10/31/2014

Column: Up, up and away with aircraft tires

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By Edward Noga

Two tires blew out on an Aeromexico jetliner about to take off from Los Angeles the other day. It reminded me that I don't enjoy flying anymore.

Oh, it's not the tires blowing out. I'm not at all concerned about that.

No, it's being packed in like sardines in a can. The battle for the armrest between you and your fellow sardines. The struggle to claim your leg room vs. the person in front claiming his/her reclining room—lately causing cage-fighting incidents between passengers. The nickel and diming over baggage and the preferred seating of exit aisles.

Obviously, I rarely fly business class, let alone first class.

I don't complain about the lack of or quality of the food today. It generally sucked anyway. Long lines caused by security? Welcome to post 9/11. Deal with it.

I deal with it by driving, except for the need for urgent arrival or very long distance travel. I used to fly from Akron to Detroit. I wouldn't even think of that anymore.

Yet while I don't fly anywhere near as frequently as I used to, I do still have a warm spot in my heart for aircraft tires. Go ahead and laugh.

Fact is, tires in general are products that deal with extremely contradictory requirements: hold the vehicle to the road in all conditions, but provide low rolling resistance; weigh as little as possible, but withstand heavy loads ... you know the rest.

Most folks don't have a clue about the engineering that goes into tires. Or really care, unless they fail.

Ah, but aircraft tires are a special breed. A commercial airliner, fully loaded with passengers and cargo, can weigh hundreds of tons, incredible loads for a pneumatic tube of rubber and reinforcing components.

The tires have to withstand high speeds on takeoff, temperatures as cold as -85°F at high altitude. Then the big finale, the landing—an enormous jetliner, coming in at say 120-130 knots per hour, and the tires going from zero to that speed, with the subsequent skidding, smoke and noise. Impressive.

Aircraft tires typically hold up under that stress. When they don't, and a couple hundred lives are in the balance, that's big news. It happens rarely enough not to worry me when I do fly.

I have a confession to make. If I happen to be talking to a fellow passenger, I often can't help but casually mention before landing that those critically important tires probably are retreads. “Really?” “Oh yeah. Probably been retreaded several times.”

I guess I can be a bad person. But not too bad, because after getting the shocked expression, I quickly explain the value of retreading for aircraft, the rigorous inspection the tires go through, the fact that something like 80 percent of all tires in service have been retreaded.

Just for a moment, though, I'm not very nice.

Noga is a contributing editor for RPN and its former editor. He can be reached at elnmails@yahoo.com.