Med-Trans Bell 407 accident
Bell 407 · Accident: loss of engine power (partial) en route
From Fort Stockton, TX to Shannon Medical Center Heliport (03TS)
Event
- NTSB case
- CEN13LA119
- 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
- 0
- 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
- Charter & commuter
- 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 407
- Aircraft type
- Bell 407
- 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
- N534MT
- Operator
- Med Trans
- Onboard fatalities
- Unknown
- Route
- From Fort Stockton, TXTo Shannon Medical Center Heliport (03TS), San Angelo, TX
- 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
- Part 135: Air Taxi & Commuter
- 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
- En route · cruise
- Defining eventThe 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
- Loss of engine power (partial)
- 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
- Aircraft › Aircraft power plant
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that, while in cruise flight, the helicopter suddenly yawed 10 degrees right. He was able to control the yaw and subsequently heard an alarm and observed an rpm warning light. After silencing the alarm, he noticed a 2- to 3-percent decrease in rpm for the engine and rotor. As the pilot began to scan the flight controls and instruments, he saw the "check instrument segment" illuminate, and the measured gas temperature gauge begin to flash and display a reading of "E 920." The pilot stated that all of the other engine indications were in the normal operating ranges. During the precautionary landing, when the helicopter was about 10 to 15 ft above ground level and 20 knots, the engine "quit." The pilot responded by moving the throttle to idle and increasing the collective pitch. The helicopter subsequently hit the ground hard, which resulted in substantial damage to the tailboom.
During the postaccident examination of the engine, three fractures were found in the outer combustion case at the fuel nozzle port. Two of the three fractures originated at the intersection of the circumferential weld that joined the reinforcing ring to the main skin and exhibited heat tinting consistent with the cracks having been open during engine operation. The third fracture ran adjacent to the reinforcing ring to the main skin interface. All three fractures exhibited signatures consistent with high-cycle fatigue. The investigation determined that the operator was not conducting the manufacturer-recommended postflight and scheduled maintenance inspections of the outer combustion case; these cracks would likely have been detected during such inspections.
Probable cause
The loss of engine power due to the fatigue failure of the outer combustion case at the fuel nozzle port. Contributing to the accident was the operator’s failure to conduct the recommended routine inspections of the outer combustion case.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN13LA119
- Event ID
- 20130101X65128
- Case number
- CEN13LA119
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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. 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: 8ff8faf4147dc64e713cbb9e08fffd3c46ade3427dbc82c7a71838a957985d7c; retrieved 2026-09-15T20:41:19.291Z.