I am totally pissed! I did it again! It was not even 3 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 the fix to the problem…
The Malibu has inverted master brake cylinders on the rudder pedals. Normally, the brakes work wonderfully and there are no problems. Yet an insidious problem can develop. There are 3 O-rings on each master cylinder and I have now come to the realization that these O-rings can seep. Yet, they don’t seep fluid out from the system, they let air into the system. Since the Malibu is pressurized, when flown with a high differential cabin pressure, the cabin is much like a balloon. The air which is under relatively high pressure in the cabin looks for any opening in the cabin which to escape to equalize the pressure. When the O-ring in the brake system allows seepage, air enters the braking system, almost always on only one side. If allowed to persist, a large air bubble can be present in the system, rendering the brakes on the affected side ineffective…or even non-existent.
Upside-down brake master cylinders...
As you would expect, the bubble migrates upwards and enters the brake lines even so insidiously. In the picture, the right brake on the pilot’s side has been removed for repair.
Here’s the deal, I’ve had two brake failures in the Malibu and both of them occurred on flights where the brakes worked perfectly on run-up and preflight checks. The problem does not reveal itself until the brakes are checked just prior to landing…that is, if the brakes are checked prior to landing.
Although the checklist in the Malibu clearly states to check the brakes prior to landing, I’ve seen maybe 10% of pilots actually check the brakes just prior to landing. Many of the after-market or home-made checklists that are being used by many pilots today do not have the brake-check even listed on the check-list. I’ve now been guilty of realizing I had a brake failure on two separate flights only after actually touching down on the runway. Clearly, I’ve not made the brake-check a mandatory part of my pre-landing checks and am one of the guilty.
Main point—do the brake-check prior to landing. If either side of the braking system is weak or non-existent, perform a go-around and consider your options. You might want to fly to an airport with a longer runway. You might want to fly an approach a little slower and maybe plan to touch down as early as practicable on the runway. You might want to call for safety vehicles to be ready in case there is a an issue. In any case, you do not want to touch down on the runway and then realize you’ve got a brake problem.
