Helicopters Unlimited Piper PA-31-350 accident
Piper PA-31-350 · Accident: partial loss of engine power (mechanical failure) on approach
From Upland-Cable Airport (CCB) to Hayward Executive Airport (HWD)
Event
- NTSB case
- LAX88FA169
- 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
- Charter & commuter
- 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
Piper PA-31-350
- Aircraft type
- Piper PA-31
- 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
- N3588Y
- Operator
- Helicopters Unlimited
- Onboard fatalities
- Unknown
- Route
- From Upland-Cable Airport (CCB), Upland, CATo Hayward Executive Airport (HWD), Hayward, CA
- 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 135: Air Taxi & Commuter
- 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
- Approach · VFR pattern base
- 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
- Destroyed
Cause areas
- Pilot in command › Emergency procedure, not followed
- Propeller system/accessories, feathering system › Failure, partial
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
UPON ARRIVING AT HIS DESTINATION THE PILOT BEGAN A VISUAL, NIGHT DESCENT TO HIS DESTINATION AIRPORT. AS THE AIRCRAFT DESCENDED THE PILOT REDUCED THE AIRSPEED AND DEPLOYED FLAPS. AS THE AIRCRAFT NEARED THE AIRPORT THE PILOT INCREASED THE FLAP ANGLE AND ADJUSTED THE PROPELLERS TO THE LANDING RPM AND THE AIRSPEED DECREASED. THE PILOT STATED THAT AT THIS TIME HE HEARD A NOISE THAT SOUNDED LIKE A FLUTTER WHICH HE THOUGHT WAS EMANATING FROM THE RIGHT ENGINE. FULL THROTTLE WAS APPLIED, BUT THE AIRSPEED CONTINUED TO DECREASE AND THE PILOT ELECTED TO LAND ON A FREEWAY. THE AIRCRAFT COLLIDED WITH A MOTOR VEHICLE ON TOUCHDOWN AND SLID TO A STOP. POST CRASH EXAM REVEALED THE RPM CONTROL LEVERS AND BELLRANKS TO BE IN THE HIGH RPM SETTINGS. THE LEFT PROP WAS FOUND IN THE FEATHERED POSITION.
Probable cause
PILOT'S FAILURE TO DETECT AN UNCOMMANDED PROPELLER FEATHERING PROCEDURES ESTABLISHED IN THE PILOT'S OPERATING HANDBOOK.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX88FA169
- Event ID
- 20001213X25490
- Case number
- LAX88FA169
- 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: b5b892a75234ad76c199620d92a2de094e2917528978aeee6cbc456143280538; retrieved 2026-09-18T19:22:50.924Z.