# NTSB CHI98LA326: Cessna 150B, N1239Y, Lamar, MO, August 21, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 21, 1998, 15:45 local (20:45 UTC) - Place: Lamar, MO - Coordinates: 37.490222, -94.269462 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.4902&lon=-94.2695&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 16, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 43755 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI98LA326 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43755/pdf - Page: https://openairdocs.org/ntsb/CHI98LA326 ## Probable cause inadequate lubrication of the torque plate holes and torque pins by the mechanic who performed the airplane's last annual inspection. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - roll - landing gear,normal brake system - locked - maintenance,lubrication - inadequate, other maintenance personnel (cause) - Loss of control - on ground/water, landing - roll - remedial action - attempted, pilot in command - On ground/water encounter with terrain/water, landing - roll - terrain condition - ditch ## Analysis The pilot said her landing in the tail wheel airplane was uneventful. During the landing roll, the airplane suddenly veered to the left while in a 3-point attitude. The pilot said right rudder did not stop the turn and the airplane ran off the runway edge and into a 4-foot deep ditch. The on-site investigation revealed that the left main landing gear's brake torque plate holes and torque pins were dry. The wheel would not rotate. According to the pilot, she had never experienced dragging brakes while flying the airplane. ## Factual narrative On August 21, 1998, at 1545 central daylight time (cdt), a Cessna 150, N1239Y, piloted by a private pilot, was substantially damaged when it nosed over when it collided with a ditch shortly after departing the left edge of Runway 21 (2,905' X 40', dry asphalt) at the Lamar Municipal Airport, Lamar, Missouri. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 flight was not operating on a flight plan. The pilot reported no injuries. The flight departed Pittsburg, Kansas, 1515 cdt. According to the pilot, the wind sock at the landing was "...limp." She said she landed the airplane in a 3-point attitude and was on an uneventful landing roll when the airplane suddenly veered to the left. She said right rudder correction did not stop the turn. The ditch N1239Y collided with was about 30-feet from the runway edge and about 4-feet deep. According to the Federal Aviation Administration Principal Maintenance Inspector (PMI) who examined N1239Y, "...the [left main landing gear's brake] torque plate holes and torque pins were dry... ." The PMI said, "...a person who had assisted in the recovery of the airplane stated that after the airplane was [being] towed... he noted that the left main wheel would not rotate." The PMI said the dry torque plate and pins "...[have] been observed to cause locking of brake assemblies in this inspector's experience." Statements from the mechanic and PMI are appended to this report. The PMI said lubrication of the torque plates and pins normally should take place during the annual inspection and whenever the brakes appear to drag during service. The pilot/owner said she had not experienced any dragging brakes during the time she flew the airplane. ## Aircraft - Registration: N1239Y (not matched to a registry record) - Reported make and model: Cessna 150B - Category: Airplane - Serial number: 15059639 - Airframe hours: 3508 - Engines: Continental O-200-A reciprocating - Damage: Substantial damage - Fire: Unknown - Flight: Personal, Part 91 - Operator: Diana J. Richards - Registered owner: Diana J. Richards - Airworthiness certificate: Standard, Utility; Standard, Normal - Last inspection: Annual, July 1, 1998, 13 hours before - Departed: PTS, PITTSBURG, KS - Destination: LLU - Airport: LLU, Lamar Municipal Airport, runway 21, 2,905 × 40 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; private; airplane ratings: single-engine land; medical: class 3, unknown; seat: left ## Weather - Conditions: Visual (VMC), Not reported - Wind: 50° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F - Altimeter: 30.00 inHg - Observed at: JLN ## 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 19980821021499A](https://openairdocs.org/incident/19980821021499A), Aug 21, 1998: Cessna 150B, Lamar, MO, Substantial damage. (-23) Aircraft landed on runway 21, during this roll out the aircraft veered to the left of centerline and left the runway. Aircraft struck a drainage culvert… 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.