Amateur-built Bakeng Duce accident near Ramona, California, May 9, 2009
On May 9, 2009 at about 9:35 pm local time, a amateur-built Bakeng Duce, registered N86YP, was substantially damaged in an accident during maneuvering near Ramona, California (Ramona airport). It was a personal flight under general aviation rules (Part 91). 2 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
An in-flight separation of the right wing, which resulted from the pilot's performance of a maneuver that produced aerodynamic loads that exceeded the wing spar’s degraded strength. The wing spar strength degradation was due to the builder's failure to comply with Federal Aviation Administration recommended guidelines to select and incorporate wood in the spar with a grain pattern aligned with the longitudinal axis of the spar.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 9, 2009 · about 9:35 pm local time
- Place
- Ramona, California · Ramona · map
- Type
- Accident
- Injuries
- 2 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built Bakeng Duce
- Registration
- N86YP · no longer on the register · serial 572
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot and pilot-rated passenger departed for a personal flight in the borrowed experimental amateur-built airplane, which was equipped with dual flight controls. No determination could be made regarding which occupant was handling the controls during the flight. Recorded radar data indicated that 11 minutes into the flight, a series of maneuvers were performed. A witness stated that he observed the accident airplane spiral downward until it impacted the ground. He also reported observing a wing, which was separated from the main body of the airplane, fall to the ground nearby. Right wing spar fragments and the right aileron were found between 0.1 and 0.3 mile from the main wreckage, indicating that the right wing had separated in flight. Postaccident examination of fragments from the right wing’s broken wood wing spar revealed that the spar had been constructed with a wood grain orientation 12 degrees from the spar's longitudinal axis. This angle was inconsistent with published Federal Aviation Administration (FAA) guidance stating that grain deviation from the longitudinal axis of the spar should be no more than 3.8 degrees. The maximum grain deviation is limited because the relative strength and stiffness of an airplane’s wood wing spar is reduced when the grain structure within the spar is not oriented parallel to the longitudinal axis of the spar. With a 12-degree grain orientation, the spar’s load-carrying capability was compromised and reduced to between 30 to 70 percent of that of a spar with a 0-degree (parallel) grain orientation. It is likely that the wing spar failed when the pilot performed a maneuver that produced aerodynamic loads exceeding its degraded strength.
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
- Miscellaneous/other during prior to flight
- Aircraft structural failure during maneuvering defining event
- Part(s) separation from AC during maneuvering
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
The NTSB's findings
- cause Organizational issues › Development › Manufacture/production › (general) › Manufacturer
- cause Aircraft › Aircraft structures › Wing structure › Spar (on wing) › Damaged/degraded
- cause Aircraft › Aircraft structures › Wing structure › Spar (on wing) › Failure
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Dynamic load › Capability exceeded
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 1,450 hours in all
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rear
- Injury: fatal
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane; rotorcraft: glider
- Flight time: 1,050 hours in all
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: frt
- Injury: fatal
The aircraft
- Airframe total time: 480 hours
- Last inspection: annual inspection, May 2, 2009
- Maximum gross weight: 1,600 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-290D (piston); 0 hours total
The flight
- Departed from: RNM Ramona CA at 9:23 pm
- Destination: RNM Ramona CA
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 280° at 11 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 55°F (13°C)
- Altimeter: 29.86 inHg
- Observation at 9:53 pm from RNM, 7 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
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.