# NTSB FTW97LA216: Wsk Pzl Mielec M-18, N6220C, Swifton, AR, June 12, 1997 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: June 12, 1997, 10:00 local (15:00 UTC) - Place: Swifton, AR - Coordinates: 35.820796, -91.120018 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.8208&lon=-91.1200&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report June 9, 1999 - Report: Approved by Office Director - NTSB case key (mKey): 20239 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW97LA216 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20239/pdf - Page: https://openairdocs.org/ntsb/FTW97LA216 ## Probable cause Main landing gear collapse resulting from a failure of the torque link assembly attaching bolt. A factor was the lack of required maintenance (lubrication of the bolt) which resulted in the bolt becoming dry and corroded. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Gear collapsed, takeoff - roll/run - maintenance,lubrication - not performed, company maintenance personnel (contributing factor) - landing gear,main gear strut scissors - miscellaneous,bolt/nut/fastener/clamp/spring - failure (cause) - miscellaneous,bolt/nut/fastener/clamp/spring - corroded (contributing factor) ## Analysis During takeoff, after the tail wheel came up and before attaining flying speed, the right main landing gear collapsed. Subsequently, the right wheel assembly castored about 90 degrees, causing the aircraft to veer off the side of the runway, and travel about 100 yards through a plowed field. Just prior to coming to rest, the aircraft rolled inverted and a post impact fire consumed the engine compartment and hopper area. Examination of the right main landing gear assembly revealed that the right main landing gear torque link assembly attaching bolt failed. The external surface of the bolt was corroded, and the fracture surface showed evidence of overload failure. There was no evidence of lubrication residues on the bolt and adjacent torque link assembly. According to the aircraft's maintenance manual, the main landing gear torque link assembly attaching bolt should be lubricated every 50 hours. Examination of the maintenance records, did not show any entries made regarding the lubrication of the aforementioned items. ## Factual narrative On June 12, 1997, approximately 1000 central daylight time, a Wsk Pzl Mielec M-18 agricultural airplane, N6220C, was destroyed during takeoff following a collapse of the right main landing gear. The commercial pilot, sole occupant, received minor injuries. No flight plan was filed and visual meteorological conditions prevailed for the Title 14 CFR Part 137 aerial application flight. In a telephone interview with the NTSB investigator-in-charge, the pilot reported that, during takeoff, after the tail came up and before attaining flying speed, the right main landing gear collapsed. Subsequently, the right wheel assembly castored about 90 degrees, causing the aircraft to veer off the side of the runway, and travel about 100 yards through a plowed field. Just prior to coming to rest, the aircraft rolled inverted and a post impact fire consumed the engine compartment and hopper area. The operator, via NTSB form 6120.1/2, reported that examination of the wreckage revealed that the right main landing gear assembly had failed due to a "cracked bolt" that connected the upper and lower arms of the main landing gear strut scissors assembly. Examination of the right main landing gear assembly by a FAA inspector revealed that the right main landing gear torque link assembly attaching bolt failed. The external surface of the bolt was corroded, and the fracture surface showed evidence overload failure. The pilot reported that when the bolt failed the lower part of the main landing gear tire assembly swiveled and dragged in the dirt (as evidence by ground scars). Additionally, the inspector stated that there was no evidence of lubrication residues on the bolt and adjacent torque link assembly. According to the aircraft's maintenance manual, the main landing gear torque link assembly attaching bolt should be lubricated every 50 hours. Examination of the maintenance records did not show annotations regarding the lubrication of the aforementioned items. ## Aircraft - Registration: [N6220C](https://openairdocs.org/deregistered/N6220C-1998-12-09), registration cancelled 1998-12-09, S/N 1Z02301 (OpenAirDocs) - Reported make and model: Wsk Pzl Mielec M-18 - Registry model: [Wsk-Pzl-Mielec PZL-M-18](https://openairdocs.org/model/wsk-pzl-mielec-pzl-m-18) (registry code 9810102) (OpenAirDocs) - Category: Airplane - Serial number: 1Z023-01 - Airframe hours: 2816 - Engines: Pzl-Kalisz ASZ-621RM18 967 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Aerial application, Part 137 - Registered owner: Leon Jacoby - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, May 18, 1997, 90 hours before - Departed: NONE - Airport: NONE, Private Airstrip, runway 36, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 12,100 total, 35 in the last 90 days, 35 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 250° at 9 knots - Visibility: 5 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 64 °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 19970612013879A](https://openairdocs.org/incident/19970612013879A), Jun 12, 1997: Wsk PZLM18, Swifton, AR, Destroyed. Aircraft landing gear collapsed on takeoff. (-23) on take off after aircraft got light, the pilot said aircraft started to the right and he could not control… 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.