Saturday, October 19, 2019

Quality time with Sally

https://youtu.be/gPGYrRuuvhM


The student was "No-Show". He had looked at the weather and decided there was no way I would let him fly with Tropical Storm Nester bearing down on us. His text message failed and I assumed he was on his way to the airport. Never assume.

So the preflight was done. I had a good hour of useable fuel. The winds were light out of the north and the cold front had dropped our Florida Autumn Temperatures by about 10 degrees. I taxied from the ramp to the run-up area for RWY5 then waited my turn to get into the pattern.

Two busy flight schools keep the airport busy. Add in some Police helicopters and a few corporate jets and the pattern can get downright interesting.

Tuesday, October 1, 2019

Spongy Brakes

One of my more advanced students started to complain about weak brakes as we taxied back in after a flight. I took the airplane, checked brake pressure and found nothing abnormal. Later, another student lodged the same complaint. We had practiced simulated aborted takeoffs and I attributed the problem to hot brakes. Again, when I took the airplane there seemed to be nothing wrong. When another student complained I knew I was missing something. I took the LEFT seat to taxi back to the hangar after the debrief and found out the right brake was spongy.
I learned that the two independent brake systems have their master cylinders behind the rudder pedals on the pilot side (#1 & #2).  This means the reservoir can get low on the pilot's side before I notice a problem in the right seat. There isn't a common brake reservoir to simply add fluid. Fluid must be pumped in from the low spot in the system.

I needed to assemble some parts to make a kit to add fluid to the right brake system. The first step was to get some kind of a "pressure pot" to push the fluid into the system from the lowest point. Certus lent me theirs, a sophisticated version of a garden pump sprayer. ACE Hardware had everything else.

Problem:  As I tried to loosen the valve it wouldn't budge. More pressure started to loosen the entire fitting so I held that in place with another wrench. I applied more pressure and it gave. Unfortunately, it sheared the valve off.
Fortunately, it was broken in the shut position but I now had to get another valve. Ace Hardware doesn't carry them. Certus does. FedEx delivered it this morning.

The replacement was easy. The original fitting replaced, I tested the valve to insure it worked properly and was relieved to see a drop of fluid when I loosened the valve.

The trick is to get the fluid started into the system then check the brake reservoir to see it get filled. I lined the cockpit floor with rags, opened the valve and stood by the cockpit watching bubbles come out of the vent hole on top of the cylinder. In a few moments, I had a steady stream of fluid spilling over on my rags so shut the valve.

I sat in the left seat and pushed on the toe brake. Good.

I cleaned everything up and did a thorough preflight. I pulled Sally out and checked the right brake for any drips. The taxi test went well. I did a full runup without issue. Then taxied back to the hangar and checked again. No runs, no leaks, no errors.

I put Sally back on the flight schedule.