Mode S waiver 135.143

[340drvr]

Anybody recently bumped into 135.143 and the Mode S requirements? Specifically, getting another older aircraft on your 135 certificate, but that aircraft has had an avionics upgrade recently with new transponder installed. Have you been forced to replace transponders with Mode S? Are there waivers issued? Thanks for any insight.

 

[cvsfly]

I thought I read they were suspending the waiver program for Part 135 Mode S a year or so ago. They had an Operation Specification for the deviation before. I'm not sure if original equipment is still OK or if it only applies to transponder replacement.

 

[100-1/2]

Read the WHOLE reg.

Older aircraft with older txponders are exempt under C-2. "Installation" does not include removal and maintenance [of older txponders]

ie - if you change what is already there and "install" a different model unit [after 1992] must meet the current TSO (Mode S). Or; can't swap an old Collins or ARC for a Bendix (Non-Mode S).