Eurocopter AS350 B3 N820NA

Summary

On 4 November 2003 at about 00:45 local time, a Eurocopter AS350 B3 registered N820NA, operated by Native American Air Ambulance Inc, was involved in an accident near Mesa, Arizona, United States. 4 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

4 November 2003 at 00:45

Classification

Accident

Location

Mesa, Arizona, United States

Nearest airport

Falcon Field Airport (FFZ)

Coordinates

33.4608, -111.7283

Aircraft

Eurocopter AS350 B3

Registration

N820NA

Category

Helicopter

Engines

1

Operator

Native American Air Ambulance Inc

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Show Low → Scottsdale

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

LAX04LA035

Nobody was injured.

The pilot's inadvertent activation of the hydraulic test switch, which resulted in a loss of the hydraulic system pressure, and his failure to maintain directional control.

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

Read the full NTSB narrative

The helicopter impacted a taxiway after a experiencing a loss of anti torque control during an emergency landing. The pilot reported a hydraulic system failure and diverted to the nearest airport. During the emergency landing, after slowing the helicopter and descending through 100 feet, the helicopter yawed to the left. The pilot attempted to apply right pedal but was met with more force than he was expecting to overcome in moving the anti torque pedals. The pilot attempted to keep the helicopter in a level attitude; however, he was unable to stop the helicopter from spinning. The helicopter touched down, and rotated on the ground until the right landing gear skid collapsed and the main rotor system impacted the ground. The helicopter came to rest on its right side. The engine continued to operate and the main rotor blades repeatedly impacted the ground until the fire department was able to shutdown the engine by directing a stream of firefighting foam into the engine intake. The pilot turned off the electrical master switch and exited the helicopter. The AS350 B3 is equipped with four servo actuators, three for the main rotor system and one for the tail rotor blade pitch control. The flight manual emergency procedures section notes that without any hydraulic pressure, the anti torque pedal operating force is very high on the helicopter. Post accident examination of the wreckage revealed the hydraulic test switch was depressed. Activation of the hydraulic test switch will dump hydraulic pressure and is used during the preflight inspection to test the hydraulic accumulator pressure. If it is depressed during flight, the hydraulic system will dump pressure and mirror a hydraulic system failure. No other anomalies were noted with the hydraulic system during post accident examinations and testing. The recommended emergency procedures for a hydraulic system failure dictates that the pilot make a flat approach over a clear landing area and land with slight forward speed.

Quoted verbatim from the NTSB record.