NTSB Probable Cause Report Released For September, 2008
Accident
The NTSB has released its probable
cause report in the crash of a Convair CV-580 which killed the
pilot and two others on board. The accident occurred on September
1st of last year. The 57-year-old pilot had over 16 thousand hours,
and held Airline Transport, Multi-engine Land, and Single-engine
Land ratings. The NTSB determined cross-connected elevator trim
cables following maintenance of the aircraft caused the
accident.
The report concludes:
The accident flight was the first flight following maintenance that
included flight control cable rigging. The flight was also intended
to provide cockpit familiarization for the first officer and the
pilot observer, and as a training flight for the first officer.
About one minute after takeoff, the first officer contacted the
tower and stated that they needed to return to land. The airplane
impacted a cornfield about one mile southwest of the approach end
of the runway, and 2 minutes 40 seconds after the initiation of the
takeoff roll.
The cockpit voice recorder (CVR) indicated that, during the
flight, neither the captain nor the first officer called for the
landing gear to be raised, the flaps to be retracted, or the power
levers to be reduced from full power. From the time the first
officer called "rotate" until the impact, the captain repeated the
word "pull" about 27 times. When the observer pilot asked, "Come
back on the trim?" the captain responded, "There's nothing anymore
on the trim."
The inspection of the airplane revealed that the elevator trim
cables were rigged improperly, which resulted in the trim cables
being reversed. As a result, when the pilot applied nose-up trim,
the elevator trim system actually applied nose-down trim.
An examination of the maintenance instruction cards used to
conduct the last inspection revealed that the inspector's block on
numerous checks were not signed off by the Required Inspection Item
(RII) inspector. The RII inspector did not sign the item that
stated: "Connect elevator servo trim tab cables and rig in
accordance with Allison Convair [maintenance manual]...” The
item had been signed off by the mechanic, but not by the RII
inspector.
File Photo
The card also contained a NOTE, which stated in bold type, "A
complete inspection of all elevator controls must be accomplished
and signed off by an RII qualified inspector and a logbook entry
made to this effect." The RII inspector block was not signed
off.
The National Transportation Safety Board determines the probable
cause(s) of this accident as follows:
The improper (reverse) rigging of the elevator trim cables by
company maintenance personnel, and their subsequent failure to
discover the misrigging during required post-maintenance checks.
Contributing to the accident was the captain’s inadequate
post-maintenance preflight check.