Page 16 - Volume 10 Number 10

The odd thing about this squawk on the B100 is that the other seven roller bearings were fine; they had Teflon washers properly installed. Only one out of eight was bad, and it was really bad. To do that much damage to the flap track, it had been that way for a while. I wonder how many mechanics, supervisors, inspectors and QC personnel missed it. No shop is perfect, but this was another shocker. About 65 hours prior to our discovery, this King Air went through a Phase 1-4 pre- buy inspection and an Airworthiness Certification, as it had been out of the United States prior to the sale. It was inspected and certified by a company-owned shop that had the aircraft for seven months.
The B200 – Failed Bearing
On the heels of the three other King Airs, came a B200 for a Phase 1-2 inspection. We found a failed roller bearing at the inboard position of the R/H outboard flap. The bearing had just begun to scrape the flap track bracket. This is a sure sign of bearing failure and easily found upon close inspection. I wasn’t expecting to find a bad bearing on this King Air, but it is exactly why we do regular inspections!
Some things degrade slowly and you can keep a watchful eye until it fails or is out of limits, as in the 300 discussed earlier. Other times failure is sudden
and unanticipated. Periodic inspections coupled with the proper remedy help keep sudden problems from escalating into extensive and expensive repairs.
Flap Self-Check
You can check your own King Air for Teflon washers and you can see if the washers and rollers are in the correct position. For a 90 or 100 model, put the flaps down and stand at the trailing edge of any flap. For a 200, 300 or 350, choose either outboard flap.
Forget inboard versus outboard and left wing versus right wing. Just look at the flap from the trailing edge. A flashlight may be helpful. There’s a flap track on each side, coming out of the wing structure. It runs between two brackets which are attached to the flap itself. The brackets closest to the outside edge of the flap I’m calling the outer brackets and the ones closer to the center of the flap I’m calling the inner brackets.
Shift the flap to the right to get a better view of the flap track on the left side. Between the track and the inner bracket, you can glimpse the roller bearing; the edge of the shoulder looks silvery. The Teflon washer is skinnier than the shoulder and white-ish. It goes around the bearing and lies flat between the bearing shoulder and the flap track.
A view of the flap track on the left side (shown above, left). Between the track and the inner bracket, you can see the roller bearing and Teflon washer (white-ish in color). The flap track on the right side (shown above, right) should be a mirror image of what’s on the track’s left side. The roller bearing is always between the flap track and the inner flap bracket, and Teflon washer is always between the bearing shoulder and the track.
14 • KING AIR MAGAZINE OCTOBER 2016