# NTSB CHI08LA070: Beech 58, N4626A, Cahokia, IL, January 23, 2008 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: January 23, 2008, 10:15 local (16:15 UTC) - Place: Cahokia, IL - Coordinates: 38.570556, -90.156112 - Nearby events: https://openairdocs.org/map.md?lat=38.5706&lon=-90.1561&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-flare/touchdown: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 28, 2008 - Report: Approved by Office Director - Parties: FAA - NTSB case key (mKey): 67524 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI08LA070 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/67524/pdf - Page: https://openairdocs.org/ntsb/CHI08LA070 ## Probable cause Maintenance personnel's improper replacement of the landing gear leg brace assembly which subsequently failed to keep the landing gear in the locked position. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: replacement](https://openairdocs.org/ntsb-findings/02062020): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Beech 58, 1 case](https://openairdocs.org/ntsb-findings/02062020/cases.md?model=1152740), [All aircraft, 70 cases](https://openairdocs.org/ntsb-findings/02062020/cases.md) - [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Beech 58, 11 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=1152740), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-flare/touchdown: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Beech 58, 8 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=1152740), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot reported that while landing, during the post maintenance test flight, he felt "a falling motion to the back right." He aborted the landing and flew by the control tower for a landing gear check. He was informed the landing gear appeared down. He then returned to his departure airport and while landing there he felt the right wing drop closer to the ground than normal. He aborted the landing again and began to troubleshoot the landing gear system. The pilot flew by the air traffic control tower two more times and performed the Emergency Gear Extension checklist. The pilot then used the Gear-Up Landing emergency checklist and landed the airplane. During the landing roll the right main gear collapsed and the right wing contacted the runway. As a result, the right wing and aileron were substantially damaged. The pilot reported that he had received a gear down and locked indication every time he extended the landing gear during the flight. The post accident inspection of the landing gear revealed that it could be released from the down and locked position by pushing on it with hand pressure. The leg brace portion of the landing gear retract brace assembly was replaced during the annual inspection. The leg brace that was installed was not purchased from Beechcraft. According to Beechcraft they do not sell the leg brace as a separate item from the upper brace assembly because of the close tolerance required between the two braces in order for the gear to properly lock in the extended position. There is no information in the BE-58 maintenance manual which indicating that the upper brace assembly and the leg brace must be replaced as a unit for the main landing gear. ## Factual narrative On January 23, 2008, at 1015 central standard time, a Beech 58, N4626A, operated by Flight Express, experienced a right main gear collapse upon landing at the St. Louis/Downtown Airport (CPS), Cahokia, Illinois. The commercial rated pilot was not injured. The airplane was substantially damaged. The 14 Code of Federal Regulation Part 91 was operating in visual meteorological conditions without a flight plan. The local flight originated from CPS at 0920. An annual inspection had just been completed on the airplane and the pilot was performing a maintenance test flight. The pilot reported that after departure he climbed to altitude to check the flight controls and aircraft performance. He reported he cycled the landing gear several times, each time receiving a down and locked indication. The pilot then flew to the Scott Air Force base/Mid-America (BLV) airport to practice an approach and landing. The pilot stated that during the landing roll he felt "a falling motion to the back right" at which time he applied full power and took off. The pilot contacted the air traffic control tower and asked them to visually check the landing gear. The controller reported the gear appeared to be down. The pilot then returned to CPS to land. He reported having a gear down and locked indication, but stated that during the landing roll, the right wing seemed closer to the ground than normal. Again, he aborted the landing. He requested that the CPS air traffic control tower visually check the landing gear. The controller replied that it appeared down, but that it looked "weak" during the landing roll. The pilot then climbed to altitude to troubleshoot the landing gear. He reported he used the Emergency Gear Extension checklist and during the manual extension process, he was only able to turn the extension handle 1-1/2 turns. He made another fly-by the tower for a gear check and was informed that it appeared to be down. The pilot then used the Gear-Up Landing emergency checklist and landed the airplane. During the landing roll the right main gear collapsed and the right wing contacted the runway. As a result, the right wing and aileron were substantially damaged. The investigation revealed that the leg brace portion of the landing gear retract brace assembly was replaced during the annual inspection. The leg brace that was installed was not purchased from Beechcraft. According to Beechcraft they do not sell the leg brace as a separate item from the upper brace assembly because of the close tolerance required between the two braces in order for the gear to properly lock in the extended position. In reference to the nose gear, the BE-58 maintenance manual states that the upper brace assembly and the leg brace must be replaced as a unit. It does not state this information in reference to the main landing gear. A Federal Aviation Administration Inspector from the St. Louis, Missouri, Flight Standards District Office reported that after the accident, with the right gear extended, he was able to release it from the locked position by pushing on it with his hands. ## Aircraft - Registration: [N4626A](https://openairdocs.org/deregistered/N4626A-2014-08-26), registration cancelled 2014-08-26, S/N TH-39, built 1970 (OpenAirDocs) - Reported make and model: Beech 58 - Registry model: [Beech 58](https://openairdocs.org/model/beech-58) (registry code 1152740) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: TH-39 - Airframe hours: 12385 - Engines: Continental IO-520-CB7B 285 horsepower reciprocating - Damage: Substantial damage - Flight: Flight test, Part 91 - Registered owner: Flight Express, Inc - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 1, 2008 - Departed: CPS, Cahokia, IL - Destination: CPS, Cahokia, IL - Airport: CPS, St. Louis/Downtown, runway 30L, 6,997 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 26; injuries: none; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review January 1, 2008; seat: left; flight hours: 1,601 total, 71 in this make and model, 1,466 as pilot in command, 229 in the last 90 days, 70 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 19 °F, dew point 10 °F - Altimeter: 30.22 inHg - Observed at: CPS ## 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 20080123835479A](https://openairdocs.org/incident/20080123835479A), Jan 23, 2008: Beech 58, Cahokia/St Lou, IL, Substantial damage. (-23) Pilot departed cps and was performing a post maintenance check flight on subject aircraft to include several practice approaches at blv. While performing… ## Other investigations on N4626A (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 NYC72DNC30](https://openairdocs.org/ntsb/NYC72DNC30), Mar 7, 1972: Beech 58 (N4626A), Millinocket, ME, substantial damage 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.