Riddell LANCAIR 235 N17S
1 February 1991 · Agua Caliente, California, United States · Serious injuries
Summary
On 1 February 1991 at about 20:30 local time, a Riddell LANCAIR 235 registered N17S, operated by Kenneth E. Parks, was involved in an accident near Agua Caliente, California, United States. 2 people were on board and 2 were seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.
The record
- Date
- at 20:30
- Classification
- Accident
- Location
- Agua Caliente, California, United States
- Coordinates
- 32.7897, -116.9595
- Aircraft
- Riddell LANCAIR 235
- Registration
- N17S
- Category
- Airplane
- Engines
- 1
- Operator
- Kenneth E. Parks
- Operating rule
- Part 91: General Aviation
- Purpose of flight
- Personal
- Phase of flight
- Not recorded
- Route
- San Diego → Unknown
- Aircraft damage
- Substantial
- Weather
- VMC
- Light
- Day
- NTSB number
- LAX91LA090
People
2 people were seriously injured.
| On board | Died | Serious | Minor | Uninjured |
|---|---|---|---|---|
| 2 | 0 | 2 | 0 | 0 |
Probable cause
THE FAILURE OF THE PROPELLER BLADES DUE TO A WEAKENING OF THE WOOD STRUCTURE DUE TO ACID HYDROLYSIS. A FACTOR IN THE ACCIDENT WAS THE INADEQUATE MAINTENANCE OF THE PROPELLER ASSEMBLY BY ALLOWING EXPOSURE TO EXCESSIVE MOISTURE AND HEAT.
Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.
Read the full NTSB narrative
THE AIRCRAFT WAS ON CLIMB OUT WHEN A LOUD BANG WAS HEARD, FOLLOWED BY AN ENGINE OVERSPEED THEN ENGINE STOPPAGE. AFTER THE FORCED LANDING, THE PILOTS FOUND THAT BOTH WOODEN PROPELLER BLADES HAD SEPARATED FROM THE STEEL HUB ASSEMBLY. THE PROPELLER HUB WAS REMOVED FROM THE ENGINE AND SENT TO THE MANUFACTURER FOR FUNCTIONAL ANALYSIS AND DISASSEMBLY UNDER THE SUPERVISION OF FAA INSPECTORS. THE MANUFACTURER STATED THAT ALL INTERNAL COMPONENTS WERE FUNCTIONAL, HOWEVER, THE CAM ADJUSTMENT FOR THE HIGH AND LOW PITCH STOP SETTINGS HAD BEEN ALTERED FROM THE FACTORY SETTINGS. THE BLADE BUTT ENDS RETAINED IN THE HUB WERE REMOVED AND SUBMITTED TO THE FOREST PRODUCTS LABORATORY OF THE US DEPARTMENT OF AGRICULTURE FOR ANALYSIS. ACCORDING TO THE LABORATORY THE WOODEN BLADES FRACTURED AND SEPARATED DUE TO A HYDROLYSIS INTERACTION BETWEEN THE WOOD AND THE ADHESIVE CAUSED BY EXCESS MOISTURE AND HEAT. THE HYDROLYSIS IS A CHEMICAL DECOMPOSITION PROCESS OF THE WOOD AND GLUE RELATIONSHIP.
Quoted verbatim from the NTSB record.
Other accidents in this area
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 20 Jul 1991 | Cessna C-172P | Hesperia, California, United States | South Bay Aviation | No injuries | - |
| 24 Jul 1991 | Cessna 172N | Napa, California, United States | Bridgeford Flying SVC. | No injuries | - |
| 24 Jul 1991 | Beechcraft 76 | Sacramento, California, United States | Altair Aviation Corp. | No injuries | - |
| 27 Jul 1991 | Ayres S2R | Visalia, California, United States | Gilbert Aviation Industries | Serious injuries | - |
| 1 Aug 1991 | Cessna 421C | Auburn, California, United States | Edward Mueller | No injuries | - |
| 2 Aug 1991 | Champion 7GCBC | Lake Elsinore, California, United States | Halbeisen, John F | Fatal | 2 |