Amateur-built YAK 3UPW accident near Half Moon Bay, California, March 22, 2010
On March 22, 2010 at about 9:30 pm local time, a amateur-built YAK 3UPW, registered N153U, was substantially damaged in an accident during landing (landing roll) near Half Moon Bay, California (Half Moon Bay airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of left main landing gear actuator to lock in the down position due to low down-lock pressure as a result of a contaminated down-lock track and corroded down-lock balls.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 22, 2010 · about 9:30 pm local time
- Place
- Half Moon Bay, California · Half Moon Bay · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built YAK 3UPW
- Registration
- N153U · no longer on the register · serial 005
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Prior to landing the pilot observed 3 green lights indicating that the landing gear was down and locked. During the landing roll the left main landing gear collapsed, which resulted in substantial damage to the left wing and aileron. A Federal Aviation Administration inspector reported that a postaccident examination of the left main landing gear's pneumatic actuator revealed that the actuator's down-lock ball track was contaminated with dirt and that the steel down-lock balls were corroded. The combination of dirt in the actuator's down-lock track, the corroded down-lock balls, and the low down-lock pressure likely caused the gear to collapse.
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
- Landing gear collapse during landing (landing roll) defining event
The NTSB's findings
- cause Aircraft › Aircraft systems › Landing gear system › Landing gear actuator › Malfunction
- cause Aircraft › Aircraft systems › Landing gear system › Landing gear actuator › Fatigue/wear/corrosion
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 3,746 hours in all; 21 in this make and model; 3,746 as pilot in command
- Last flight review: July 2, 2008
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: frt
- Injury: no injuries
The aircraft
- Airframe total time: 21 hours
- Last inspection: annual inspection, March 1, 2010; 21 hours since
- Maximum gross weight: 6,143 lb
- Seats: 2
- Landing gear: retractable
- Engine: Pratt & Whitney R-1830 (piston); 0 hours total
The flight
- Departed from: HAF Half Moon Bay CA at 9:10 pm
- Destination: HAF Half Moon Bay CA
- Flight plan: none
- Runway 30, 5,000 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 330° at 15 knots, gusting 21
- Visibility: 6 statute miles
- Sky: clear
- Temperature: 57°F (14°C), dew point 48°F (9°C)
- Altimeter: 30.06 inHg
- Observation at 9:35 pm from HAF
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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.