The Cessna 152 Tyre Checks

[CaptainKing]

Hi there,

Could someone please inform me of what the preflight checks on the tyres are. I know the basics of a tyres (tyre pressure, no leakage from brakes, etc). I have been told about the "tread" but wasn't sure what I was looking for.

Thanks

[CaptainKing]

Thanks for your input, will keep that in mind for the next preflight.

Cheers

[Jazzy78910]

Just run your fingers across the tread face on each wheel and check that there is sufficient pattern (tread) remaining, and that there is no bald spots.

[CaptainKing]

Thanks guys for the great input!

I have also been told about slip? There is a red mark on the tyre and you are supposed to see how far from the centre it is?

Could someone please tell me a little about that.

Thanks

[dogcharlietree]

Of course if the tyre is so bald that you can see the canvas starting to show then its time for a replacement!

Possibly correct on a C152. However, on some aircraft you are allowed up to a certain number of layers of canvas to be exposed before the tyre is deemed unserviceable.

[SNS3Guppy]

So long as no cord is showing on the tire, then the wear isn't legally excessive. However, a tire with tread present save for a big flat spot will be out of balance...which leads to vibration that can lead to airframe damage, cracking, etc.

The tire wear should be uniform. Note excess wear on one side of the tire, on the crown, or on the tire shoulders. Uneven wear on the crown (middle of the tire) indicates excess tire pressure, and shoulder wear indicates underinflation. Wear on one shoulder or side of the tire and not the other indicates tire misallignment, or a repeated landing or takeoff without the longitudinal axis of the airplane aligned with the direction of travel (landing or taking off in a crab). This may be an indicator for a need for maintenance, or a change in pilot technique.

Look for the bolts and nuts holding the wheel halves together. In a small wheel assembly, this may be as little as three bolts. Ensure they're present; it's possible to have one break or fail and be missing. If this happens, the wheel halves will often fail shortly thereafter, or cause cracking in the wheel assembly.

Tire slippage with the tire moving separately from the wheel assembly is very rare. In fact, even with the tire completely deflated, it's often difficult to break the "bead" or seal between the rubber and the wheel assembly. If you're looking for the red stripe (or other weight mark) to be aligned with the valve stem or wheel weights...it won't tell you much about slippage. In a tubed tire, if the tire has slipped in relation to the wheel assembly, then you'll have a sheared valve stem and a deflated tire. Look for a valve stem at an angle, and a flat tire.

The colored markings on the wheel aren't slippage marks, but represent the heavy part of the tire. These are put on the tire to aid the mechanic in aligning the wheel assembly, tube, and tire during buildup of the wheel, for balance purposes. There's little you can do about it save for disassembling the wheel, manually "breaking the bead," and putting it back together more closely aligned. Accordingly, you don't need to worry about the balance markings.

If the wheel has been built up properly, it should have been balanced, and may have lead weights or other balance devices (sometimes screws with washers) in the recess near or sometimes opposite to the valve stem. Check that they're secure, intact, and won't come off during operation. Often they're attached with double-backed adhesive foam strips, and do fall off.

As others mentioned, check the rubber itself for nicks, cuts, scratches, foreign objects, and other obvious damage.

Check your axle nut (not visible on all airplanes, as sometimes it's covered by a plate, and sometimes by wheel spats or wheel pants) for security. Ensure the wheel nut is secure with either a cotter pin, or two bolts and nuts keeping it in place (depending on which axle assembly is installed). This may seem obvious, but I have seen wheels fall off of airplanes during takeoff when pilots failed to make this important check.

While you're inspecting the wheel, check the brake assembly for security, that the axle is bolted securely in place with all bolts present, and that the brake isn't leaking. Check the brake line for security.

[CaptainKing]

Thanks for taking the time to write a detailed answer.

I just checked my POH and read that you must check the creep marks. Has this been mentioned in the above story, maybe by a different name. Could someone please tell me.

Thanks

[SNS3Guppy]

Not sure what to tell you. I just looked at two different Cessna 152 aircraft flight manuals, and one provided direction to "Check for proper inflation, cuts, and wear", and the other simply states "Check for proper inflation."

Where slippage marks are placed on a tire assembly, they show movement between the tire and the wheel. In theory this might occur in a case where the tire "bead" isn't properly seated against the metal wheel when the new tire is installed or rotated. It might occur if brakes are suddenly applied after takeoff when the tire attempts to keep rotating, but the wheel assembly is held fast by the brake.

In truth there isn't enough inertia in a small tire to cause that, and breaking the seal or "bead" between the tire and metal wheel is difficult even with tools. Slippage just isn't an issue, and if it occurs at all, it's rare.

You can see slippage having occured in a wheel assembly that uses an inner tube by noting the angle of the inflation stem. If it's angled other to one side or the other, the tire has slipped and moved the inner tube, possibly tearing the stem or causing a leak.

Weight marks on the tire aren't the same as slippage marks. If a slippage mark is used, it will be a paint stripe that entends across the tire and wheel, and will be the same color paint, chalk, or tape.

[hole.digger]

Hasn't your instructor been instructing? Have things really gotten to to point where a student has to ask pretty easy, pretty safety critical questions of strangers on the internet? The horror... the horror.

[ForkTailedDrKiller]

Could someone please inform me of what the preflight checks on the tyres are

Are they round?

The ones that are flat on the bottom make for really rough TO's.

Dr :E

[tio540]

However, on some aircraft you are allowed up to a certain number of layers of canvas to be exposed before the tyre is deemed unserviceable.


I have heard this said by engineers, but never seen it in any POH or Flight Manual. Is this verified anywhere?

[dogcharlietree]

From memory it was allowed in the P3B AFM.

[Sunfish]

Wot everyone else said, but also check that there is some "meat" on the brake pads. The brake is not fixed rigidly either, it "floats" in its mount, not that you can move it much at all. If you find something you don't understand, ask if it's normal if you can't work it out yourself.

But Two other things.

If possible, always do your check with a rag in hand and touch things and maybe even wipe off a little dirt (Do NOT do this to the windscreen or anything Perspex - separate instructions for that.) Use what's left of your fuel check on the rag to gently clean any dirt off the nose oleo, maybe take a wipe at the wheel spats , but look, push or prod. Rattle your flaps gently and feel the clearance, prod the brackets in case one is cracked and moving excessively. Feel the movement of the elevator and ailerons.

If at all possible, befriend the LAMES in the hangar. Spend time with them regularly. Watch what they do every day learn what is under the hood and see how an aircraft is put together. Learn how to change a wheel and tire and tube, learn how to change a spark plug (definitely requires supervision).

That way you won't be just gazing at stuff, but really looking at it when you do your checks. (hope there is no karma in this, knocks on wood:E)

[SNS3Guppy]

I have heard this said by engineers, but never seen it in any POH or Flight Manual. Is this verified anywhere?


This is because that information will be found in the aircraft maintenance manual...which really should be required reading for pilots.

The AFM or POH is just enough dumbed-down information for pilots, but the better systems information for any aircraft is always found in the mx manual. If you want to know your airplane (and you should), start there.

[Lodown]

I used to do a lot of operations from grass strips and the weld between the brake disc and the brake mount bracket would wear out pretty quickly with hot brakes and wet grass. I almost took the main windows out in the old Archerfield briefing office one day when the weld let go on a turn into a park. I was holding my breath and the wingtip must have cleared by just centimetres. Don't know how to do an effective check on it though. It's either broken or it's not. One to leave to the engineers, but they rarely seem to catch it.

[SNS3Guppy]

That's interesting. I've never seen that happen. I'm not sure how wet grass heats a brake up more than pavement, because if anything less brake is in order to prevent wheel lockup (wet grass is slick).

[Lodown]

I was told it makes the weld corrode faster. Just in combination of the moisture in the wet grass brushing the weld. That's what I was told anyway. Landing on beaches wouldn't have helped either. The disc itself was always within tolerance. It was the weld that went. Maybe more to do with a tight aircraft owner. Perhaps an engineer can comment. It happened to me a few times. The only time it was critical was that day in Archerfield. Always tried to give myself plenty of room to turn after that.

[SNS3Guppy]

I'm an "engineer," (mechanic), and I've never seen it happen. Interesting.

[bin b'archin]

Give it a F:mad:ing good boot.

[Atlas Shrugged]

Remember, oil is yellow/brown, hydraulic fluid is red ;)