NTSB Identification: FTW85FA131.
The docket is stored on NTSB microfiche number 28022.
Accident occurred Sunday, March 03, 1985 in STIGLER, OK
Aircraft: PIPER PA-34-220T, registration: N8160K
Injuries: 4 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.

THE PLT FILED A VFR FLT PLAN AFTER THE WX IMPROVED FROM IFR TO VFR WITH A CHANCE OF THUNDERSTORMS EN ROUTE. OCNL MOD TURBULENCE BELOW 5000 FT WAS FORCAST DUE TO STRONG/GUSTY LOW LVL WNDS. WHILE THE ACFT WAS EN ROUTE, A GND WITNESS HEARD THE ENGS REV UP MORE THAN NORMAL, THEN HE SAW THE ACFT ON A NORTHERLY HEADING. SHORTLY THEREAFTER, HE HEARD A LOUD NOISE& SAW 2 OR MORE PIECES SEPARATE FROM THE ACFT. IT THEN ENTERED AN UNCONTROLLED DSCNT & CRASHED. THERE WAS EVIDENCE THAT THE ACFT SUFFERED AN IN-FLT SEPARATION OF THE FIBERGLASS NOSE ASSEMBLY, THAT PORTIONS OF THE SEPARATED NOSE STRUCK THE STABILATOR & THAT A DAMAGED AREA ON THE RT STABILATOR ACTED AS A TRIM TAB & CAUSED A PITCH-UP OF SUFFICIENT MAGNITUDE TOCAUSE POSITIVE BENDING IN THE WINGS. THE LOADING ON THE STABILATORS CAUSED THEM TO FAIL IN NEG BENDING. THE ACFT THEN ENTERED A DESCENDING COUNTER-CLOCKWISE SPIN WHICH CONTINUED UNTIL GROUND IMPACT OCCURRED. PARTS OF THE ACFT & ITS CONTENTS SEPARATED & DESCENDED IN SCATTERED FRAGMENTS.

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

FUSELAGE,CARGO COMPARTMENT..DISINTEGRATED

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

FLIGHT CONTROL,STABILATOR..FAILURE,TOTAL

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

WING,SPAR..FAILURE,PARTIAL

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

DESIGN STRESS LIMITS OF AIRCRAFT..EXCEEDED

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

DESIGN STRESS LIMITS OF AIRCRAFT..EXCEEDED

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

DESIGN STRESS LIMITS OF AIRCRAFT..EXCEEDED


Contributing Factors

EMERGENCY PROCEDURE..NOT POSSIBLE..PILOT IN COMMAND

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