# NTSB LAX86DVA06: Bell UH-1B, N910PD, Chowchilla, CA, April 16, 1986

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Final report
- Date: April 16, 1986, 11:24 local (19:24 UTC)
- Place: Chowchilla, CA
- Coordinates: 37.069702, -120.27005 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.0697&lon=-120.2700&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 24864
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX86DVA06
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/24864/pdf
- Page: https://openairdocs.org/ntsb/LAX86DVA06

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, cruise - normal
  - lubricating system,oil gasket - distorted (cause)
  - fluid,oil - exhaustion (cause)
  - misc rotorcraft,transmission oil press ind - no pressure (cause)
  - rotor drive system,main gearbox/transmission - jammed (cause)
- Forced landing, descent - emergency
  - operation with known deficiencies in equipment - continued, pilot in command (cause)
  - autorotation - not performed, pilot in command
- Roll over, landing - flare/touchdown

## Analysis

WHILE RETURNING FROM A SPRAYING OPERATION THE PLT OBSERVED THAT THE MAIN TRANSMISSION OIL PRESSURE GAGE INDICATED ZERO. THE PLT REPORTED THAT THE ENGINE MASTER CAUTION DID NOT ILLUMINATE AND THAT THE OIL TEMPERATURE GAGE WAS NORMAL. THE PLT STATED THAT HE DECIDED THAT THE OIL PRESSURE GAGE WAS FAULTY AND ELECTED TO CONTINUE THE FLT. ABOUT 5 MINUTES LATER, THE TRANSMISSION OIL TEMP GAGE BEGAN TO RISE RAPIDLY.THE HELICOPTER BEGAN TO SHAKE VIOLENTLY AND THE MAIN ROTOR RPM BEGAN TO DECAY. THE PLT, UNABLE TO PERFORM AN AUTOROTATION DUE TO LOW ROTOR RPM EXECUTED A POWER ON LANDING, AND THE HELICOPTER ROLLED OVER AT IMPACT. POST ACCIDENT INVESTIGATION DISCLOSED THE OIL COLLER HOUSING GASKET WAS DAMAGED AND THE TRANSMISSION OIL RESERVOIR DID NOT CONTAIN ANY OIL. THE TRANSMISSION OUTER HOUSING AND PLANETARY GEARS EXHIBITED HIGH TEMPERATURE DISTRESS.

## Aircraft

- Registration: [N910PD](https://openairdocs.org/deregistered/N910PD-2013-06-07), registration cancelled 2013-06-07, S/N 62-1954, built 1962 (OpenAirDocs)
- Reported make and model: BELL UH-1B
- Registry model: [Bell UH-1B](https://openairdocs.org/model/bell-uh-1b) (registry code 1181410) (OpenAirDocs)
- Registry engine: [Lycoming T-53 series](https://openairdocs.org/engine/lycoming-t-53-series) (registry code 41552, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 474
- Airframe hours: 9090
- Engines: LYCOMING T53-L11D 1100 horsepower turbo shaft
- Damage: Destroyed
- Flight: Ferry, Part 91
- Operator: San Joaquin Helicopter, Inc.
- Registered owner: San Joaquin Helicopters
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, July 1, 1985, 65 hours before
- Departed: SNELLING, CA
- Destination: DLO, DELANO, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 10,000 total, 50 in the last 90 days, 20 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 63 °F, dew point 37 °F
- Altimeter: 30.00 inHg
- Observed at: FAT, 20 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19860416012089A](https://openairdocs.org/incident/19860416012089A), Apr 16, 1986: Bell UH1B, Chowchilla, CA, Destroyed. The engine lost power and the helicopter rolled over during an emergency landing. No oil in transmission.

## Other investigations on N910PD (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB LAX82DA264](https://openairdocs.org/ntsb/LAX82DA264), Jul 18, 1982: Bell 204 (N910PD), Delano, CA, destroyed

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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