Eurocopter AS 350 B3 accident near Parker, Arizona, March 16, 2010
On March 16, 2010 at about 4:30 pm local time, a Eurocopter AS 350 B3 (helicopter), registered N4282, was substantially damaged in an accident during maneuvering (hover) near Parker, Arizona (Lapaz Regional Hospital Helpt airport). It was an other work-use flight under general aviation rules (Part 91). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The mechanics' failure to account for all the tools following a maintenance procedure and the pilot's failure to perform a preflight check before a maintenance test flight.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 16, 2010 · about 4:30 pm local time
- Place
- Parker, Arizona · Lapaz Regional Hospital Helpt · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Eurocopter AS 350 B3 · all AS 350 B3s on the register
- Registration
- N4282 · registry record · serial 4282
- Damage
- Substantial damage
- Flight
- Other work-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot of the helicopter told the lead mechanic that the main rotor blade needed to be balanced. Two mechanics showed up on the morning of the accident and installed the balancing equipment. A test flight was flown. The two men performed the necessary work, which required a second adjustable wrench on the top of the rotor head to hold the bolt while the nut below was removed and later torqued back on. When the work was finished, the men gathered their tools. The pilot asked the lead mechanic if they had gathered all their tools and the mechanic replied "yes." The three men got on the helicopter for a test hover to check their work. As the main rotor speed reach 100 percent, the three occupants heard a "bang." As the helicopter hovered, the two mechanics thought the balancing equipment readings were worse than the first flight, and the vibrations in the aircraft had increased. The pilot landed the helicopter so that the mechanics could make additional adjustments. The mechanics discovered that they were missing the adjustable wrench that had been used on the top of the main rotor head. Postaccident examination revealed that one main rotor blade, the tail boom, and the lower vertical stabilizer had received damage from the unaccounted for wrench.
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
- Aircraft maintenance event during prior to flight
- Aircraft inspection event during prior to flight
- Miscellaneous/other during maneuvering (hover) defining event
The NTSB's findings
- cause Personnel issues › Task performance › Maintenance › Scheduled/routine maintenance › Maintenance personnel
- cause Personnel issues › Task performance › Inspection › Preflight inspection › Pilot
- Environmental issues › Physical environment › Object/animal/substance › Debris/dirt/foreign object › Effect on equipment
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 3,900 hours in all; 1,354 in this make and model; 28 in the last 90 days
- Last flight review: March 21, 2009
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 819 hours
- Last inspection: approved inspection programme, February 3, 2010
- Maximum gross weight: 4,960 lb
- Seats: 5
- Landing gear: fixed
- Engine: Turbomeca ARRIEL 2B1 (turboshaft); 0 hours total
- Operator: Omniflight Helicopters Inc.
The flight
- Departed from: AZ47 Parker AZ
- Destination: AZ47 Parker AZ
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 050° at 5 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 70°F (21°C), dew point 39°F (4°C)
- Altimeter: 30.30 inHg
- Observation at 4:52 pm from BLH
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 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.