# NTSB NYC05IA093: Saab-Scania 340A, N40SZ, Dulles, VA, June 9, 2005 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: June 8, 2005, 21:37 local (Jun 9, 2005, 01:37 UTC) - Place: Dulles, VA - Coordinates: 38.944442, -77.455833 - Nearby events: https://openairdocs.org/map.md?lat=38.9444&lon=-77.4558&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 30 uninjured - Status: Completed, report August 29, 2006 - Report: Approved by Office Director - Parties: Saab Aircraft, Shuttle America, FAA FSDO-27 - NTSB case key (mKey): 61652 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC05IA093 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/61652/pdf - Page: https://openairdocs.org/ntsb/NYC05IA093 ## Probable cause Failure of the right main landing gear to extend and lock for undetermined reasons, which resulted in the right main landing gear collapsing during touchdown. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - landing gear,main gear - failure - gear down and locked - not possible - Gear collapsed, emergency landing - On ground/water encounter with terrain/water, emergency landing - terrain condition - runway ## Analysis During the approach, the flightcrew was unable to get the right main landing gear extended and locked. After several attempts, while conferring with the checklist and company personnel, the flightcrew performed an emergency landing with the unsafe landing gear indication. During the landing, the right main landing gear slowly collapsed, and the airplane came to rest off the right side of the runway. Examination of the right main landing gear revealed that the retract actuator fitting was secured with two fasteners, a smaller bolt, and a larger bolt. The nut and cotter key were not recovered with the smaller bolt, and 8 of the 12 threads on the smaller bolt were stripped consistent with an overstress pulling of the nut away from the bolt. The larger bolt was bent and separated near the head, consistent with a tension and overstress separation as a result of the smaller bolt failure. The overstress failures were consistent with the right main landing gear not being locked in the extended position when aircraft weight was applied; however, examination of the right main landing gear down lock system could not determine any pre-impact mechanical malfunctions. Further, the right main landing gear retract actuator was tomography scanned, and no anomalies were noted. The unit was then functionally tested at the manufacturer's facility, under the supervision of an FAA inspector. The unit tested successfully, with no anomalies noted. ## Factual narrative On June 8, 2005, at 2137 eastern daylight time, a Saab 340A, N40SZ, operated by Shuttle America Corp. as United Express flight 7564, sustained minor damage during an emergency landing at Washington Dulles International Airport (IAD), Dulles, Virginia. There were no injuries to the 3 crewmembers and 27 passengers. Visual meteorological conditions prevailed for the flight that originated from Westchester County Airport (HPN), White Plains, New York. An instrument flight rules flight plan was filed for the air carrier flight conducted under 14 CFR Part 121. According to the captain, the airplane was approaching IAD when the flightcrew attempted to extend the landing gear. A yellow transit light cockpit indication was observed, which alerted the flightcrew that the right main landing gear had not fully extended and locked. After "recycling" the landing gear, the flightcrew noted the same anomaly. The flightcrew advised air traffic control (ATC) of the problem, performed a missed approach, and climbed to 3,000 feet over the airport. While circling the airport, the flightcrew performed all relevant checklists in the quick reference handbook (QRH); however, they could not correct the anomaly. In addition, the flightcrew performed a low pass over the airport. Ground personnel observed the gear extended, but could not confirm that it was locked in the fully extended position. The flightcrew also contacted their company twice to discuss the problem. The decision was made to perform an emergency landing with the unsafe landing gear indication. After completing the emergency checklist items in the QRH, the flightcrew performed an emergency landing on runway 19L. During the landing, the right main landing gear slowly collapsed, and the airplane came to rest in a grassy area off the right side of the runway. An emergency evacuation of the airplane was performed successfully, and no serious injuries were reported. The airplane was equipped with a cockpit voice recorder (CVR) and flight data recorder (FDR), which were forwarded to the Safety Board's vehicle recorders laboratory for readout. Data on the recorders confirmed the captain's statement. Components of the right main landing gear were examined at the Safety Board's materials laboratory. The right main landing gear retract actuator fitting was secured with two fasteners, a smaller bolt (part number AIR 134736) and a larger bolt (part number AIR 124792). The nut and cotter key were not recovered with the smaller bolt, and 8 of the 12 threads on the smaller bolt were stripped consistent with an overstress pulling of the nut away from the bolt. The larger bolt was bent and separated near the head, consistent with a tension and overstress separation as a result of the smaller bolt failure. The overstress failures were consistent with the right main landing gear not locked in the extended position while aircraft weight was applied to it; however, examination of the right main landing gear down lock system could not determine any pre-impact mechanical malfunctions. Further, the right main landing gear retract actuator was subjected to x-ray computed tomography (CT) and digital scanning under the direction of the Safety Board. The CT scan did not reveal any anomalies with the actuator. The unit was then functionally tested at the manufacturer's facility, under the supervision of an FAA inspector. The unit tested successfully, with no anomalies noted. The airplane was maintained under a continuous airworthiness maintenance program, and had accumulated about 164 hours of operation since its last inspection, which was performed on April 30, 2005. ## Aircraft - Registration: [N40SZ](https://openairdocs.org/deregistered/N40SZ-2013-08-07), registration cancelled 2013-08-07, S/N 340A-040, built 1985 (OpenAirDocs) - Reported make and model: Saab-Scania AB (Saab) 340A - Registry model: [Saab-Scania SF340A](https://openairdocs.org/model/saab-scania-sf340a) (registry code 7860100) (OpenAirDocs) - Registry engine: [GE CT7-SER series](https://openairdocs.org/engine/ge-ct7-ser-series) (registry code 30031, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 40 - Airframe hours: 41441 - Engines: General Electric CT75A2 1735 horsepower turbo prop; General Electric CT75A2 1735 horsepower turbo prop - Damage: Minor damage - Flight: Part 121 - Operator: Shuttle America Corporation, doing business as United Express - Registered owner: Lambert Leasing - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, April 1, 2005, 164 hours before - Departed: HPN, White Plains, NY - Destination: IAD, Dulles, VA - Flight plan: IFR - Airport: IAD, Washington Dulles Internationa, runway 19L, 11,500 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 32; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1; last flight review February 1, 2005; seat: left; flight hours: 4,673 total, 3,476 in this make and model, 2,660 as pilot in command, 205 in the last 90 days, 85 in the last 30 days, 6 in the last 24 hours - Co-pilot; age 32; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review October 1, 2004; seat: right; flight hours: 2,050 total, 620 in this make and model, 1,300 as pilot in command, 249 in the last 90 days, 71 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night - Wind: 200° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 63 °F - Altimeter: 29.98 inHg - Observed at: IAD ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20050608012329I](https://openairdocs.org/incident/20050608012329I), Jun 8, 2005: Saab SF340A, Washington, DC, Minor damage. (-23) Right main landing gear was unable to be locked in the down position. Upon landing right main gear collapsed causing aircraft to depart runway. 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.