It is used in the process of one of the secondary ways to radar identify an aircraft. Also, when ATC deems that the secondary is not necessary upon the aircraft getting within 15 nm from destination airport, they may instruct to turn off the transponder. Also during certain phenomena such as ring around, ATC may instruct the pilot to turn off the transponder to reduce ring around or if there is a high population of actual targets (aircraft) to reduce scope clutter.
100% WRONG, in 30 years ive never ask to have a TXP turned off because i didnt think i needed the secondary target.do you even know what happens to an ARTS/STARS data block when the TXP is turned off ?...IT DROPS OFF AFTER 3 SWEEPS WITH WITH OUT A TXP SIGINAL
5−2−12. STANDBY OR LOW SENSITIVITY
You may instruct an aircraft operating on an assigned
code to change transponder to “standby” or “low
National standards no longer require improved transponder
to be equipped with the low sensitivity feature.
Therefore, aircraft with late model transponders will be
unable to respond to a request to “squawk low.”a. When approximately 15 miles from its
destination and you no longer desire operation of the
b. When necessary to reduce clutter in a
multi-target area, or to reduce “ring-around” or other
phenomena, provided you instruct the aircraft to
return to “normal sensitivity” position as soon as
It is not a requirement AT ALL, but for whatever reason it is in the book. Have I ever used it? Nope. I can't figure out why anybody would use it, but it is an answer for OP.