Turn It On For Safety (TP 2228E-17)
Transponders are found in most aircraft today, yet many people do not turn them on unless required to do so by ATC. It is interesting that a piece of equipment that is often left turned off could save your life and the lives of many others.
There are two good reasons to turn your transponder on while in the air.
The first reason is that ATC is able to "see" your aircraft and all others that have their transponders "on" and will be able to pass conflicting traffic information to all concerned. In addition, if your transponder is able to reply on ModeC, which is automatic altitude reporting, controllers can more quickly determine where potential conflicts could occur.
- The second reason is that aircraft (usually commercial and corporate aircraft) with a traffic alert and collision avoidance system (TCAS) installed and working will be able to detect all other aircraft that have their transponders on. TCAS-equipped aircraft will detect your aircraft and, if your transponder has an altitude reporting capability, will take the necessary action to avoid a collision with you.
You have to admit that avoiding mid-air collisions is in the best interests of everyone concerned. So the next time you go flying, plan to use your transponder. You will be safer because ATC and aircraft with TCAS will detect all transponder codes, so adjust your transponder to reply as instructed by ATC or in the absence of ATC instructions, as follows:
VFR at or below 12,500 ft. ASL: Mode A, Code 1200, plus Mode C.
VFR above 12,500 ft. ASL: Mode A, Code 1400, plus Mode C.
IFR in low level airspace: Mode A, Code 1000, plus Mode C.
- IFR in high level airspace: Mode A, Code 2000, plus Mode C.
And just prior to takeoff, don't forget to "TURN IT ON FOR SAFETY."
Note: TCASII, version 7, is the same as what ICAO refers to as "ACASII." ICAO refers to this system as an "airborne collision avoidance system" (ACAS). Further, ICAO uses the term "traffic advisory" and not "traffic alert."
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