# NTSB LAX90DVD03: Texas Helicopter M47A Wasp, N43921, Stockton, CA, August 27, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: August 27, 1990
- Place: Stockton, CA
- Coordinates: 37.959621, -121.259399 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.9596&lon=-121.2594&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report November 9, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26568
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90DVD03
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26568/pdf
- Page: https://openairdocs.org/ntsb/LAX90DVD03

## Probable cause

THE PILOT MISJUDGED THE ALTITUDE DURING THE FLARE/TOUCHDOWN PHASE OF THE AUTOROTATION. FACTORS RELATING TO THIS ACCIDENT ARE FAILURE OF THE RIGHT MAGNETO.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, takeoff - initial climb
  - ignition system,magneto - failure,total (contributing factor)
- Forced landing, descent - emergency
- Hard landing, landing - flare/touchdown
  - altitude - misjudged, pilot in command (cause)

## Analysis

THE PILOT LANDED THE HELICOPTER AND IT WAS RELOADED WITH CHEMICALS FOR ANOTHER AGRICULTURAL SPRAYING FLIGHT. SHORTLY AFTER DEPARTING THE LOAD SITE, THE PILOT HEARD A LOUD SOUND ENAMATE FROM THE ENGINE AREA FOLLOWED BY A SUDDEN LOSS OF POWER AND VIBRATION. THE PILOT IMMEDIATELY EXECUTED AN AUTOROTATION TO THE OPEN AREA, BUT MISJUDGED THE FLARE ALTITUDE AND EXPERIENCED A HARD LANDING WHICH CAUSED SUBSTANTIAL DAMAGE TO THE HELICOPTER. THE INVESTIGATION REVEALED THAT THE RIGHT MAGNETO CONTACT POINTS FAILED.

## Aircraft

- Registration: [N43921](https://openairdocs.org/aircraft/N43921), registered now, S/N 76-003, built 1977 (OpenAirDocs)
- Reported make and model: Texas Helicopter M47A WASP
- Registry model: [Texas Helicopter OH-13E/M74](https://openairdocs.org/model/texas-helicopter-oh-13e-m74) (registry code 8930103) (OpenAirDocs)
- Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 76-003
- Airframe hours: 2311
- Engines: LYCOMING VO-435-A1F 265 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Ag Air, Inc.
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: 100 hour, August 2, 1990, 48 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 2,500 total, 600 in this make and model, 2,200 as pilot in command, 200 in the last 90 days, 95 in the last 30 days, 8 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 5 knots
- Visibility: 40 statute miles
- Lowest ceiling: none
- Temperature: 70 °F, dew point 54 °F
- Altimeter: 30.00 inHg
- Observed at: SCK, 10 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 19900827037099A](https://openairdocs.org/incident/19900827037099A), Aug 27, 1990: Bell OH13M74TEXH, Stockton, CA, Substantial damage. Rough engine and power loss on takeoff. Dropped to ground causing substantial damage. Mag timing improperly set.

## Other investigations on N43921 (2)

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 WPR12LA115](https://openairdocs.org/ntsb/WPR12LA115), Feb 22, 2012: Texas Helicopter OH-13E/M74 (N43921), Farmington, CA, substantial damage. Probable cause: The in-flight separation of the wood portion of one main rotor blade while maneuvering at low level, the reason for which could not be determined because postaccident examination did not reveal any…
- [NTSB LAX91LA388](https://openairdocs.org/ntsb/LAX91LA388), Sep 11, 1991: Texas Helicopter M74 (N43921), Farmington, CA, destroyed, 1 fatal. Probable cause: LOSS OF ENGINE POWER FOR AN UNDETERMINED REASON. FACTORS RELATED TO THE ACCIDENT WERE: THE EXCESSIVE GROSS WEIGHT OF THE HELICOPTER, AND THE PILOT'S IMPROPER USE OF FLIGHT CONTROLS DUE TO IMPAIRMENT…

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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