Robinson R44 II N6960

Summary

On 13 July 2024 at about 16:35 local time, a Robinson R44 II registered N6960, operated by Takeflight LLC, was involved in an accident near Herriman, Utah, 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

13 July 2024 at 16:35

Classification

Accident

Location

Herriman, Utah, United States

Coordinates

40.5051, -112.0550

Aircraft

Robinson R44 II

Registration

N6960

Category

Helicopter

Year built

2023

Engines

1

Operator

Takeflight LLC

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

West Jordan → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR24LA241

Nobody was injured.

A hard landing following a total loss of engine power due to fuel starvation as a result of the improper idle setting of the helicopter’s engine. Contributing to the loss of engine power was the instructor’s reduction of engine power past that recommended by the manufacturer for practice autorotations.

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

Read the full NTSB narrative

The helicopter flight instructor was demonstrating a practice autorotation with a power recovery for the student. The instructor stated that he reduced the throttle to idle and entered the autorotation. After noticing several caution lights illuminate, the instructor attempted to increase engine power and realized that the engine had lost total power. The cockpit video recorder showed that the engine tachometer needle decreased from 100% to below 46% rpm, below idle. The instructor continued the autorotation to a field and the helicopter landed hard. During the landing, the main rotor blades struck the tailboom, resulting in substantial damage. A postaccident examination and engine run revealed that the engine would not start and idle unless the electric boost pump was set to ON. Subsequent bench testing of the mechanical fuel pump and fuel injection servo revealed no anomalies. The flight instructor reported that he noticed the helicopter’s engine would idle about 50-52% rpm, but stated that the engine did not have any issues when he previously demonstrated practice autorotations. He added that he did not notify maintenance of the low idle setting, as he was not aware that it was adjustable. According to the operator’s maintenance manual, the idle setting for the accident engine mode should be 58-62%. According to the pilot’s operating handbook (POH), “Idle mixture and speed may require adjustment as conditions vary from sea level standard.” The accident helicopter’s maintenance logs did not indicate that the flight idle was adjusted as recommended by the manufacturer after the helicopter was received from the factory. It is likely that, given the engine’s low idle setting, the instructor did not immediately recognize that the rpm continued to decrease past idle and the subsequent loss of engine power due to fuel starvation. It is also likely that, had the instructor followed the manufacturer's recommendation to lower tachometer needle separation to the desired level, usually below 80% but above idle, the engine would not have lost power.

Quoted verbatim from the NTSB record.