Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Learjet Model 45 series airplanes. This proposal would require repetitive application of grease to the rotating disk assembly of the nose landing gear squat switch mechanism. Application of grease to the squat switch assembly is necessary to prevent moisture contamination and subsequent formation of ice. Such ice formation could result in bending or damaging of the nose landing gear squat switch assembly, which could drive the nose wheel to an uncommanded angle against the force of the steering system. This condition, if not corrected, could result in the airplane departing from the runway at high speeds during landing.