Piper PA-18 accident near Fairbanks, Alaska, August 30, 2019
On August 30, 2019 at about 9:10 pm local time, a 1955 Piper PA-18, registered N1124, was substantially damaged in an accident during enroute (cruise) near Fairbanks, Alaska. It was a personal 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
The inappropriate application of paint underneath the engine cylinder hold-down nuts, which resulted in inadequate torque and the subsequent in-flight separation of the No. 3 cylinder, and resulted in a total loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 30, 2019 · about 9:10 pm local time
- Place
- Fairbanks, Alaska · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-18, built 1955 · all PA-18s on the register
- Registration
- N1124 · registry record · serial 18-3985
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The commercial pilot reported that while in cruise flight in her float-equipped airplane, the engine began to sound "funny," so she elected to return to her destination airport rather than selecting a suitable nearby lake for landing. About 16 minutes later, the engine lost all power and she conducted an emergency landing to a heavily forested area. The airplane sustained substantial damage to the wings. Examination of the engine revealed that the No. 3 cylinder had separated from the engine's case, but the two No. 3 cylinder hold-down studs were intact and the studs’ threads were in relatively good condition; the other cylinder studs were fractured with fretting present on the engine's case. In addition, paint was chipped and broken around the cylinder hold-down nuts and paint was present inside the cylinder stud holes located on the cylinder's flange. The Lycoming overhaul manual states that "All machined bosses should be masked before painting. Do not paint areas under hold-down nuts where torque is required." Due to the presence of paint inside the cylinder stud holes and broken and chipped paint around the hold-down nuts, it is likely that paint was applied inappropriately under the cylinder hold-down nuts, which would have led to an inaccurate torque reading during assembly, which allowed them to back off over time, resulting in overload failure of the other nuts and separation of the No. 3 cylinder.
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
What happened, in order
- Loss of engine power (total) during enroute (cruise) defining event
- Aircraft maintenance event during prior to flight
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- Personnel issues › Task performance › Maintenance › Replacement › Maintenance personnel
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Incorrect service/maintenance
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; single-engine sea; instrument: airplane
- Flight time: 4,858 hours in all; 586 in this make and model; 73 in the last 90 days; 58 in the last 30 days; 4,717 as pilot in command
- Last flight review: October 6, 2018
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: frt
- Injury: no injuries
The aircraft
- Airframe total time: 3,984.4 hours
- Last inspection: annual inspection, September 11, 2018
- Maximum gross weight: 1,760 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-320 A1H (piston); 3,637 hours total
The flight
- Departed from: Fairbanks AK
- Destination: Fairbanks AK
- Flight plan: VFR
Weather at the time
- Light: daylight
- Wind: from 020° at 4 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 6,000 ft
- Temperature: 63°F (17°C), dew point 43°F (6°C)
- Altimeter: 30.04 inHg
- Observation at 9:53 pm from PAFA
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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.
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.