One nav radio

Groundpounder

Groundpounder

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Emerson Bigguns
I'm in the market for an airplane, in case you couldn't tell by my 100's of stupid posts, and I have noticed a few aircraft with newer avionic installs have only a single VHF nav radio. I am looking at one now that has a GTN650, a Garmin GTR 225 (VHF com radio) and a Garmin transponder. Perfectly adequate for flying IFR, but if the GTN has a failure, you have zero navigation ability at that point. I know you can navigate with an iPad, but you can't fly IFR legally, and you for sure can't fly an approach with it. I just don't know why someone wouldn't spend a few extra AMU's and have a second nav radio in there.
 
What type of plane? How much IFR do you plan on doing?

I have a GNC255 and a GTR225, so only one NAV and no GPS and I'm doing my instrument training with it.
 
Mtns2Skies said:
What type of plane? How much IFR do you plan on doing?

I have a GNC255 and a GTR225, so only one NAV and no GPS and I'm doing my instrument training with it.
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182. A fair amount.

How do you plan on doing non precision approaches with one nav radio? Does the GTR have DME built in?
 
Groundpounder said:
182. A fair amount.

How do you plan on doing non precision approaches with one nav radio? Does the GTR have DME built in?
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No DME. To be perfectly honest I don't plan on doing much IFR except for a pop-up clearance to get through a thin layer or something... and to lower my insurance. It's a new panel, and all the upgrade I could afford, but it allows me to get my IR training done. It does exactly what I want/need.

IMG_20181107_154414.jpg
 
Seems silly to me but a lot of people think their GTN/GNS will never fail. Truth is though that an ipad (or other tablet for the snowflakes) is accurate to get you down in an emergency.
 
I'm in the midst of an avionics upgrade and I'm going down to 1 nav. Pulling a NAV/COMM and installing a Garmin GTN625 (GPS only) and a GTR comm. IMHO, with a WAAS GPS, there is no need for dual VHF NAVs anymore. If I have a radio failure, I've still got an iPad if I need it (and I could shoot a non-precision GPS approach with it in a real pinch). Remember, while an iPad isn't a legal nav source under normal circumstances, if you start having radio failures in IMC, you've got an emergency and you can use whatever you need to in order to safely get on the ground.
 
Mtns2Skies said:
No DME. To be perfectly honest I don't plan on doing much IFR except for a pop-up clearance to get through a thin layer or something... and to lower my insurance. It's a new panel, and all the upgrade I could afford, but it allows me to get my IR training done. It does exactly what I want/need.

View attachment 69927
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Fair enough, but its gotta be a heck of a challenge shooting a non precision approach with that set up.

Grum.Man said:
Seems silly to me but a lot of people think their GTN/GNS will never fail. Truth is though that an ipad (or other tablet for the snowflakes) is accurate to get you down in an emergency.
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Yes it would get you down in an emergency, but lets say you are landing at a field that isn't home. You're grounded if its IFR if your GTN fails. With a separate nav radio you could at least legally fly home IFR.

bradg33 said:
I'm in the midst of an avionics upgrade and I'm going down to 1 nav. Pulling a NAV/COMM and installing a Garmin GTN625 (GPS only) and a GTR comm. IMHO, with a WAAS GPS, there is no need for dual VHF NAVs anymore. If I have a radio failure, I've still got an iPad if I need it (and I could shoot a non-precision GPS approach with it in a real pinch). Remember, while an iPad isn't a legal nav source under normal circumstances, if you start having radio failures in IMC, you've got an emergency and you can use whatever you need to in order to safely get on the ground.
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See above.
 
Groundpounder said:
Yes it would get you down in an emergency, but lets say you are landing at a field that isn't home. You're grounded if its IFR if your GTN fails. With a separate nav radio you could at least legally fly home IFR.
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...or just wait until VFR conditions exist. As I get more and more into the IFR world it's like pilots forget that VFR exists. They spend many 10's of AMU's in order to get a more advanced IFR panel, which only gets used 2% of the time... and the reality is, I'm not sure that I'm even comfortable flying in IMC in a single... it's a pretty big penalty for failure if the engine goes. SO I don't see the point in spending gobs and gobs of money on an over-the-top IFR panels in a single, when they fly just fine IFR, but need "redundancy".. the redundancy is flying VFR. You (probably) don't need IFR redundancy, you're not a part 135 operator.

*rant over*
 
Groundpounder said:
Fair enough, but its gotta be a heck of a challenge shooting a non precision approach with that set up.



Yes it would get you down in an emergency, but lets say you are landing at a field that isn't home. You're grounded if its IFR if your GTN fails. With a separate nav radio you could at least legally fly home IFR.



See above.
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Well, in my case I do retain a separate nav from the GTN, but in any event, I'm betting the failure rate of the GTNs is very, very low. Sure, it might happen, but I'm betting you've got a much higher chance of OTHER parts of the airplane grounding you before a failed GTN does. For the most part, modern avionics are quite reliable.
 
Mtns2Skies said:
...or just wait until VFR conditions exist. As I get more and more into the IFR world it's like pilots forget that VFR exists. They spend many 10's of AMU's in order to get a more advanced IFR panel, which only gets used 2% of the time... and the reality is, I'm not sure that I'm even comfortable flying in IMC in a single... it's a pretty big penalty for failure if the engine goes. SO I don't see the point in spending gobs and gobs of money on an over-the-top IFR panels in a single, when they fly just fine IFR, but need "redundancy".. the redundancy is flying VFR. You (probably) don't need IFR redundancy, you're not a part 135 operator.
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That is great, but waiting for VFR in the northeast could take a few days. I'm not planning on flying in 200/1/2 but if its 1500 ovc with good visibility, that is easy IFR, but a challenge for VFR.

I guess my original point is that if you are going to spend $35k on a new panel, why not spend a little more and have a second nav radio, just in case? What is the price difference between a GTR225 com and a GNC255 nav/com?
 
Groundpounder said:
Fair enough, but its gotta be a heck of a challenge shooting a non precision approach with that set up.



Yes it would get you down in an emergency, but lets say you are landing at a field that isn't home. You're grounded if its IFR if your GTN fails. With a separate nav radio you could at least legally fly home IFR.



See above.
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What is challenging about shooting a non precision approach with a CDI? And I agree, I would not intentionally design a panel with only one nav source but in the rare circumstance it failed I would just wait for better weather or get a spam can ticket.
 
Groundpounder said:
I guess my original point is that if you are going to spend $35k on a new panel, why not spend a little more and have a second nav radio, just in case? What is the price difference between a GTR225 com and a GNC255 nav/com?
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GTR225 = 1400

GNC255 = 4500 + 1500 CDI = 6000 total. + additional labor at $110/hr

Avionics ain't cheap. It's not a "little more". It might be in the world of avionics, but that could buy me a new interior and a new exhaust and ADSB (GDL82).

Edit: And they're decommissioning VOR's left and right... and I don't want to pay the recurring subscription costs of keeping an IFR GPS's database current.
 
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Grum.Man said:
What is challenging about shooting a non precision approach with a CDI? And I agree, I would not intentionally design a panel with only one nav source but in the rare circumstance it failed I would just wait for better weather or get a spam can ticket.
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How do you determine step down fixes on an approach, or intersections while enroute?

Keep in mind, its been a long time since I have had to even think about that kind of thing.

Mtns2Skies said:
GTR225 = 1400

GNC255 = 4500 + 1500 CDI = 6000 total. + additional labor at $110/hr

Avionics ain't cheap. It's not a "little more". It might be in the world of avionics, but that could buy me a new interior and a new exhaust and ADSB (GDL82).
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I guess if flying IFR isn't a priority, I can see the reasoning.
 
Switch between nav frequencies. In the real world you will not be identifying that many intersections on a flight as you usually fly VOR to VOR. Most approaches only have 1 or maybe 2 stepdowns once past the IAF.
 
I did 430W with an SL-30 as #2. So I have 1 GPS, 2 Navs. My potential failure point is that both radios feed my EFIS. No backup CDI's. So if Dynon goes dark I would need to rely on the CDI page of each radio. Better than nothing.
 
Grum.Man said:
Switch between nav frequencies. In the real world you will not be identifying that many intersections on a flight as you usually fly VOR to VOR. Most approaches only have 1 or maybe 2 stepdowns once past the IAF.
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I can't even. But I guess it's not a huge issue flying an approach at 80 knots vs 160 or so like I do at work.
 
Groundpounder said:
That is great, but waiting for VFR in the northeast could take a few days. I'm not planning on flying in 200/1/2 but if its 1500 ovc with good visibility, that is easy IFR, but a challenge for VFR.

What is the price difference between a GTR225 com and a GNC255 nav/com?
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$2k. A GTR225 is about $1800; a GNC255 is about $4k (plus add another $1500 for a compatible nav indicator). If your A&P is not unreasonable, you can even go with the GTR200 for $1100, bringing the spread to $3k + indicator.
 
Groundpounder said:
I actually saw that when I was poking around to see if there are all in one nav receivers. Didn't Narco used to make one, back in the day? What was the model number?
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Narco Nav 122. Pre-upgrade I had a Narco IDME-891 which is an all-in-one NAV/DME/CDI... unfortunately the DME was kaput, but it's a cool museum piece :D.

@bradg33 beat me by a second
 
Mtns2Skies said:
...or just wait until VFR conditions exist. As I get more and more into the IFR world it's like pilots forget that VFR exists. They spend many 10's of AMU's in order to get a more advanced IFR panel, which only gets used 2% of the time... and the reality is, I'm not sure that I'm even comfortable flying in IMC in a single... it's a pretty big penalty for failure if the engine goes. SO I don't see the point in spending gobs and gobs of money on an over-the-top IFR panels in a single, when they fly just fine IFR, but need "redundancy".. the redundancy is flying VFR. You (probably) don't need IFR redundancy, you're not a part 135 operator.

*rant over*
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That was far from a rant. It's a valid argument that leads to something that many people seem to miss: If your personal risk tolerance is such that it is not safe to fly IFR with only a GNS or GTN, why would it be safe to take off planning to fly IFR with a only a single VOR receiver? That is, after all, exactly what you are doing if you take off IFR with a broken GNS/GTN.

Either the GNS/GTN is enough to fly IFR or the backup VOR is not, and even with one in the plane you should wait out the weather before attempting to fly home when the GNS/GTN is inoperable.

If you are on the ground and your IFR navigator is not working, you just don't launch into IMC. If you are in IMC and your IFR navigator fails, you can exercise emergency authority and use something else to get down. Radar vectors to VMC, ASR or PAR approach, or a non-IFR GPS all work for this. I could fly an LNAV approach using my iPhone if I had to. It would undoubtedly be easier than flying the same approach partial panel. I am more concerned about vacuum pump failure than my GNS dying. Not because it's more likely (even though it is), but because the challenge of flying without it is greater.
 
To get back to the OP's question, in the olden days even though single nav was the legal minimum for IFR, the 2nd nav was really needed as a practical matter. The fact that it provided redundancy was just a bonus. Today, a single GPS is all you need for practical IFR. The second nav source is ONLY for redundancy, and a VFR-only GPS is a viable, inexpensive alternative. Practicality is a greater priority compared to redundancy. Thus, I think you will see more pilots flying IFR with single nav.

C.
 
The other day while doing some practice approaches, my CFII partner 'failed' the 530. The LOC approach has an IAF that is defined by a VOR/DME fix. Took some knob twirling and thinking to fly the procedure turn, but in the end, like magic, a runway appeared.
I prefer to have a nav that is separate from the Garmin box. Those Narcos were a nice solution to the problem, but nobody makes anything like that these days.
 
weilke said:
The other day while doing some practice approaches, my CFII partner 'failed' the 530. The LOC approach has an IAF that is defined by a VOR/DME fix. Took some knob twirling and thinking to fly the procedure turn, but in the end, like magic, a runway appeared.
I prefer to have a nav that is separate from the Garmin box. Those Narcos were a nice solution to the problem, but nobody makes anything like that these days.
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MGL makes a nice, affordable Nav radio that works as well as the SL30 (so they say).

MGL N16 Navigation Receiver
 
There's a control/display head that goes in an instrument hole and the radio mounts remotely. Doesn't take up space in the stack.

C.
 
weilke said:
What would that use for display ? The beauty of the narco 122 was that it didn't take up any space in the stack. Just a hole for the display.
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There are two options to control the unit. One will control a single NAV or COM, the other will control both a NAV and a COM. If you have an MGL EFIS, it controls both as well (no need for the control head). Other EFIS MFGs are supported through the control head (Razor or Vega).

http://www.mglavionics.com/
 
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