NTSB Identification: DEN89FA155.
The docket is stored on NTSB microfiche number 40323.
Accident occurred Tuesday, July 04, 1989 in MINOT, ND
Probable Cause Approval Date: 06/18/1990
Aircraft: PIPER PA-16, registration: N5295H
Injuries: 1 Serious,1 Minor.

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.

AS THE PLT TURNED ON FINAL APCH TO LND, HE HEARD A 'THUD,' THEN THE ACFT ENTERED AN UNCONTROLLED LEFT TURN. AFTER TURNING ABOUT 360 DEG, IT IMPACTED THE GROUND IN A LEFT WING LOW, NOSE LOW ATTITUDE. AN INVESTIGATION REVEALED A FAILUREOF THE AIRFRAME TUBING AT THE LOWER FORWARD DOOR FRAME. THE FAILURE WAS IN THE AREA OF A CONGLOMERATE WELD WHERE THE TUBING WAS PART OF THE DOOR FRAME, FIRE WALL/ENGINE MOUNT, & RIGHT FORWARD LIFT STRUT SUPPORT. AN EXAM REVEALED THE TUBING HAD SEPARATED PRIOR TO IMPACT. APRX 3/4 OF THE FRACTURE WAS THE RESULT OF CORROSION; THE REMAINING FRACTURE WAS FROM OVERLOAD, BUT NOT DUE TO IMPACT. WITH THIS FAILURE, THE LEADING EDGE OF THE RIGHT WING WOULD TWIST UPWARD & THE ENGINE (WITH POWER) WOULD MOVE UP & TO THE LEFT. PIPER SERVICE BULLETING #819, SUBJECT: FUSELAGE DOOR FRAME TUBE CORROSION, DATED 2/28/86, ADDRESSED THE HAZARD OF CORROSION IN THIS AREA.

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

FAILURE OF THE AIRFRAME TUBING (LONGERON) AT THE LOWER FORWARD DOOR FRAME DUE TO CORROSION. A CONTRIBUTING FACTOR WAS FAILURE OF MAINTENANCE PERSONNEL TO COMPLY WITH SERVICE BULLETIN #819.

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