Summary
We propose to adopt a new airworthiness directive (AD) for certain Learjet Inc. Model 60 airplanes. This proposed AD was prompted by a report of a reverse thrust command accelerating the airplane instead of decelerating the airplane. The acceleration with reverse thrust commanded occurred when the thrust reverser doors were in the stowed position instead of the deployed position. This proposed AD would require installing a Thrust Reverser (T/R) Voice Command Warning System (VCWS) to alert the crew of a T/R malfunction. We are proposing this AD to address the unsafe condition on these products.