# Accident 19980815038059A: Cessna 172, Palmer, AK, August 15, 1998 - Type: FAA accident report (Accident/Incident Data System), as reported - Date: August 15, 1998, 14:15 local time - Place: Palmer, AK - Airport: Palmer Municipal Airport - Damage: Substantial damage - Phase of flight: Forced/Precautionary Landing - Operating rules: General operating rules (Part 91) - Location: 61.6195° N, 148.9791° W: From the FAA, an estimate near the named town, within about 3 miles - Nearby events: https://openairdocs.org/map.md?lat=61.6195&lon=-148.9791&mi=10 - Aircraft: N7966B, registered now (https://openairdocs.org/aircraft/N7966B) (OpenAirDocs) - Registry model: Cessna 172 (registry code 2072402, https://openairdocs.org/model/cessna-172) (OpenAirDocs) - Registry engine: Continental 0-300 series (registry code 17022, https://openairdocs.org/engine/continental-0-300-series) (OpenAirDocs) - Reported make and model: CESSNA 172 - Reported engine: LYC O360A1A - People aboard: 1 - Fatal injuries: 0 - Pilot certificates: Student - Pilot flight hours: 12 total, 9 in this make and model, 9 in the last 90 days - NTSB investigation: [NTSB ANC98LA131](https://openairdocs.org/ntsb/ANC98LA131) (OpenAirDocs) - FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/) - Page: https://openairdocs.org/incident/19980815038059A ## Narrative As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^. (.19) ON AUGUST 15, 1998, ABOUT 1415 ALASKA DAYLIGHT TIME, A WHEEL EQUIPPED CESSNA 172 AIRPLANE, N7966B, SUSTAINED SUBSTANTIAL DAMAGE DURING AN EMERGENCY LANDING AFTER TAKEOFF FROM THE PALMER MUNICIPAL AIRPORT, PALMER, ALASKA. THE AIRPLANE WAS BEING OPERATED AS A VISUAL FLIGHT RULES LOCAL AREA INSTRUCTIONAL FLIGHT UNDER TITLE 14 CFR PART 91 WHEN THE ACCIDENT OCCURRED. THE AIRPLANE IS REGISTERED TO AND OPERATED BY MUSTANG AIR, INC., PALMER. THE SOLO STUDENT PILOT WAS NOT INJURED. VISUAL METEOROLOGICAL CONDITIONS PREVAILED, AND COMPANY FLIGHT FOLLOWING PROCEDURES WERE IN EFFECT. THE FLIGHT ORIGINATED AT THE PALMER MUNICIPAL AIRPORT, ABOUT 1413. DURING A TELEPHONE CONVERSATION WITH THE NATIONAL TRANSPORTATION SAFETY BOARD INVESTIGATOR-IN-CHARGE, ON AUGUST 15, THE STUDENT PILOT REPORTED THAT HE WAS DEPARTING ON RUNWAY 15. HE SAID THAT AS THE AIRPLANE CLIMBED TO ABOUT 600 FEET ABOVE THE RUNWAY, NEAR MIDFIELD, THE ENGINE DEVELOPED A SEVERE VIBRATION FOLLOWED BY A "VERY LOUD BANG." THE PILOT STATED THAT HE MADE AN EMERGENCY LANDING ON A GOLF COURSE AT THE SOUTHEAST END OF THE AIRPORT. DURING THE LANDING ROLL, THE AIRPLANE'S RIGHT WING STRUCK A STAND OF TREES. AFTER THE EMERGENCY LANDING, THE PILOT NOTICED THAT THE ENTIRE PROPELLER, PROPELLER FLANGE AND THE OUTBOARD END OF THE ENGINE CRANKSHAFT WERE MISSING FROM THE ENGINE. THE MISSING PROPELLER COMPONENTS WERE LATER LOCATED NEAR THE MIDPOINT OF THE DEPARTURE RUNWAY. THE AIRPLANE'S RIGHT WING SUSTAINED SUBSTANTIAL DAMAGE. (.4) THE STUDENT PILOT WAS DEPARTING ON RUNWAY 15, ON HIS FIRST SOLO FLIGHT. HE STATED THAT DURING THE INITIAL CLIMB, THE ENGINE DEVELOPED A SEVERE VIBRATION FOLLOWED BY A 'VERY LOUD BANG'. HE MADE A FORCED LANDING ON A GOLF COURSE AT THE SOUTHEAST END OF THE AIRPORT. DURING THE LANDING ROLL, THE AIRPLANE'S RIGHT WING STRUCK A SMALL HILL, AND SUSTAINED SUBSTANTIAL DAMAGE. AFTER LANDING, THE PILOT DISCOVERED THAT THE ENTIRE PROPELLER, PROPELLER FLANGE, AND THE OUTBOARD END OF THE ENGINE CRANKSHAFT WERE MISSING. THEY WERE LATER LOCATED NEAR THE MIDPOINT OF THE DEPARTURE RUNWAY. AN FAA AIRWORTHINESS INSPECTOR'S REVIEW OF THE ENGINE LOG BOOK DISCOVERED THAT THE ACCIDENT ENGINE HAD PREVIOUSLY SUSTAINED TWO PROPELLER STRIKES. HE REPORTED THAT THE LOG BOOK FAILED TO REFLECT ANY INSPECTION FOLLOWING THE PROP STRIKES. AN NTSB METALLURGICAL EXAMINATION OF THE PROPELLER FL ANGE ASSEMBLY REVEALED MULTIPLE CLAMSHELL MARKS, TYPICAL OF FATIGUE CRACKING. THE ENGINE IS THE SUBJECT OF A LYCOMING ENGINE SERVICE LETTER, L163C, THAT RECOMMENDS THAT ANY ENGINE INVOLVED IN A SUDDEN STOPPAGE EVENT BE REMOVED, DISSEMBLED, AND INSPECTED PRIOR TO RETURNING THE ENGINE TO SERVICE. (-23) ON AUGUST 15, 1998, AT APPROXIMATELY 1430 DAYLIGHT TIME, CESSNA 172, AIRCRAFT N766B, MADE A FORCED LANDING ON THE GOLF COURSE PARALLEL TO RUNWAY 15, AFTER DEPARTURE AT PALMER, ALASKA. THE CRANKSHAFT BROKE OFF JUST AHEAD OF THE NOSE CASE AT APPROXIMATELY 600 FEET IN THE AIR, THE PROPELLER/CRANKSHAFT FLANGE LANDED ON THE RUNWAY. AFTER REVIEW OF THE LOG BOOKS, IT WAS DETERMINED THAT IN THE PAST, THE ENGINE HAD A PROP STRIKE AND THE OWNER AT THE TIME, ELECTED NOT TO DISSASSEMBLE AND INSPECT THE CRANKSHAFT AS PER THE MANUFACTURER'S RECOMMENDATIONS. ## The NTSB's investigation of this event (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB ANC98LA131](https://openairdocs.org/ntsb/ANC98LA131), Aug 15, 1998: Cessna 172 (N7966B), Palmer, AK, substantial damage. Probable cause: Fatigue of the forward end of the engine crankshaft resulting in separation of the propeller assembly, and the operator's failure to comply with a required maintenance procedure. A factor was uneven… ## Other reports on N7966B (1) Matched to the same aircraft by N-number and date. - [Accident 19910819034809A](https://openairdocs.org/incident/19910819034809A), Aug 19, 1991: Cessna 172 (N7966B), Montague Island, AK, Substantial damage. Lost control landing on a beach. Nosed over in soft sand. Blamed brakes. No defects found. From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.