Robinson R44 N4167Y

Summary

On 18 November 2018 at about 14:30 local time, a Robinson R44 registered N4167Y was involved in an accident near Knox City, Texas, 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

18 November 2018 at 14:30

Classification

Accident

Location

Knox City, Texas, United States

Coordinates

33.5150, -99.9536

Aircraft

Robinson R44

Registration

N4167Y

Category

Helicopter

Year built

2008

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Aerial Observation

Phase of flight

Not recorded

Route

Knox City → Knox City

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

GAA19CA063

Nobody was injured.

The pilot's failure to maintain adequate airspeed with a tailwind, which resulted in the helicopter settling with power, and his subsequent incorrect collective application while attempting to recover, which resulted in a loss of helicopter control due to a loss of tail rotor effectiveness.

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

Read the full NTSB narrative

The helicopter pilot reported that, while conducting a photography flight about 70 ft above ground level, the helicopter's heading was 190°, and the airspeed was less than 9 knots. With a 10-knot tailwind, the helicopter began to settle with power. The pilot increased the collective and applied forward cyclic to increase the airspeed, but the helicopter continued to settle and impacted the ground hard. The helicopter sustained substantial damage to the main rotor system and fuselage. The pilot reported that there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation. The pilot reported that the wind about the time of the accident was from the north at 10 knots. According to the Helicopter Flying Handbook, Chapter 11, page 11-10 When recovering from a settling with power condition, the pilot tends first to try to stop the descent by increasing collective pitch. However, this only results in increasing the stalled area of the rotor, thereby increasing the rate of descent. Since inboard portions of the blades are stalled, cyclic control may be limited. Recovery is accomplished by increasing airspeed, and/or partially lowering collective pitch. In many helicopters, lateral cyclic combined with lateral tailrotor thrust will produce the quickest exit from the hazard assuming that there are no barriers in that direction. In a fully developed vortex ring state, the only recovery may be to enter autorotation to break the vortex ring state.

Quoted verbatim from the NTSB record.