# NTSB BFO93IA070: Fokker F28-MK-0100, N867US, Pittsburgh, PA, May 7, 1993 - Type: NTSB incident investigation - Classification: Incident · Minor injuries · Incident investigation · Final report - Date: May 7, 1993, 12:51 local (16:51 UTC) - Place: Pittsburgh, PA - Location: 40.4914° N, 80.2327° W: Placed by OpenAirDocs at PITTSBURGH INTL (PIT), within about a mile (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=40.4914&lon=-80.2327&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 50 uninjured - Status: Completed, report November 3, 1993 - Report: Approved by Office Director - Safety recommendations: Yes - NTSB case key (mKey): 11878 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO93IA070 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/11878/pdf - Page: https://openairdocs.org/ntsb/BFO93IA070 ## Probable cause THE IMPROPER INSTALLATION OF THE SPACERS BY THE MECHANIC AND THE UNCLEAR INFORMATION SUPPLIED FROM THE MANUFACTURER AND OPERATOR REGARDING THE INSTALLATION OF THE SPACERS. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Main gear collapsed, landing - roll - landing gear,main gear shock absorbing strut - vibration - landing gear,main gear shock absorbing strut - sheared - maintenance,installation - improper, company maintenance personnel (cause) - information unclear, manufacturer (cause) - information unclear, company/operator management (cause) ## Analysis SHORTLY AFTER TOUCHDOWN AT MEMPHIS, TN, A SEVERE VIBRATION WAS FELT BY THE FLIGHTCREW IN THE COCKPIT. THE FLIGHTCREW THOUGHT THE VIBRATION WAS GENERATED BY THE RIGHT MAIN GEAR SO THEY HAD MAINTENANCE PERSONNEL CHECK THE RIGHT MAIN GEAR. NO ANOMALIES WERE NOTED. THE FLIGHT CONTINUED TO PITTSBURGH, PA, AND SHORTLY AFTER TOUCHDOWN, THE LEFT MAIN GEAR COLLAPSED. POST INCIDENT EXAMINATION OF THE LEFT MAIN GEAR REVEALED THAT TWO SPACERS IN THE TORQUE LINK ASSEMBLY WERE FOUND TO HAVE BEEN IMPROPERLY INSTALLED. THE INVESTIGATION ALSO REVEALED THAT DURING RE INSTALLATION OF THE TORQUE LINKS AND SHIMMY DAMPER AT THE LAST MAINTENANCE CHECK, THE TWO SPACERS WERE INSTALLED IN REVERSE OF THEIR NORMAL POSITIONS. ACCORDING TO FOKKER, REVERSAL OF THE TWO SPACERS WOULD RESULT IN AN UNDAMPED FREE PLAY BETWEEN THE UPPER AND LOWER TORQUE LINK RESULTING IN OSCILLATIONS IN THE LATERAL MODE OF THE LANDING GEAR. REVIEW OF USAIR'S AIRCRAFT MAINTENANCE MANUAL, SUPPLIED BY FOKKER, REVEALED THAT THE TWO SPACERS THAT WERE INCORRECTLY INSTALLED ON THE INCIDENT AIRPLANE WERE NOT DESCRIBED BY DIMENSIONS OR VERBIAGE. ## Aircraft - Registration: [N867US](https://openairdocs.org/deregistered/N867US-2004-02-03), registration cancelled 2004-02-03, S/N 11312, built 1990 (OpenAirDocs) - Reported make and model: FOKKER F28-MK-0100 (F28-MK-010) - Registry model: [Fokker F.28 MK 0100](https://openairdocs.org/model/fokker-f-28-mk-0100) (registry code 4990807) (OpenAirDocs) - Registry engine: [Rolls-Royce TAY-650-15](https://openairdocs.org/engine/rolls-royce-tay-650-15) (registry code 54557, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 11312 - Airframe hours: 6578 - Engines: Rolls-Royce TAY MK 650-15 15100 lbs thrust turbo jet - Damage: Minor damage - Flight: Part 121 - Operator: Usair - Registered owner: Usair - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, February 4, 1993, 416 hours before - Departed: MEM, MEMPHIS, TN - Flight plan: IFR - Airport: PIT, Greater Pittsburgh, runway 32, 8,100 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 10,200 total, 600 in this make and model, 100 in the last 90 days, 20 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 350° at 8 knots - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 41 °F - Altimeter: 30.00 inHg - Observed at: PIT, 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 19930507017479I](https://openairdocs.org/incident/19930507017479I), May 7, 1993: Fokker F28MK0100, Pittsburgh, PA, Minor damage. Left main gear departed aircraft on rollout. Left gear torque links and shimmy damper spacers were transposed. ## Other investigations on N867US (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 MIA98FA089](https://openairdocs.org/ntsb/MIA98FA089), Feb 26, 1998: Fokker F28 MK 0100 (N867US), Birmingham, AL, substantial damage. Probable cause: Were the 1) the inoperative alternate anti-skid control valve due to the disconnected electrical connector on the parking brake shut-off valve, the area was inspected 2 days earlier 2) the total loss… 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.