ATL92LA063 · Beech A36
Beech A36 · Accident: total loss of engine power (mechanical failure) en route
From Huntsville International Airport (HSV) to Abraham Lincoln Capital Airport (SPI)
Event
- NTSB case
- ATL92LA063
- 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
Beech A36
- Aircraft type
- Beechcraft 36
- 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
- N174OD
- Operator
- Snyder, Michael C. · private individual
- Onboard fatalities
- Unknown
- Route
- From Huntsville International Airport (HSV), Huntsville, ALTo Abraham Lincoln Capital Airport (SPI), Springfield, IL
- 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)
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- 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
- Engine assembly, cylinder › Undertorqued
- Manufacturer › Maintenance, overhaul, inadequate
- Manufacturer › Procedure inadequate
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
WHILE CRUISING THE ENGINE DEVELOPED A VIBRATION AND STARTED RUNNING ROUGHLY. THE PILOT REDUCED POWER AND ESTABLISHED A TRACK FOR AN EMERGENCY LANDING TO A NEARBY COUNTY AIRPORT; THE AIRPLANE CRASHED ABOUT ONE MILE SHORT OF THE AIRPORT. EXAMINATION OF THE ENGINE ASSEMBLY DISCLOSED THAT A PIECE OF THE CRANKCASE WAS BROKEN ABOVE NUMBER 2 CYLINDER AND THE CYLINDER WAS PARTIALLY SECURED BY ONE HOLD DOWN NUT ON THE BOTTOM LEFT SIDE. FURTHER EXAMINATION REVEALED FRETTING BETWEEN THE CYLINDER FLANGE AND THE ENGINE CASE. ALL CRANKCASE FRACTURES SHOWED SIGNS OF OVERLOAD FAILURE. THE ENGINE MAINTENANCE LOGS DISCLOSED THAT THE ENGINE'S CRANKCASE HAD BEEN REPLACED ON 10/24/90; THIS ENGINE MALFUNCTION OCCURRED 258 HOURS LATER. SUBSEQUENT TO THIS ACCIDENT, CONTINENTAL MOTORS ISSUED A SERVICE BULLETIN WHICH INCREASED THE TORQUE VALUE FOR THE CYLINDER HOLD DOWN NUTS, AND INSTRUCTED THAT THE STANDARD SIX POINT HOLD DOWN NUTS BE REPLACED WITH TWELVE POINT NUTS DURING OVERHAUL.
Probable cause
THE MANUFACTURER'S FAILURE TO PROVIDE ADEQUATE TORQUE INFORMATION WHICH RESULTED IN THE LOSS OF TORQUE ON THE CYLINDER HOLD DOWN NUTS AND THE COMPLETE LOSS OF ENGINE POWER.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ATL92LA063
- Event ID
- 20001211X14218
- Case number
- ATL92LA063
- 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: c0dc1405f18476b3158472f2684cbc482c4e1d931147923a987041f2579d4e6e; retrieved 2026-09-21T15:04:41.772Z.