luvflyin
Touchdown! Greaser!
Gotcha. You don't need, make that 'have to have, dual NAVs but some redundancy may be required behind GPS. I just read thru the thread. Lots of food for thought.
Are Dual NAV's necessary anymore
- Thread starter Jason Larkin
- Start date
Gotcha. You don't need, make that 'have to have, dual NAVs but some redundancy may be required behind GPS. I just read thru the thread. Lots of food for thought.
Jason Larkin
Pre-Flight
I wouldn't call it skipping right over. More like looking down it, getting that uneasy feeling of vertigo, going around and hope you don't trip.
Jason Larkin
Pre-Flight
Yes, lots of good insight. Didn't expect this much conversation this quick. You guys are great. Love being a pilot!
topgun260
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Topgun260
Maybe consider adding an ADF as well if you don't have one. AM radio stations will still be transmitting long after the Chinese destroy our GPS satellites and/or the zombie apocalypse begins!
Has anyone done a NDB approach lately?
Has anyone done a NDB approach lately?
Jason Larkin
Pre-Flight
Haha, I do have one of those!
N1120A
Pattern Altitude
I think having a backup IFR GPS is more important than a second NAV. I do think having a NAV radio is still important, but I think the best way to do that is having a 650/750 or 440/540/550.
I've never done an NDB approach and plan to keep that up.
I've never done an NDB approach and plan to keep that up.
Bill Watson
En-Route
1 WAAS GPS, 1 Nav, 2 Comms, and the unavoidable 2nd and 3nd non-WAAS GPSs that seem to replicate on their own.
I’ve been carrying around a 2nd Nav for no good reason and have never felt better safer because it’s there.
Just voting here. You are on the right track.
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I’ve been carrying around a 2nd Nav for no good reason and have never felt better safer because it’s there.
Just voting here. You are on the right track.
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Jason Larkin
Pre-Flight
Hmm. Well a new 255A nav/com is about 3600 + install. What about picking up a used 430. The non waas units are going for right about that same price. It could then be both a backup nav and com with gps?
Eric Lehto
Pre-takeoff checklist
I'm starting to think about these needs as well. I've got an old Narco radio stack and some steam gauges, all of which are probably on their way out.
I've been seriously considering the Aspen E5 to replace the steam gauges. The GNC 355 (GPS/comm) would make a great primary navigator. I think I'd want to get a good VHF nav/com for the #2 position. The E5 can use multiple sources for its nav signal....so I could wire the GPS and the nav radio in to it. I'd lose the redundancy of a second CDI, but it would declutter the panel and remove a little weight.
Just not sure how wise/legal it would be to only have one nav indicator with two sources? I'm also currently VFR only, thinking about working on my IFR. Do not plan to ever fly IMC regularly.
I've been seriously considering the Aspen E5 to replace the steam gauges. The GNC 355 (GPS/comm) would make a great primary navigator. I think I'd want to get a good VHF nav/com for the #2 position. The E5 can use multiple sources for its nav signal....so I could wire the GPS and the nav radio in to it. I'd lose the redundancy of a second CDI, but it would declutter the panel and remove a little weight.
Just not sure how wise/legal it would be to only have one nav indicator with two sources? I'm also currently VFR only, thinking about working on my IFR. Do not plan to ever fly IMC regularly.
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Bill Watson
En-Route
Backups and redundancy are attractive on the face of it but there are other considerations.
Background: My experience is essentially limited to 2 aircraft; a Maule I flew for 1700 hours and got my ticket in, and an RV10 experimental where I designed and installed an IFR centric panel in - 1200 hours and counting. I file on 95% of my flights and get as much actual as a year round traveler in the SE US is likely to get (too many storms to circumnavigate on a daily basis, never enough low weather to stay current in actual).
The Maule had dual NavComms and a non-WAAS Garmin GPS that could do enroute and non-precision approaches (no AP). Dual NavComms are basically mandatory in that configuration because you always want a precision approach capability and 2 Comms just make you more effective. The GPS is gravy but it’s good gravy and quickly assumes all enroute navigation leaving the radio Navs unused until an approach is required. The main challenge with such a panel (beyond single pilot IFR sans AP) is staying proficient with one’s VOR skills, and that was back in the 90s and 00s when one would still get radial intercept instructions.
In the past 8 years of IFR flight in the ‘10, I can recall the 3 times I have been asked intercept a radial. I fumbled 1 request until they gave me something else and had to work long and hard on the latter 2. If you don’t use it, you lose it. In today’s GPS oriented IFR world, staying proficient in VOR ops is a constant challenge for this pilot.
Now I fly with (3) EFIS units from GRT, a G430w, a SL30 NavComm and TruTrak AP. All enroute Nav is GPS, approaches are in order of preference; GPS LPV (precision), ILS, GPS LNAV with or without Vertical guidance,...... VOR. I fly a lot of ILSs mainly because it is the default approach at controlled airports but I’ll ask for the LPV if I’m not mixing it up with other traffic.
Reality is that it’s a GPS world now. Your number 1 NAV is essentially backup. Your number 2 is just using up amps. GPS outages and coverage issues? I just haven’t experienced any over the past 8 years (I did encounter a couple in the 90s). I have 2 Navs as backup but not sure I’m proficient enough to take advantage of more than 1.
Instead of focusing on backup avionics, what about power backups? In my Maule, staying upright after a failure was critical and my horizon was vacuum powered, so I installed a backup vacuum system. An electrical failure may leave me with some battery time but a backup battery powered comm and later an iPad was critical. Do you have a vacuum system in your ‘6? How do you keep it upright if it fails?
The ‘10 is 100% electrically dependent. All my primaries and backups require electrical power so I went full belt and suspenders with it; dual batts, dual alts, dual buses (it’s experimental so I can get carried away). If I lose an alternator on say Abaco Island, I’m likely to fill-up with fuel and fly home to NC to fix it since everything still works 100%. That backup capability is more important to me than any single instrument on the panel. I’ve had 2 inflight electrical ‘failures’ that were simply non-events.
Some random backup musings: A backup G430 that you don’t use in normal ops may be close to useless if you’ve never learned to really operate it. Having some old piece of gear installed or left in for backup requires that you know how to use it... in an emergency. A backup battery for that EFIS, and the other backup battery for the electric horizon, both need to be maintained and managed. A backup battery that is never needed and forgotten may not be ready for service when you need it (I got rid of my backup batteries and rely on the dual bus electrical system exclusively). One of my most effective backup instruments is my TT AP. It can operate independent of the rest of the panel to keep the plane upright and on course. But that works only because I’m fully knowledgeable about it’s modes of operation and proficient in using them. If you only use an über capable AP to steer using a heading bug, you may not be able to exploit it during a failure or emergency. Just some things to consider if you get that IFR ticket.
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Bill Watson
En-Route
Perfectly fine plan to improve your skills if not your capabilities. But I would suggest stop worrying about IFR configurations if you won’t be flying IFR. You can train in anything that’s legal (1 indicator is fine, 1 NavCom is fine).
It’s expensive to address the ‘what ifs’. Just setup for the VFR flying you will be doing and enjoy!
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Jason Larkin
Pre-Flight
What are you going to do about Adsb out? That where my wrench started.
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Eric Lehto
Pre-takeoff checklist
Already have a Skybeacon bolted to my left wing.
Jason Larkin
Pre-Flight
You definitely make some good points here. Yes the 6 currently has a vacuum system but that is getting removed with the install of the G5’s. I purchased the battery backups for them which are supposed to get 4 hours and self maintaining. Right now it isn’t as big of a concern as I’m VFR only. I do have a stratus and ForeFlight so in a pinch I could use that for attitude information. But going into instrument changes things a bit.
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Jason Larkin
Pre-Flight
chemgeek
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chemgeek
2 COM for sure. They are your lifeline while IFR. Beyond that, TSO 146 GPS (WAAS) and at least one VOR/ILS has you covered. In all the years I've owned a GNS-430, I've yet to fly a VOR leg anywhere. The #2 VOR I have is pretty much used only for 30 day checks.
Fracpilot
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Fracpilot
This!
In addition, I have the Aera 660 and iPad as a backup.
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Mtns2Skies
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Mtns2Skies
Yep! I also have an Area 660 panel mounted which I absolutely love.
Ravioli
Ejection Handle Pulled
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Unwanted Guest - Perma-ban Pending
Can you share your preflight RAIM check procedure? Perhaps you mean that you check RAIM PREDICTABILITY during preflight. Predictability and having RAIM in any particular phase of flight are not synonymous.
denverpilot
Tied Down
Been reading along chuckling at the “required” part of this question and answers.
Raise your hand if you’ve flown an instrument approach (I’ll admit, not IMC, under the hood) with crossing radials for step downs, with a single VOR head.
Sure is a hell of a lot nicer with two Nav radios. Or these days, a GPS and a better approach.
I did see ADF jokes up there I think. Also fun back in the day. Our malfunctioning ADF ended up on a friend’s garage workbench as an excellent AM broadcast receiver. That’s all it would do when it was yanked.
Raise your hand if you’ve flown an instrument approach (I’ll admit, not IMC, under the hood) with crossing radials for step downs, with a single VOR head.
Sure is a hell of a lot nicer with two Nav radios. Or these days, a GPS and a better approach.
I did see ADF jokes up there I think. Also fun back in the day. Our malfunctioning ADF ended up on a friend’s garage workbench as an excellent AM broadcast receiver. That’s all it would do when it was yanked.
Jason Larkin
Pre-Flight
For me the check is done in ForeFlight. When you make a navlog foreflight checks for any know raim outages. You are right that is not a guarantee but since it is so simple why not check. But again I am always on the side of caution.
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Unit74
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WannFly
Final Approach
The STC doesn’t allow the HSI to connect to 2 diff nav coms, I believe that’s what OP was asking
Unit74
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WannFly
Final Approach
Prolly, but I don’t know if the exp version supports it or not, but with exp you can have as many G5 as your heart desires
John Myers
Pre-takeoff checklist
We elected to just put in one nav and we have a battery powered handheld navcom (with glideslope) as an extra backup, although I doubt we'll ever need it. We did test it and it seems to work decently well on an approach although it is tricky if single pilot. This is more redundancy than the plane had with the dual navs before GPS.
Things to keep in mind about GPS outages:
1. They are almost always planned these days. With the additional WAAS satellites (that also function as additional GPS satellites), unplanned outages are now almost unheard of.
2. They are often planned to be at times when air traffic is low, like the middle of the night.
3. In an actual emergency, you can ask ATC to cancel the test.
4. The rings are areas where the GPS signal may be less accurate or gone, but not necessarily so.
The single vloc we have is our backup, and given the almost universal availability of GPS approaches I expect will never be used outside of training. I do think a single ground based nav receiver is important to have though, and will continue to be into the foreseeable future.
Another "backup" that is often forgotten is simply getting radar vectors to visual conditions. An airport near us also has a PAR approach, although those are usually not available at most airports.
Things to keep in mind about GPS outages:
1. They are almost always planned these days. With the additional WAAS satellites (that also function as additional GPS satellites), unplanned outages are now almost unheard of.
2. They are often planned to be at times when air traffic is low, like the middle of the night.
3. In an actual emergency, you can ask ATC to cancel the test.
4. The rings are areas where the GPS signal may be less accurate or gone, but not necessarily so.
The single vloc we have is our backup, and given the almost universal availability of GPS approaches I expect will never be used outside of training. I do think a single ground based nav receiver is important to have though, and will continue to be into the foreseeable future.
Another "backup" that is often forgotten is simply getting radar vectors to visual conditions. An airport near us also has a PAR approach, although those are usually not available at most airports.
N1120A
Pattern Altitude
There are still a few airports where having an ILS on board makes a significant difference. VNY and BUR come to mind immediately. MRY is another one where there is enough of a minimums difference to notice. MCC as well, which has no RNAV approach for some reason, but has an ILS.
John Myers
Pre-takeoff checklist
No RNAV approaches but ILSs in 2019, I would never have guessed. I wonder what the story is there, those are not remote airports.
N1120A
Pattern Altitude
Probably a combo of terrain and will. There is an RNAV 8 to KBUR, but it isn't LPV and has much higher mins.
Also, given what piles of trash that BUR LOC and GS are, you'd think they'd want something else
John Myers
Pre-takeoff checklist
Not to drift the thread too far, but I wonder if those were approved based on looser legacy criteria for ILS and they are left in for practical reasons as they can't get an LPV approved?
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Ari
For flying in the real world, I think the only thing a person would miss about having a second Nav radio is the ability to do VOR checks the easy way. With zero Nav radios, you don’t have to do VOR checks. With two Nav radios, you can check them against each other in the air as long as one VOR is in range. With a single Nav radio, you need to find a VOT, a ground checkpoint, or a prominent landmark on a Victor airway.
Jason Larkin
Pre-Flight
John Myers
Pre-takeoff checklist
You only need to check them if you need to use them on a flight (as opposed to using the receiver only for an emergency).
Also, in practice I suppose it’s more accurate (and probably safer) to use a GPS to check your VOR, if not legal. I’m sure someone can poke holes in that but in general I’d say it’s on balance safer.
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Ari
Slight correction: You only need to check them if you will use them to navigate under IFR other than in an emergency. You can use a nav radio to tune in and track a VOR or ILS under VFR without ever checking it. And you can use your radio to fly the ILS if the GPS system were disabled in such a way that causes you to experience an emergency.
When does it matter? The scenario that keeps me checking my nav radios every month is flying to a moderately busy airport under IFR and hearing “expect the ILS.” Now you need to negotiate with ATC to get a GPS approach, because you don’t have an emergency and you can’t legally fly the ILS with your non-current VOR/ILS/GS receiver. That negotiation may put you way out in the boondocks or in a hold while the beautifully stacked up ILS arrivals get in. Is that scenario likely? No. Is it possible? Yes. Possible enough that I keep doing my monthly checks so I can accept the ILS if ATC wants me to fly it.
John Myers
Pre-takeoff checklist
Well yes, obviously you don’t need any navigation receiver for VFR flight. Localizer and glide slope receivers are not the same as VOR receivers, other than the localizer and VOR receiver share an antenna and are contained in the same box. You do not need to do a VOR check to use an ILS under IFR (or obviously VFR).
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Ari
You’re supposed to learn something new every day. And thanks to your post, I snuck one in before today ended. I did know that localizer and VOR signals are different, but I did not know that the VOR check was not required to fly an ILS. Reading the regulation on VOR checks, it does indeed refer to flight using “the VOR system of radio navigation.”
So I guess I won’t worry about doing VOR checks in my experimental plane once it’s flying. Because the only time I would actually navigate under IFR using VORs would be an emergency.
denverpilot
Tied Down
At BUR it probably has something to do with two things...
Runway 8 at BUR has very tight margins for that approach. The east side north-south runway at VNY has a lower pattern altitude because of it.
Huge number of airplanes landing BUR still don’t have GPS.
Our resident TERPS experts can probably say more, but having flown out there, every little thing about every approach in the LA Basin is carefully crafted to allow as many airports as they have, crammed into a relatively small space — in terms of the sizes of typical approaches being ten or so miles out.
It’s tight out there. I doubt the reasoning is LESS accuracy of the chosen navaids.
BUR tries pretty hard not to land 8. It messes up all sorts of stuff.
BryanAV8R
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You can take redundancy to a deep level...myself? My panel has a GNS430W, KY196, KN53, HSI, and KI204 head (and a GMA audio panel). So, for the way I fly IFR, I have multiple flip/flop frequency selection, comm and nav redundancy, and I've gotten into the habit of pre-staging frequencies (tower on the 430, departure on the second comm (I have a remote comm 1/2 swap button the yoke), then next freq goes into the 430, and back and forth as needed). For me, it's just easier. For you? Once you get into instrument training, you'll figure out what your comfort level is and how you run your cockpit, which will define what gizmos you want in your stack. Everyone is different; there is no one good way.
EdFred
Taxi to Parking
He's a captain with the airlines. I'm pretty sure he knows.
PaulS
Touchdown! Greaser!
This, dual comms make life much easier.