What happened
The aircraft was operating on the ramp area when the pilot initiated a maneuver to avoid a parked aircraft. During this low-speed movement, the right main landing gear traveled off the paved surface and onto the grass. The gear then crossed over a drainage hole that had been covered with wood.
As the weight of the aircraft was applied to the cover, the wood collapsed under the load. This failure allowed the right main landing gear to partially fall into the drainage hole. Consequently, the aircraft's structure shifted, causing the right horizontal stabilizer to come into contact with the ground.
The investigation
Following the incident, an examination of the wooden grate covering the drainage area was conducted. The inspection revealed that the wood had deteriorated significantly. This deterioration compromised the structural integrity of the cover, leading to its collapse under the weight of the landing gear.
Findings
The primary factor in this accident was the condition of the infrastructure at the ramp area. The wooden cover over the drainage hole was not capable of supporting the load of an aircraft's landing gear due to advanced deterioration. The pilot's maneuver, while intended to avoid a parked aircraft, resulted in the gear striking this weakened surface.
The sequence of events indicates that the collapse of the wood was the direct cause of the gear falling into the hole. This allowed the horizontal stabilizer to strike the ground, resulting in damage to the aircraft. No other mechanical failures or weather conditions were cited as contributing factors.