Premium On Safety - Issue 15, 2014 - 4

BEST PRACTICES

PIC...

(continued from page 3)

system is powered up might leave the
The Gulfstream IV uses a system of
locks engaged while freeing the throttles.
mechanical gust locks to immobilize
However, standard procedure is to unlock
the flight controls while the airplane is
the controls before starting the engines.
parked. Ailerons and rudder are kept
It's also conceivable that a full-down
neutral, while the elevator is held in
movement of the elevator could re-engage
the full nose-down position. A mechaniits lock in the extremely unlikely event
cal interlock is designed to prevent the
that both return springs break. To avoid
throttles from being advanced more than
these risks, the Aircraft Flight Manual
six percent above ground idle while the
calls for two flight-control checks, one
locks are engaged. The
before taxi and the second at 60 knots
NTSB preliminary report
...FDR data "did not reveal any movement
during the takeoff roll (when the connotes that "the elevator
trols begin sustaining normal air loads).
control surface position
consistent with a flight control check prior
However, the relevant channels of FDR
during the taxi and takeoff
data "did not reveal any movement conwas consistent with its
to the commencement of the takeoff roll."
sistent with a flight control check prior to
position if the gust lock
the commencement of the takeoff roll." If
was engaged." However, "The gust lock
example, whether the fuel truck had the
the 60-knot control check was attempted,
handle, located on the right side of the
flattened "fishtail" nozzle that's supposed
control pedestal, was found in the forward the preliminary doesn't mention it-but
to prevent its use on piston airplanes, or
had it been tried and failed, it's not likely
(OFF) position, and the elevator gust lock
whether the Cessna had the filler port
the crew would have allowed the airplane
latch was found not engaged."
restrictors designed to exclude those
to continue accelerating.
Sources familiar with this model have
nozzles. The system isn't foolproof-the
Between them, the two pilots had
suggested several ways the throttle interinvestigation of the 2009 misfuelling
some 30,000 hours of flight time that
accident discovered that the line crew had lock might have become disengaged withincluded a combined 4,200 in the
out unlocking the flight controls. Indeed,
figured out how to use the wide nozzles
Gulfstream IV. Press reports indicate
in a Maintenance and Operations Letter
to service two JetProp-conversion Malibus
that they'd crewed together for the
issued two weeks after the accident,
that hadn't been retrofitted with corresame employer for more than a decade.
Gulfstream warned that "if proper unlock
spondingly wide filler ports-but it makes
Overlooking something as
the mistake that much harder to overlook,
...the Aircraft Flight Manual calls for
basic as the preflight control
not to mention actually carry out.
check-if that's what actually
By contrast, the cause of the May 31
two flight-control checks, one before
happened-would have been
wreck of a Gulfstream IV at Bedford,
completely out of character,
Massachusetts may prove very difficult
taxi and the second at 60 knots during but it's known to have hapto pin down. The combination of witness
pened to others. Perhaps it's
reports and the record preserved by the
the takeoff roll...
only slightly more unlikely than
flight data recorder does establish some
the pilot of a piston twin talking to the
procedures are not followed, movement
salient facts. The airplane accelerated to
fueller, replacing the caps, and signing
of the throttle to a position capable of
165 knots without lifting off. At the callproviding sufficient engine power for auto- for the sale without noticing that his
out to rotate, the cockpit voice recorder
tanks have just been topped with stuff
throttle engagement and takeoff power
"captured comments concerning aircraft
that will destroy his engines. Time on the
may be possible for GIV models. Throttle
control." Thrust reversers were deployed
ground isn't automatically rest. Pilot-inmovement is not an absolute indicator of
and the brakes were applied, but the
command responsibility extends to every
the gust lock status for any Gulfstream
airplane was still travelling at more than
model. The freedom of flight control move- minute that pilot spends with the aircraft.
100 knots when it went off the end
ment is the ultimate indicator the gust
of the 7,011-foot runway, through the
David Jack Kenny is the Air Safety
lock is fully released..."
approach lighting and localizer antenna,
Institute's statistician. He is a fixed-wing
The interlock is controlled solely by
and into a gully. Again, a post-crash fire
ATP with private pilot privileges for heliconsumed most of the aircraft, and there the position of the gust lock control
copters and the owner of a Piper Arrow.
handle. Unlocking it after the hydraulic
were no survivors.
seem to have offered a good chance to
notice the characteristic smell of jet fuel
(though to be fair that smell tends to wash
around lots of airports in any case). And
actually reading the ticket he signed would
have brought the mistake to light in time to
avoid ever starting the engines.
As of this writing, key details remain
unknown. The NTSB has not disclosed, for

Premium On Safety - Issue 15, 2014

Table of Contents for the Digital Edition of Premium On Safety - Issue 15, 2014