What happened
On May 11, 2012, a Cessna 210 Centurion II, registration F-GBGF, was participating in the "Breitling 100/24" competition. The flight was part of a series of touch-and-go maneuvers across various airfields. While approaching the unpaved runway at Les Mureaux, the pilot decided to execute a go-around. During the climb, the pilot initiated the landing gear retraction sequence. However, at an altitude of approximately 7 meters, the aircraft encountered wind shear, causing a loss of altitude. At this moment, the gear retraction process was incomplete, resulting in the landing gear doors striking the unpaved runway.
Following the encounter, the pilot noted an orange landing gear position indicator light. After unsuccessful attempts to cycle the gear, the pilot diverted to Nangis airfield, where the aircraft's maintenance facility is located. During the landing on the unpaved runway at Nangis, the main landing gear, which was not locked, retracted completely, resulting in heavy damage to the aircraft.
The investigation
The investigation focused on the mechanical state of the landing gear and the hydraulic system. Examination of the aircraft revealed that while the nose gear remained locked in the down position and undamaged, the main gear and its doors were significantly deteriorated. A critical finding was a crack in the body of the left main landing gear hydraulic actuator, which had caused a substantial hydraulic fluid leak. This failure rendered the landing gear non-functional.
Investigators analyzed the kinematics of the gear system, noting that the nose gear retracts toward the rear, whereas the main gear operates differently. The investigation also considered the meteorological conditions, confirming that wind shear related to convective cells was present at Les Mureaux at the time of the incident. Additionally, the pilot's fatigue levels were noted to be higher than anticipated due to the demands of the 24-hour competition.
Findings
- The primary cause of the gear retraction at Nangis was a crack in the left main landing gear hydraulic actuator.
- The crack led to a significant loss of hydraulic pressure, preventing the main gear from locking in the extended position.
- The investigation could not definitively determine if the crack occurred due to the impact with the runway at Les Mureaux or during the gear's extension/retraction sequence.
- Wind shear at Les Mureaux contributed to the initial altitude loss and the subsequent contact between the gear doors and the runway surface.