LAX04TA018 · Bell UH-1H
Bell UH-1H · Accident: total loss of engine power (mechanical failure) on approach
From Rancho Murietta, CA to McClellan Airfield (MCC)
Event
- NTSB case
- LAX04TA018
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Government
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Bell UH-1H
- Aircraft type
- Bell UH-1
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N114FD
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Rancho Murietta, CATo McClellan Airfield (MCC), Sacramento, CA
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Public Aircraft
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Approach · VFR pattern downwind
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Total loss of engine power (mechanical failure)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Compressor assembly › Foreign object damage
- Reduction gear assembly, accessory drive gear › Fatigue
- Reduction gear assembly, accessory drive gear › Separation
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The helicopter landed hard following a loss of engine power in the traffic pattern. The pilot reported that he picked up the helicopter after maintenance was performed on the audio and visual low rpm warning systems and was positioning the helicopter to back to the airport. As he entered the pattern, he heard a bang and what he described as "a horribly loud grinding sound coming from the rear of the aircraft," and lost engine power. The pilot entered an autorotation to a clear area on the airport. As the helicopter neared the touchdown point, the pilot realized the selected landing area was sloped and so he increased collective to extend the glide to reach a flat area. The helicopter landed hard. A teardown and examination of the engine disclosed that the type and degree of damage to the engine was indicative of the separation of a portion of a planetary reduction gear, which resulted in a piece of inlet housing entering the compressor. This resulted in damage to the compressor airfoils and a loss of power. The separation of the portion of planetary reduction gear was determined to be the result of a fatigue fracture emanating from the aft root corner of one gear tooth. The root cause of the fatigue fracture could not be determined due to smearing of the initiation site. The planetary gears installed in the engine were military direct purchase breakout parts. The engine manufacturer does not approve of the use of military direct purchase hardware in FAA certified or military surplus engines used in public-use operations.
Probable cause
The loss of engine power due to the fatigue failure of a planetary reduction gear.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX04TA018
- Event ID
- 20031114X01910
- Case number
- LAX04TA018
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 7bb22c50749904bfde30507a66c394083d6179872b485b1d3ecf006c5e33bdbb; retrieved 2026-09-18T21:17:14.431Z.