Robinson R-22 BETA N8118L

Summary

On 8 July 2004 at about 17:18 local time, a Robinson R-22 BETA registered N8118L was involved in an accident near Rochester, Minnesota, United States. 2 people were on board and one died, 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

8 July 2004 at 17:18

Classification

Accident

Location

Rochester, Minnesota, United States

Coordinates

43.9631, -92.4269

Aircraft

Robinson R-22 BETA

Registration

N8118L

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Austin → Rochester

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

CHI04FA177

1 person died.

The loss of control due to the student pilot's failure to maintain rotor RPM and the flight instructor's inadequate supervision.

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

Read the full NTSB narrative

A helicopter piloted by a student pilot and a flight instructor was destroyed when it impacted terrain during a landing approach. A witness reported that the helicopter appeared to be making a normal approach toward the helicopter pad. He reported the helicopter was about 100 feet above the ground and going about 30 knots. When he looked at the helicopter again, he saw it "bobble" twice (yawing motion). Within 2-3 seconds, the helicopter rolled, "fell out of the sky" and impacted the ground. The flight instructor reported he could not remember much about the accident. He reported that the student pilot was at the controls and they were flying a right downwind approach to the helicopter pad. He reported that he did not think there was anything mechanically wrong with the helicopter, and did not remember anything being out of the ordinary. The inspection of the helicopter revealed that here were no ground impact marks other than the ground scars immediately below the main wreckage of the helicopter. The helicopter came to rest on its right side in a nose down attitude. The main rotor blades had severed the tailcone. The tail rotor drive shaft was found in one piece about 150 feet from the main wreckage with a 90-degree bend in it. The post accident inspection of the helicopter's airframe and engine revealed no preexisting anomalies that could be associated with a pre-impact condition. The Robinson Helicopter Company issued Safety Notice SN-24 in September 1986 with a revision in June 1994. The safety notice stated the following warning: LOW RPM ROTOR STALL CAN BE FATAL. The safety notice stated, "Rotor stall … can occur at any airspeed and when it does, the rotor stops producing the lift required to support the helicopter and the aircraft literally falls out of the sky." The safety notice explained, "As with the airplane wing, the blade airfoil will stall at a critical angle, resulting in a sudden loss of lift and a large increase in drag. The increased drag on the blades acts like a huge rotor brake causing the rotor RPM to rapidly decrease, further increasing the rotor stall. As the helicopter begins to fall, the upward rushing air continues to increase the angle-of-attack on the slowly rotating blades, making recovery virtually impossible, even with down collective."

Quoted verbatim from the NTSB record.