Cessna 172G accident near Washington, California, June 2, 2021
On June 2, 2021 at about 3:00 pm local time, a 1965 Cessna 172G, registered N3871L, was substantially damaged in an accident during enroute (cruise) near Washington, California. It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were 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 during an enroute climb due to a stuck exhaust valve and multiple failed piston compression rings.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 2, 2021 · about 3:00 pm local time
- Place
- Washington, California · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172G, built 1965 · all 172Gs on the register
- Registration
- N3871L · no longer on the register · serial 17254040
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that he was climbing the airplane at full engine power and an airspeed of 80 mph, and he had progressively leaned the fuel/air mixture during the climb. About 6,000 ft mean sea level (msl), he noted that the the engine oil temperature was indicating its maximum limit of 240°F. The pilot lowered the nose to increase airspeed and reduced engine power to cool the engine. About 10 minutes later, the engine oil temperature decreased below redline and he resumed his climb with a slightly richer mixture setting. About 8,500 ft msl, the engine produced a “backfire” sound, the engine rpm decreased, and a loss of engine power ensued. The pilot declared an emergency and performed a forced landing to mountainous terrain, during which the airplane sustained substantial damage. Examination of the engine revealed that the No. 2 cylinder’s piston exhibited a stuck top compression ring. The No. 3 cylinder exhibited a stuck exhaust valve, and the No. 3 piston’s top compression ring had separated into two. The No. 5 intake valve exhibited excessive clearance within its guide. The No. 6 cylinder’s piston top compression ring had separated into four pieces. A review of the airframe and engine maintenance logbooks indicated that the last annual inspection was completed 6 months before the accident. At the time of the annual inspection, the engine had amassed a total time of 4,027 hours, and 1,896 hours since major overhaul. The engine tachometer indicated 2,277 hours during the last annual inspection and indicated 2,288.8 at the time of the accident. The engine-manufacturer recommended overhaul interval is 1,800 hours or 12 years, whichever occurs first.
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
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Malfunction
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 7,000 hours in all; 3,000 in this make and model; 5.8 in the last 90 days; 3.4 in the last 30 days; 6,000 as pilot in command; 4,000 on instruments
- Last flight review: March 4, 2020
- Medical certificate: BasicMed
- Seat: left
- Injury: no injuries
Passenger
- Seat: rear
- Injury: no injuries
The aircraft
- Airframe total time: 3,981.8 hours
- Last inspection: annual inspection, December 6, 2020; 11.8 hours since
- Maximum gross weight: 2,300 lb
- Seats: 4
- Landing gear: fixed
- Engine: Continental O-300-D (piston); 4,027 hours total
The flight
- Departed from: O52 Yuba City CA at 2:20 pm
- Destination: RNO Reno NV
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 270° at 3 knots
- Visibility: 10 statute miles
- Temperature: 79°F (26°C), dew point 41°F (5°C)
- Altimeter: 30.18 inHg
- Observation at 9:52 am from KBLU, 8 miles away
Weather report (METAR): KBLU 021652Z AUTO 27003KT 10SM CLR 26/05 A3018 RMK AO2 SLP105 T02560050 $
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
10 documents, released by the NTSB on June 14, 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, 9 pages | View Download |
| 2 | Record of Conversation -pilot and FAA Email | PDF, 2 pages | View Download |
| 3 | Annual Inspection -airframe | PDF, 2 pages | View Download |
| 4 | Annual Inspection -engine | PDF, 1 page | View Download |
| 5 | Continental Service Interval -time Between Overhaul | PDF, 1 page | View Download |
| 6 | N3871L Airframe and Engine Examination Report | PDF, 11 pages | View Download |
| 7 | Engine Manufacture Type Certificate | PDF, 1 page | View Download |
| 8 | Photographs | PDF, 5 pages | View Download |
| 9 | Wreckage Release Form | PDF, 1 page | View Download |
| 10 | Certification of Party Representative | 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.
Other NTSB records under N3871L 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.