Eurocopter AS 350 B3 N4282

Summary

On 16 March 2010 at about 16:30 local time, a Eurocopter AS 350 B3 registered N4282, operated by Omniflight Helicopters inc., was involved in an accident near Parker, Arizona, United States. 3 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

16 March 2010 at 16:30

Classification

Accident

Location

Parker, Arizona, United States

Nearest airport

Lapaz Regional Hospital Helpt (AZ47)

Coordinates

34.1367, -114.2856

Aircraft

Eurocopter AS 350 B3

Registration

N4282

Category

Helicopter

Engines

1

Operator

Omniflight Helicopters inc.

Operating rule

Part 91: General Aviation

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Route

Parker → Parker

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR10CA164

Nobody was injured.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.