Flat Tire Repair in the field

In general, how hard is it to take the tire off of the wheel? Do they often come off easily or hard? I saw one tire that was stubbornly stuck to the wheel halves. It was difficult to break the bead and remove from the rim. The rim was already damaged so further damage was not a problem.

What is the best way to fix a flat or change a tube or tire in the field? Squeeze the tire in a vice, stand on 2X4s, pour soapy water into the rim/bead area, head for the local service station?

Take this for what it's worth ... I've changed the tires on my skyhawk once; they had been on for about 6 years and were very difficult to remove. I had to use the motorcycle bead breaker trick of a couple 2x4s and the underside of my car. Not very easy.


Thomas

Gas station - Changing tires

I am no expert, but it's not hard. I'll go so far as saying the actual tire / tube replacement is easy compared to other wheels. There is however several steps and a few challenges you would face on a trip away from home, mostly involving tools.

It sounds like you have never changed an aircraft tire before? I'll hit the highlights and difference between aircraft and car/bike tire mounting (no soapy water).

First any local FBO with rudimentary maintenance facility has the tools to change a tire. OF course they will charge a bunch $. Frankly I would not want anyone working on my plane. I much prefer to do it myself because I know it will be right.

The one issue you'll face (we all do) is finding a short jack for a low wing RV's. A Cessna and Piper wing is higher above the ground so the min heights of standard jacks often tend to be too tall for RV'ers. Look at the jacks at FBO's they are tall, even at the min height.



Changing a tire out on a trip will require: basic hand tools, place to do it and parts (tire,tube,talk). The big tools is a jack and air compressor. It is not difficult but there are many steps. Forget a car gas station. Your best bet is find a local RV'er.

Jacking, be careful. The method I use is place a bolt in the in tie down ring fitting in the wing (about mid span). The trick is finding a jack that is short enough to get under the wing. There is the Avery jack that slides into the axial. You are probably not carry this tool around, but you could. It works with a simple bottle jack from an auto store. http://www.averytools.com/pc-181-57-rv-jack-stand.aspx

Be aware on a tail dragger, when you jack, some RV's tend to tip forward (mine did), so weigh or tie down the tail wheel.

The other method some used to jack the plane is an engine host. You pick the whole front of the plane up from the engine mount. I never did this but don't see why it would not work, if have the engine host, straps rated for the whole weight of the plane.

After jacking you need to remove the wheel pants (screw driver), brake caliper (safety wired bolts, so you need safety wire and safety wire pliers), axle nut (larger cotter pin, need replacement pin, some reuse but they are cheap insurance. All is needed is needle nose pliers. The axle nut is large but it is not torqued down, so a rag and channel locks can get that off easily.) When you tighten the axle nut, it's just snug, hand tight and than backed off one serration (castellated nut). The cotter pin inserts thru the hole that aligns with the nut and hole in axle.

Once the tire / wheel assembly is off, deflate the tire and take the thru bolt/nut's apart. You will need a socket/ratchet and wrench. THIS IS CRITICAL. Do not try to separate the halves until the tire is 100% deflated. Remove the valve-stem valve with a valve removal tool, a small cheap tool from an auto part store).

The halves come apart easily and you can reinstall a new tube. Usually some rags or wood block on the floor and some finger / foot pressure will separate the tire from the beed. It's not like putting a car or bike tire on at all. Do not pry on the wheel halves and protect the rim and tire for abrasion.

Part of this whole aircraft maintenance thing is INSPECTION. Every thing you touch should be looked at and inspected for any abnormal condition. Brakes, tire, tube, rims, bearings. It's also a good time for preventative maintenance, like re-grease the bearings. Something to consider. This is the golden opportunity to check everything out very thoroughly. An old hand and their eyes may especially be of help here, inspection. I know because they sometimes see things I miss.

Take care to find why the leak occurred and assure there is no foreign object in the tire. The tube is installed with lightly lubricated with talc powder to assure the tube does not pinch or fold or bunch in the tire. It is special stuff. Usually a light dusting inside the entire tire before installing the tube is fine.

You'll need an air compressor. It helps to have a little air in the tube when you install it. Just let all the air back out before refilling. Than you fill to say 25#'s than deflate than re-inflate to final pressure. This lets everything move around. Also make sure you don't pinch the tires in between the halves. Pinching happens but easy to avoid with care.


From FAA best practices AC 43 13-1B Chap 9
"Align the heavy spot of the tube (usually marked with a yellow line) with the light spot of the tire (usually marked with a red dot). If the tube does not have a balance mark, align the valve of the tube with the balance mark on the line. Remove the valve core and inflate the tube momentarily to ? seat ? the tube and let the air run out. Put one wheel half in the tire and align the wheel half with the valve hole up with the valve on the tube. Insert the other wheel half in the tire and align the bolt holes. Insert the wheel bolts and torque to the manufacturer ? s recommended value."

Just keep in mind the tire and tube balance marks. The tire and wheel assembly can be balanced but not everyone has access to the equip, but the balance is usually a very basic static balance, nothing high tech in my experience. Just an axle on a stand and adding weigh opposite the heavy side. There's a definite benifit to balance, but most don't bother with a small tire. Also keep in mind tires have a rotation direction. Observe those marks.

Reverse the steps and reinstall the wheel/tire, axle nut, cotter pin, brake caliper/pad bolts, safety wire (brake line remains connected), wheel pants and let the plane down. Functional check the brakes and move the plane to assure it looks right and clearances are good. NOT NOT ALL TIRES ARE THE SAME SHAPE. If you put a different tire on it can hit the wheel pants. That is unacceptable. You must have clearance all around. This is VERY CRITICAL with the nose tires on the "A" model.

Here is a Goodyear manual that will be of more help.
http://www.goodyearaviation.com/img/pdf/aircraftmanual.pdf

All I can say if you never changed a tire, acquire the tools, get someone who knows how to show you and practice in the comfort of your hanger. The Jack or Jack tool is the biggest investment. If you can borrow or go in with several RV'ers better. We had two Jacks between a group of RV's which made the rounds. You don't need a jack that often.

Good practice is to rotate the tires from left to right. This requires both tires be removed from the rims and the tires switched on the opposite rim. Remember the tires rotate in one direction and you are trying to get the thread that was on the inside on the outside and vise a verse. Rotating the tires left to right can increase tire life and even the wear.

Tire rotation is a good opportunity to practice tire work. You will need to have both wheels/tires off at the same time. You can use a wood block to support the axle if you only have one jack. After you switch the tires you will be an expert. You just don't want to drop the plane or punch a hole in the wing.

Consider when you go on a trip, taking basic hand tools you'll need and may a spare tube. This does not weigh much. You could go so far as flying with the Avery Jack tool and a bottle Jack. Add a battery powered compressor and you conceivably are self supporting. I would not go that far but depends on where you'll be flying and how much of a boyscout you are. I always carry tools and some spare parts on a trip. That is from my days riding dirt bikes on trails, you always carried tools and parts. Knowing what to carry is the Trick that comes with experience. At least have enough had tools to take the cowl off, fairings off and tools and parts to trouble shoot basic engine and electrical problems. Spare parts?

Another option is to carry a can of Fix a Flat or similar. available at most automotive stores, even some supermarkets. I've had to use it twice and amazingly it works quite well.
Tom
Rv3

I agree with Tin Man, a can of stuff to squirt in and fix properly as soon as you get home. On the road you face a couple of problems - RVs are difficult to jack (a couple of people under the wing the their backs on the spar is probably easiest, put the axle on blocks), and it will be really difficult to get the tire off the rim. The main wheels will be really tricky if they have been on any length of time, and the nose wheel almost impossible. If you can find a bead breaker it will save you several hours of hassle. Once the tube is out most automotive parts stores will sell a patch kit - again fix properly with a new tube when you get home.

Pete

thanks for the advice

A lot of good points. As always George, your comprehensive answer is much appreciated.

I used to change split-rim truck tires in the field (very dangerous) and have changed a bunch of car tires back when they had tubes. I would just caution all to be very careful with the pressure until the bead has migrated into place and is firmly seated on the rim. I don't know about the small airplane tires, but car tires can "jump" the rim (looks and sounds like an explosion) instead of popping into place on the rim if the pressure is too high before they seat. Keep your head clear.

I am glad to hear that the fix-a-flat in a can works. I will probably put a can in the airplane. I would be concerned that the leak would not be fixed and I would have another flat tire landing especially for the nose gear. Also, could the fluid settle during flight and result in an out-of-balance problem at spin-up? Would it be better to only use a portion of the can?

Caution: my brother Terry Darley was killed when a jet tire exploded while he was helping to change it. It had a much higher pressure than an RV tire. (OSHA requires a tire cage to change tires)

That said, a few months ago I felt a tire blow as I was landing at a remote airfield. On preflight I had decided that the tire was wearing and needed changing after that flight. As the 6A was slowing, I attempted to turn off onto a 90 degree taxiway. As I slowed and turned off,the right wing settled toward the ground and the plane would no longer roll. The right wheel had blown and the plane was sitting on the right wheel pant.

A flat spot had formed on the tire and I apparently landed on a small rock which punctured the tube. Patching it was not an option.

I borrowed tools from a RV'er. I was able to use my back to lift the right wing while a friend removed the wheel. After putting on a used tire and wheel, I again used my back to lift the RV to slip the wheel back on.

Lesson learned: it is a miserable feeling to be stranded in the middle of an airport with a flat. Keep an eye on tire pressure and tire condition.

Fix a flat can?

tin man said:

Another option is to carry a can of Fix a Flat or similar. available at most automotive stores, even some supermarkets. I've had to use it twice and amazingly it works quite well.
Tom
Rv3

Click to expand...

I've talked with our field's A&P guru Randy Richmond and he says taking off with a tire of fix-a-flat in it can ruin your day. SWA mechanic and RV-8 driver at 52F Bob Stack concurs. Tom above has apparently done it, so it I guess it does work.

Apparently it changes the balance of the tire so drastically that under fast rotation it feels like the gear leg is going to vibrate itself off. Often does wheel pant damage. Same on landing.

Never tried it, but I trust the opinion of these two A&Ps.

b,
d

There was a thread here a few weeks ago about vibration related to fix a flat - I think it was related to a question about -4 gear legs (I'd search but I'm on dialup and it is painfully slow).
I think message being, maybe for one takeoff to get back home but you'd better replace the tube after as all that slime in there is like a slug of water and will unbalance the tire something fierce.

T.