There are only two ways to make enough heat to catch the brakes & wheels on fire. One is extremely hard braking during an aborted takeoff, after a long taxi, while using brakes to steer in a stiff crosswind or by using too much power to taxi. The other is simply dragging the brakes lightly during a normal taxi. It is exceedingly rare to have a mechanical issue affect both brakes in the same manner. The only thing in common is the parking brake valve. Taxiing with the parking brake on is possible if you use enough power, or if the parking brake had a light application when last set, and you taxied away with it on. Light pressure from an unreleased parking brake could do what you describe. It would manifest itself in requiring more power than normal to taxi.
And the brakes would feel light because when you press down, they are already partly on. But if you press hard enough to really steer, the parking brake would release automatically.So you have a bit of a mystery here, but none of it points to a mechanical failure, unless your brake discs were worn so thin that the caliper pistons stuck at angles and wouldn’t retract. This is also rare.
That ONE side of the caliper’s pads was worn to the rivets and gouged the rotor, and the outboard wasn’t?
Near as I can tell, the pins were not lubricated and perhaps one side of the caliper got stuck?
Every annual I would take the time myself to disassemble the callipers, scuff out the cylinder with some emery paper, put in a new o-ring and polish up the caliper pins and their holes and put a schmear of nickle anti-seize on the pins. I had a sig brake failure once in a Comanche and it was a non-event. I’d hate to lose one on a Cirrus under hard braking, so I spend the two hours and clean 'em up every year.
As an engineer, I have GOT to chime in on this! There are compromises in every design. From butter knife to space shuttle. No design can be expected to accommodate every behavior of the user (like riding the brakes). The best we can hope for is the 99% rule. Unfortunately, the Cirrus pant, brake, heat combination exceeds that rule.
OK, get over it. As a user of this device YOU must accommodate the design. I’m not touting our IceSkates™. That was my solution to the heat problems, but it’s not everyone’s. There are no surprises here. These are known issues. If you don’t really inspect the condition of your brakes, the pads, the disk, the tire, the fluid, etc, then you are being foolish. After all, who is the PIC?
This really is a debate that keeps coming up over and over. The fact is that the brake system on the Cirrus is no different than thousands of other non Cirrus models. What has been suggested is that the unique design of the wheel pant makes these brakes unusually susceptible to over heating. But as others have pointed out, it still takes a lot of high brake use to get them that hot. There are two solutions to this issue.
First you can get your Cool Skates and heat management is much better with that design. But the second and more important is better pilot behavior. Cirrus has investigated brake fires and found that people are applying the brakes at much higher RPMS over the recommended value (1000 RPMs). That is the equivalent of have your foot on the brakes of your car while driving with the other foot on the accelerator. It is just bad form. But our planes has free castering nose wheels so it is a a temptation to use the brakes to steer improperly. there si nothing wrong with the wheel or the brakes. It is the pilot not using proper technique that causes this issue.
From the looks of your video, the slider pins looked dry and lacked anti-seize lubricant.
But overtorquing came to me last night in my sleep.
Few mechanics bother, or know (or remember in my case!) to properly torque the backer plate tie bolts when reassembling the brake calipers. Over torquing can deform the plate and cause the assembly to deform and cause brake binding exactly as you experienced.
"Apply an antiseize compound conforming to
MIL-T-5544 to all friction surfaces.
Overtorquing (exceeding these values)
could cause depressions in the brake cylinder, which result in dragging
or bound up brakes. Use a torque wrench when installing back plate
bolts to insure the proper torquing values are attained. Replace the
back plate tie bolts with approved bolts as shown in the Cleveland Product
Catalog. Depressions in the brake cylinder (surface A) exceeding 0.005
inch (0.127 mm) deep require replacement of the brake cylinder."
I couldn’t agree more. Let’s take some responsibility. A 777 pilot still does a walk around, checks the wheels and brakes and knows he can’t take off until the brakes cool from landing. That’s not the fault of the aircraft. It’s the known limitation of the aircraft. Don’t taxi with your feet on the brakes…same thing.
Did your mechanic sort out why the caliper was getting stuck, and has it happened again?
I’m experiencing the same problem. I’ve had two rotors replaced on my right main over the last 70 hrs. The inboard brake linings have worn to the rivets and gouged the rotor as shown in your videos.
After 35 flight hours on the new rotor, the lining still looks fine.
Here are my 2 cents. Go look at the wheels on a Bonanza, Baron or King Air and then look at a Cirrus wheels.
Beech is has bigger wheels and I assume the rotors are a little bigger too, what is the other difference? They are not in a wheel pant that does not vent so well so they do not cool as well. They are also not exposed it is not so easy to inspect because they have a nice aerodynamic wheel cover.
Cirrus also has a castering front wheel so I think people ride the brakes
Cirrus uses smaller tires to make the plane aerodynamic, so it can have better performance and a gear that was designed to be fixed to absorb some of the shock of a Chute landing. People posted here about 500+ hours on brakes some are changing in 100 hours. My plane went through some serious training with two pilots and the brakes are fine 100+ hours. I think its the pilots, instructors and maintenance that are the problem.
Only brake issue I’ve ever experienced in my 800 hours in the Cirrus was a Union fitting on the Main gear brake line loosened up slightly, and there was evidence of brake fluid on the fairing. As a CSIP and working at a Service Center where a fractional ownership program was as well. I’ve seen numerous over-temped brake linings and even a few flat spotted tires. All of which are attributed to pilots, not the aircraft. Elementary taxing skills never being taught and not being used. People landing with the brakes on, taxing to quickly so they don’t have to use the brakes to the point they have rudder authority, or riding the brakes around, or worse yet riding the brakes and power at the same time!
