Cessna 172 accident near Palmer, Alaska, August 15, 1998
On August 15, 1998 at about 10:15 pm local time, a Cessna 172, registered N7966B, was substantially damaged in an accident near Palmer, Alaska (Palmer Municipal Airport). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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 terrain.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 15, 1998 · about 10:15 pm local time
- Place
- Palmer, Alaska · Palmer Municipal Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172 · all 172s on the register
- Registration
- N7966B · registry record · serial 29766
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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 forward 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 flange 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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: student
- Flight time: 12 hours in all; 9 in this make and model
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 5,645 hours
- Last inspection: 100-hour inspection, February 25, 1998; 58 hours since
- Maximum gross weight: 2,200 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-360-A1A (piston); 0 hours total
The flight
- Departed from: PAQ at 5:15 pm
- Flight plan: none
- Runway 15, 6,000 ft by 100 ft
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 64°F (18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N7966B the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.