Event Description
On 10 September 2000 at 1100 hours UTC, a Piper PA-25-235 Pawnee (G-ASLK) was returning to Nympsfield Airfield after its fifth glider towing sortie of the day. The pilot chose to land deeper than usual on the westerly grass runway to maintain clearance between the tow rope and cattle grazing adjacent to the threshold. Touchdown occurred beyond a slight plateau on the undulating runway, on a downslope approximately in line with a row of trailers parked about 50 to 65 metres to the right. As the tail settled at an estimated 30 mph, the pilot began normal braking. The left brake failed without prior fading, causing the aircraft to yaw 30° to 40° right before the pilot released the right brake pedal. Despite full left rudder, the aircraft headed toward a car park. The pilot re-applied both brakes, but only the right brake functioned, slewing the aircraft further right. It slid, broke through a low wooden fence, and came to rest just inside the car park corner, damaging the lower rudder. The pilot was not injured and shut down the engine before vacating.
Post-Flight Findings
Examination revealed the left brake pedal was "floppy" due to lack of hydraulic pressure, though pressure reportedly returned after repeated applications. The pilot noted a history of brake fluid seepage from the left system, reported in the Daily Inspection book multiple times. After such reports, the brake hydraulic reservoir was topped up pending the next 150-hour check. During the aircraft's subsequent 150-hour check at a maintenance organisation where the pilot was also employed, the pilot queried the brake defect and was told its rectification was deferred until the Annual Inspection due in December 2000. The pilot could not identify who made that decision.
Additional Comments
The pilot commented that if rudder-to-tailwheel interconnecting springs had been installed, it might have been possible to turn the aircraft during the seconds between the initial swing and the final brake application.