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 November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 4, 2009 · about 3:50 pm local time · cases in 2009
- Place
- Benson, Arizona · Benson Municipal Airport · cases near this 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
3 documents, released by the NTSB on August 31, 2009. 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 | Photo 1 - Left Side of the Helicopter | PDF, 1 page | View Download |
| 3 | Photo 2 - Right Side of the Helicopter | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Connections how this case links to the rest of the register
- N6641D: not on the register today · the record of its deregistration
- Hughes OH-6 28 registered today · the model family and its accident history
- Hughes 386 aircraft on the register
- Engine: Allison (R/R) 250-C20B 113 aircraft carry this series today · as the NTSB recorded it
- Benson Muni/Paul Kerchum Field · nearest airport
- Tucson International · departed from
- Accidents and incidents in Arizona 2,985 since 1982 · 468 in the last ten years
- Arizona 8,426 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/WPR09TA277.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.