Eurocopter France AS355N N355J

Summary

On 18 April 2003 at about 16:30 local time, a Eurocopter France AS355N registered N355J was involved in an accident near Redding, California, United States. 2 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

18 April 2003 at 16:30

Classification

Accident

Location

Redding, California, United States

Nearest airport

Redding Muni (RDD)

Coordinates

40.5803, -122.4133

Aircraft

Eurocopter France AS355N

Registration

N355J

Category

Helicopter

Engines

2

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Redding → Redding

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

LAX03LA138

Nobody was injured.

Failure of the pilot to maintain adequate obstruction clearance during landing, which resulted in the tail rotor contacting a brush pile. The accident sequence was precipitated by the initiation of a precautionary landing by the pilot due to a discrepancy with the engines' torque meter gauge.

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

Read the full NTSB narrative

The helicopter's main rotor and tail rotor blades contacted a brush pile during a precautionary landing that was preceded by a discrepancy in the engine/power torque indication gages. The flying pilot (FP) conducted a normal start up and hover taxied the helicopter to a predetermined location for takeoff. He observed a discrepancy between the two engine torque indicator needles, with no other engine, systems, or rotor indications noted, which led him to make the precautionary landing. As the FP hovered the helicopter in a high hover about 10 feet above the ground, he initiated a slow left turn, with the intention of keeping an adjacent brush pile in view. The pilot reported that the initial 45 degrees of the left turn were normal. Unbeknownst to the pilot, the tail rotor had contacted a brush pile. After the tail rotor contacted the brush pile and the tail rotor gear box separated from the tail boom, the helicopter pitch attitude changed to a nose low attitude and the helicopter started to yaw to the left with the yaw rate increasing. The FP attempted to counteract the loss of control with full aft cyclic and full right pedal, with no effect. Ultimately the main rotor struck the brush pile and the helicopter rotated to the left. The helicopter manufacturer does not identify a torque split between the number 1 and number 2 engines as an emergency. The normal procedure for a torque split discrepancy is to utilize the equalizing trim to balance the torque loads. The FP indicated there was very little apparent vibration, and the NFP did not report any vibrations. After the accident it was observed that the tail and tail rotor assembly had separated from the tail boom, and one of the STARFLEX rotor head arms were fractured at a 45-degree angle. Left yaw of the helicopter is consistent with a loss of tail rotor authority, and the change in noise level heard by the crew could be associated with the tail rotor's interaction with the brush pile. Both engines were test run at the Turbomeca factory in Texas, under the auspices of a Safety Board Investigator on September 3, 2003. No discrepancies were noted with the test run.

Quoted verbatim from the NTSB record.