Beechcraft B1900C Landing Gear Collapse at San Antonio, TX, 8 May 2020 (Ameriflight, N31704)
On 8 May 2020 Ameriflight Beechcraft 1900C N31704 was damaged in an accident at San Antonio, Texas. The aircraft was being flown single pilot as a Part 135 cargo flight.
Ameriflight B1900C N31704 Damaged Left Wing (Credit: FAA via NTSB)
The US National Transportation Safety Board (NTSB) preliminary report states that:
…the flight departed the Corpus Christi International Airport (CRP), Corpus Christi, Texas, at 2004 with 631 lbs of cargo and a fuel load of 2,800 lbs. During the initial climb, the captain selected the landing gear handle to the UP position to retract the landing gear. The attempt was unsuccessful, and the captain attempted to cycle the landing gear handle once more yielding the same result.
Following the second unsuccessful gear retraction, the captain elected to leave the landing gear handle in the DOWN position and continued to the San Antonio International Airport (SAT), San Antonio, Texas, where more services would be available if needed. The airplane climbed to 8,000 ft mean sea level and cruised below the maximum landing gear extended speed (VLE).
Nearing San Antonio, the pilot completed the before landing checklist and noted ‘three greens’ which indicated the landing gear was down and locked. However…
As the main landing gear touched down…the left main landing gear collapsed, the red unsafe light in the landing gear handle illuminated…followed by an aural horn indicating the landing gear was now unlocked and unsafe for landing.
Simultaneously, the airplane began to dip toward the left, causing the left wing tip to contact the runway [which resulted in] momentum taking the airplane from the runway centerline off the runway and into the grass area several thousand feet from the runway 4 threshold. Once the airplane came to a complete stop, the captain shutdown all power to the airplane and exited through the main entry air stairs.
A postaccident damage assessment by the operator revealed that the left main landing gear brace was fractured.
Ameriflight B1900C N31704 Fracture Left MLG Drag Brace (Credit: FAA via NTSB)
The operator reported that the airplane’s weight at the time of the accident was 14,381 lbs (the airplane’s maximum gross weight is 17,120 lbs).
UPDATE 30 March 2022: NTSB Final Report & Probable Cause Issued
The NTSB final report reveals:
…the left main landing gear upper drag leg arm fractured in bending and twisting overload.
There was no evidence of preexisting cracking or corrosion. The dimensions of the part were consistent with the drawing and the chemical composition and microstructure were consistent with 7075 aluminum alloy, as required. The mechanical properties were lower, and the electrical conductivity was higher than the requirements for 7075-T6 aluminum alloy.
The measured mechanical properties and electrical conductivity did not conform to any standard temper for 7075 aluminum alloy.
The NTSB probable cause was determined to be:
The failure of the left main landing gear upper drag leg arm due to substandard mechanical properties, which resulted in a collapse of the landing gear upon landing.
Safety Resources
Our past B1900, B99 and King Air safety articles include:
- B1900D Emergency Landing: Maintenance Standards & Practices
- Beech 99A MLG Collapse
- Incorrectly Rigged B1900D Charlotte, NC, 8 January 2003: 21 Fatalities
- Crossed Cables: Colgan Air B1900D N240CJ Maintenance Error
- B1900C PSM+ICR Accident in Pakistan 2010
- Distracted B1900C Wheels Up Landing in the Bahamas
- Operator & FAA Shortcomings in Alaskan B1900 Accident
- Alaska B1900C Accident – Contributory ATC Errors
- B1900D Window Blowout
- King Air 200 Smoke and Fumes From Windshield Electrical Fault
- King Air 100 Stalls on Take Off After Exposed to 14 Minutes of Snowfall: No De-Icing Applied
- Indian King Air Take Off Accident: Organisational & Training Weaknesses
- LOC-I Departure: AAIB Report on King Air 200 Accident
- MC-12W Loss of Control Orbiting Over Afghanistan: Lessons in Training and Urgent Operational Requirements
We have also written these landing gear related articles:
- Eclipse 500 Landing Gear Production Defect
- Significant Twin Otter NLG Crack
- Poor Painting Prevents Proper Performance: Shorts Sherpa NLG Collapse
- A Lufthansa MD-11F Nose Wheel Detached after Maintenance Error
- B747 Landing Gear Failure Due to Omission of Rig Pin During Maintenance
- When Down Is Up: 747 Actuator Installation Incident
- Lost in Translation: Misrigged Main Landing Gear
- Maintenance Human Factors in Finnish F406 Landing Gear Collapse
- S-92A Nose Landing Gear Incidents
- UPDATE 12 October 2020: Frozen Dash 8-100 Landing Gear After ‘Improper Maintenance Practices’ Say NTSB
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Ameriflight B1900C N31704 at San Juan International in 2008 (Credit: James Willamon, CC BY-SA 2.0)
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