Heard Alan E MOSQUITO XE N911CY

Summary

On 24 April 2018 at about 18:00 local time, a Heard Alan E MOSQUITO XE registered N911CY was involved in an accident near Albion, New York, United States. One person was on board and one was seriously injured. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

24 April 2018 at 18:00

Classification

Accident

Location

Albion, New York, United States

Nearest airport

Gaines Valley Aviation Airport (NY06)

Coordinates

43.2964, -78.2225

Aircraft

Heard Alan E MOSQUITO XE

Registration

N911CY

Category

Helicopter

Year built

2010

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Albion → Albion

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

ERA18LA135

1 person was seriously injured.

The pilot's inadvertent, improper configuration of the engine fuel system, which resulted in an excessively lean air-to-fuel ratio and resulted in a loss of engine power; and the pilot's subsequent failure to maintain main rotor rpm following the loss of engine power, which resulted in a hard landing.

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

Read the full NTSB narrative

The day before the accident, the pilot conducted flight tests in the experimental, amateur-built helicopter with the newly-installed engine autotuner in order to determine the proper air-to-fuel ratio (AFR); however, the pilot inadvertently failed to complete the autotuner setup, and the autotuner reverted back to a lean air-fuel ratio setting. The next day, while departing on a local flight about 75 ft above ground level (agl), the engine started to backfire and the engine power began to surge. The pilot decided to land straight ahead, but the main rotor rpm was low, which precluded entering an autorotation, and the engine subsequently lost total power about 50 ft agl. The helicopter entered an uncontrolled descent and impacted the ground; a postcrash fire ensued. Postaccident examination of the thermally-damaged engine revealed no evidence of preimpact failure or malfunction of the powertrain or lubrication system. Although the autotuner was destroyed in the postcrash fire, the in-flight separation of one air induction filter, the coloration of the spark plugs, and the backfiring engine were consistent with the engine operating in an excessively lean air-fuel condition. The partial, then total, loss of engine power was likely due to the engine computer (ECU) detecting the backfiring and putting the engine into a self-preserving partial, then idle, power mode. It is likely that the pilot's failure to maintain rotor rpm following the loss of engine power resulted in the uncontrolled descent and hard landing.

Quoted verbatim from the NTSB record.