# NTSB DEN90FA055: Mitsubishi MU-2B-60, N64MD, Rapid City, SD, February 9, 1990

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: February 9, 1990, 11:14 local (18:14 UTC)
- Place: Rapid City, SD
- Coordinates: 44.070594, -103.229591 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.0706&lon=-103.2296&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal, 1 serious, 2 minor
- Status: Completed, report June 30, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 17818
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN90FA055
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17818/pdf
- Page: https://openairdocs.org/ntsb/DEN90FA055

## Probable cause

FAILURE OF THE PILOT TO MAINTAIN ADEQUATE AIRSPEED (VMC), WHICH RESULTED IN A LOSS OF AIRCRAFT CONTROL. A FACTOR RELATED TO THE ACCIDENT WAS: FATIGUE FAILURE OF A COUPLING SHAFT IN THE #1 ENGINE, WHICH RESULTED IN LOSS OF POWER IN THAT ENGINE.

## 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, takeoff - initial climb
  - engine assembly - fatigue
- Loss of control - in flight, takeoff - initial climb
  - airspeed(vmc) - not maintained, pilot in command
  - aircraft control - not maintained, pilot in command
- In flight collision with terrain/water, takeoff

## Analysis

WITNESSES RPRTD THAT SHORTLY AFTER LIFT-OFF, THE ACFT ENTERED AN UNUSUALLY STEEP, NOSE HIGH ATTITUDE, WHILE STILL AT LOW AIRSPEED. ONE WITNESS (AN ATP PLT) RPRTD THE ACFT ATTAINED AN ALT OF APRX 75 TO 100 FT AND APPEARED TO SLOW DOWN AND ENTER A VMC ROLL, THEN IT CRASHED. IMPACT OCCURRED IN AN INVERTED, NOSE DOWN ATTITUDE, LEFT OF THE RWY. AN INVESTIGATION REVEALED THAT A COUPLING SHAFT (PN 865888-3) HAD FAILED IN THE LEFT ENG & THE LEFT PROP HAD FEATHERED. A METALLURICAL EXAM OF THE COUPLING SHOWED EVIDENCE OF FATIGUE.

## Aircraft

- Registration: [N64MD](https://openairdocs.org/deregistered/N64MD-1990-03-16), registration cancelled 1990-03-16, S/N 747SA (OpenAirDocs)
- Reported make and model: MITSUBISHI MU-2B-60
- Registry model: [Mitsubishi MU-2B-60](https://openairdocs.org/model/mitsubishi-mu-2b-60) (registry code 5780460) (OpenAirDocs)
- Category: Airplane
- Serial number: 747SA
- Airframe hours: 4382
- Engines: GARRETT TPE-331-10 715 horsepower turbo prop
- Damage: Substantial damage
- Fire: On-Ground
- Flight: Part 135
- Operator: Aeromedical Services Intl, doing business as Associated Jet Charter
- Registered owner: Chancellor Aircraft Leasing
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, February 4, 1990, 14 hours before
- Departed: RAP
- Destination: CYWG, MANITOBA,CANADA, OF
- Flight plan: VFR/IFR
- Airport: RAP, Rapid City Regional, runway 14, 8,701 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 46; airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane, helicopter; medical: class 1, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 5,985 total, 291 in this make and model, 4,185 as pilot in command, 140 in the last 90 days, 53 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 170° at 14 knots
- Visibility: 35 statute miles
- Lowest ceiling: 7,000 ft broken
- Temperature: 32 °F, dew point 18 °F
- Altimeter: 29.00 inHg
- Observed at: RAP, 5 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 19900209001819A](https://openairdocs.org/incident/19900209001819A), Feb 9, 1990: Mtsbsi MU2B60, Rapid City, SD, Substantial damage, 1 fatal. Left engine failed. Aircraft in nose high attitude. Rolled left, crashed inverted. Turbine coupling shaft failed.

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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