# NTSB ANC91IA046: Nihon YS-11A-600, N173RV, Anchorage, AK, March 27, 1991

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: March 27, 1991, 16:23 local (20:23 UTC)
- Place: Anchorage, AK
- Coordinates: 61.160049, -149.99028 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=61.1600&lon=-149.9903&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed, report May 5, 1993
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5497
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC91IA046
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5497/pdf
- Page: https://openairdocs.org/ntsb/ANC91IA046

## Probable cause

A JAMMED NOSE GEAR DUE TO INCORRECT INSTALLATION OF THE SHEAR PIN. CONTRIBUTING TO THE ACCIDENT WAS THE INSUFFICIENTLY DEFINED MAINTENANCE PROCEDURE.

## Sequence of events

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

- Gear not extended, landing
  - landing gear,nose gear assembly - jammed (cause)
  - maintenance,major repair - improper, company maintenance personnel (cause)
  - condition(s)/step(s) insufficiently defined, manufacturer (contributing factor)

## Analysis

THE CREW OF FOUR WERE ON A TRAINING FLIGHT AND WERE PREPARING TO PERFORM APPROACH TO LANDING STALLS.  DURING THE MANEUVER, THEY NOTICED THE NOSE GEAR WOULD NOT EXTEND.  UNABLE TO EXTEND THE NOSE GEAR, THEY LANDED WITH THE NOSE GEAR UP CAUSING MINOR DAMAGE TO THE AIRPLANE.  SUBSEQUENT EXAMINATION REVEALED THAT THE RIVETS WHICH RETAIN THE CENTERING CAM SHEAR PINS WERE SHEARED.  THE SHEAR PINS WERE NOT SHEARED.  AN EXAMINATION BY MITSUBISHI HEAVY INDUSTRIES, NAGOYA AIRPLANE WORKS, INDICATED THAT THE SHEAR PINS MAY HAVE BEEN INSTALLED IN REVERSE.  THE OVERHAUL MANUAL ALSO CONTAINED AMBIGUOUS INFORMATION CONCERNING THE INFORMATION.  THE GRAPHICAL DISPLAY SHOWED THE INSTALLATION INCORRECTLY, BUT THE TEXT EXPLAINED THE INSTALLATION CORRECTLY.

## Aircraft

- Registration: [N173RV](https://openairdocs.org/deregistered/N173RV-2019-09-06), registration cancelled 2019-09-06, S/N 2173, built 1972 (OpenAirDocs)
- Reported make and model: NIHON YS-11A-600
- Registry model: [Nihon YS-11A-600](https://openairdocs.org/model/nihon-ys-11a-600) (registry code 6310420) (OpenAirDocs)
- Registry engine: [Rolls-Royce DART-542 series](https://openairdocs.org/engine/rolls-royce-dart-542-series) (registry code 54522, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 2173
- Airframe hours: 19730
- Engines: Rolls-Royce 542-10K 2775 horsepower turbo prop
- Damage: Minor damage
- Flight: Instructional, Part 91
- Operator: Reeve Aleutian Airways, Inc.
- Registered owner: Reeve Aleutian Airways, Inc.
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, January 27, 1991, 126 hours before
- Flight plan: IFR
- Airport: ANC, Anchorage, runway 6, 10,600 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; flight instructor, airline transport, commercial, private; 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: 12,000 total, 4,694 in this make and model, 2,788 as pilot in command, 125 in the last 90 days, 39 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 60° at 7 knots
- Visibility: 1 statute miles
- Lowest ceiling: 4,000 ft overcast
- Temperature: 37 °F, dew point 30 °F
- Altimeter: 29.00 inHg
- Observed at: ANC, 1 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).

- [Incident 19910327013299I](https://openairdocs.org/incident/19910327013299I), Mar 27, 1991: Nihon YS11A600, Anchorage, AK, Minor damage. Unable to lower nose gear. Landed nose gear up.

## Other investigations on N173RV (1)

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 ANC81FA043](https://openairdocs.org/ntsb/ANC81FA043), Apr 18, 1981: Nihon YS-11A (N173RV), Sand Point, AK, substantial 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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