Brake Inspections
Posted: Fri Apr 29, 2022 5:36 pm
I have Cleveland brakes on my B-model and when I replace brake linings/pads I prefer the Rapco brand not just because they are less expensive, but also because they include an easily-observed wear-indicator on their linings. (Typical is .100” or one-tenth of inch remaining). The linings have small “divots” at each end and when those divots disappear from wear…. IT’s TIME to replace them.
I’m posting this info/discussion-thread because one of our Members emailed me recently about some brake issues he’s having…. which prompted some of my sleeping brain-cells to wake-up and recall a learning event I experienced in my early/young flying which I shared with him.
Now that I’ve let the cat out of the bag I might as well share it for everyone’s entertainment…. here’s part of what I replied in my email to him:
I'm very picky about brakes.
Back as a younger aviator (1970, had maybe 200 hrs) I rented a previously-unknown-to-me C-175 from an A&P mechanic to fly to Western Texas for aerial inspection of a hunting lease one of the airport workers wanted to evaluate for his family. (side-note: It’s been my experience that, not all, and no offense intended to any of “Our” guys who may be reading this, but many A&P types, like plumbers, electricians, and auto-mechanics, might take considerable literary-license with mx records and be more willing to defer or accept mx items more readily than most owners. I have learned to take especial care when reading the fiction often contained in logs of airplanes being offered for-sale by those types. This particular episode may have been the first time I witnessed this hazard.)
When I rented it, the A&P owner mentioned that when I brought it back (the C-175) he intended to overhaul the brakes. I suppose that was his hint.... Which didn't sink in…
(Anyway, I rented the plane and picked up my line-man friend and we took off out of Houston for an unpublished strip near Boerne, Tx.)
We landed on this short grass strip at the base of a steep hill on the threshold which one had to negotiate at landing... And the only hangar on the strip was at the base of the hill.. which also had to be overflown at threshold. I'd never been there before and being a private strip (in those days) there was no prior info available on it... The discovery being made upon arrival.
To add to the challenges of the inexperience of which I was afflicted.... For the hunting-land-inspection flight, upon arrival My principal passengers' scarecrow thin uncle and "carnival fat lady wife" climbed aboard the back seats for the flight over the hunting area.
The high density altitude take off ran out of runway length so yours-truly just yanked back on the yoke and the airplane staggered into the air with stall warning screaming... And we listened to that noise for the next half mile as tree top branches scraped the bottom of both wings. Eventually sufficient speed was obtained to make the stall Horn shut up... And we slowly gained about 1K feet AGL .... And I finally summoned the courage to actually bank the airplane into a turn to go look over the property in-question.
When we came back to land, over the hill, scrape the top of the hangar,. And plop it down onto the grass...I applied brakes as I retracted the flaps for better wheel contact and braking... Only to feel the pedals have excellent, firm pressure... But the wheels behaved as if on ice.... The pedals were firm but the airplane seemed to actually SPEED UP!
It became evident we were not going to be able to stop before the departure end and the forest of trees rapidly growing larger in the windshield... There's was only a deep ravine / gully on the right,….full of car-sized boulders.... On the left were more trees and bystanders interested in this outcome... So that was out of the question... There was only an 8-foot pile of rocks at the far-left corner at the departure end which had been removed when the landing strip had been created years previously.... So that's where I headed.
With butt up off the seat cushion and full body weight applied to the useless brake- pedals we headed for the rock pile and to protect the nose gear as much as possible as the pile arrived I pulled full aft on the yoke... And THAT is where the fat lady gave her assistance... her weight forced the tail cone with it's tie-down ring to dig down into the earth and slowed us sufficiently such that we arrived at the rock pile with the mains and nose gear simply kissing the rocks as we dragged to a stop!! It looked as if I’d simply parked the airplane on the side of a huge pile of rocks!
My knees were shaking and it was damned difficult to get out of that thing with it's tail sitting on the ground held down so firmly by the combination of the rock pile and that huge woman, but we finally managed to get out and with considerable effort to extract her also.
When we examined the brakes it turned out that there was Zero lining material on the steel backing plate of those pucks. They were plain steel burned blue from heat.
With no way to make any repairs, my 200 flying-hours superior judgement was to return to our point of origin (Houston Hobby airport) to hand this plane back to it's owner.
Aware now of it's braking deficiency...I made certain to touch down ON the threshold of that 5,000' concrete Runway 35 at minimum speed... And even then, had to pull the mixture and turn off AT THE FAR END still traveling about 20 mph with the Brakes Applied!
I have ever since insisted on careful evaluation of braking action on any airplane flown over the next 13,745 hrs I've managed to cheat.
(I also make damned certain to look at the brake puck lining thicknesses when preflighting.)
Again, here’s where to look on Rapco’s
Now that I’ve let the cat out of the bag I might as well share it for everyone’s entertainment…. here’s part of what I replied in my email to him:
I'm very picky about brakes.
Back as a younger aviator (1970, had maybe 200 hrs) I rented a previously-unknown-to-me C-175 from an A&P mechanic to fly to Western Texas for aerial inspection of a hunting lease one of the airport workers wanted to evaluate for his family. (side-note: It’s been my experience that, not all, and no offense intended to any of “Our” guys who may be reading this, but many A&P types, like plumbers, electricians, and auto-mechanics, might take considerable literary-license with mx records and be more willing to defer or accept mx items more readily than most owners. I have learned to take especial care when reading the fiction often contained in logs of airplanes being offered for-sale by those types. This particular episode may have been the first time I witnessed this hazard.)
When I rented it, the A&P owner mentioned that when I brought it back (the C-175) he intended to overhaul the brakes. I suppose that was his hint.... Which didn't sink in…
(Anyway, I rented the plane and picked up my line-man friend and we took off out of Houston for an unpublished strip near Boerne, Tx.)
We landed on this short grass strip at the base of a steep hill on the threshold which one had to negotiate at landing... And the only hangar on the strip was at the base of the hill.. which also had to be overflown at threshold. I'd never been there before and being a private strip (in those days) there was no prior info available on it... The discovery being made upon arrival.
To add to the challenges of the inexperience of which I was afflicted.... For the hunting-land-inspection flight, upon arrival My principal passengers' scarecrow thin uncle and "carnival fat lady wife" climbed aboard the back seats for the flight over the hunting area.
The high density altitude take off ran out of runway length so yours-truly just yanked back on the yoke and the airplane staggered into the air with stall warning screaming... And we listened to that noise for the next half mile as tree top branches scraped the bottom of both wings. Eventually sufficient speed was obtained to make the stall Horn shut up... And we slowly gained about 1K feet AGL .... And I finally summoned the courage to actually bank the airplane into a turn to go look over the property in-question.
When we came back to land, over the hill, scrape the top of the hangar,. And plop it down onto the grass...I applied brakes as I retracted the flaps for better wheel contact and braking... Only to feel the pedals have excellent, firm pressure... But the wheels behaved as if on ice.... The pedals were firm but the airplane seemed to actually SPEED UP!
It became evident we were not going to be able to stop before the departure end and the forest of trees rapidly growing larger in the windshield... There's was only a deep ravine / gully on the right,….full of car-sized boulders.... On the left were more trees and bystanders interested in this outcome... So that was out of the question... There was only an 8-foot pile of rocks at the far-left corner at the departure end which had been removed when the landing strip had been created years previously.... So that's where I headed.
With butt up off the seat cushion and full body weight applied to the useless brake- pedals we headed for the rock pile and to protect the nose gear as much as possible as the pile arrived I pulled full aft on the yoke... And THAT is where the fat lady gave her assistance... her weight forced the tail cone with it's tie-down ring to dig down into the earth and slowed us sufficiently such that we arrived at the rock pile with the mains and nose gear simply kissing the rocks as we dragged to a stop!! It looked as if I’d simply parked the airplane on the side of a huge pile of rocks!
My knees were shaking and it was damned difficult to get out of that thing with it's tail sitting on the ground held down so firmly by the combination of the rock pile and that huge woman, but we finally managed to get out and with considerable effort to extract her also.
When we examined the brakes it turned out that there was Zero lining material on the steel backing plate of those pucks. They were plain steel burned blue from heat.
With no way to make any repairs, my 200 flying-hours superior judgement was to return to our point of origin (Houston Hobby airport) to hand this plane back to it's owner.
Aware now of it's braking deficiency...I made certain to touch down ON the threshold of that 5,000' concrete Runway 35 at minimum speed... And even then, had to pull the mixture and turn off AT THE FAR END still traveling about 20 mph with the Brakes Applied!
I have ever since insisted on careful evaluation of braking action on any airplane flown over the next 13,745 hrs I've managed to cheat.
(I also make damned certain to look at the brake puck lining thicknesses when preflighting.)
Again, here’s where to look on Rapco’s
(I’d rather be lucky than good any day…)