Piper PA-28 181 Archer II EC-DKB Landing Gear Failure at Aeródromo de la Axarquía

Incident Overview and Flight Details On Friday, May 20, 2005, at 11:00 local time, a Piper PA-28 181 Archer II with registration EC-DKB was conducting traffic pattern training around runway 13 at Aeródromo de la Axarquía (LEAX) in Málaga. The aircraft was operated by the Real Aeroclub de Málaga and was equipped with a single Lycoming O-360-A4M R-8057 engine. The flight was a general aviation instruction operation during the final approach phase. ## Crew and Passenger Information The pilot in command was a 41-year-old commercial pilot with a total of 4,500 flight hours, including 1,800 hours on the type. The student pilot had 13 hours and 35 minutes of total flight time, with 12 hours and 45 minutes on the type. Both the instructor and the student were seated in the aircraft, with the instructor in the right seat and the student at the controls in the left seat. ## Sequence of Events During the sixth circuit, while on the right downwind leg, the crew heard impacts under the left wing and observed that the left main landing gear leg had detached, remaining suspended by the brake hose. The instructor verified that the flaps, ailerons, and elevator were functioning normally. Ground personnel confirmed the complete detachment of the left gear leg. The instructor took control of the aircraft and initially considered diverting to Málaga airport but ultimately decided to land at Aeródromo de la Axarquía. ## Landing and Aftermath The aircraft touched down first on the right wheel, followed by the nose wheel, and finally the damaged left gear leg. After the damaged gear made contact with the ground, the aircraft traveled 5 meters. The fuel switch, magnetos, and battery were shut off, and the aircraft was abandoned immediately. No fire occurred, despite a small hole behind the left wing fuel tank caused by the shock absorber impacts. Both the student and instructor exited the aircraft unharmed. ## Aircraft Damage and Maintenance History The aircraft sustained minor damage. The left main landing gear trunnion broke at the area where it was attached to the upper part of the scissor mechanism. Impact damage was also observed on the left wing flap and the skin covering the underside of the wing behind the fuel tank. The aircraft was manufactured in 1980 and had 5,219 flight hours at the time of the accident. The last 100-hour inspection was performed nine days prior at 5,187 hours, with no deficiencies noted in the landing gear. ## Technical Investigation and Findings Nine months after the accident, a crack was detected in the right main landing gear trunnion at the same location as the left gear failure. The crack affected the full thickness of the lower area of the trunnion, measured 15 mm in length, and covered 60% of the inner lateral wall. Laboratory analysis of both the fractured left trunnion and the cracked right trunnion revealed no metallurgical defects, macroscopic plastic deformation, typical fatigue lines, or signs of corrosion. Microfractographic examination indicated that the fracture surfaces exhibited characteristics consistent with progressive static overload rather than instantaneous failure or fatigue. No evidence of abnormal forces in unintended areas was found. ## Conclusions The instructor's response to the landing gear failure was deemed appropriate, and the decision to land at Aeródromo de la Axarquía was supported by the favorable outcome and minimal damage. The investigation concluded that the probable cause of the accident was the successive application of multiple static overloads, likely associated with hard landings during flight school operations. These overloads, while not exceeding design values, placed the loads in the interval between limit and ultimate load values, causing deformations that weakened the material.