Cessna TU206 accident near Twentynine Palms, California, November 21, 2020
On November 21, 2020 at about 8:50 pm local time, a 1978 Cessna TU206, registered N878AH, was substantially damaged in an accident during takeoff near Twentynine Palms, California (29 Palms Airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 6 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot’s decision to takeoff with a known mechanical engine anomaly, and the failure of the No. 2-cylinder exhaust valve, which resulted in a total loss of engine power during the initial climb and subsequent impact with terrain.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 21, 2020 · about 8:50 pm local time
- Place
- Twentynine Palms, California · 29 Palms Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 6 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna TU206 G, built 1978 · all TU206s on the register
- Registration
- N878AH · no longer on the register · serial U20604570
- 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 during the first cross-country flight after an annual inspection, he experienced a rough running engine. He noted that when the engine roughness began, the airplane’s airspeed decreased by 23 knots, and the No. 2 cylinder head temperature decreased from 1,350° F to 650° F. He decided to continue flight at the slower airspeed. The engine roughness once again returned, and the pilot elected to land as soon as practical and have a mechanic look at the engine. However, there were no mechanics available, so the pilot decided to refuel and takeoff. The first takeoff attempt was unsuccessful because the pilot felt a slight hesitation in the engine power during the takeoff roll, and he aborted the takeoff. During the second takeoff attempt, at 250 ft agl, the engine lost power. The airplane descended to the ground, impacted a sand berm, and nosed over. It sustained substantial damage to the right wing and wing left strut A postaccident examination of the engine revealed that the No. 2-cylinder exhaust valve failed. The No. 2 cylinder exhaust valve was missing about 45 percent of the valve head and foreign object compression signatures were sustained to the No. 2 piston and cylinder head. The missing exhaust valve head was not present in the No. 2 cylinder. Additionally, the No. 5 cylinder piston and cylinder head sustained foreign object compression signatures. The No. 5 cylinder intake valve exhibited material deformation around the valve seat. The engine total time was 2,180.1 hours when the annual inspection was completed. The engine had acquired 3 hours since the last annual. The engine was overhauled after acquiring 909 hours. At the time of the accident, the engine had amassed 1,274.1 hours since major overhaul. It is likely that the initial engine roughness and partial loss of engine power, followed by the total loss of engine power during takeoff was due to the failure of the exhaust valve.
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 takeoff defining event
The NTSB's findings
- Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Failure
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 1,550 hours in all; 1,500 in this make and model; 8 in the last 90 days; 1,550 as pilot in command
- Last flight review: May 25, 2020
- Medical certificate: BasicMed (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 4,555 hours
- Last inspection: annual inspection, November 1, 2020; 3 hours since
- Maximum gross weight: 3,600 lb
- Seats: 6
- Landing gear: fixed
- Engine: Continental TSIO-520-M (piston); 2,183 hours total
The flight
- Destination: TRM Thermal CA
- Flight plan: none
- Runway 26, 5,531 ft by 75 ft
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 84°F (29°C), dew point 27°F (-3°C)
- Altimeter: 30.06 inHg
- Observation at 11:53 am from KPSP, 33 miles away
Weather report (METAR): METAR KPSP 211953Z 00000KT 10SM CLR 29/M03 A3006 RMK AO2 SLP177 T02941028=
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 5 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on August 25, 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 | N878AH Examination Report | PDF, 16 pages | View Download |
| 3 | Engine Logbook Entries | PDF, 8 pages | View Download |
| 4 | Work Order Invoice | PDF, 1 page | View Download |
| 5 | Photo Confirming Substantial Damage | 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 N878AH 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.