Pilot Debrief

Robinson R22 near Madill, OK — 2019-03-20

Final reportCEN19LA106
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Date
2019-03-20
Location
Madill, OK, USA
Aircraft
Robinson R22
Registration
N7782H
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Climb

Probable cause

The failure of the V-belts due to improper maintenance, which resulted in the loss of power to the helicopter's rotor system and subsequent forced landing on rough terrain.

NTSB narrative

The pilot reported that about 10 minutes after takeoff, the helicopter was in level flight about 700 to 800 ft above ground level when the clutch actuator warning/caution light illuminated. He entered an autorotation intending to do a power recovery close to the ground. He indicated that, within a "short second or two" after the clutch light illuminated, he heard a "bang" and felt the helicopter shudder. He continued the autorotation and landed on rough terrain. The helicopter rolled onto its left side and sustained substantial damage to the tail boom, main rotor, and fuselage. The examination of the helicopter revealed that the two double V-belts had separated from the upper sheave and that there was a field repair on the wire connections at the clutch actuator fuse holder. The terminals were wrapped in tape and a wire tie. When the wire tie and tape were removed, the fuse holder terminal fell and fractured from the holder, and the wires separated from the solder on the terminal. The extension limiter was found at 1.65 inches, which is the maximum extension limit; the normal range was 1.1 to 1.3 inches. The improper repair of the clutch actuator fuse holder likely caused the loose condition of the V-belts, which resulted in V-belt failure and the loss of power to the helicopter's rotor system, subsequent autorotation, and forced landing.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot should have landed immediately after clutch light illuminated.

NTSB coding

Evidence available

  • Photos
  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

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