Page 22 - June 2022

5 pounds up. If the manufacturer suggests a range of pressure (say between 100 and 110 psi), choose the higher number.
My observation over the years is that all King Airs sit better on the center of the tread with about five extra pounds in the main tires. This is especially true for King Airs that are routinely operated close to gross weight. I also found that the customers who got the most wear out of their tires were the ones that monitored their tire pressures and kept the mains at the extra 5 pounds up.
Nose Tires
Nose tires are not subject to the punishment of landing. They should last you about 1,000 hours unless the aircraft sits outside. The tip I just mentioned about keeping tires at 5 pounds up is for main tires only, not nose tires. Over-servicing the nose tire causes premature wear in the center treads.
Torque Knees and Uneven Tire Wear
If I’m looking at a King Air with dual truck main gear (the model F90, 100 and up) and I see tires that are worn prematurely around an outside edge, I want to take a look at the landing gear. The tire wear on a new King Air is usually very even; but as the years go by and the landing gear goes through an overhaul (or two or three), sometimes the “toe in” of the main gear can be off.
Too much “toe in” or “toe out” will cause your tires to wear too fast along one edge. If you see this on your main tires, have your shop check the washer arrangement on the torque knees and also have them check for excess play at the center point of the torque knees. Either one of these situations (improper washer setup or too much play) will cause uneven and premature wear on your main gear tires.
Unfortunately for you model 90 drivers, the main tires on the 90s tend to wear unevenly. I can’t tell you exactly why and I don’t have a remedy for it. It is what it is.
Flat Spots and Double Trucks
Imagine the tires on your R/H gear are about 75% worn and you flat-spot the outboard tire. Many pilots expect to replace the damaged tire only, but the proper thing to do is replace both tires. It may look like your maintenance provider it trying to jack up the bill, but they are saving you money in the long run. If you install a brand-new tire right next to a worn tire that’s lost three-fourths of its tread, that fat new tire is begging to be squared off!
I had a customer do exactly that – he squared off a tire on his R/H gear but would only replace the one he flat-spotted, thinking he’d save a few bucks. Three months later he was back with another squared off tire on the R/H side; it was the new tire. Again, he had me
20 • KING AIR MAGAZINE
JUNE 2022