Page 18 - Volume 10 Number 10

Now shift the flap to the left and check the right flap track. The set-up should be a mirror-image of the other side. The roller bearing is between the inner bracket and the track; again, the shoulder is thicker than the washer and has a silver appearance. The thin white Teflon washer lies between the bearing shoulder and the track.
This is the proper set-up, regardless of whether it’s an inboard flap or an outboard flap. The roller bearing is always between the flap track and the inner flap bracket. The Teflon washer is always between the bearing shoulder and the track. That wasn’t hard, was it?
Flap Movement
You just saw that the flap will shift a little bit, side to side. This is normal and desirable. The flap should also move up and down a tad, maybe an eighth- to a quarter-inch of movement. It shouldn’t be totally rigid in place. If it is, the flap rigging needs attention. Put this on your squawk list.
Wind Load
Your flaps take a beating at all times during flight. When they’re down, they get maximum wind load. The wind pushes against the flap which presses the bearing against the top edge of the flap track slot.
When the flaps are up and you are cruising at altitude, the flaps are still getting buffeted about in all directions:
up, down and side to side. In fact, the greatest wear and tear on the flap track slot happens in the flaps-up position. Over thousands of hours of flight time, there is gradual wearing away of the flap track slots.
Of much greater concern, however, is a damaged flap track or bracket caused by failed roller bearings and/or bad or missing Teflon washers. This damage is preventable with good and regular maintenance. You can add the flap self-check described earlier to your pre-flight routine. Why not? You know the saying about an ounce of prevention versus a pound of cure?
I’d hate to see your flaps create a flap. Happy flying. KA
Dean Benedict is a certified A&P, AI, with over 40 years of maintaining King Airs. He owned and managed Honest Air Inc., a maintenance shop specializing in Beech aircraft with an emphasis on King Airs, for
15 years. In his new venture, BeechMedic LLC,
Dean consults with King Air owners and operators on maintenance management, troubleshooting, pre-buys, etc. The Honest Air operation merged with Apex Aviation (KHND) where Dean oversees all King Air
and Beechcraft activity. He can be reached at drdean@BeechMedic.com.
16 • KING AIR MAGAZINE
OCTOBER 2016