# NTSB LAX87FA290: de Havilland DHC-6, N931MA, Palmdale, CA, August 4, 1987

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Field investigation · Final report
- Date: August 4, 1987, 12:19 local (19:19 UTC)
- Place: Palmdale, CA
- Coordinates: 34.520126, -118.080924 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.5201&lon=-118.0809&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 11 uninjured
- Status: Completed, report June 7, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 25414
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX87FA290
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/25414/pdf
- Page: https://openairdocs.org/ntsb/LAX87FA290

## Sequence of events

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

- Midair collision, descent - normal
  - visual lookout - inadequate, pilot in command (cause)
  - visual lookout - inadequate, pilot of other aircraft (cause)
- Midair collision, cruise - normal
  - visual lookout - inadequate, pilot in command (cause)
  - visual lookout - inadequate, pilot of other aircraft (cause)

## Analysis (aircraft 2)

A DEHAVILLAND DHC-6, N931MA, OPERATING AS TRANSWORLD EXPRESS FLT 7591 (TWE 7591) & A CESSNA 172N, N737EV, COLLIDED ABT 10 MILES WEST/SOUTHWEST OF PALMDALE, CA AT ABT 5500 FT MSL. TWE 7591 WAS DESCENDING ON A 355 DEG MAG HEADING; N737EV WAS LEVEL AND WAS MAINTAINING A 060 DEG MAG HEADING. THE CAPT ABOARD TWE 7591 WAS FLYING THE AIRPLANE & THE FIRST OFFICER OBSVD N737EV JUST PRIOR TO IMPACT AND TOOK THE CONTROLS AND EXECUTED AN ABRUPT RIGHT TURN; THE CAPT THEN CONTINUED THE DESCENDING RIGHT TURN BUT TO NO AVAIL - THE AIRPLANE'S LEFT WING COLLIDED WITH N737EV. THE PLT OF N737EV REPORTED THAT HE DID NOT SEE TWE 7591 UNTIL THE COLLISION. THE CONVERGENCE ANGLE OF 7591 WAS 53 DEG AND 62 DEG FOR 737EV. BOTH AIRPLANES LANDED SAFELY - TWE 7591 LANDED AT WILLIAM J. FOX ARPT, LANCASTER, CA. & N737EV LANDED AT PALMDALE ARPT.

## Aircraft 1

- Registration: [N931MA](https://openairdocs.org/deregistered/N931MA-1993-06-22), registration cancelled 1993-06-22, S/N 169 (OpenAirDocs)
- Reported make and model: de Havilland DHC-6
- Registry model: [Dehavilland DHC-6 TWIN OTTER](https://openairdocs.org/model/dehavilland-dhc-6-twin-otter) (registry code 2802606) (OpenAirDocs)
- Category: Airplane
- Serial number: 169
- Airframe hours: 30907
- Engines: P&W PT-6-20 550 horsepower turbo prop
- Damage: Substantial damage
- Flight: Part 135
- Operator: Resort Commuter Inc., doing business as Trans World Express
- Registered owner: Jim Slemons Import Inc,
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, July 29, 1987, 31 hours before
- Departed: LAX, LOS ANGELES, CA
- Destination: WJF, LANCASTER, CA
- Flight plan: Company VFR
- Airport: PMD, Palmdale, runway 6, 5,001 × 150 ft, asphalt

## Aircraft 2

- Registration: [N737EV](https://openairdocs.org/deregistered/N737EV-2018-05-09), registration cancelled 2018-05-09, S/N 17269369, built 1977 (OpenAirDocs)
- Reported make and model: CESSNA 172N
- Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 17269369
- Airframe hours: 889
- Engines: LYCOMING O-320-H2AD 160 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Venco Pacific Aviation
- Registered owner: Trefethen, M. W. & Gray, P. T.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, July 3, 1987, 18 hours before
- Departed: OXR, OXNARD, CA
- Destination: LAS, LAS VEGAS, NV
- Flight plan: VFR
- Airport: PMD, Palmdale, runway 7, 12,002 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot, aircraft N931MA; age 41; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 7,000 total, 375 in this make and model, 6,738 as pilot in command, 176 in the last 90 days, 42 in the last 30 days, 3 in the last 24 hours
- Pilot, aircraft N737EV; age 31; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 1,725 total, 67 in this make and model, 709 as pilot in command, 13 in the last 90 days, 4 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 290° at 4 knots
- Visibility: 40 statute miles
- Lowest ceiling: none
- Altimeter: 29.00 inHg
- Observed at: WJF, 9 nm away

## FAA reports on this event (2)

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

- [Accident 19870804045101A](https://openairdocs.org/incident/19870804045101A), Aug 4, 1987: Dhav DHC6*, Palmdale, CA, Substantial damage. During descent overtook and struck,N737EV, that was level on converting course. Landed safe. ATC not aware.
- [Accident 19870804045102A](https://openairdocs.org/incident/19870804045102A), Aug 4, 1987: Cessna 172N, Palmdale, CA, Substantial damage. Level cruise. Overtaken and struck by descending DHC6 N931MA. Was able to land safely with severe damage.

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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