Piper PA-28-140 accident near Yacolt, Washington, March 29, 2021
On March 29, 2021 at about 10:47 pm local time, a 1971 Piper PA-28-140, registered N665FL, was substantially damaged in an accident during enroute (cruise) near Yacolt, Washington. It was a personal flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A partial loss of power caused by carbon build up in the cylinders, which prevented the exhaust valves from seating properly. Contributing to the accident was flying in moderate icing conditions which resulted in reduced aircraft performance and vibrations.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 29, 2021 · about 10:47 pm local time
- Place
- Yacolt, Washington · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-28-140, built 1971 · all PA-28-140s on the register
- Registration
- N665FL · no longer on the register · serial 28-7125587
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The airplane was the subject of a Federal Aviation Administration Alert Notification (ALNOT) when the pilot reported a rough running engine and then radio contact was lost with the airplane. A few hours later, the airplane’s wreckage was located by Navy search and rescue in heavily forested terrain. The pilot reported that while in cruise flight at 8,000 ft mean sea level (msl), and in instrument meteorological conditions (IMC), he felt a vibration in the airplane and thought it was from airframe icing, however he soon realized that the engine was running rough. He applied carburetor heat and requested a lower altitude. However, the engine seemed to run worse and lose power, so the pilot requested vectors to the nearest airport. While being vectored and after exiting IMC, he elected to make a forced landing in a nearby clearing. While the pilot reported no airframe icing, a review of weather conditions in the area and a sounding model performed over the accident site revealed that the freezing level was about 3,227 ft mean sea level (msl) and supported broken to overcast clouds from about 3,000 ft to 8,000 ft msl and icing in the clouds. Additionally, AIRMET Zulu was current over the area for occasional moderate icing conditions from the freezing level, estimated at 3,000 ft, to 12,000 ft msl. It is likely that airplane experienced moderate icing conditions that contributed to the decrease in the airplane’s performance and some of the vibrations felt by the pilot. Postaccident examination of the engine revealed that during manual rotation, thumb compression was not obtained on the Nos. 1 and 3 cylinders. Borescope examination of the cylinder’s interior revealed carbon deposits lodged in the area where the exhaust valve seats, preventing proper sealing.
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 (partial) during enroute (cruise) defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Damaged/degraded
- Environmental issues › Conditions/weather/phenomena › Temp/humidity/pressure › Conducive to structural icing › Effect on equipment
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot, flight engineer
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 19,427 hours in all; 498 in this make and model; 11 in the last 90 days; 7 in the last 30 days; 13,831 as pilot in command; 2,497 on instruments
- Last flight review: March 20, 2020
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: minor injuries
Pilot-Rated Passenger
- Certificate: private
- Ratings: single-engine land
- Seat: rgt
- Injury: minor injuries
The aircraft
- Airframe total time: 3,842 hours
- Last inspection: annual inspection, September 2, 2020
- Maximum gross weight: 2,200 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-360-A1A (piston); 0 hours total
- Operator: Treetop Flyers LLC
The flight
- Departed from: BDN Bend OR at 2:10 pm
- Destination: TIW Tacoma WA
- Flight plan: IFR
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 350° at 3 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 3,500 ft
- Temperature: 57°F (14°C), dew point 45°F (7°C)
- Altimeter: 30.09 inHg
- Observation at 3:53 pm from KPDX, 21 miles away
Weather report (METAR): METAR KPDX 292253Z 35003KT 10SM BKN035 14/07 A3009 RMK AO2 SLP189 T01440072
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
4 documents, released by the NTSB on January 26, 2023. 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, 11 pages | View Download |
| 2 | Weather Information | PDF, 8 pages | View Download |
| 3 | Engine Examination Summary | PDF, 4 pages | View Download |
| 4 | Release of Aircraft Wreckage, NTSB Form 6120.15 | 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.