Mike Saathoff-Director of Sales Operations & Engine and Accessory Sales
|
|
|
|
A Beechjet is a unique airframe as it does not have a pneumatic blowdown for landing gear. It primarily relies on airspeed and gravity. When the landing gear and trunnion have been maintained and repaired properly, this is never an issue. However, if the trunnion bearings are not aligned properly a slow wear eventually causes it to bind requiring repair to the trunnion bearing journals of the main landing gear.
Last year we had an AOG situation with a customer located in Caracas, Venezuela, that required this repair. The customer ran an approach to Miami and did not have all three landing gear down and locked. They cycled the landing gear a couple of times with no luck. They declared an emergency and proceeded to land anyway. As they taxied to the FBO, the line service technician noticed the left side main landing gear was not locked. They brought the aircraft in for swing tests and discovered that the left side landing gear was not swinging freely, in fact, it would fall only 7/8ths of the way down and not lock.
The aircraft was ferried back to its home base to troubleshoot the landing gear. They found that the landing gear would not pass the free fall test and removed the affected landing gear from the aircraft. During the inspection of the trunnion, they found the forward trunnion bearing was seized and needed to be replaced. In this particular instance, there was an initial repair of the trunnion bearing journals where the bore was not reamed correctly and an oversized bearing was installed. This caused a misalignment, which ultimately caused the bearing to seize and the landing gear to not fall freely.
In this instance, the customer was very lucky. In these situations, the landing gear can collapse on landing or turns. In order to provide on our core values of Unmatched Quality, Uncompromising Integrity, and Unbeatable Customer Service, our team traveled to Venezuela amid political turmoil just days after Hugo Chavez’s death to make the repair. The aircraft was returned to service in less than five days and our team returned two days before the Venezuelan Presidential election.
Another instance where this repair applies is when the factory bearing bore is enlarged due to repeated landings. If the bearings do not have an interference fit, this repair must be done in order to prevent further damage to the airframe.
At Elliott Aviation, we have seen this issue occur at least half a dozen times in Beechjets. Properly repairing this requires pinpoint accuracy of lining up the bearing bore to the opposite side and our specialized tooling is centered between both pieces. In fact, we have developed a special tooling system that includes a series of reamers, specialized bushings, and NDT capabilities to ensure the repair is handled correctly.
Find out more about our accessory and landing gear capabilities here.
About the Author
Mike Saathoff has over 20 years of experience in corporate aircraft maintenance. He has held several service technician and quality control positions with Elliott Aviation and currently serves as the Director of Sales Operations & Engine and Accessory Sales. He has an Airframe and Powerplant and Inspection Authorization license with the FAA. You can email him at msaathoff (at) elliottaviation.com