NTSB Identification: DEN93FA099.
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Accident occurred Friday, August 06, 1993 in DELIGHT, AR
Probable Cause Approval Date: 06/22/1994
Aircraft: PIPER PA-32-300, registration: N479KC
Injuries: 6 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

AFTER BEING CLEARED FOR THE LOCALIZER APPROACH TO THE TEXARKANA AIRPORT, THE PILOT CANCELLED HIS IFR FLIGHT PLAN, AND SAID HE WOULD PROCEED VFR TO NASHVILLE, AR. SHORTLY THEREAFTER, THE PILOT REPORTED HE WAS IN THE CLOUDS AND THAT HE HAD LOST HIS VACUUM, THE TURN COORDINATOR DID NOT WORK, AND HE WAS ON THE VERGE OF VERTIGO. THE CONTROLLER ATTEMPTED TO VECTOR THE PILOT BACK TO TEXARKANA, BUT NOTED HE WAS HAVING DIFFICULTY HOLDING A HEADING. THE AIRPLANE BROKE UP IN FLIGHT. THE LEFT WING SPAR WAS FOUND TWISTED UP AND AFT, THE RIGHT WING SPAR WAS BENT SLIGHTLY DOWN AND AFT, AND THE VERTICAL STABILIZER SPAR WAS BENT AFT. LABORATORY EXAMINATION OF THE VACUUM PUMP REVEALED THE DRIVE SHAFT HAD SHEARED IN TORSION, THE ROTOR HAD BROKEN IN OVERSTRESS, AND THE VANES WERE WORN. IT COULD NOT BE DETERMINED IF THE INOPERATIVE TURN COORDINATOR, WHICH HAD AN ELECTRICAL IMPEDANCE OF 10,000 OHMS, HAD FAILED PRIOR TO OR ON THE ACCIDENT FLIGHT.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

THE FAILURE OF THE VACUUM PUMP, AND AN INOPERATIVE TURN COORDINATOR. FACTORS WHICH CONTRIBUTED TO THE ACCIDENT WERE: THE PILOT'S LOSS OF CONTROL OF THE AIRPLANE AS A RESULT OF SPATIAL DISORIENTATION, THE PILOT EXCEEDING THE DESIGN STRESS LIMITS OF THE AIRPLANE, AND THE WEATHER CONDITIONS (CLOUDS).

Full narrative available

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