Dual comms?

Discussion in 'Avionics and Upgrades' started by C_Parker, Apr 18, 2019.

  1. C_Parker

    C_Parker Pre-Flight

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    Have a KX-155 nav/com and an old garmin 250 vfr gps. Looking to swap out the 250 for a new 175 and replace my attitude and DG with G5's.

    Ditching the 250 means losing my second comm radio. When I emailed the radio shop asking about the install, the owner suggested that I would need to buy the 175 and a comm radio since I am round filing the 250.

    Are there any legal requirements about the number of comm radios available for IFR? I realize two is better than one but I carry a handheld backup and I really don't think a second comm radio is worth $3,000.
     
  2. Jesse Saint

    Jesse Saint Pre-takeoff checklist

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    I don't think there is a requirement for a second COM radio, but it is a good idea. If you can monitor the backup frequency on the primary COM, that is a benefit. You can even put in a panel-mounted BNC connector to connect your handheld to the external antenna, then have a headset adapter, and that would suffice for a second COM radio.
     
  3. Flybuddy

    Flybuddy Pre-Flight

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    No requirement, I flew a Mooney for many years with a single radio. Suggest for your back up handheld you have ability to hook to headset. Another thing you might consider is leaving the BNC wire accessible from the 2nd radio so you can hook to handheld if needed.
     
  4. N1120A

    N1120A Pre-takeoff checklist

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    I wouldn't use a single radio, and not just for the obvious issue about redundancy. Unless your radio offers a monitor function, which is fairly rare, you have to go off frequency for ATIS. That's just not something you want to do IFR, especially in IMC. If you go to the right place, you can get a 650 for under $10000 these days - or you can go and find a 430W or 530W out there for a decent price - and then you not only have a WAAS GPS, but a proper NAV/COM.
     
  5. MBDiagMan

    MBDiagMan En-Route

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    The 175 and 375 make good solutions when there are already good, solid radios in place. In the OP’s case I believe that a 650 or maybe even a 430W would be a better solution than a 375 and an additional radio purchase. I AM, however, in the camp of having a backup radio in good order. Until you’ve had to complete a flight NORDO, you don’t appreciate its value.
     
    Last edited: May 8, 2019
  6. EdFred

    EdFred Touchdown! Greaser! PoA Supporter

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    I've done a 5+ hour flight under IFR with most of it in IMC with 1 comm radio. I won't do that again unless forced to.
     
  7. jsstevens

    jsstevens En-Route PoA Supporter

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    As a training flight, I did a hold at an intersection defined by two VOR radials in a plane with one Nav-com that was not a flip flop. It was an educational experience but I would not willingly do it for real.
     
  8. murphey

    murphey Final Approach PoA Supporter

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    Is there room in the panel to keep the 250? Another option is find a used SL 40. It’s a half-height radio. Or the SL30 which is the SL40 with built in NAV with indicator.