# NTSB DCA90MA030: Boeing 737-2X6C, N670MA, Unalakleet, AK, June 2, 1990

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Class 1 · Major · Final report
- Date: June 2, 1990, 09:37 local (17:37 UTC)
- Place: Unalakleet, AK
- Coordinates: 64.089195, -160.359024 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=64.0892&lon=-160.3590&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 3 minor
- Status: Completed, report May 3, 1993
- Report: Board-adopted at Board Meeting
- Investigation class: Class 1
- NTSB office: Major Investigations Division
- Safety recommendations: Yes
- NTSB case key (mKey): 15936
- NTSB case page: https://www.ntsb.gov/investigations/Pages/DCA90MA030.aspx
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15936/pdf
- Board report AAR9102 (PDF): https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR9102.pdf
- Page: https://openairdocs.org/ntsb/DCA90MA030

## Probable cause

DEFICIENCIES IN FLIGHTCREW COORDINATION, THEIR FAILURE TO ADEQUATELY PREPARE FOR AND PROPERLY EXECUTE THE UNK LOC RWY 14 NONPRECISION APPROACH AND THEIR SUBSEQUENT PREMATURE DESCENT.

## Sequence of events

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

- In flight collision with terrain/water, approach - iaf to faf/outer marker (ifr)
  - crew/group coordination - inadequate, pilot in command (cause)
  - crew/group coordination - inadequate, copilot/second pilot (cause)
  - ifr procedure - not followed, pilot in command (cause)
  - descent - premature, pilot in command (cause)
  - monitoring - inadequate, copilot/second pilot (cause)
  - minimum descent altitude - not maintained

## Analysis

ON JUNE 2, 1990, AT 09:37 ALASKAN DAYLIGHT TIME, MARKAIR, INC., FLIGHT 3087, A BOEING 737-2X6C, REGISTERED IN THE US AS N670MA, CRASHED ABOUT 7.5 MILES SHORT OF RUNWAY 14, UNALAKLEET, ALASKA, WHILE EXECUTING A LOCALIZER APPROACH TO THAT RUNWAY.  THE FLIGHT ORIGINATED AT 0828 AT ANCHORAGE INTERNATIONAL AIRPORT, ANCHORAGE, ALASKA.  INSTRUMENT METEOROLOGICAL CONDITIONS EXISTED AT THE TIME, AND THE FLIGHT WAS ON AN IFR FLIGHT PLAN.  THE CAPTAIN, THE FIRST OFFICER, AND A FLIGHT ATTENDANT SUSTAINED MINOR INJURIES.  ANOTHER FLIGHT ATTENDANT SUSTAINED SERIOUS INJURIES.  THERE WERE NO PASSENGERS ON BOARD, AND THE AIRCRAFT WAS DESTROYED.  THE FLIGHT WAS OPERATED UNDER FAR PART 121.  (SEE NTSB/AAR-91/02 FOR FURTHER INFORMATION)

## Aircraft

- Registration: [N670MA](https://openairdocs.org/deregistered/N670MA-1990-12-12), registration cancelled 1990-12-12, S/N 23121 (OpenAirDocs)
- Reported make and model: BOEING 737-2X6C
- Category: Airplane
- Serial number: 23121
- Engines: P&W JT8D-17A 16000 lbs thrust turbo fan
- Damage: Destroyed
- Flight: Part 121
- Operator: Markair
- Airworthiness certificate: Standard, Transport
- Departed: ANC, ANCHORAGE, AK
- Flight plan: IFR
- Airport: UNK, Unakaleet, runway 14, 6,010 × 170 ft, gravel

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; commercial, airline transport, private; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 12,000 total, 6,400 in this make and model

## Weather

- Conditions: Instrument (IMC), Day
- Wind: calm
- Visibility: 1 statute miles
- Lowest ceiling: 500 ft overcast
- Temperature: 48 °F
- Altimeter: 29.00 inHg
- Observed at: UNK, 7 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 19900602018109A](https://openairdocs.org/incident/19900602018109A), Jun 2, 1990: Boeing 7372X6C, Unalakleet, AK, Destroyed. Descended below mda on IFR approach. Crashed 7 miles short of runway. First officer failed to note unsafe procedure

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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