American Aviation Corp. (Aac) AA-1A accident near Philadelphia, Pennsylvania, October 11, 2000
On October 11, 2000 at about 10:14 am local time, a American Aviation Corp. (Aac) AA-1A, registered N9394L, was substantially damaged in an accident near Philadelphia, Pennsylvania (Northeast Philadelphia airport). It was an aerial observation flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A hole in the #4 piston for undetermined reasons which resulted in engine oil starvation and engine stoppage.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 11, 2000 · about 10:14 am local time
- Place
- Philadelphia, Pennsylvania · Northeast Philadelphia · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- American Aviation Corp. (Aac) AA-1A
- Registration
- N9394L · no longer on the register · serial AA-1A-0094
- Damage
- Substantial damage
- Flight
- Aerial observation flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 2,083 hours in all; 1,630 in this make and model; 163 in the last 90 days; 94 in the last 30 days; 2,016 as pilot in command
- Last flight review: May 4, 2000
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: unk
- Injury: minor injuries
The aircraft
- Airframe total time: 2,937 hours
- Last inspection: annual inspection, May 1, 2000; 448 hours since
- Maximum gross weight: 1,500 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-235C (piston); 0 hours total
The flight
- Departed from: PNE Philadelphia PA at 10:05 am
- Flight plan: none
Weather at the time
- Light: dawn
- Wind: from 220° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 45°F (7°C), dew point 36°F (2°C)
- Altimeter: 30.00 inHg
- Observation at 9:54 am from PNE, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.