Main Landing Gear Collar Update

Main Landing Gear Hydraulic Actuator Attach Stud

This photograph shows the broken Main Landing Gear Hydraulic Activator attach stud that was removed from John Fonville’s SX (N5SX). This stud failed while taxiing. You can clearly see a series of ridges or steps in the radius area of the stud below the fracture point. The hole was drilled into the broken stud and threaded to extract the stud from the gear trunnion. A close inspection of this stud is recommended to prevent this kind of failure on other SX300’s. New pins are available from Airight, Inc and are fairly smooth. A MS20002-6 should be used; placed on the stud first, then the actuator rod end. This washer is a countersunk type and will fit over the radius area and seat on the base portion of the stud.

See drawing below for more information.

Main Landing Gear Collar Update

The FAA has notified Bill Johns that they are considering issuing an Air Worthiness Directive (AD), making replacement of the collars mandatory. This has been an issue with that office since Jim Kennedy’s accident and it does not seem to be going away. He will keep the group posted as needed. For a look at the collars , old versus new, scoring and other things that a photograph will show, see item below.

Main Landing Gear Collars

This is a good illustration of a new steel collar verses an original aluminum collar. The new steel collars are manufactured out of 4130 steel and cadmium plated. Note the elimination of the machined step on the steel collar.

As we have mentioned before, contact Doug Poli to order these new collars. If you have misplaced Doug’s address and telephone number please email [email protected] for that information.