Tyre wear, canvas showing. Would you not take the plane up?

[Andy_P]

I think the title says it all. But might I add, flat spot in tyre, now showing canvas. Me personally, I would not ride my motorcycle like that, and I would not drive a car like that. I know nothing about plane tyres (yet) so please enlighten me.

[S-Works]

Nope. Unless it was to get it to maintenance then I might consider it.

[maxred]

flat spot in tyre, now showing canvas

That could ruin your day.....

Get it fixed, 100.00 quid well spent

[sunday driver]

Likely failure either just before rotation, or at touchdown.
Similar speed.
Probably similar result (unplanned runway exit).
Plus paperwork, questions, finger pointing.

SD

[Andy_P]

Thanks gents. Guess I wont be flying Sunday then. I called it today from preflight, was told the boss was ok with it. Stupidly went up and did probably 8-9 landings. Lesson learned.

[3 Point]

There are some tyres that are designed to wear through several layers of canvas before they are unservicable. I would not make a decision to accept an aeroplane with some canvas showing until I understood what type of aircraft, what type of tyres, what do the aircraft manual, the tyre manufacturer and the maintenance organisation say about it.

Andy, don't know who "the boss" is; could it be that he has sought information as above and reached the conclusion that the tyre is OK? In any case, the decision is for the aircraft commander alone to make so, if you're not happy then don't take it.

3 point

[Genghis the Engineer]

But certainly don't be afraid to ask for the evidence upon which "the boss" made that decision, and ensure he's recorded that decision in the tech log as well.

G

[Andy_P]

Thanks for the info 3 Point. Where do I find the info on tyres being serviceable? All I can tell you is the aircraft is a Cessna 172S, not sure of the exact year but its a g1000 model so not too old.

[BackPacker]

I do remember a similar thing. With a six ply tire, one layer of canvas may be showing through before the tire needs to be replaced. Or something along those lines.

Then again, I don't have a reference to hand and without that reference and some thorough checking I would not be happy taking such an aircraft up too. Furthermore, once the canvas is showing through it's pretty likely most of the profile has been worn off too. That means that wet runway performance, and possibly grass field performance, will be compromised too. So even if the manufacturer (or boss) would say it's OK, I would not take the aircraft up to land at a "limiting" airfield.

If it's just a single spot in an otherwise good tire, then most likely someone landed the aircraft with the brakes engaged. It may be worth checking the creep marks thoroughly in that case.

[S-Works]

I am not aware of any tyres that are allowed continued operation other than for expeditious replacement when they are through the canvass.

I would be interested in examples.

At work if we canvass a tyre we are required to have it replaced before continuing.

[BackPacker]

A quick Google search came up with this:

http://www.goodyearaviation.com/reso...raftmanual.pdf

Treadwear
Inspect treads visually and check remaining tread. Tires should be removed when tread has worn to the baseof any groove at any spot, or to a minimum depth as specified in aircraft T.O.’s.

Return To Base Limits
Goodyear tires can remain in service with visible cord in the tread area only as long as the top fabric layer is not worn through or exposed for more than 1/8 of the circumference of the tire, and not more than one inch wide. Tires within these limits can continue in service no longer than necessary to return to a maintenance base and be replaced. (This applies to the proper tires for the aircraft as specified in its Aircraft Maintenance Manual.) For all other circumstances, normal removal criteria are still recommended as per the rest of this manual. This does not apply to military tires with Maximum Wear Limits marked on the sidewall.
NOTE: Further use of tires beyond this point may render a tire unsafe or unretreadable.

[...]

Flat Spots
Generally speaking, tires need not be removed because of flat spots due to touchdown and breaking or hydroplaning skids unless fabric is exposed. If objectionable unbalance results, however, rebalance the assembly or remove the tire from service.

[S-Works]

So that basically confirms what I was saying.

[Genghis the Engineer]

The definitive answers will be the aircraft flight and maintenance manuals, which should always be available to you on request.

If the flight manual especially is not available to you, just go find somewhere else to fly.

G

[m.Berger]

This suggests that "The Boss" is either ignorant of the implications; (he should not be,) or is happy to skimp on maintainance as he knew that the tyre was unsafe but was happy to let you carry the can for it.
I'd find somewhere else to fly.

[3 Point]

As I said (and others confirmed) you need to know the aircraft type, tyre type, and what the aircraft manual and the maintenance manual say before you can make a decision.

m.berger; you may be being unfair to the boss who may have access to all the required information and may have made a well reasoned and justifiable decision. Of course, if that's the case he will be able to explain it and demonstrate the associated procedures if asked. I doubt it; but best not hang the guy before the trial eh!

3 Point

[m.Berger]

I used the word "suggests", chosen with care in order to allow for that possibility but I would not fly that aircraft and I would not trust the things I could not verify to have been correctly carried out.

[mad_jock]

Depends if I was somewhere I wanted to be or it would mean I was stuck in a poo hole.

I certainly wouldn't leave anywhere with engineering support without getting them changed.

[phiggsbroadband]

I think it all depends upon which plane it is fitted to..

If it's a 747 then they have 27 plies, so that would probably be ok.

We used to run them until they had worn through about 12 plies...

*

*

*

*

There again we were using them fitted to an agricultural slurry tanker, and we never exceeded the 210 knots max...

[mad_jock]

Oh and our manual says down to the second weave. But we change them before the first because you can re tread them which costs half as much as a new tyre.

[Andy_P]

Originally Posted by mad_jock

Oh and our manual says down to the second weave. But we change them before the first because you can re tread them which costs half as much as a new tyre.

This may well be the case and the reason I asked before jumping in and having a go at the CFI. Thing is, the aircraft at the club are normally meticulously maintained so I was at odds as to why they would allow the aircraft to be flown with the tyre the way it was.

And, we do have access to all records and manuals, thats all part of the learning strategy!

I am down at the club on Sat for a private flyaway, so will put the question to the chief flying instructor then. I am booked in to fly the same aircraft on Sun, so depending on what he says will depend on if I cancel!