Cosmos PHASE II accident near El Mirage, California, September 20, 2010
On September 20, 2010 at about 2:40 pm local time, a Cosmos PHASE II (weight-shift aircraft), registered N56078, was substantially damaged in an accident during standing (engine(s) start-up) near El Mirage, California (El Mirage airport). It was a personal flight under general aviation rules (Part 91). 1 person was killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's improper preflight and starting procedures, which resulted in an inadvertent takeoff with the gust lock still installed.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 20, 2010 · about 2:40 pm local time
- Place
- El Mirage, California · El Mirage · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Cosmos PHASE II · all PHASE IIs on the register
- Registration
- N56078 · no longer on the register · serial 21132
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
A witness reported that the non-certificated pilot's normal procedure was to start the engine while seated in the weight-shift-control trike. Once started, he would then exit while the engine warmed up, and put on his helmet and glasses. On the day of the accident, the pilot was seated and unrestrained in the aircraft, with the gust lock installed, and appeared to be having difficulty starting the engine. He then moved the throttle to the full forward position and attempted a restart. This time the engine started, and immediately accelerated to high power. The aircraft then accelerated forward, rotated, and began a steep climb followed by a stall and uncontrolled descent to the ground. Throughout the maneuver the pilot appeared to be struggling to stay within the aircraft. The engine manufacturer's instructions specified that the throttle control should be set to the idle position during engine startup. Additionally, the manual stated that the operator should be able to operate the engine controls instinctively at startup, and be in a position to turn off the ignition switch instantly if necessary. No anomalies were noted with the throttle control, which was observed in the full open position. The pilot did not use wheel chocks to secure the trike prior to engine start.
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 control on ground during standing (engine(s) start-up) defining event
- Attempted remediation/recovery during takeoff
- Loss of control in flight during initial climb
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
The NTSB's findings
- cause Personnel issues › Action/decision › Action › Incorrect action selection › Pilot
- cause Aircraft › Aircraft power plant › Engine controls › Power lever › Incorrect use/operation
- Aircraft › Aircraft handling/service › Parking/securing › Tie › down/mooring › Incorrect use/operation
- cause Aircraft › Aircraft systems › Flight control system › Elevator control system › Inoperative
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Pitch control › Not attained/maintained
- cause Personnel issues › Action/decision › Action › Incorrect action sequence › Pilot
- cause Personnel issues › Task performance › Inspection › Preflight inspection › Pilot
Pilot
- Seat: sngl
- Injury: fatal
The aircraft
- Maximum gross weight: 900 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 618 (piston); 0 hours total
The flight
- Departed from: PVT El Mirage CA at 2:40 pm
- Destination: PVT El Mirage CA
- Flight plan: none
- Runway 08, 1,500 ft by 50 ft
Weather at the time
- Light: daylight
- Wind: from 240° at 6 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 57°F (14°C), dew point 48°F (9°C)
- Altimeter: 29.86 inHg
- Observation at 1:58 pm from VCV, 13 miles away
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.