Using brakes to stop tire rotation

Eric Janson · Tue Mar 24, 2020 8:49 am

Since we have a great deal of experience here....

I am seeing a lot of videos where guys are tapping the brakes to stop tire rotation as they are retracting the gear. I've never seen this in any aircraft manuals as a procedure.

I was always cautioned never to do this as the tire could turn on the rim shearing off the valve stem.

DC-3 had snubbers just above the oil cooler to stop the tire rotation on retraction.

A340 automatically brakes the tires as they retract but there is/was a snubber for the nose gear. This has been removed on quite a few aircraft and we get a nice shake in the cockpit about 30 seconds after take-off as the nose wheel spins down. Not sure what happens with the center gear as it has no brakes (probably a snubber).

Just curious what other people's views are.

Liquid_Charlie · Tue Mar 24, 2020 1:48 pm

I have slapped (well not really) but I think you might call it a good ass reaming many young fellows over this. It is poor airman-ship and could do damage, as you pointed out. I have no idea where it came from but it has rooted itself into certain pilots who likely pass it on until such time a newer ass is chewed.

Colonel · Tue Mar 24, 2020 2:09 pm

An interesting question. From a physics standpoint, if the momentum of just the tire's mass
rotating on the rim is sufficient to rotate the tire on the wheel and shear the valve (when
brakes are applied to the wheel) ...

What about during heavy braking? The entire weight of the aircraft would try to rotate the
tire on the rim, and shear the valve, correct?

Which exerts more force? The mass of the spinning tire, or the entire aircraft? From a kinetic
energy standpoint, how fast would the tire have to spin, for the force to be equal? Obviously
a tire rotating at 1 mph would be no problem. At 1000 mph?

We need Photofly. He eats this shit with a spoon, and has four degrees. I only have one,
and I am also much lazier :^)

Slick Goodlin · Tue Mar 24, 2020 2:41 pm

For me it’s mostly a no but sometimes a yes*. Seems like a poor choice, especially in the winter, but if after liftoff I can feel a wheel off balance or a loose bearing I’ll give the brakes a little squeeze for passenger comfort and mechanical sympathy. Sometimes I’m smart enough to slow them one at a time to isolate where the problem is. Sometimes.

*I should clarify that I just do this on simple master-slave cylinder systems like you’d find on a King Air or smaller. Once you get into various means of boosting brake pressure, or anti-skid systems, or fly by wire and whatnot I choose to not to dick with things.

Colonel · Tue Mar 24, 2020 2:46 pm

Texted Photofly. My suspicion is that low tire pressure is a more likely culprit
of tire creep on the rim, and resulting valve shearing, but we shall see.

JW Scud · Tue Mar 24, 2020 3:35 pm

I have heard both arguments. I started doing it after getting some Diamond TwinStar experience.

From the POH:

When safe climb is established:
8. LANDING GEAR . . . . . . . . . . . . . . . . . . . . . . apply brakes; UP,
check unsafe light off
NOTE
To avoid damage and excessive wear of the main landing
gear wheels, firmly apply brakes before selecting gear up.

No idea if that is based on actual testing or just an assumption. If based on testing, it could be type specific.

John Swallow · Tue Mar 24, 2020 5:10 pm

I only flew one aircraft that called for the application of brakes after take off prior to retraction...

Unfortunately, can't remember the make or model..

Jamesel · Tue Mar 24, 2020 6:23 pm

Bored...

I go type specific & don’t brake unless POH or really knowledge A.M.E. says to.

Cessna single POHs seem to like braking after lift off. ‘70s Cutlass RG, Cardinal RG, ‘80s 182RG, 210.
Smaller Cessna twins - 310, 337 same

Douglas A-26 POH - do NOT brake after take-off, but no reasons given in any manuals I can find.

David MacRay · Wed Mar 25, 2020 2:48 am

Sometimes after lift of in a 172 with flat spots on the tires there is vibration, I like to tap the brakes to stop it.

Liquid_Charlie · Wed Mar 25, 2020 1:53 pm

I guess it could be back ground and experience. I went from flying a J-3 which wheel spin was not an issue and the next aircraft I flew with breaks was a bch18 and DC3 five years later. I spent the first 5 years of my commercial flying with no breaks at all, except for digging floats and planned ground loops (all those happened on the DC3 with break failure or fade.) All aircraft since, I flew, had snubbers of some sort of automatic break application.