Aviation Accident Summaries

Aviation Accident Summary MIA94LA054

Aircraft #1

N193HC

ROBINSON R22B

Analysis

THE PILOT STATED THAT DURING CRUISE FLIGHT DURING A DARK NIGHT OVER UNSUITABLE TERRAIN AT 1,800 FEET MSL, THE CLUTCH LIGHT FLICKERED MOMENTARILY THEN REMAINED ILLUMINATED. HE WAITED FOR 5 SECONDS THEN PULLED THE CLUTCH CIRCUIT BREAKER AND INITIATED AN EMERGENCY DESCENT FOR A FORCED LANDING. WHEN THE FLIGHT WAS ABOUT 50 FEET ABOVE GROUND LEVEL (AGL) THE PILOT INITIATED THE CYCLIC FLARE. THEN WHEN THE FLIGHT WAS ABOUT 10 FEET AGL, HE PULLED COLLECTIVE CONTROL BUT THE HELICOPTER LANDED HARD. EXAMINATION OF THE HELICOPTER REVEALED THAT ONE OF THE TWO VEE- BELTS HAD COMPLETELY SEPARATED AND 1/2 OF THE REMAINING BELT HAD ALSO COMPLETELY SEPARATED. REVIEW OF THE MAINTENANCE RECORDS REVEALED THAT THE TENSION OF THE BELTS WAS CHECKED ABOUT 42 HOURS BEFORE. THE VEE-BELTS WERE INSTALLED WHEN THE HELICOPTER WAS MANUFACTURED ABOUT 442 HOURS BEFORE THE ACCIDENT.

Factual Information

On January 15, 1994, about 2220 Atlantic standard time, a Robinson R22 Beta, N193HC, registered to Initiative Trade Corporation, was substantially damaged during an autorotative landing near Gurabo, Puerto Rico, while on a 14 CFR Part 91 aerial advertising flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The commercial-rated pilot, the sole occupant, was not injured. The flight originated about 2115, from the Fernando Luis Ribas Dominicci Airport, San Juan, Puerto Rico. The pilot stated that during cruise flight during the dark night at 1,800 feet mean sea level, he smelled something burning and the clutch warning light flickered momentarily, then remained illuminated. He waited for 5 seconds then pulled the clutch circuit breaker and initiated an emergency descent for an autorotative landing. When the flight was about 50 feet above ground level he initiated a cyclic flare and about 10 feet above ground level, pulled collective pitch control for landing. The helicopter landed hard on unsuitable terrain. Examination of the helicopter revealed that one of the two vee-belts completely separated and 1/2 of the remaining belt had completely separated. Only 1/2 of one belt remained. According to the maintenance records, the vee-belt tension was checked about 42 hours earlier. The vee-belts had accumulated about 442 hours since new.

Probable Cause and Findings

COMPLETE SEPARATION OF ONE OF THE TWO VEE-BELTS, AND COMPLETE SEPARATION OF 1/2 OF THE REMAINING BELT. CONTRIBUTING TO THE ACCIDENT WAS THE DARK NIGHT CONDITION AND UNSUITABLE TERRAIN ENCOUNTERED DURING THE AUTOROTATIVE LANDING.

 

Source: NTSB Aviation Accident Database

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