What happened
On October 2, 2013, an Embraer EMB-810D, registration PT-VLO, operated by Amapil Táxi Aéreo Ltda., was performing a scheduled flight from Barra do Garças, MT, to Campo Grande, MS. The aircraft was carrying two crew members and two passengers.
During the approach to Campo Grande, the crew attempted to extend the landing gear, but the nose gear failed to deploy, while the main landing gear successfully locked down. The crew requested airspace to perform emergency procedures at 6,000 feet. They attempted to troubleshoot the system by swapping indicator bulbs and performing multiple extension attempts via the normal hydraulic system. When these efforts failed, they attempted the emergency gravity-extension procedure, which also proved unsuccessful.
The pilot decided to proceed with an emergency landing at Estância Santa Maria Aerodrome (SSKG). During the landing roll, the propeller blades of both engines struck the runway multiple times. The lower portion of the fuselage dragged along the runway for approximately 180 meters. All four occupants escaped the aircraft uninjured, though the aircraft sustained substantial damage.
The investigation
CENIPA investigators examined the aircraft's hydraulic and mechanical systems to determine why both the primary and emergency extension methods failed. The investigation revealed that the hydraulic reservoir was empty, and the main hydraulic pump's circuit breaker had tripped. Laboratory testing of the nose gear actuator (part number 79847-02) identified a leak at the connection between the hose and the actuator body. This leak had depleted the hydraulic fluid, rendering the normal extension system inoperable.
Furthermore, the investigation looked into why the emergency gravity-extension failed. Investigators found physical interference between the lateral vibration damper rod's mounting bolt and the nose gear door mechanism axis. This friction was caused by the use of an improper, non-standard spacer that exceeded the manufacturer's specified dimensions. The investigation also noted that the bolt used was intended for a castle nut and cotter pin configuration rather than the self-locking nut found on the aircraft.
Findings
- Hydraulic leak: A leak at the nose gear actuator connection caused the depletion of hydraulic fluid, leading to the failure of the primary landing gear extension system.
- Improper maintenance: The use of non-standard parts, including an incorrectly sized spacer and an adapted bolt assembly, created mechanical friction that prevented the nose gear from deploying via gravity.
- Maintenance and supervision: Inadequate maintenance practices and a lack of effective management oversight contributed to the installation of non-compliant components.