Hughes OH-6A accident near Benson, Arizona, June 4, 2009
On June 4, 2009 at about 3:50 pm local time, a Hughes OH-6A (helicopter), registered N6641D, was substantially damaged in an accident during landing (flare/touchdown) near Benson, Arizona (Benson Municipal Airport). It was a public-use flight (federal) 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 pilot under instruction's inadequate autorotation technique and the instructor pilot’s delayed remedial action to arrest the rate of descent of the helicopter while in an autorotation flare.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 4, 2009 · about 3:50 pm local time
- Place
- Benson, Arizona · Benson Municipal Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Hughes OH-6A · all OH-6As on the register
- Registration
- N6641D · no longer on the register · serial 66-07855
- Damage
- Substantial damage
- Flight
- Public-use flight (federal) · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The instructor pilot reported that they were practicing autorotations to the runway. During a straight-in autorotation at approximately 200 feet above ground level, the instructor called for an increase in throttle to bring rotor rpm into the normal operating range in preparation for landing. Between 200 feet and 100 feet agl, the instructor assisted the flying pilot with the throttle increase when he realized that the pilot had delayed throttle application. The flying pilot then initiated the flare at approximately 50 feet agl. The flying pilot leveled the helicopter and applied collective to slow the descent rate. Upon realizing that the descent rate had not been checked prior to beginning the flare, the instructor joined the flying pilot on the controls. The helicopter landed hard on the runway and bounced, rotated to the left of runway heading as it touched down a second time, resulting in the collapse of the right landing skid. The pilot reported that were no mechanical anomalies with the flight control systems.
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
- Hard landing during landing (flare/touchdown) defining event
The NTSB's findings
- cause Personnel issues › Action/decision › Action › Delayed action › Instructor/check pilot
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 5,500 hours in all; 990 in this make and model; 141 in the last 90 days; 38 in the last 30 days; 3,500 as pilot in command; 100 on instruments
- Last flight review: May 15, 2009
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Co-pilot
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 1,540 hours in all; 208 in this make and model; 144 in the last 90 days; 69 in the last 30 days; 1,260 as pilot in command; 5 on instruments
- Last flight review: April 3, 2009
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 6,141 hours
- Last inspection: 100-hour inspection, May 6, 2009; 45 hours since
- Seats: 4
- Landing gear: fixed
- Engine: Allison (R/R) 250-C20B (turboshaft); 0 hours total
- Operator: Dept Of Homeland Security
The flight
- Departed from: KTUS Tucson AZ at 2:15 pm
- Destination: E95 Benson AZ
- Flight plan: none
- Runway 10, 4,000 ft by 75 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: at 1 knots
- Visibility: 50 statute miles
- Sky: broken clouds at 200 ft
- Temperature: 84°F (29°C), dew point 16°F (-9°C)
- Altimeter: 30.12 inHg
- Observation at 1:55 pm from KFHU, 24 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.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number WPR09TA277.