise higher by a 
couple thousand feet.  This was believed to save on fuel while adding a few 
precious knots to the cruise speed."
<http://fromtheflightdeck.com/Reviews/727/TWA727/>

The report also criticizes the pilot for erasing the cockpit voice
recorder.  21 minutes of the 30-minute tape were blank.  The last
9 minutes of taxiing were recorded with perfect fidelity.

http://amelia.db.erau.edu/reports/ntsb/aar/AAR81-08.pdf

"We believe the captain's erasure of the CVR is a factor we cannot ignore and
cannot sanction. Although we recognize that habits can cause actions not desired
or intended by the actor, we have difficulty accepting the fact that the
captain's putative habit of routinely erasing the CVR after each flight was not
restrainable after a flight in which disaster was only narrowly averted. Our
skepticism persists even though the CVR would not have contained any
contemporaneous information about the events that immediately preceded the loss
of control because we believe it probable that the 25 minutes or more of
recording which preceded the landing at Detroit could have provided clues about
causal factors and might have served to refresh the flightcrew's memories about
the whole matter."

						Marty