What happened
On November 5, 2022, a Cessna 310R, registration PT-OIN, was performing a private ferry flight from Manaus (SBEG) to Flores (SWFN), Amazonas. The aircraft was carrying a pilot and one passenger. Upon landing at Flores Aerodrome, the pilot experienced a failure in the braking system during the landing roll. This failure caused the aircraft to veer off the right side of the runway at low speed, traveling approximately 10 meters onto soft ground. Both occupants of the aircraft were uninjured, though the aircraft sustained light damage.
The investigation
CENIPA investigators conducted a visual inspection of the braking and hydraulic systems two days after the event. While the hydraulic lines and reservoir appeared intact with no visible leaks, investigators discovered that the hydraulic fluid levels were critically low. The left brake assembly contained only 40 ml of fluid, while the right side contained 100 ml. After the system was replenished with new fluid, the brakes functioned normally during testing.
The investigation also reviewed maintenance records. The aircraft had undergone a 200-hour inspection on September 19, 2022, which, according to the maintenance manual, should have included bleeding the braking system and replenishing the fluid. However, there was no specific detail in the logs confirming this task had been completed. Furthermore, the aircraft's logbooks for the airframe, engines, and propellers were not up to date, with the last entries dating back to September 2021.
Findings
- The primary cause of the runway excursion was the insufficient amount of hydraulic fluid in the braking system.
- A failure to properly execute or supervise the brake system service during the 200-hour inspection approximately 45 days prior to the incident is a likely contributing factor.
- Maintenance records and aircraft logbooks were not properly updated.
- The aircraft was operating within weight and balance limits, and meteorological conditions were favorable.