# NTSB ANC87LA006: Short Brothers SC7, N406TH, Nightmute, AK, October 21, 1986

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: October 21, 1986, 14:30 local (22:30 UTC)
- Place: Nightmute, AK
- Coordinates: 60.48973, -164.810226 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=60.4897&lon=-164.8102&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 4802
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC87LA006
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/4802/pdf
- Page: https://openairdocs.org/ntsb/ANC87LA006

## Sequence of events

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

- In flight collision with terrain/water, landing - flare/touchdown
  - weather condition - downdraft (contributing factor)
  - compensation for wind conditions - inadequate, pilot in command (cause)
  - airport facilities,runway/landing area condition - rough/uneven (contributing factor)
- Airframe/component/system failure/malfunction, landing - flare/touchdown
  - landing gear,main gear - overload
- Loss of control - on ground/water, landing
  - directional control - not possible
  - ground loop/swerve - uncontrolled

## Analysis

ACCORDING TO THE PLT-IN-COMMAND (PIC), WHEN THE ACFT WAS ON FINAL APCH TO THE 1600 FT RWY, IT ENCOUNTERED A DOWNDRAFT. SUBSEQUENTLY, THE ACFT HIT HARD ON THE LIP OF THE RWY, THEN BOUNCED & TOUCHED DOWN ON THE RWY. AFTER THE 2ND TOUCHDOWN, THE ACFT VEERED TO THE RIGHT, EXITED THE RWY & CONTD ONTO OPEN TUNDRA. THE ACFT'S RIGHT MAIN GEAR, RIGHT WING, RIGHT PROP & NOSE GEAR WERE DAMAGED DRG THE SEQUENCE.

## Aircraft

- Registration: [N406TH](https://openairdocs.org/deregistered/N406TH-2014-10-06), registration cancelled 2014-10-06, S/N 1862 (OpenAirDocs)
- Reported make and model: Short Brothers SC7
- Registry model: [Short Bros. & Harland SC7 SERIES 3](https://openairdocs.org/model/short-bros-harland-sc7-series-3) (registry code 8100512) (OpenAirDocs)
- Category: Airplane
- Serial number: 1862
- Airframe hours: 10107
- Engines: AIRESEARCH TPE-331-F 650 horsepower turbo prop
- Damage: Substantial damage
- Flight: Part 135
- Registered owner: Troy Air Service
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, September 8, 1986, 33 hours before
- Departed: BET, BETHAL, AK
- Flight plan: VFR
- Airport: AK08, Nightmute, runway 2, 1,600 × 40 ft, gravel

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 31; flight instructor, commercial, airline transport; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 2,590 total, 152 in this make and model, 2,500 as pilot in command, 250 in the last 90 days, 140 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 20° at 20 knots
- Visibility: 90 statute miles
- Lowest ceiling: none
- Temperature: 28 °F, dew point 21 °F
- Altimeter: 29.00 inHg

## 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 19861021052939A](https://openairdocs.org/incident/19861021052939A), Oct 21, 1986: Stbros SC73, Nightmute, AK, Substantial damage. Pilot failed to maintain directional control during a hard landing. Aircraft departed the side of the runway.

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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