MIA97LA222 · Waco YMF5
Reilly Aviation Waco YMF5 · Accident: total loss of engine power (mechanical failure) en route
From Kissimmee Gateway Airport (ISM) to an unrecorded destination
Event
- NTSB case
- MIA97LA222
- 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
Waco YMF5
- Aircraft type
- Waco YMF5
- Category
- Airplane
- 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
- N14128
- Operator
- Reilly Aviation
- Onboard fatalities
- Unknown
- Route
- From Kissimmee Gateway Airport (ISM), Kissimmee, FLTo not recorded
- 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 · cruise
- 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
- Company maintenance personnel › Maintenance, installation, improper
- Engine assembly, crankshaft › Failure, total
- Engine assembly, crankshaft › Fatigue
- Propeller system/accessories, prop blade retention › Loose part/bolt/nut/clamp/etc
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During cruise flight, the pilot noted an engine vibration followed by a total loss of engine power. He made a forced landing, but was unable to reach suitable terrain. During the landing rollout, he observed a ditch and intentionally ground looped the airplane, but the airplane collided with a pole. Examination of the propeller revealed the propeller retention nut was hand tight. Galling was present on the propeller hub mounting flange and the rear cone. Disassembly of the engine assembly revealed the crankshaft was broken at the counterweight flange. Visual inspection of the shear surfaces on the crankcase showed tell tale benchmarks that appeared to have originated at the oil way plug threads and progressed through approximately one fifth of the crank circumference. Interviews with personnel involved with the installation revealed they had retorqued the propeller, but had not followed accepted industry practices in establishing proper hub to rear cone contact surfaces.
Probable cause
failure of maintenance personnel to follow installation procedures pertaining to the torque of the propeller retention nut, which resulted in a loose propeller retention nut, subsequent fatigue failure of the crankshaft, and loss of engine power. The lack of suitable terrain for an emergency landing was a related factor.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record MIA97LA222
- Event ID
- 20001208X08472
- Case number
- MIA97LA222
- 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: 9b464d9a1482def38a0467f3e3b64c776db0a0a512df814083ff2dada5763894; retrieved 2026-09-22T18:59:33.608Z.