Robinson R22 N931SH

Summary

On 7 June 2016 at about 18:28 local time, a Robinson R22 registered N931SH, operated by MY Sky LLC, was involved in an accident near Cahokia/St. Louis, Illinois, 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

7 June 2016 at 18:28

Classification

Accident

Location

Cahokia/St. Louis, Illinois, United States

Nearest airport

St Louis Downtown (CPS)

Coordinates

38.5703, -90.1550

Aircraft

Robinson R22

Registration

N931SH

Category

Helicopter

Year built

2005

Engines

1

Operator

MY Sky LLC

Operating rule

Part 91: General Aviation

Purpose of flight

Business

Phase of flight

Not recorded

Route

Cahokia/St. Louis → Cahokia/St. Louis

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

GAA16CA296

Nobody was injured.

The flight instructor's delayed remedial action and his failure to remain vigilant as the helicopter entered the weathercock stability region, in gusting wind conditions, resulting in loss of tail rotor effectiveness and ground impact.

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

Read the full NTSB narrative

According to the flight instructor, he was instructing his student in hovering flight operations. He reported that he instructed the student to execute a right pedal turn at a three foot hover. The instructor recalled that the student complied and during the turn, as the tail came into the wind, the helicopter started to weathervane, and the turn rate increased rapidly and did not subside until the helicopter impacted the ground. The helicopter sustained substantial damage to the fuselage and both rotor systems. The instructor reported that there were no mechanical anomalies or malfunctions with any portion of the helicopter that would prevent normal flight operations. The instructor reported that the wind velocity at the time of the accident was 11 knots gusting to 16 knots. Weathercock stability is defined as a region of loss of tail rotor effectiveness (120 degree - 240 degree tailwind) that will weathervane the helicopter, and if not prevented will result in a loss of helicopter control about the horizontal axis. According to the Helicopter Flying Handbook (FAA 8083-21A):   Pilots who put themselves in situations where the combinations above occur should know that they are likely to encounter LTE. The key is to not put the helicopter in a compromising condition but if it does happen being educated enough to recognize the onset of LTE and be prepared to quickly react to it before the helicopter cannot be controlled.

Quoted verbatim from the NTSB record.