Is it as simple as a drop in?

the400kid

the400kid

Pre-takeoff checklist
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My KT76-C transponder is in the fritz and the repair station doesn't think it's worth repairing. He has one he can sell me but for $1,700. I see these units all over the place for less than $500.

Can I buy a cheap, yellow tagged unit and simply slip it in, or does it need the Mode S code entered?
 
Simply slide a serviceable one in. There is no Mode S code to deal with because it’s not a Mode S transponder.

On side side not you could also use a KT76A transponder as its tray compatible.
 
+1 on above... grab a pito-static check while at it
 
It does not need yellow tag since you have to get the transponder test anyway. You can also get a King KT-74 or Trig 31 and those are a slide in replacement but has Mode S and is solid state for more reliability. You should be able to find one of those used for $1700 or new for $2300 or so.
 
the400kid said:
Can I buy a cheap, yellow tagged unit and simply slip it in, or does it need the Mode S code entered?
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FYI: to add to the above, the KT76C is not mode S, only an AP can slip it in, and the replacement xspndr will require a 91.413 check by a CRS.
 
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Capt. Geoffrey Thorpe said:
Transponders are excluded from "preventative maintenance" slide in replacement. Part 43, appendix A, (c) (31).
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<thread drift> So if it were say perhaps a rack mount COM radio like an KY197A, could an owner slide in a KY197 or an ICOM A220 as "preventive maintenance"?
 
asicer said:
<thread drift> So if it were say perhaps a rack mount COM radio like an KY197A, could an owner slide in a KY197 or an ICOM A220 as "preventive maintenance"?
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asicer said:
If it were a KY197-A220 swap,
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Different scenario. Is the the A220 an approved drop-in replacement for a KY197? If not, it doesn't fit the definition of "replacement" so becomes an alteration which requires an AP.

As to any EW W&B computations this also requires an AP unless the weight difference is 1lb or less for 5000lb EGW aircraft, 2 lbs or less for 5000-50000lbs EGW, etc.
 
the400kid said:
My KT76-C transponder is in the fritz and the repair station doesn't think it's worth repairing. He has one he can sell me but for $1,700. I see these units all over the place for less than $500.

Can I buy a cheap, yellow tagged unit and simply slip it in, or does it need the Mode S code entered?
Click to expand...
You can buy a used unit. It may last 6 months or 6 years. I would upgrade to mode S now rather than tossing money at an obsolete transponder.
 
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