What happened
On August 7, 2008, an EMB-820C, registration PP-EHX, was operating a flight from Cacoal to Fazenda Pouso Redondo, Brazil, carrying one pilot and five passengers. Due to changing weather conditions, the flight was diverted toward Vilhena. However, while passing over Cerejeiras, the pilot decided to land at a local, non-certified, and unregistered dirt airstrip, reportedly because a passenger was feeling unwell.
Upon landing at the Cerejeiras airstrip, the pilot applied the brakes to decelerate. During the landing roll, the right brake failed to engage, causing the aircraft to yaw sharply to the left. The aircraft veered off the centerline and collided with a wire fence, eventually coming to a stop on a road parallel to the runway. The impact caused the left wing to strike the fence and the nose gear to collapse, resulting in the propellers striking the ground. While the aircraft sustained substantial damage, all six occupants escaped without injury.
The investigation
CENIPA investigators examined the aircraft's hydraulic system and maintenance records. The investigation revealed that the hydraulic fluid reservoir was completely empty. Technical inspections identified a loose connection on the right main gear brake line (PN 42112-01 Tube Assy Main Gear Brake Line Right). The connection showed evidence of a leak due to insufficient torque being applied to the threads.
Evidence, including hydraulic oil residue mixed with dust on the landing gear housing, suggested that this leak had been present for some time and likely predated the flight. Investigators could not determine if the loss of torque was caused by vibration or improper maintenance procedures. Furthermore, the investigation noted that the pilot's decision to land at an unauthorized airstrip deviated from the established flight plan, which had designated Vilhena as the official alternate.
Findings
- Inadequate pilot judgment regarding the decision to land at an uncertified and unregistered airstrip instead of proceeding to the planned alternate.
- Failure of the right brake system caused by a hydraulic leak stemming from an improperly torqued connection.
- Maintenance uncertainty, as the cause of the loose connection (either vibration or improper torque during maintenance) remained undetermined.
- Operational non-compliance, as the use of a non-homologated runway increased the risks associated with the mechanical failure.