PA-46 Malibu/Malibu Mirage/Malibu Matrix
Maintenance Airframe; Maintenance Inspection Authority; Maintenance Powerplant
Maintenance Inspector 30; Maintenance Repairman 35
Troubleshooting
Aircraft Equipment Problem Critical
General Maintenance Action
Aircraft
Pressurized brakes...It did it again. It was not even X years ago that I landed a Piper Malibu on a short runway only to notice upon touchdown that one complete side of the brake system was completely inoperative. Now; just last week; it happened again. Here's the story; and Piper needs to fix to the design problem...The Malibu has inverted master brake cylinders on the rudder pedals like many Pipers. Normally; the brakes work and there are no problems. Yet an insidious problem will develop. There are 3 O-rings on each master cylinder and these O-rings will leak. Yet; they will not leak brake fluid out of the system; they will and do let air into the system. The Malibu is pressurized; and when flown with a differential cabin pressure; the pressure is pushing air in to the brakes system thru the brake master cylinders. The cabin air which is under pressure is flowing to any opening in the cabin which to escape. When the O-rings in the brake system allows the cabin air to enter the braking system; the brakes stop working. If allowed to persist; the air in the system renders the brakes on the affected side or both sides ineffective...or even non-existent.Upside-down brake master cylinders...As you would expect; the air migrates upwards and enters the brake lines even so insidiously and it doesn`t take much air to make the brakes disabled. Here's the issue; Malibu brake failures are common on flights where the brakes worked perfectly on run-up and pre flight checks. The problem does not reveal itself until the brakes are used on landing.Although the checklist in the Malibu clearly states to check the brakes prior to takeoff. How do you check the brakes in flight prior to landing?If either side of the braking system is weak or non-existent; perform a go-around and consider your options. Pilot might want to fly to an airport with a longer runway if they have fuel. They may want to fly an approach a little slower and maybe plan to touch down as early as practicable on the runway. They might want to call for safety vehicles to be ready in case there is a landing over run issue and notify the FAA. In any case; you do not want to touch down on the runway and then realize you've got a brake problem. Many Piper pilots and passengers are in danger when this occurs.
PA-46 Malibu pilot reported brake failure during landing rollout; citing a possible design flaw in the braking system.