Cessna 207 accident near Iliamna, Alaska, August 7, 2018
On August 7, 2018 at about 8:15 pm local time, a 1978 Cessna 207, registered N7379U, was substantially damaged in an accident during initial climb near Iliamna, Alaska (Iliamna Airport). It was flown under charter and air-taxi rules (Part 135). 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
A total loss of engine power due to detonation/preignition damage of the No. 2 cylinder and piston for reasons that could not be determined.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 7, 2018 · about 8:15 pm local time
- Place
- Iliamna, Alaska · Iliamna Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 207, built 1978 · all 207s on the register
- Registration
- N7379U · registry record · serial 20700427
- Damage
- Substantial damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that shortly after takeoff, as he began to configure the airplane for cruise flight, the engine began to run rough and lose power, and he elected to immediately return to the airport. The engine subsequently lost total power and the pilot performed a forced landing on tundra-covered terrain, during which the airplane sustained substantial damage. Examination revealed that the No. 2 piston was eroded on the bottom side, and a hole was burned through. The No. 2 piston and cylinder head were mechanically damaged by loose piston ring debris. Closer examination of the No. 2 cylinder head revealed re-solidified molten metal around the bottom Heli-Coil tang notch. All damage discovered was consistent with a pre-ignition/detonation event; however, the cause of the pre-ignition and/or detonation could not be determined based on the available information.
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 emergency descent
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
- Loss of engine power (total) during initial climb defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Damaged/degraded
- Aircraft › Aircraft power plant › (general) › (general) › Failure
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane single-engine; instrument: airplane
- Flight time: 10,000 hours in all
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 18,642.1 hours
- Last inspection: 100-hour inspection; 51.2 hours since
- Maximum gross weight: 3,803 lb
- Landing gear: fixed
- Engine: Continental IO 520 SERIES (piston); 101,269 hours total
- Operator: Iliamna Air Taxi Inc
The flight
- Destination: 9K2 Kokhanok AK
Weather at the time
- Light: daylight
- Wind: from 320° at 10 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 6,500 ft; a few clouds at 3,400 ft
- Temperature: 55°F (13°C), dew point 0°F (-18°C)
- Altimeter: 29.75 inHg
- Observation at 2:53 pm from IlI, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on March 16, 2022. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | Airframe and Engine Examination | PDF, 8 pages | View Download |
| 3 | Continental Motors Engine Examination Report | PDF, 12 pages | View Download |
| 4 | Statement of Party Representatives to NTSB Investigation | PDF, 1 page | View Download |
| 5 | Photos (Courtesy of FAA) | PDF, 3 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.