Hawker NLG Strut Leak Concerns

October 2009

Cable, Jerry - Accessory Tech Rep - Lincoln, NE (LNK). Aviation professional since 1991.

Airframes: Astra, Challenger, Citation, Embraer, Falcon, Gulfstream, Hawker, Learjet, King Air, Global, Westwind

Hydraulic equipment and pumps, Pneumatic valves, Wheel and Brake, Emergency Power Supplies, Electric Motors, Mechanical Actuators, Landing Gear and Accessory Components and Systems Specialist.

Direct: 402.479.8112
Mobile: 402.432.0154

Wintertime is just around the corner and with it typically come small leaks in your hydraulic system. Over the years many Hawker operators have noticed that when it gets cold out, their NLG Struts start to leak. Most of the time the leak is not significant enough to be concerned about; however, HawkerBeechcraft has recently released Communiqué HK-0012, displaying concerns for the Piston Seal, PN 25UN523, in the NLG Strut.

It has been noted that this seal may last for many flights, even in Arctic temperatures, but start leaking without warning. The leaks may only be small, but can often be severe enough to deplete the NLG Strut of all fluid.

This seal cannot be seen once it’s installed and may only exhibit leaks during the cold periods of the year. If you start to experience leaking NLG struts, especially when the temperature plummets, you may want to consider having your NLG Struts resealed and ensure that a properly manufactured and inspected seal is installed.