Amateur-built CH701 accident near Bothell, Washington, July 20, 2022
On July 20, 2022 at about 5:00 am local time, a 2011 amateur-built CH701, registered N8787G, was substantially damaged in an accident during enroute near Bothell, Washington (Snohomish County (Paine Fld) airport). It was a personal flight under general aviation rules (Part 91). 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power due to the fatigue failure of the engine’s flywheel screws that were likely overloaded when the engine was involved in a previous accident.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 20, 2022 · about 5:00 am local time
- Place
- Bothell, Washington · Snohomish County (Paine Fld) · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built CH701, built 2011
- Registration
- N8787G · no longer on the register · serial 7-6684
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported the takeoff and en route portions of the flight were uneventful. While descending to the traffic pattern altitude at the destination airport, the engine lost power and the propeller stopped. The pilot made an emergency landing on a vacant road, colliding with powerlines. A postaccident examination of the engine revealed that the flywheel screws had separated due to fatigue, resulting in an engine failure. Examination of the screws showed multiple fatigue cracks and wear consistent with low-stress bending fatigue. Maintenance records revealed that the engine had been installed in another airplane that was involved in an accident where the propeller was damaged. According to the engine manufacturer, abrupt propeller stoppage can produce a spike of torque along the crankshaft, overloading the flywheel screws and causing failure. There was no evidence that the screws were replaced after that accident.
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 defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip engine power section › Fatigue/wear/corrosion
Pilot
- Certificate: commercial pilot, private
- Ratings: single-engine land; instrument: airplane
- Flight time: 377 hours in all; 27 in this make and model; 116 in the last 90 days; 37 in the last 30 days; 172 as pilot in command
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 70.5 hours
- Last inspection: condition inspection, June 20, 2022
- Maximum gross weight: 1,100 lb
- Seats: 2
- Landing gear: fixed
- Engine: Jabiru 3300A (piston); 0 hours total
The flight
- Departed from: TIW Tacoma WA at 4:10 am
- Destination: PAE Everett WA
- Flight plan: none
- Runway 34R, 9,010 ft by 150 ft
Weather at the time
- Light: night
- Wind: from 350° at 6 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 63°F (17°C), dew point 52°F (11°C)
- Altimeter: 30.05 inHg
- Observation at 9:53 pm from KPAE, 9 miles away
Weather report (METAR): KPAE 200453Z AUTO 35006KT 10SM CLR 17/11 A3005 RMK AO2 SLP174 T01670111
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
6 documents, released by the NTSB on July 17, 2024. 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 | Materials Laboratory Factual Report 24-020 | PDF, 10 pages | View Download |
| 3 | Investigative Supplemental Material (Master) | PDF, 10 pages | View Download |
| 4 | Engine Examination | PDF, 9 pages | View Download |
| 5 | Engine Service Bulletin | PDF, 12 pages | View Download |
| 6 | Release of Wreckage | PDF, 1 page | 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.