Boeing A75N1(PT17) accident near Hollister, California, May 26, 2021
On May 26, 2021 at about 9:30 pm local time, a 1942 Boeing A75N1(PT17), registered N75016, was substantially damaged in an accident during initial climb near Hollister, California (Frazier Lake Airpark airport). 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
The improper installation of a relief valve spring that was shorter than the standard spring length, which slowed the response of the propeller governor to change the pitch of the blades during climbout, resulting in a partial loss of power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 26, 2021 · about 9:30 pm local time
- Place
- Hollister, California · Frazier Lake Airpark · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing A75N1(PT17), built 1942 · all A75N1(PT17)s on the register
- Registration
- N75016 · registry record · serial 75-3418
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The airplane was climbing out shortly after takeoff when the pilot noticed that the engine rpm was decreasing, and that the airplane was not gaining altitude. The pilot added that, even with the decrease in engine rpm, the engine was still producing some engine power. The pilot-rated passenger stated that the airplane was not gaining or losing altitude and that he verified that the propeller, throttle, and mixture control levers were in the correct settings. The pilot decided to maneuver away from power lines and make a forced landing onto a field. Subsequently, the lower part of both wings impacted the ground and sustained substantial damage. A postaccident examined revealed that the propeller governor had a relief valve spring that was shorter in length than a standard relief valve spring. The shorter relief valve spring resulted in an internal governor pressure of 125 psi, which was less than the manufacturer’s setting of 180 to 200 psi. The lower internal pressure setting slowed the governor’s ability to make the immediate corrections in propeller blade pitch necessary to maintain the engine rpm during the climb out, which caused the engine to lose partial power.
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 initial climb defining event
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- Aircraft › Aircraft propeller/rotor › Propeller system › Propeller governor › Incorrect service/maintenance
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 2,774 hours in all; 24 in this make and model; 74 in the last 90 days; 16 in the last 30 days; 2,586 as pilot in command
- Last flight review: July 29, 2020
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rear
- Injury: no injuries
Passenger
- Seat: frt
The aircraft
- Airframe total time: 6,420 hours
- Last inspection: annual inspection, May 14, 2021; 1 hours since
- Maximum gross weight: 2,950 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming R-680-13 (piston); 2,741 hours total
- Operator: One Slim Rabbit LLC
The flight
- Flight plan: none
- Runway 23, 2,500 ft by 100 ft
Weather at the time
- Light: daylight
- Wind: from 240° at 19 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 75°F (24°C), dew point 46°F (8°C)
- Altimeter: 30.02 inHg
- Observation at 2:15 pm from KCVH, 4 miles away
Weather report (METAR): KCVH 262115Z AUTO 24019KT 10SM CLR 24/08 A3002 RMK A01
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
11 documents, released by the NTSB on November 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 | Pilot Record of Convesation | PDF, 2 pages | View Download |
| 3 | Passenger Record of Conversation | PDF, 2 pages | View Download |
| 4 | Memorandum for Record FAA Airframe & Engine Exam Notations | PDF, 3 pages | View Download |
| 5 | Memorandum for Record FAA Follow Up Engine Exam Notations | PDF, 2 pages | View Download |
| 6 | Memorandum for Record Propeller Governor Exam | PDF, 2 pages | View Download |
| 7 | Woodward Governor Relief Valve Excerpts and Diagrams | PDF, 5 pages | View Download |
| 8 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 2 pages | View Download |
| 9 | Evidence Control Form - Propeller Governor | PDF, 2 pages | View Download |
| 10 | Photos from Propeller Governor Exam | PDF, 7 pages | View Download |
| 11 | Accident Photo | 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.