# NTSB LAX05LA130: Cessna 421B, N637SC, Lake Havasu Cit, AZ, April 4, 2005 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 4, 2005, 12:25 local (19:25 UTC) - Place: Lake Havasu Cit, AZ - Coordinates: 34.571109, -114.358055 - Nearby events: https://openairdocs.org/map.md?lat=34.5711&lon=-114.3581&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report August 29, 2006 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 61257 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX05LA130 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/61257/pdf - Page: https://openairdocs.org/ntsb/LAX05LA130 ## Probable cause the fracture of the landing gear shaft roll pin that resulted in a main gear collapse during the taxi. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Gear collapsed, taxi - from landing - landing gear,main gear - collapsed (cause) - miscellaneous,dowel/pin - fractured (cause) ## Analysis The left main landing gear collapsed during a precautionary landing. The pilot reported that after takeoff, he suspected a landing gear malfunction and returned to the airport. He made a gear up low approach to the airport. Maintenance personnel told him that the left gear was still extended. The pilot cycled the gear down and observed the landing gear lights were illuminated, indicating the gear was down and locked. The pilot made a soft field landing and let the airplane roll to the end of the runway. As he started to turn left, the left main gear collapsed. Post accident examination of the landing gear assembly revealed that the roll pin (part number NAS561P4-28) that retains the attaching shaft to the trunnion assembly had fractured and failed. This allowed the landing gear attaching shaft to shift from its installed position, resulting in the trunnion assembly separating from the landing gear support structure. ## Factual narrative On April 4, 2005, about 1225 mountain standard time, a Cessna 421B, N637SC, had the left main gear collapse after landing at Lake Havasu City Airport (HII), Lake Havasu City, Arizona. Sun Western Flyers, Inc., d.b.a. Sun Care Air Ambulance, was operating the airplane under the provisions of 14 CFR Part 91. The airline transport pilot and the two medical crewmembers were not injured; the airplane sustained substantial damage. The cross-country repositioning flight departed HII, about 1215, with a planned destination of Las Vegas, Nevada. Visual meteorological conditions prevailed, and a company flight plan had been filed. The approximate global positioning system (GPS) coordinates of the primary wreckage were 34 degrees 34.16 minutes north latitude and 114 degrees 21.29 minutes west longitude. The National Transportation Safety Board investigator-in-charge (IIC) interviewed the pilot via telephone. The pilot reported that after takeoff he had an unsafe gear indication; he recycled the landing gear two or three times until the gear appeared to be secured. He then noticed that the airspeed was too slow for the airplane's current flight configuration. The pilot suspected a landing gear malfunction and returned to HII. He then made a low approach to the runway and was told by his maintenance personnel that the left gear was still extended. The pilot cycled the gear down and observed that the landing gear lights were illuminated, indicating that the gear was down and locked. The pilot made a soft field landing onto runway 32. The pilot let the airplane roll to the end of the runway, and started to turn to the left, when the left main gear collapsed. The airplane's left wing came to rest on the runway. The reported damage to the airplane was confined to the left engine nacelle and the left wing in the area of the main landing gear. The airplane was removed from the runway and secured for further investigation. Federal Aviation Administration inspectors and maintenance personnel from Sun Western Flyers examined the airplane's left main landing gear assembly following the accident. The examination revealed that the roll pin (part number NAS561P4-28) that retains the attaching shaft to the trunnion assembly had fractured and failed. This allowed the landing gear attaching shaft to shift from its installed position, resulting in the trunnion assembly separating from the landing gear support structure. ## Aircraft - Registration: [N637SC](https://openairdocs.org/deregistered/N637SC-2013-12-03), registration cancelled 2013-12-03, S/N 421B0274, built 1972 (OpenAirDocs) - Reported make and model: Cessna 421B - Registry model: [Cessna 421B](https://openairdocs.org/model/cessna-421b) (registry code 2076014) (OpenAirDocs) - Registry engine: [Continental GTSIO-520-C](https://openairdocs.org/engine/continental-gtsio-520-c) (registry code 17035, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 421B0274 - Airframe hours: 8443.9 - Engines: Continental GTSIO 520H 375 horsepower reciprocating; Continental GTSIO-520H 375 horsepower reciprocating - Damage: Substantial damage - Flight: Positioning, Part 91 - Registered owner: Sun Western Flyers Inc - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, January 1, 2005, 95.1 hours before - Departed: HII, LAKE HAVASU CIT, AZ - Destination: LAS, LAS VEGAS, NV - Flight plan: Company VFR - Airport: HII, Lake Havasu City, runway 32, 8,000 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: none; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review March 1, 2005; seat: left; flight hours: 8,500 total, 100 in this make and model, 8,300 as pilot in command, 75 in the last 90 days, 25 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 15 knots, gusting 26 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 23 °F - Altimeter: 29.97 inHg - Observed at: HII ## 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 20050404007439A](https://openairdocs.org/incident/20050404007439A), Apr 4, 2005: Cessna 421B, Lake Havasu Cit, AZ, Substantial damage. (-23) On April 04, 2005, around 1200 MST, Cessna 421B, N637SC, operated by sun western flyers, dba sun care air ambulance, landed at the lake Havasu airport,… 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.