On January 11, 2004, an Aero Commander 500 (registration N800SL) was involved in an aviation accident near Allendale, SC. Investigators recorded the probable cause as: The failure of the hydraulic brake system accumulator due to a ruptured diaphragm. A factor was the ditch. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During takeoff roll, the airplane tracked right; differential braking was applied to realign. When brakes were applied to stop, they failed, causing the airplane to veer left into a ditch. Examination revealed leaking hydraulic pucks, worn brake disc and linings, and a ruptured accumulator diaphragm.
Accident Overview
During the takeoff roll, the airplane began to track right. The pilot applied differential braking to line up the airplane with the runway centerline. When brakes were subsequently applied to stop the airplane, they failed, and the airplane veered off the left side of the runway into a ditch.
Pilot Report
The pilot reported no other flight control or mechanical problems.
Examination Findings
Examination of the wheel brakes revealed that the hydraulic pucks were leaking, and the brake disc and linings were worn. Examination of the accumulator revealed that the diaphragm was ruptured and the system would not maintain pressure.