A Beechjet is a unique airframe as it does not have a pneumatic blow down 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 trouble shoot 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 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, I 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 I 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 a 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.
Brian McKenzie started with Elliott Aviation in 2007 as a Quality Control Inspector and led the development of Elliott Aviation’s Accessory Shop in 2011. He received his A&P in 2004, IA in 2009 and ASNT NDT Level III in 2010. Brian started his career in the US Navy where he was part of the fixed wing and rotor wing maintenance and aircrew. He has maintained airframes and components on a diverse number of aircraft including Beechcraft products, Gulfstreams, Citations, Falcons and helicopters. Brian has also worked for Aero Air, Evergreen International, Flightcraft and Jet Services Inc.
Elliott Aviation is a second-generation, family-owned business aviation company offering a complete menu of high quality products and services including aircraft sales, avionics service & installations, aircraft maintenance, accessory repair & overhaul, paint and interior, charter and aircraft management. Serving the business aviation industry nationally and internationally, they have facilities in Moline, IL, Des Moines, IA, and Minneapolis, MN. The company is a member of the Pinnacle Air Network, National Business Aviation Association (NBAA), National Air Transportation Association (NATA), and National Aircraft Resale Association (NARA).