CHI97LA222 · Morgan MINI-500
Morgan MINI-500 · Accident: loss of engine power en route
From Cabool Memorial Airport (TVB) to Ava Bill Martin Memorial Airport (AOV)
Event
- NTSB case
- CHI97LA222
- 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
- General aviation
- 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
Morgan MINI-500
- Aircraft type
- Morgan MINI-500
- 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
- N500XM
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Cabool Memorial Airport (TVB), Cabool, MOTo Ava Bill Martin Memorial Airport (AOV), MO
- 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 91: General Aviation
- 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 · descent
- 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
- Loss of engine power
- 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
- Cooling system, lines › Leak
- Terrain condition › None suitable
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot was completing a series of flight tests that involved transitions from cruise flight into a hover. The pilot reported the exhaust gas temperature (EGT) was higher in cruise flight than when hovering and that the EGT cooled rapidly when the helicopter went from cruise flight into the hovering maneuver. The pilot stated that approximately two miles from his destination, at 2,500 feet mean sea level (msl), he began a 200 to 300 foot/min descent to reach the airport's traffic pattern altitude. He said that as soon as the descent was initiated he experienced unusual engine noises and an abrupt loss of engine power. He lowered the collective and applied full power, but received no indication of engine power. He then initiated an autorotation to landing on a field with a 30-degree slope. Upon landing, the aircraft rolled over and came to rest on its port side causing the rotor to impact the tail boom. Examination of the engine showed evidence that the engine had seized during flight. Inspection of the fuel metering system showed that the accident airplane had not complied with Revolution Helicopter Service Information Letter number 042696, which requires the original factory carburetor jet setting to be adjusted to insure that the EGT be between 1,000 and 1,150 degrees Fahrenheit. No engine coolant was found in the coolant tank and the coolant hose tee was found to be deformed and leaking fluid.
Probable cause
Loss of engine power due to loss of engine cooling fluid. Related factors were maintenance service bulletin not complied with by the owner/pilot mechanic resulting in low output of the carburetor, and unsuitable terrain.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI97LA222
- Event ID
- 20001208X08334
- Case number
- CHI97LA222
- 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. 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: 448d31dc6d5c53e138eaf12ea5f01e9503b25562068454a784af266d78fa9fb1; retrieved 2026-09-22T19:06:09.115Z.