NTSB Identification: DEN84LA153.
The docket is stored on NTSB microfiche number 24499.
Accident occurred Friday, May 18, 1984 in WIGGINS, CO
Aircraft: GRUMMAN G-164A, registration: N9822
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

WHILE EN ROUTE TO A FIELD FOR AERIAL APPLICATION, AN OIL MIST APPEARED ON THE WINDSHIELD OF THE ACFT. SHORTLY AFTER THAT, THE ENG PROGRESSIVELY LOST POWER & THE PLT MADE A FORCED LANDING IN A PASTURE. DURING THE LANDING ROLL, THE ACFT HIT A HOLE IN THE GROUND & NOSED OVER. AN EXAM OF THE ENG REVEALED THAT THE EXHAUST ROCKER BOX ON THE #1 CYLINDER HAD CRACKED & SEPARATED WHERE THE OIL LINES WERE ATTACHED. THERE WERE 2 PRATT & WHITNEY SERVICE BULLETINS CONCERNING R-1340-AN1 CYLINDERS THAT WERE NOT COMPLIED WITH. SB-1720 RECOMMENDED AN INSPECTION OF THE CYLINDER HEADS DURING OVERHAUL. SB-1743 CALLED FOR REPLACEMENT OF ALL CYLINDERS WITH IMPROVED CYLINDERS HAVING A 5/8 INCH REENFORCEMENT WEB ON THE EXHAUST ROCKER BOX. THE OLD CYLINDERS HAD 1/2 INCH WEB. THE ACFT HAD FLOWN 360 HRS SINCE THE LAST MAJOR OVERHAUL.

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

ENGINE ASSEMBLY,CYLINDER..FATIGUE


Contributing Factors

TERRAIN CONDITION..ROUGH/UNEVEN


Contributing Factors

MAINTENANCE,SERVICE BULLETIN/LETTER..NOT FOLLOWED..OTHER MAINTENANCE PERSONNEL

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