# NTSB ANC93IA084: Boeing 737-200, N673MA, Anchorage, AK, June 7, 1993

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: June 6, 1993, 22:28 local (Jun 7, 1993, 06:28 UTC)
- Place: Anchorage, AK
- Coordinates: 61.159931, -149.989868 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=61.1599&lon=-149.9899&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report September 26, 1994
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 2319
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC93IA084
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/2319/pdf
- Page: https://openairdocs.org/ntsb/ANC93IA084

## Probable cause

THE FAILURE OF THE NOSE LANDING GEAR INNER CYLINDER FROM AN OVERLOAD/OVERSTRESS CONDITION.

## Sequence of events

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

- Nose gear collapsed, landing - flare/touchdown
  - landing gear,nose gear - failure,total (cause)
  - landing gear,nose gear - overload (cause)

## Analysis

WHILE TAXIING OFF THE RUNWAY AT DILLINGHAM, ALASKA, THE FLIGHT CREW HEARD A 'POP' AND 'GRINDING' SOUND. THE AIRPLANE WAS SUBSEQUENTLY FERRIED TO ANCHORAGE WITH THE NOSE GEAR PINNED IN THE DOWN POSITION.  UPON TOUCHDOWN IN ANCHORAGE, THE NOSE GEAR SEPARATED FROM THE AIRPLANE.  A METALLURGICAL EXAMINATION OF THE AFFECTED COMPONENTS, PRIMARILY THE NOSE LANDING GEAR INNER CYLINDER, SHOWED THAT THE INNER CYLINDER HAD SEPARATED CLOSE TO THE LOWER END NEAR THE AXLES FOR THE TIRES.  VISUAL EXAMINATION OF THE FRACTURE SURFACE WITH THE AID OF A BENCH BINOCULAR MICROSCOPE REVEALED FEATURES TYPICAL OF AN OVERSTRESS SEPARATION INCLUDING CHEVRON MARKS OVER THE MAJORITY OF THE FRACTURE SURFACE AND THE PRESENCE OF A 45 DEGREE FRACTURE PLANE.  DURING THE PREVIOUS 12 MONTH PERIOD THERE WERE NO 'HARD' LANDINGS ON RECORD FOR THE AIRPLANE.

## Aircraft

- Registration: N673MA (not matched to a registry record)
- Reported make and model: BOEING 737-200
- Category: Airplane
- Serial number: 23124
- Airframe hours: 25472
- Engines: P&W JT8D-17A turbo fan
- Damage: Minor damage
- Flight: Ferry, Part 91
- Operator: Markair Inc.
- Registered owner: Markair Inc.
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, June 6, 1993, 1 hours before
- Departed: DLG, DILLINGHAM, AK
- Flight plan: IFR
- Airport: ANC, Anchorage International, runway 14, 10,496 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; airline transport, commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 7,500 total, 3,000 in this make and model, 112 in the last 90 days, 26 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 140° at 12 knots
- Visibility: 60 statute miles
- Lowest ceiling: 12,000 ft broken
- Temperature: 52 °F, dew point 39 °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 19930607019809I](https://openairdocs.org/incident/19930607019809I), Jun 7, 1993: Boeing 7372X6C, Anchorage, AK, Minor damage. Experienced difficulty turning aircraft after landing. Returned to Anchorage. Found nose gear strut broken.

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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