IAD01LA002 · American Aviation Corp. (AAC) AA-1A
American Aviation Corp. (AAC) AA-1A · Accident: total loss of engine power (mechanical failure) during an emergency descent
From Northeast Philadelphia Airport (PNE) to an unrecorded destination
Narrative check · The NTSB narrative appears to contradict this record's injuries. Values are shown as recorded, not corrected; compare with the narrative.
Event
- NTSB case
- IAD01LA002
- 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
American Aviation Corp. (AAC) AA-1A
- Aircraft type
- American Aviation Corp (aac) AA-1
- 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
- N9394L
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Northeast Philadelphia Airport (PNE), Philadelphia, PATo 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
- Emergency 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
- 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
- Engine assembly, cylinder › Failure
- Fluid, oil › Starvation
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The airplane was on a traffic observation flight when it experienced a total loss of engine power. The pilot performed a forced landing to a schoolyard and escaped uninjured. Initial examination revealed heat damage to the #4 cylinder and no oil in the engine. Removal of the #4 cylinder revealed a hole in the #4 piston at the 12 o'clock position beneath the piston ring lands. The hole carried through to the interior of the piston. Removal of the #2 cylinder revealed that the #1 connecting rod was separated from the crankshaft. In addition to the hole through the #4 piston, examination revealed a deep groove in the side of the piston in line with the forward piston pin plug. The plug was worn and heat damaged, with significant material loss. Material transfer in line with the piston plug was observed on the wall of the #4 cylinder. The oil-scraper piston rings on the #1 and #2 pistons were installed backwards. The #3 cylinder had 3 base nuts installed upside down. Examination of the #1 and #2 cylinder assemblies revealed they were Superior cylinders. The number #3 and #4 cylinder assemblies were reworked Lycoming cylinders. The individual piston part numbers could not be determined. Examination of the maintenance records revealed the owner/operator replaced the #3 and #4 cylinder assemblies 337 aircraft hours prior to the accident. The owner/operator serviced the engine with 80 weight oil, and returned the airplane to service. The #1 and #2 cylinder assemblies were replaced by a maintenance facility 235 aircraft hours prior to the accident, and the engine was serviced with mineral oil as recommended by the engine manufacturer.
Probable cause
A hole in the #4 piston for undetermined reasons which resulted in engine oil starvation and engine stoppage.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record IAD01LA002
- Event ID
- 20001212X22166
- Case number
- IAD01LA002
- 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, coordinates. 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: 1bf6592b4f454a1d0164d2f716319c6a70e99650d6c335acc529d24e9163377f; retrieved 2026-09-21T20:04:00.574Z.