Amateur-built S1S accident near Van Nuys, California, August 17, 1997
On August 17, 1997 at about 8:00 pm local time, a amateur-built S1S, registered N10HJ, was destroyed in an accident near Van Nuys, California. It was a personal flight under general aviation rules (Part 91). 1 person was killed. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
the operation of the propeller beyond the design rpm limitations and the resultant gyroscopic loads from aerobatics. Contributing to the accident was the lack of a required instrument panel rpm restriction for the propeller mandated by an airworthiness directive.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 17, 1997 · about 8:00 pm local time
- Place
- Van Nuys, California · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built S1S
- Registration
- N10HJ · registry record · serial 001HJ
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot departed and requested a right-hand departure to the practice area. During the downwind departure he declared an emergency and witnesses observed the aircraft spiraling downward at a 45-degree angle into a residential street. Parts from the aircraft were found some distance from the accident site. The propeller along with the severed crankshaft flange were found still bolted together less part of one propeller blade. Metallurgical examination revealed that a blade had failed midspan due to fatigue. The propeller was being operated above the design rpm red line of 2,700. Additionally, the propeller was being subjected to gyroscopic aerobatic loads. An rpm restriction for the propeller mandated by an airworthiness directive was not placarded on the instrument panel per the AD. The engine was designed for a type certificated helicopter application and was approved for a 3,200 rpm red line.
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: private
- Ratings: single-engine land
- Flight time: 238 hours in all; 43 in this make and model
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: unk
The aircraft
- Airframe total time: 494 hours
- Last inspection: annual inspection, March 26, 1997; 84 hours since
- Landing gear: fixed
- Engine: Lycoming HIO-360-D1A (piston); 0 hours total
- Not recorded
The flight
- Departed from: KVNY CA at 7:55 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: not reported
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 88°F (31°C), dew point 0°F (-18°C)
- Observation at 8:00 pm from KVN
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.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number LAX97FA291.