# NTSB DFW08TA128: Beech C90, N21SP, Baton Rouge, LA, April 25, 2008 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: April 25, 2008, 11:23 local (16:23 UTC) - Place: Baton Rouge, LA - Coordinates: 30.532777, -91.149719 - Nearby events: https://openairdocs.org/map.md?lat=30.5328&lon=-91.1497&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 6 uninjured - Status: Completed, report July 30, 2008 - Report: Approved by Office Director - Parties: FAA FSDO - ADs cited in the narratives: [AD 2002-01-10](https://openairdocs.org/ad/2002-01-10) (OpenAirDocs) - NTSB case key (mKey): 67933 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW08TA128 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/67933/pdf - Page: https://openairdocs.org/ntsb/DFW08TA128 ## Probable cause Structural failure of the right main landing gear torque knee. A contributing factor was the failure to inspect the torque knee at the designated interval. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: main gear strut/axle/truck](https://openairdocs.org/ntsb-findings/01023213): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [All aircraft, 86 cases](https://openairdocs.org/ntsb-findings/01023213/cases.md) - [Inspection: scheduled/routine inspection](https://openairdocs.org/ntsb-findings/02061520): Personnel issues › Task performance · Pilot (probable cause); cases with it: [All aircraft, 167 cases](https://openairdocs.org/ntsb-findings/02061520/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The private pilot was landing at the airport when the airplane's right main landing gear collapsed. A preexisting fracture with corrosion was discovered on the right main landing gear torque knee. The main landing gear upper and lower torque knees require an inspection every 1,000 hours by airworthiness directive. Compliance with the airworthiness directive was not maintained and the airplane was allowed to operate without an inspection. ## Factual narrative On April 25, 2008, at approximately 1123 central daylight time, a Beech C90, N21SP, was substantially damaged when the right main landing gear collapsed during the landing roll. The commercial pilot and five passengers were not injured. The airplane was owned by Southwest Aviation Specialties LLC and operated by the United States Marine Corps (USMC). The local flight originated at Baton Rouge Metropolitan Airport (BTR), Baton Rouge, Louisiana at approximately 1030. Visual meteorological conditions prevailed and a visual flight rules (VFR) flight plan was filed for the Title 14 Code of Federal Regulations Part 91 public-use flight. In a telephone interview, the pilot reported the accident occurred after landing on runway 13 at BTR. During the landing roll, the pilot felt the airplane shake "as if we hit a pothole." Furthermore, the pilot reported that the airplane began to shimmy, the right wing dropped, and the airplane began to slide. Once the airplane came to a halt, the pilot and his passengers were able to egress without assistance. The responding Federal Aviation Administration (FAA) inspector discovered that the upper torque knee failed which resulted in a collapse of the right main gear. Examination of the upper torque knee revealed a preexisting fracture with associated coloring consistent with corrosion. Another fracture located on the same component was found to be shiny and without corrosion. On January 22, 2002, airworthiness directive (AD) 2002-01-10 required an inspection of the main landing gear upper and lower torque knees for fatigue cracks. An inspection was to be performed at the next 100 hour inspection and at a subsequent interval not to exceed 1,000 hours time in service. A review of the logbooks revealed that the last recorded inspection of the torque knees occurred on January 3, 2003 at which time the airframe had 9,327.7 hours. On July 27, 2007 a logbook entry recorded the airframe time as 10,306.8 hours. The only hours that could be verified after this logbook entry was from the USMC pilot. The pilot's logbook recorded his flights in N21SP starting on October 1, 2007. From October 1 to October 23, the pilot logged over 23 hours in the airframe requiring an inspection to be in compliance with AD 2002-01-10. There is no record of the compliance with the AD despite continued operation. The airplane owner leased the airplane to a company who provided an airplane and maintenance by contract to the USMC. ## Aircraft - Registration: N21SP (not matched to a registry record) - Reported make and model: Beech C90 - Category: Airplane - Serial number: LJ-630 - Engines: Pratt & Whitney PT-6A-20 550 horsepower turbo prop; Pratt & Whitney PT-6A-20 550 horsepower turbo prop - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: United States Marine Corps - Registered owner: Southwest Aviation Specialties LLC - Airworthiness certificate: Standard, Normal - Departed: BTR, Baton Rouge, LA - Destination: BTR, BATON ROUGE, LA - Flight plan: VFR - Airport: BTR, Baton Rouge Metropolitan, Ryan, runway 13, 7,004 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; injuries: none ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 1,800 ft broken - Temperature: 75 °F, dew point 66 °F - Altimeter: 30.01 inHg - Observed at: BTR ## 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 20080425839969A](https://openairdocs.org/incident/20080425839969A), Apr 25, 2008: Beech C90, Baton Rouge, LA, Substantial damage. (-23) Upon landing the right main landing gear upper torque knee broke causing the right tire to turn sideways and came out of the upper trunnion causing the… 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.