What happened
On December 15, 2015, a Beechcraft G58, registration PR-ARK, was performing a private passenger flight from Uberaba, Minas Gerais, to Araguaína, Tocantins. The flight involved one pilot and three passengers. As the aircraft approached Araguaína, weather conditions deteriorated significantly due to heavy rain in the area.
The pilot executed a long landing on runway 27, touching down approximately 400 meters from the threshold. During the landing roll, the aircraft experienced a loss of directional control and failed to decelerate as expected. In an attempt to stop the aircraft within the remaining runway distance, the pilot commanded a left turn to induce a lateral skid, hoping to increase friction.
During this maneuver, the aircraft yawed to the left and the right landing gear retracted unexpectedly. This caused the right wing and the propeller blades of the right engine to impact the ground. The aircraft eventually came to a stop near the threshold of runway 09. All four occupants escaped the incident without injury, though the aircraft sustained light damage.
The investigation
CENIPA's investigation focused on the sequence of events leading to the loss of control and the mechanical failure of the landing gear. Investigators examined the aircraft's maintenance records, the pilot's credentials, and the environmental conditions at the time of the accident.
Technical analysis of the runway markings and tire evidence revealed the occurrence of hydroplaning and rubber reversion. The investigation also scrutinized the pilot's decision-making process regarding the landing under adverse weather and the specific flight controls used during the landing roll. Physical examination of the landing gear mechanism revealed that the retraction lock bar broke, which led to the uncommanded retraction of the right gear, likely due to the stresses imposed by the skid.
Findings
- The pilot's decision to proceed with the landing despite deteriorating weather conditions and the lack of a pre-planned contingency or alternative airport.
- The execution of an unstabilized approach, characterized by a long touchdown.
- The use of an improper flight maneuver, as the pilot'mandated a left turn to induce a skid, a technique not supported by technical manuals; standard practice recommends a go-around in such situations.
- The occurrence of hydroplaning and rubber reversion on the wet runway, which reduced available friction.
- The mechanical failure of the right landing gear retraction lock bar due to the forces generated during the skid.