Originally Posted by punkalouver
It has been over 21 years now since the midair collision over L.A. of a DC-9 and a mode-C equipped Piper.
The Piper involved in the Aeromexico 498 collision (31.08.1986) was not equipped with a mode-c capable transponder.
Originally Posted by Investigation Report
N4891F was equipped with a NARCO Model AT-50A transponder without a mode C altitude encoder.