Accident Overview
On May 8, 2020, at approximately 2050 central daylight time, a Beechcraft 1900C airplane, registration N31704, sustained substantial damage during an accident near San Antonio, Texas. The pilot reported no injury. The aircraft was operating as Ameriflight Flight 1829 under Title 14 Code of Federal Regulations Part 135 as a cargo flight.
Landing Gear Issue Post-Takeoff
The flight departed Corpus Christi International Airport (CRP) at 2004 with 631 lbs of cargo and 2,800 lbs of fuel. During initial climb, the captain moved the landing gear handle to the UP position, but the gear did not retract. A second attempt to cycle the handle also failed. The captain then left the handle in the DOWN position and continued to San Antonio International Airport (SAT), where more services would be available if needed.
Approach and Landing
At SAT, air traffic control cleared the airplane for a visual approach. The pilot entered a right base leg and completed the before-landing checklist, which showed three green lights and no red lights, indicating the landing gear was down, locked, and safe. The airplane touched down at about 90 knots near the aiming point marker on runway 4. As the main landing gear made contact with the dry concrete, the left main landing gear collapsed. The red unsafe light in the landing gear handle illuminated, followed by an aural horn, signaling the gear was unlocked and unsafe. The airplane dipped left, causing the left wing tip to contact the runway. The pilot reported no side loading during touchdown. The airplane exited the runway and came to a stop. The left wing sustained substantial damage.
Post-Accident Examination
After the accident, the airplane was lifted to allow manual extension and pinning of the left main landing gear. The upper drag leg arm was found fractured, and the actuator forward rod end was bent. The left main landing gear drag brace assembly (Beech part number 114-810023-1, serial number ARC31209-5) and the left main landing gear actuator (Beech part number 114-380041-21, APPH part number 40600-12, serial number 14) were retained for further examination. Examination revealed that the upper drag leg arm fractured in bending and twisting overload, with no evidence of pre-existing cracking or corrosion. Its dimensions were consistent with the drawing, and chemical composition and microstructure were consistent with 7075 aluminum alloy. However, mechanical properties were lower and electrical conductivity higher than requirements for 7075-T6 aluminum alloy, and did not conform to any standard temper for 7075 aluminum alloy.
A functional test of the left main landing gear actuator found no anomalies. Laboratory analysis of a hydraulic fluid sample also found no anomalies.
Maintenance Records
According to the operator's maintenance records, on April 29, 2020, both left and right main landing gear drag brace assemblies were replaced because they were due for overhaul. The left main landing gear drag brace assembly installed was the one removed after the accident (serial number ARC31209-5). This drag brace assembly had been overhauled by Ameriflight in February 2020, which involved disassembly, paint stripping, inspection, repaint, and reassembly with new hardware.
The airplane's cargo load manifest indicated it was within weight and balance limits. The aircraft was not equipped with a cockpit voice recorder or flight data recorder, nor was it required to be.