# NTSB MIA96IA114: Mitsubishi MU-2G-30, N920S, Columbia, SC, April 12, 1996 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: April 12, 1996, 08:34 local (12:34 UTC) - Place: Columbia, SC - Coordinates: 33.940902, -81.150657 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.9409&lon=-81.1507&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report October 4, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 37921 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA96IA114 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/37921/pdf - Page: https://openairdocs.org/ntsb/MIA96IA114 ## Probable cause failure of the nose landing gear bearing due to improper assembly and staking (inadequate quality control) by the manufacturer; which prevented the nose gear from retracting and the main gear from extending, and resulted in a subsequent landing on the nose gear and tail assembly. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, climb - to cruise - landing gear - failure (cause) - inadequate quality control, manufacturer (cause) - Dragged wing,rotor,pod,float or tail/skid, emergency landing ## Analysis The pilot stated the nose gear did not retract during the initial climb after takeoff. Emergency procedures were completed (but the nose gear would not retract and the main gear would not extend). The airplane was landed with the nose gear extended and the main gear retracted. A check of the landing gear system after landing revealed a faulty (nose gear) bearing. Examination of the bearing revealed evidence that it had not been properly assembled and staked when it was manufactured. ## Factual narrative On April 12, 1996, about 0834 eastern daylight time, a Mitsubishi MU-2G-30, N920S, registered and operated by Bankair Inc., as a 14 CFR Part 135 on-demand air taxi non-scheduled cargo flight, made a forced landing at the Columbia Metropolitan Airport, Columbia, South Carolina. Visual meteorological conditions prevailed and an instrument flight plan was filed. The airplane sustained minor damage, and the airline transport pilot reported no injuries. The flight departed Atlanta, Georgia, 2 hours 9 minutes before the incident and while en route to Birmingham, Alabama, diverted to Columbia. The pilot stated the nose gear did not retract on initial takeoff climb. He recycled the landing gear and completed the emergency procedures with negative results. He contacted company operations and was instructed to divert to Columbia. The airplane was landed with the nose gear down and the main landing gear in the retracted position. Examination of the bearing carrier and bearings by the NTSB Material Laboratory Division revealed one end of one of the bearing outer races contained a uniform dark bank around the circumference of the race. Detailed examination revealed a series of several faint dark lines at the boundary of this region. The length and spacing of the lines roughly corresponded to the length and spacing of the staking lines on the end of the housing. Examination of the interior of the housing revealed evidence of contact with the bearings over most areas. However, the interior surface contained less evidence of contact over a circumferential area corresponding to the most deeply inserted portion of the bearings. For additional information see NTSB Metallurgist's Factual Report No. 96-117. The bearing carrier and bearings were released to Mr. John E. Dickerson, President, Bankair, on July 29, 1996. ## Aircraft - Registration: [N920S](https://openairdocs.org/deregistered/N920S-2007-03-16), registration cancelled 2007-03-16, S/N 534, built 1971 (OpenAirDocs) - Reported make and model: Mitsubishi MU-2G-30 - Registry model: [Mitsubishi MU-2B-30](https://openairdocs.org/model/mitsubishi-mu-2b-30) (registry code 5780410) (OpenAirDocs) - Registry engine: [AiResearch TPE331 series](https://openairdocs.org/engine/airesearch-tpe331-series) (registry code 01514, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 534 - Airframe hours: 11580 - Engines: Garrett TPE-331-1-151 665 horsepower turbo prop - Damage: Minor damage - Flight: Part 135 - Registered owner: Bankair - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, April 4, 1996 - Departed: ATL, ATLANTA, GA - Destination: BHM, BIRMINGHAM, AL - Flight plan: IFR - Airport: CAE, Columbia Metropolitan, runway 23, 7,000 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 5,600 total, 1,160 in this make and model, 232 in the last 90 days, 60 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 250° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 55 °F, dew point 36 °F - Altimeter: 30.00 inHg - Observed at: CAE ## 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 19960412045149A](https://openairdocs.org/incident/19960412045149A), Apr 12, 1996: Mtsbsi MU2B30, Columbia, SC, Minor damage. Nose gear failed retract departing atl. Diverted cae. Landed mains up. Wheel bearing failed jammed in housing. 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. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.