Guimbal CABRI accident near Santa Ana, California, September 3, 2018
On September 3, 2018 at about 10:37 pm local time, a 2017 Guimbal CABRI (helicopter), registered N401SH, was substantially damaged in an accident near Santa Ana, California (John Wayne Airport-Orange Coun). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The flight instructor's delayed application of power during a power recovery following an autorotation, which resulted in an unrecoverable low rotor rpm during the landing flare and subsequent loss of control.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 3, 2018 · about 10:37 pm local time
- Place
- Santa Ana, California · John Wayne Airport-Orange Coun · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Guimbal CABRI G2, built 2017
- Registration
- N401SH · registry record · serial 1195
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The flight instructor and private pilot receiving instruction (pilot) initiated a practice autorotation from about 700 ft in the airport traffic pattern. As the helicopter reached about 150 ft, the instructor slightly opened the twist grip throttle to initiate a power recovery but realized shortly thereafter that the applied power was insufficient to arrest the helicopter’s autorotative descent. The instructor applied additional power, and as the helicopter reached 40 ft, the pilot receiving instruction raised the collective, but the helicopter continued to descend in a flat attitude. The instructor then advanced the twist grip to full power but reported that the engine power did not increase as expected. The low rotor rpm horn activated, the nose yawed left, the helicopter rolled to the left, and the main rotor blades impacted the ground, resulting in substantial damage. A detailed examination of the collective control, twist-grip throttle, and governor control system revealed no pre-impact mechanical anomalies. It is likely that the flight instructor could not apply sufficient power to abort the practice autorotation following the pilot’s collective input, which resulted in an unrecoverable low rotor rpm condition and subsequent loss of control. The helicopter’s flight manual stated that the lowest recommended height for aborting an autorotation was 300 ft; however, the instructor initiated the recovery at 150 ft, which resulted in reduced time and altitude available to recognize that the engine was not responding as expected and continue with a power-off, touchdown autorotation. In a service letter published after the accident, the manufacturer advised against initiating a power recovery from an autorotation in the flare, as it could result in a loss of yaw control upon application of maximum engine torque.
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
- Autorotation Attempted remediation/recovery
- Autorotation Miscellaneous/other defining event
- Autorotation Collision with terrain or object (not controlled flight into terrain)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine controls › (general) › Incorrect use/operation
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Instructor/check pilot
Flight instructor
- Certificate: flight instructor
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 819 hours in all; 15 in this make and model; 198 in the last 90 days; 81 in the last 30 days; 758 as pilot in command; 566 on instruments
- Last flight review: October 6, 2017
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
Dual student
- Certificate: private
- Ratings: rotorcraft: helicopter
- Flight time: 99 hours in all; 13 in this make and model; 34 in the last 90 days; 11 in the last 30 days; 18 as pilot in command
- Last flight review: July 25, 2018
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 436.5 hours
- Last inspection: 100-hour inspection, August 9, 2018; 47 hours since
- Maximum gross weight: 1,540 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming Engines O-360-J2A (piston); 436 hours total
- Operator: One Above Aviation
The flight
- Departed from: SNA Santa Ana CA at 9:00 pm
- Destination: SNA Santa Ana CA
- Flight plan: none
- Runway 20L, 2,887 ft by 75 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 230° at 9 knots
- Visibility: 10 statute miles
- Sky: scat at 2,600 ft
- Temperature: 77°F (25°C), dew point 63°F (17°C)
- Altimeter: 29.82 inHg
- Observation at 10:53 pm
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
9 documents, released by the NTSB on June 3, 2021. 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 | Weather Reports and Records | PDF, 2 pages | View Download |
| 3 | Record of Conversations | PDF, 5 pages | View Download |
| 4 | NTSB Examination Report | PDF, 9 pages | View Download |
| 5 | Excerpt from Aircraft Logbooks | PDF, 3 pages | View Download |
| 6 | Service Letter Sl 19-001 | PDF, 6 pages | View Download |
| 7 | Service Letter Sl 19-002 | PDF, 8 pages | View Download |
| 8 | Excerpt from Rotorcraft Flight Manual | PDF, 4 pages | View Download |
| 9 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 2 pages | 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.