No fatalities

18 Nov 2018: Robinson R44 — Knox City, TX

Knox City, TX, United States

On 18 Nov 2018, a Robinson R44 Undesignat was involved in an aviation accident near Knox City, TX. No fatalities were reported. Investigators recorded the probable cause as: 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… This summary draws on records from NTSB; 12 related events involving the same aircraft type or operator are linked below.

SourcesNTSBPrimary reportUpdated 1778583330Data APIEditorial standards

A helicopter conducting a photography flight at about 70 ft AGL with a 14-knot tailwind entered settling with power. The pilot increased collective and applied forward cyclic but the helicopter impacted the ground, causing substantial damage.

Accident Details

According to the pilot's report, the helicopter was on a photography flight at an altitude of approximately 70 feet above ground level (AGL). The helicopter's heading was 190°, and its airspeed was less than 9 knots. At the time, there was a 14-knot tailwind from the north.

Pilot Report

The pilot reported that the helicopter began to settle with power under these conditions. In response, he increased collective pitch and applied forward cyclic to increase airspeed. However, the helicopter continued to descend and impacted the ground.

Damage

The accident resulted in substantial damage to the main rotor system and the fuselage of the helicopter.

Mechanical Status

The pilot stated that there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation.

Reference to Helicopter Flying Handbook

The Helicopter Flying Handbook, Chapter 11, page 11-10, describes the recovery from a settling with power condition. It notes that when attempting to recover, pilots often first increase collective pitch, but this action typically increases the stalled area of the rotor and the rate of descent. The handbook states that recovery is achieved by increasing airspeed and/or partially lowering collective pitch. In many helicopters, lateral cyclic combined with lateral tailrotor thrust can produce the quickest exit from the hazard, provided 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.

Contributing factors

Causes

PilotAirspeed — Not attained/maintainedProp/rotor parameters — Not attained/maintained

Other contributing factors

Effect on operation