Subject: Explanation why the shape of grommet U10293-000 doesn’t match the shape of inspection plates U60742-000 and U60742-001.
Applicability: Univair part number U10293-000
Download PDF: U10293-000-Grommet-Shape-Not-Right.pdf
Piper Jack Screw Grommets and Inspection Plates
Grommet Wrong Shape
Cover numbers U60742-000 and U60742-001, & grommet U10293-000
About 4 to 5 times a year a customer will call up saying the shape of our grommets don’t match the shape of the inspection plates. They are not supposed to. Some customers are of the belief that the hole on the grommet where the liner tube for the link passes through (U86062-079) should align with the rounded area in the inside corner of that “L” shaped inspection plate. This is not the situation. It cannot be the situation.
The stabilizer link and liner tube passes through the fuselage forward of the elevator spar. As the trim is adjusted, the angle of attack on the horizontal stabilizer will move up and down. It needs to have some clearance to do so. The open gap, space, area, void - whatever you want to call it - needs to be there so that the front tube of the elevator has room to move.
The later PA-18s and PA-25 use a larger but similar shaped grommet and inspection plate. The fit and function of those two are identical of how they are on the J-3 through the PA-22.
Revised 10/20/08