What happened
On June 13, 2016, a Beechcraft 58P, registration PR-GEO, was performing a local flight at the Pirapora Aerodrome (SNPX) in Minas Gerais, Brazil. The pilot, who was conducting a training flight after a period of inactivity with this specific model, approached runway 10 at approximately 100 knots.
Upon touchdown, the pilot attempted to apply the brakes and the parking brake; however, the braking system proved completely ineffective. Unable to decelerate the aircraft, the pilot maintained a straight path, which resulted in the aircraft overrunning the runway end. The aircraft crossed the runway boundary and traveled approximately 58 meters into an unpaved area before striking a stormwater drainage ditch. The impact caused light damage to the nose landing gear, propellers, and forward fuselage. The pilot was uninjured.
The investigation
CENIPA investigators examined the aircraft's maintenance history and the braking system's condition. It was discovered that the hydraulic fluid reservoir for the brakes was empty at the time of the incident. While the aircraft had undergone maintenance the previous day to address reported low brake effectiveness—including cleaning components and refilling the reservoir—the investigation found that a leak had persisted.
Subsequent inspections revealed that the brake master cylinders installed in the aircraft had different part numbers. Although the maintenance manual did not explicitly require identical part numbers, the manufacturer (Textron Aviation) had recommended that these cylinders be of the same part number and replaced in pairs to ensure consistent pedal feel. Furthermore, investigators found that the aircraft's pre-flight checklist did not include a requirement to check the hydraulic fluid level for the brakes, a procedure that was only mandated during 100-hour inspections. The investigation also noted that the runway safety area at the end of runway 28 contained an obstacle (the drainage ditch) that was not entirely free of obstructions as required by regulation.
Findings
- Loss of braking effectiveness due to the complete depletion of hydraulic fluid in the system.
- A leak in the left brake master cylinder caused the fluid to gradually escape.
- The use of brake master cylinders with different part numbers contributed to inconsistent system performance.
- The pre-flight inspection procedures for the Beechcraft 58P lacked a specific check for the brake hydraulic fluid level.
- Inadequate airport infrastructure, specifically the presence of an exposed drainage ditch in the runway safety area, amplified the consequences of the excursion.
- Maintenance actions performed the previous day were insufficient to resolve the underlying braking issue.