# NTSB MIA94LA054: Robinson R22B, N193HC, Gurabo, PR, January 16, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: January 15, 1994, 22:20 local (Jan 16, 1994, 02:20 UTC) - Place: Gurabo, PR - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report December 7, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 37481 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA94LA054 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/37481/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=37481 - Page: https://openairdocs.org/ntsb/MIA94LA054 ## Probable cause 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. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - normal - rotor drive system,main rotor drive belt - separation (cause) - Forced landing, descent - emergency - light condition - dark night (contributing factor) - Hard landing, landing - flare/touchdown - unsuitable terrain or takeoff/landing/taxi area - encountered, pilot in command (contributing factor) ## 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 narrative 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. ## Aircraft - Registration: [N193HC](https://openairdocs.org/deregistered/N193HC-1998-11-23), registration cancelled 1998-11-23, S/N 1924 (OpenAirDocs) - Reported make and model: ROBINSON R22B - Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs) - Category: Helicopter - Serial number: 1924 - Airframe hours: 442 - Engines: LYCOMING O-320-B2C 160 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Registered owner: Initiative Trade Corp. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 5, 1993, 27 hours before - Destination: SIG, SAN JUAN, PR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 23; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 1,475 total, 760 in this make and model, 1,225 as pilot in command, 70 in the last 90 days, 25 in the last 30 days ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 180° at 3 knots - Visibility: 12 statute miles - Lowest ceiling: 25,000 ft overcast - Temperature: 73 °F, dew point 72 °F - Altimeter: 30.00 inHg - Observed at: SJU, 11 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19940115048809A](https://openairdocs.org/incident/19940115048809A), Jan 15, 1994: Robsin R22BETA, Gurabo, Puerto Rico, Substantial damage. Burning smell overheated clutch light. Autorotated. Hard landing in rough area. Clutch v belts had separated. ## Docket (2 files) The files NTSB released with the investigation on June 6, 1995, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=37481. 473 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2 (item 1, .PDF, 395 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40449160&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%2F2-Redacted.PDF - Reports from Federal Agencies (item 2, .PDF, 78 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40449161&FileExtension=.PDF&FileName=Reports%20from%20Federal%20Agencies-Redacted.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.