What happened
On February 8, 2017, a Cessna 210R, registration PR-ORL, departed from the Destilaria Medasa airfield in Caravelas, Bahia, bound for Vitória, Espírito Santo. The flight was a private ferry mission operated by Quanti Participações Ltda. Shortly after takeoff, the pilot noticed that the main landing gear failed to lock in the up position.
Despite multiple attempts to manually extend the gear, the pilot was unable to secure the landing gear in the down position. After approximately two hours and twenty minutes of flight, the pilot decided to perform an emergency landing back at the point of origin. During the landing roll, the aircraft drifted to the right, veering off the runway and striking a perimeter fence with the right wing, resulting in substantial damage to the aircraft.
The investigation
CENIPA investigators examined the aircraft's hydraulic system, which utilizes a single reservoir to power both normal and emergency gear extension. The investigation established that the pilot observed a red "gear unlocked" light and noted that the hydraulic pump temperature had increased, causing the hydraulic pump breaker to trip. The hydraulic reservoir was found to be empty.
Upon inspection of the hydraulic lines, investigators discovered that an aluminum flanged tube (P/N 1280523-1) had disconnected from the left actuator cylinder. The flange had slipped inside the sleeve and nut, allowing the entire hydraulic fluid volume to leak out. Further analysis of the tube revealed that its total length was insufficient to allow both flanges to reach their connections properly. This improper installation, likely occurring during a previous maintenance intervention, subjected the tube to tensile stress. Under operational vibrations and pressure, the non-compliant flange—which featured incorrect thickness and angles—deformed, leading to the eventual disconnection.
Findings
- Maintenance error involving the improper installation of a hydraulic flanged tube.
- The hydraulic fluid reservoir was depleted due to a leak caused by a disconnected aluminum tube.
- The tube (P/N 1280523-1) was of an incorrect length, preventing proper coupling at the connections.
- The flange on the affected tube did not meet specifications regarding thickness, size, or angle.
- Standard maintenance inspections (50, 100, and 200-hour intervals) were unable to detect the defect because they did not require the disassembly of the affected component.