FTW97LA322 · Rockwell S-2R
Rockwell S-2R · Accident: partial loss of engine power (mechanical failure) while maneuvering
From Deming Municipal Airport (DMN) to an unrecorded destination
Event
- NTSB case
- FTW97LA322
- 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
Rockwell S-2R
- Aircraft type
- Rockwell S-2
- 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
- N4893X
- Operator
- Robert J. Mamuzich · private individual
- Onboard fatalities
- Unknown
- Route
- From Deming Municipal Airport (DMN), Deming, NMTo 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 137: Agricultural
- 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
- Maneuvering · aerial application
- 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
- Partial 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
- Engine assembly, rocker arm/tappet › Separation
- Engine assembly, valve, exhaust › Separation
- Pilot in command › Aircraft control, uncontrolled
- Pilot in command › Incapacitation(loss of consciousness)
Approximate · Estimated position: the centre of Columbus, NM, the place the record names. Not the accident site.
NTSB narrative
The airplane impacted terrain following a loss of engine power while maneuvering. The pilot stated 'on the final pass [he] pulled up out of the field and initiated a turn towards Deming, when an object came through the right corner windshield striking [him] in the head,' rendering him unconscious. A witness who was approximately 1 mile from the accident site stated that he saw the airplane 'flying straight and then nose into the ground.' The witness did not hear any engine noises. Several workers, in a nearby field, reported that they observed the airplane pull out of the field and start to turn, when the engine quit. The owner examined the engine and determined that the exhaust side rocker box and exhaust valve mechanism had broken off the number 7 cylinder. There was a 'deep groove' on the back side of a propeller blade. The owner stated that the rocker box could have been ejected from the engine and contacted a propeller blade which deflected the rocker box into the cabin.
Probable cause
a loss of engine power due to failure of an exhaust side rocker box and valve mechanism, and pilot incapacitation due to loss of consciousness after being struck in the head by parts separating from the engine.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record FTW97LA322
- Event ID
- 20001208X08634
- Case number
- FTW97LA322
- 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: a8e32df1510114027c4ac7d9829869544efcc312c069e0d578d3d78827197783; retrieved 2026-09-21T11:52:53.593Z.