What happened
Four aircraft had backtaxied south along runway 16/34 with the intention of taking off from the northern end at runway 34. Upon reaching the southern terminus, the first three aircraft moved aside onto a designated run-up area. The pilot of the first aircraft positioned his plane for takeoff just as the fourth aircraft arrived.
The fourth aircraft, a Piper PA-34 with registration N31856, approached the turn-off point. The pilot applied the wheel brakes but found the left brake to be ineffective. In response, he released the right brake and attempted to use differential power and nosewheel steering to execute a left turn and avoid a collision.
The attempt was unsuccessful. The right wing tip of N31856 scraped against the right wing tip of a Cessna 414, registered as N711RT, causing only minor damage to that aircraft. After clearing the Cessna, the right wing of N31856 struck the leading edge of the right wing of a Beech 95-B55, registration N25631. The Piper then spun around, and its propellers impacted the trailing edge of the Beech's right wing and right horizontal stabilizer. This sequence caused substantial damage to both aircraft involved in the secondary impact.
The investigation
An examination of the Piper PA-34 revealed that the brake fluid reservoir for the left brake was completely empty. When the system was serviced and refilled, the brakes operated normally, indicating a loss of hydraulic pressure rather than mechanical failure of the braking components themselves.