# Accident 19981223041899A: Bell UH1H, Quincy, CA, December 23, 1998

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: December 23, 1998, 11:51 local time
- Place: Quincy, CA
- Damage: Destroyed
- Phase of flight: Low Level Operations
- Operating rules: Rotorcraft external load (Part 133)
- Operator: IAVA
- Location: 39.9608° N, 121.0001° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=39.9608&lon=-121.0001&mi=10
- Aircraft: N4590, a cancelled registration (https://openairdocs.org/deregistered/N4590-2000-01-07) (OpenAirDocs)
- Registry model: Bell UH-1H (registry code 1181407, https://openairdocs.org/model/bell-uh-1h) (OpenAirDocs)
- Reported make and model: BELL UH1H
- Reported engine: LYC T53L13B
- People aboard: 1
- Fatal injuries: 1
- Pilot flight hours: 15,000 total, 8,000 in this make and model, 100 in the last 90 days
- NTSB investigation: [NTSB LAX99FA057](https://openairdocs.org/ntsb/LAX99FA057) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19981223041899A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

(.19)ON DECEMBER 23, 1998, AT 1151 HOURS PACIFIC STANDARD TIME, A BELL UH-1H, N4590, ENTERED AN UNCONTROLLED DESCENT, IMPACTED AN EMBANKMENT AND ROLLED INTO BELDEN RESERVOIR, 7 MILES WEST OF QUINCY, CALIFORNIA. THE AIRCRAFT WAS APPROACHING A LANDING SPOT WHEN THE EVENT OCCURRED.  THE HELICOPTER WAS DESTROYED AND THE COMMERCIAL LICENSED PILOT WAS FATALLY INJURED.  VISUAL METEOROLOGICAL CONDITIONS PREVAILED FOR THE EXTERNAL LOAD OPERATION THAT WAS CONDUCTED BY WESTWIND HELICOPTERS, INC., UNDER 14 CFR PART 133.(.4) WHILE CONDUCTING EXTERNAL LOAD OPERATIONS, THE PILOT RADIOED THAT THE ENGINE HAD FAILED. WITNESSES REPORTED VISUALLY OBSERVING THE MAIN ROTOR SLOWING AND THE INDIVIDUAL BLADES BECOMING VISIBLE BEFORE THE HELICOPTER DESCENDED STEEPLY INTO A RESERVOIR FROM ABOUT 200 FEET AGL. THE MAIN ROTOR DRIVESHAFT, MAIN ROTOR BLADES, AND THE TAIL ROTOR BLADES EXHIBITED SIGNATURES CONSISTENT WITH LOW ROTOR RPM AT IMPACT. ENGINE EXAMINATION REVEALED THAT THE GAS PRODUCER AND POWER TURBINE ASSEMBLY HAD FAILED AS A RESULT OF THE CUMULATIVE EFFECTS OF THERMAL STRESS DUE TO OVER-TEMPERATURE OPERATION. FURTHER EXAMINATION REVEALED THAT THE EXHAUST GAS TEMPERATURE HARNESS ON THE ENGINE HAD A     LOW SIGNAL OUTPUT RESULTING IN A LOW EGT INDICATION IN THE COCKPIT WHICH CAUSED THE COMPANY PILOTS TO UNKNOWINGLY OPERATE THE ENGINE IN EXCESS OF MAXIMUM EGT. ACCORDING TO OTHER COMPANY PILOTS WHO FLEW THIS HELICOPTER ON TYPICAL EXTERNAL LOAD OPERATIONS, THE ENGINE WOULD REACH ITS EGT LIMIT BEFORE THE MAXIMUM TORQUE WAS ACHIEVED. THE OPERATOR DID NOT ROUTINELY PERFROM HEALTH INDICATOR TESTS (HIT CHECKS) WHICH WERE DEVELOPED BY THE U. S. ARMY TO DETECT CHANGES IN ENGINE POWER OUTPUT. REVIEW OF THE HELICOPTER'S FAA TYPE CERTIFICATE DATA SHEET (H15NM) REVEALED THE REQUIREMENT FOR HIT CHECKS TO BE ACCOMPLISHED PRIOR TO EACH TAKEOFF AND RECORDED IN A LOG RECORD. (-23) AIRCRAFT WAS REPORTED TO IIC 1500, 12/23/98. AIRCRAFT WAS REMOVED FROM SITE BY TOWING COMPANY AND SHERIFF'S DEPARTMENT. RELEASED AIRCRAFT WITHOUT AUTHORITY FROM FAA OR NTSB. VISITED AIRCRAFT 12/24/98 AT CRESENT TOWING. AIRCRAFT APPEARED TO BE ALL PRESENT. VISITED SITE. VERY LITTLE AT SITE. THE LIFT BASKET IS AT SITE. ONLY ONE WITNESS STATEMENT AVAILABLE AT THIS TIME. THIS IS A PRELIMINARY REPORT AND AMENDED FORM 8020-23 WILL BE FORWARDED UPON FURTHER INVESTIGATION.

## The NTSB's investigation of this event (1)

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.

- [NTSB LAX99FA057](https://openairdocs.org/ntsb/LAX99FA057), Dec 23, 1998: Bell UH-1H (N4590), Quincy, CA, destroyed, 1 fatal. Probable cause: An inaccurate exhaust gas temperature gauge, that allowed the engine to be run over-temperature unknowingly by the pilot, which resulted in the subsequent failure of the turbine sections. Also causal…

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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