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JonnyFav

Wheel and tire noise while towing

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We just received a C-130 from another unit who had already performed the carbon fiber brake TCTO. (This is our only modified aircraft) The first time we towed the aircraft, all four main tires are making an unusual popping noise like loud popcorn popping. If you put your hand on the the transducer cap you can feel it as if someone was on the other side hitting it with a ball peen hammer. First I axle jacked each wheel and spun them by hand, but couldn't duplicate the noise. I removed all the tires, inspected the brakes and wheels and replaced the bearings and hardware. It still makes the noise. Anyone ever encounter this?

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Was out at Dobbins for a Christmas party today and saw the carbon brakes on one of their H-3's they just received from the Rock. I asked one of the c/c's about the popping and clicking. He said theirs did until they got a little time on them. The wheels and hub cap sure look different from the old style. He said the carbon sure dirtied up the wheel well and anyone who climbed inside.They were told the brakes should last 10 years before wearing out. Also Mansfield C/C's were getting ready to leave with 81-0629. Bill

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I called an engineer about the issue. He told us that the popping noise was because of a lack of solid film lube between the wheel halves. We took them apart and lubed them up and now they are fine.

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I've built up quite a few of these wheels for the modification, the "popping" is because of the heat shields on the inside of the wheel. They'll tighten up over time with brake dust and what-not getting in between the tongue and groove shields. If there is a lack of solid film on the lock ring that prevents the halves from blowing apart, someone needs to be punched in the face.

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Holy cow, that GopherBoi guy sounds like a real hard ass. :D Just the kind of guy I want in my outfit.

My first crew chief was a young tough Mexican American (first one I'd met). On our first meeting he took me aside, pulled the biggest knife I'd ever seen from his pocket. He then said to me, you do everything I say or I cut you long, wide and deep. Believe me, as long as I was on his crew I followed his instruction to the letter.

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I don't know what to tell you, the engineer was absolulty correct. There was no solid film used at all. We didn't touch the heat shields and the tire don't make any more noise.

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We just changed one of these brakes the other day. Was a Rock bird and said to have been one of the first to have the mod approximately 6 years ago. So much for the 10 years. The brake on the other side is gonna need to be changes most likely next flight. Both FWDs.

We experience the same poping noise during tows. Never knew there was a fix for that (solid film). If thats true there needs to be a 22 submitted for Wheel and tire shop!

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Not sure where you got 6 years from. We only started updating our H's in the summer of 2012. And the whole 10 year thing was some really good kool-aid. The wear is leaps and bounds above the legacy brakes, but know where near 10 year lifespan unless you are talking about the Colorado springs birds that get maybe 400 hours a years. As far as numbers, I know in bagram the first one we changed had 1300 Full stop landings on it, and that plane was sent to the desert right after it was modded

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6 years came from the rock guys (young troops who most likely were guessing). I haven't a clue what the actual time frame or the number of landings is but I do know one things for sure and that is its nowhere near 10 years!

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I'll try to tie this in here since we're talking about carbon brakes:

Does anyone have experience with the creep during high power settings? I flew with carbon brakes for the first time recently and the brakes were not able to hold the airplane at 970 degrees TIT. We were noticeably moving forward, the only time I've ever seen that before was on an icy runway. We know there is supposed to be an acceptable limit for creep, but who else has experienced this? Is there a fix in the works? On a real life max effort how in the world is your TOLD data supposed to be accurate if you're already moving down the runway before you can verify the power setting?

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There was a Maintenance Advisory put out about creep with the carbon brakes. I was with them during the J-model validation during their creep tests. A J with 4 to the wall simply overpowered the brakes and the plane could easily roll forward about 30 feet at a quick walking pace. As far as legacy's i want to say the advisory stated to expect up to 1 foot/sec creep. The problem is while carbon brakes are great, when they are cold, they can't hold much, but once you get some heat in them they grab like no other.

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The abbreviated USAF carbon brake test program used an E model...at Edwards (2300 ft MSL)...in the summer. So I don't think they ever even hit the T56 torque limit during the power-against-brakes tests. Wishful thinking that the brakes would hold on all C-130 models.

How much heat is required to remain static with takeoff power? Could a few taxi stops add enough energy to prevent creep, without reducing RTO capacity?

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Don't quote me, but when they were validating the carbon brakes on J's they dide some high speed taxis while dragging the brakes and got them up above 300.

I was reading a 22 that wanted to put a note in the 32JG-40 that if the carbon brakes are removed to FOM that a brake bleed wasn't required due to the quick disconnects. They turned it down saying the QD's allowed .20 cc's of air into the brake thus causing issues with creep.

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I think they are looking for anything that might cause the creep issue and air will cause this, but 20cc I don't know. Do the KC-135's have the same issue with the carbon brakes we have??

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can anybody show me exact ..location of additional item to be installed...because i also received this tcto...need to demand in the system..

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I think they are looking for anything that might cause the creep issue and air will cause this, but 20cc I don't know. Do the KC-135's have the same issue with the carbon brakes we have??

no no no

.20 CC's of air lol

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Did the brakes hold while at 300 deg? Or did the heat dissipate quickly?

That much heat will reduce the RTO capacity, but then again the carbon brakes have a much higher capacity than steel. It depends which energy limit they are using for RTO and max brake landing plans.

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The -1 seems to imply that the brakes work better with high heat because the cooling times have been omitted and the requirement for runway available to exceed landing distance by 300' has been eliminated. Lowering the fuse plug temperatures doesn't make sense to me because a 130,000lb airplane has the same amount of energy to dissipate whether the brakes are made of steel or carbon. To answer the question, the brakes on our jet did better after a full stop landing, but still would not hold the plane static at takeoff power.

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Yes they held fine after getting some heat in them, but that is all carbon brakes in any application, be it aerospace or automotive.

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