# NTSB LAX91LA137: Sikorsky H-19/S55, N9894, Richvale, CA, March 19, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: March 18, 1991, 16:30 local (Mar 19, 1991, 00:30 UTC)
- Place: Richvale, CA
- Coordinates: 39.479099, -121.839874 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.4791&lon=-121.8399&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report March 31, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27142
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91LA137
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27142/pdf
- Page: https://openairdocs.org/ntsb/LAX91LA137

## Probable cause

THE FAILURE OF THE ENGINE'S NUMBER 4 CYLINDER INTAKE VALVE KEEPER.  TREES UNDER THE HELICOPTER AT THE TIME OF THE LOSS OF ENGINE POWER WERE FACTORS IN THE ACCIDENT.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, maneuvering - aerial application
  - engine assembly,valve,intake - open (cause)
- Forced landing, descent - emergency
- In flight collision with object, descent - emergency
  - object - tree(s) (contributing factor)
- In flight collision with terrain/water, landing - flare/touchdown

## Analysis

THE PILOT STATED THAT HE WAS DISPENSING HIS 20TH LOAD OF INSECT SPRAY OVER ALMOND TREES. DURING A SWATH RUN THE ENGINE LOST POWER AND THE HELICOPTER IMPACTED THE TREES AND THEN THE GROUND. THE ENGINE'S NUMBER 4 CYLINDER INTAKE VALVE KEEPER FAILED.

## Aircraft

- Registration: [N9894](https://openairdocs.org/aircraft/N9894), registered now, S/N 55998 (OpenAirDocs)
- Reported make and model: SIKORSKY H-19/S55
- Registry model: [Sikorsky H-19D](https://openairdocs.org/model/sikorsky-h-19d) (registry code 8141610) (OpenAirDocs)
- Category: Helicopter
- Serial number: 55998
- Engines: WRIGHT R-1300 800 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Avag, Inc.
- Last inspection: Unknown, January 2, 2000

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; flight hours: 1,756 total, 1,276 in this make and model, 1,445 as pilot in command, 141 in the last 90 days, 118 in the last 30 days, 8 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 220° at 5 knots
- Visibility: 40 statute miles
- Lowest ceiling: 20,000 ft overcast
- Temperature: -0 °F, dew point -0 °F
- Observed at: CNO, 19 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 19910318006639A](https://openairdocs.org/incident/19910318006639A), Mar 18, 1991: Orlhel H19DSKRSKY, Orland, CA, Substantial damage. Impacted trees on forced landing during a spray run. Intake valve keeper failed allowed intake valve remain open.

## Other investigations on N9894 (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 OAK79DVG21](https://openairdocs.org/ntsb/OAK79DVG21), Mar 7, 1979: Sikorsky H-19D (N9894), Vina, 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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