What Backup Do You NEED for your IFR EFIS in EAB Kit Plane.

[gmcjetpilot]

This video link was well done. FAR's are not totally clear on back up instruments for EAB kit planes. In Certified planes the requirement is in the TSO for the certified EFIS. Large jets with 4 displays and redundancy have small backup standby instruments, but then again it is a transport category.

My other post about 3.125" backup EFI PDF got me thinking. What if the main EFIS with all the info went blank (not related to electrical power). As we integrate all control of radios, transponder, engine instrument that display is critical. Not withstanding back up electrical power, what if a lighting strike took out your display?

For VFR not as critical on IFR flight in IMC. You need Attitude Instruments and NAV. The REGS for EAB Kit planes really does not specify any back up, electrical or otherwise. Of course common sense and survival instincts would say have backups.

Before EFIS in GA, many people did not do well when their Vac pump failed and went "partial panel". The EFI reliability is very good and back up standby battery power is not hard to do well. The question is how much redundancy do you need?

For me I need a back up flight instrument AI, AS, ALT. After that wet compass for heading. Nav, IFR GPS with small map and can provide at minimum lateral guidance. People point to their iPad or Tablet with built in GPS (and even rudimentary AHAR) and the EFB (Elect Flight Bag) software. That is for Ref only. As far as radio control, my EFIS can tune the radio but have separate tuning head. The transponder is remote and has no independent control. However is should keep doing it's thing and say on last squawk. I could add a discreet IDENT button in panel. Engine Inst in EFIS is back up by a EIS (Engine Information System). It is a small dedicated LCD screen with 3 buttons. This allows me to tune radio and have engine instruments. But what about Attitude Instrument flight, Attitude, Airspeed, Altitude, Slip/Skid, Rate of Turn... There are many electronic choices. It makes no sense to add a vacuum pump. However Vaccum pump has some charm, in that a lighting strike will not take it out. f

I fly and do instructing in a flight club C182 with a GTN750 and G5. The primary attitude is still Vacuum. The AI rolled over and died. It was the AI, suction was good. I switched the G5 to PDF mode for attitude. However the STEC autopilot uses the G5 in HSI mode only for commands. G5 in PFD mode I had no autopilot, no heading, no NAV track. No big deal, even on an IFR flight plan, I was in mostly VFR conditions. Could I have flown without bring up the G5 in PDF mode, leave it in HSI so Autopilot worked? Yes because I had pitot static instruments: Airspeed, VSI, Turn Coordinator, and the DG is is a Bendix/King kcs-55a all electric HSI, which gets Nav info from King KX155, #2 Nav/Com. It is nice having a mix of old school and wiz-bang.

The GTN750 is a touch screen display, with IFR WAAS GPS , COM, NAV (VOR/LOC/GS), ADS-B IN/OUT S-Transponder, Audio Panel. All in one unit.

Engine instruments are 1967's Cessna.

Makes me think, if GTN750 dies (with audio panel) will I be able to use the KX155 #2 COM? Nav to HSI should be OK. Sounds like I would lose COM (pun intended). With all eggs in on basket, be it an do it all GPS or EFIS, you should have redundancy for an IFR plane. The question for experimental how much redundancy. It really is up to you.

You can spend a lot of energy on this. I'm all GPS. no panel/aircraft mounted VOR/LOC/GS.... I do have a iPad EFB. I suppose a handheld Transceiver with VOR/LOC/GS (Yaesu FTA750A), for emergency may be a good idea. I am adding a backup PFD/EFIS, and subject of my other post.

Youtube Video

 

[Dugaru]

I suppose a handheld Transceiver with VOR/LOC/GS (Yaesu FTA750A), for emergency may be a good idea.

Definitely take the time to try it out under real world conditions. During my little evening adventure, I discovered that at a “half battery” power level, my Yaesu 750 would die when you pressed the transmit button. Which meant I couldn’t turn on pilot-controlled runway lighting, much less talk to ATC. Sort of defeated the whole purpose of having the thing.

 

[Auburntsts]

I've never read a legal requirement for backup instruments in an E-AB aircraft. Having said that just because it's legal or not ill-legal doesn't mean it's prudent or safe. In my own plane I run a 2-alternator electrical system with a backup EFIS (G5) to my primary dual-screen EFIS (G3X). I also have 2 NAV/COMs plus a hand transceiver and I'm, pretty happy with the level of risk all of this lets me operate at.

 

[airguy]

I'm, pretty happy with the level of risk all of this lets me operate at.

And that right there really sums up the requirements for backups (or lack thereof) in the EAB world. Each of us will have a different risk tolerance and will tailor our response to that risk.

Myself, I have multiple layers of redundancy - but I like gadgets.

 

[Southern Pete]

I don't know what is legally required but you may be interested to read this AC
AC 23.1309
It address exactly the point you are thinking about. As well as a second attitude source a second way to tune the radio and nav receiver is required if the primary method is through the EFIS. We are flying Class 1 aircraft, see appendix 1.

 

[mburch]

Makes me think, if GTN750 dies (with audio panel) will I be able to use the KX155 #2 COM?

All the GTN / GMA 35 installations I'm familiar with have a fail-safe feature, which connects the remote audio panel to the #2 COM radio in the event of a power failure or loss of communication with the display.

 

[gmcjetpilot]

I don't know what is legally required but you may be interested to read this AC
AC 23.1309
It address exactly the point you are thinking about. As well as a second attitude source a second way to tune the radio and nav receiver is required if the primary method is through the EFIS. We are flying Class 1 aircraft, see appendix 1.

Right on. I love the AC's.... Treasure trove of info. However this AC is aimed at Part 23. Backup instruments are required. It does not hurt EAB builders to follow these guidance and guidance of certified EFIS manufactures and their TSO.

If you watch the video (which I am taking at face value) seems reasonable. FAR's are not always black/white, explicate. Up to you on how much redundancy you want, need. If you are a VFR pilot only you can do with less. IFR rated and plan on flying "light" high mins IMC you know you need more. Hardball all weather low mins, you need more.

Some want dual alternators, back up battery to the back-up battery, triple AHAR's... etc. Others one backup battery and two AHAR's or pitot/static and Turn coordinator instrument. will do. Many pilots plan on using their iPad/Tablet and EFB with built in GPS and on board battery for back up NAV including IAP... My EFB has geo-sync approach plates that I can see using in an emergency. If you have COM but no NAV, ATC can help. ASR or PAR approach in the area (I have done them), they can talk you down to runway.

Another example to my C182K example above, is the IFR C152 I give dual in, teaching fledgling instrument students in the Flt Club's C152. It no longer has Vacuum AI or DG. It has (2) two G5's and a Garmin 430W. No backup battery or alternator. Each G5 is backed by their own onboard battery. It also has a Garmin 430W, GPS (RNAV / LPV), VOR/LOC/GS and COM, nothing else but pitot static instruments and electric Turn Coordinator.

One COM for training is a compromise. If you need to listen to ATIS you ask to go off Freq for a minute or ask ATC for ATIS (they have it). Most of the time in training we are VFR, not talking to ATC practicing "Attitude Inst Flying", Approaches, Holding, Tracking, in Class G, E and class D (talk directly with tower to negotiate a practice approach in VFR).

The C152 is 100% IFR legal with all required checks, with legal but minimum equip and backup. I say MIN equip, you can fly with just a VOR if you want, but pretty limited now a days with GPS dominating the non precision approaches. Use to be a lot of VOR approaches with VOR on field. The FAR's only say you need the equip you plan to use. I use to fly IFR with only a VOR/LOC and Marker beacon lights to commute 30 miles. It was all I needed for what I was doing. This was pre GPS, pre EFIS.... It was in radar environment and one approach was VOR on field and other LOC and FAF was at marker. Worked well. LPV approach although not "precision" is pretty good with MINS down to near CAT 1 (EDIT) (or same, 200 ft above TDZ/AGL) and as low as 1/2 mile statue Vis.... VOR and LOC not so much... GPS LPV is really amazing. That is why I only have GPS RNAV capability.

.Definitely take the time to try it out under real world conditions. During my little evening adventure, I discovered that at a “half battery” power level, my Yaesu 750 would die when you pressed the transmit button. Which meant I couldn’t turn on pilot-controlled runway lighting, much less talk to ATC. Sort of defeated the whole purpose of having the thing.

Yep HANDHELD as a back up is iffy (unless you integrate it well), and to your point flight test this backup concept of backup well. The C152 IFR trainer has one COM. I do carry my small COM only YAEUS. I have an ear-bud I put in ear under headset, marginal audibility, not practical. I have not even bothered to use it for two way COM.

As far as trying to talk ATC, CTAF, activate lights, I would say plan on tapping into the outside antenna.

Your point about battery power is well taken. Plugging into ships power as well should be in the plan if you expect a handheld to be a backup.

For my RV7 I am using an ICOM A220 with standby Freq monitoring. If I plan on using a handheld, I'd get a better handheld and one with NAV as well. NAV on handhelds do work but with limited range with rubber duck antenna. If I lose COM I lose COM... NORDO...squawk 7600.

Many pilots say I WILL CALL THEM ON MY CELL PHONE.... true with cell phones that can work. I have ARTCC for my region programmed in phone. Clearance delivery is OK but they would have to patch you in to a controller. They are all in the same building and proximity, but clearance has no scope, no radio, just a desk and computer. Many ARTCC phone numbers go to a manager and a voice answering machine, so work out a good number ahead of time if that cell phone is your COM backup plan.

If I plan on handheld as backup COM/NAV. I would integrate it into the audio / headset / intercom AND consider a way to access the BNC connection to external antenna, and plug handheld into ships power. You see many planes like Piper J3 Cubs, Ultralights with no electrical system use handhelds exclusively. It can be done, but it is more than throwing a handheld in your flight bag with half discharged battery and hope it works.

As I was thinking about the C182K with GTN750 being the audio panel. If that goes dead I lose COM. May be not. May be it fails passively, but how do you tune the #1 COM, that is gone as well. Does it default to COM 2? So consider whatever audio panel you have. I do not have an audio panel. I have a DRE intercom that is suppose fail passively, still allow you the hear COM radio and key the mic. Again NORDO is a concern but if you till have flight instruments, NAV and fuel you can get back on the ground.

Many ways to have redundancy, less or more. Up to you and your tolerance for risk.

 

[Dugaru]

Plugging into ships power as well should be in the plan if you expect a handheld to be a backup.

If I lose COM I lose COM... NORDO...squawk 7600.

Unless ship's power has taken the evening off. Ask me how I know.

 

[BobTurner]

GMC: I think you meant ‘CAT 1’. CAT 3 is the million dollar autopilot, 0-0 approach.
As to GPS as sole navigation: when it works it’s great. But I had the privilege of sitting right seat in VMC, watching the guy in the left seat under the hood shoot the LPV approach into KLVK. From my vantage point it was easy to see the green ‘LPV’ turn to yellow ‘LNAV’ on the G650, but he didn’t see it. About 30 seconds later, he says, ‘I don’t think the glide slope is working’. I replied, and pointed to the CDI, ‘Maybe that’s what the glide slope flag means!’. As I also pointed out the yellow LNAV annunciation, it turned to red, a big ‘x’ went across the screen, and the left-right cdi flagged. We landed vfr. But it certainly made me think about gps-only airplanes (I do carry an SL30 around, just because of this, although I’ve never had to use it.) My best guess about the failure, which could not be recreated, was that some truck on the freeway had a gps jammer.

 

[georgemohr]

GPS jamming, or heaven forbid, disablement due to military action, is a real possibility. How likely will this happen while you are in the soup...? Probably not.

I think the bare minimum backup instrumentation is a dissimilar attitude/altitude/speed reference. A G5 in our G3X system serves this well.

 

[gmcjetpilot]

GMC: I think you meant ‘CAT 1’. CAT 3 is the million dollar autopilot, 0-0 approach.
As to GPS as sole navigation: when it works it’s great. But I had the privilege of sitting right seat in VMC, watching the guy in the left seat under the hood shoot the LPV approach into KLVK. As I also pointed out the yellow LNAV annunciation, it turned to red, a big ‘x’ went across the screen, and the left-right cdi flagged. We landed vfr. But it certainly made me think about gps-only ..... gps jammer.

Yep CAT 1, 200ft, 1/2 mile (1800RVR). Thanks.

Yes only having GPS as single Nav has limits. I find VOR to be handy to track out bound vs program the GPS to go from waypoint. GPS is more of a goto waypoint NAV. For VOR set Freq, ident, OBS course, fly the needle. My Yaesu has VOR... it works. I would not like to be stuck in the clouds with just this...

Started flying GPS in planes in GA and commercially in 90's. The jets had IRU (Inertial Ref Unit, previously known as INS) did not have GPS. They were added later. So this discussion happens when crossing Atlantic or Pacific. No VOR/DME but had 3 IRU's. Before GPS the IRU's were the main Navigation. When you got in range of VOR/DME as you approached land, your FMC position was updated. You actually saw magenta track and plane symbol on Map display jump. GPS was later fitted. FMS gives priority over water to GPS not IRU. Still nice to have IRU backup. You are required to have VOR/DME to fly in Class A airspace. CAT 1 ILS is still bread and butter at large airports. However you NEED area Nav (GPS) to ID fixes (or DME or cross radials). Most LOM's, NDB, Beacon are gone.

I suppose a handheld with NAV would be good, but what is the chances? Alternative is ATC vectors to VFR or ASR/PAR approach? If VFR pilotage, heading, airspeed, chart, look out window...

In 30 yrs never had loss of GPS signal. You do have to check NOTAMS for GPS area outage. This YouTube channel talks of this reliance of GPS.

 

[rockyfatcat]

I don't know what is legally required but you may be interested to read this AC
AC 23.1309
It address exactly the point you are thinking about. As well as a second attitude source a second way to tune the radio and nav receiver is required if the primary method is through the EFIS. We are flying Class 1 aircraft, see appendix 1.

Hi, I have had this very same conversation with more experienced pilots in my hangar. I asked the same question when I took my check ride with my DPE, so please correct me if I’m wrong.

FAR 91.205 specifies required instruments and equipment for (a) VFR day, (b) VFR night, and (c) IFR. For part 91 operations where does it say that ANY backup instruments are REQUIRED?

 

[RVDan]

I work in aircraft certification for avionics and instrumentation. For part 23 there is a specific requirement for standby instruments under 23.1311(a)5 at amendment 23-62. 23.1311 was added to the regs in the 90’s when EFIS started becoming a thing. There is no specific requirement under part 91.
23.1309 would also require a standby with an independent power source to meet the required failure rates for this rule, as discussed in AC23.1309 -1E.
Exp has no specific requirement, other than the whatever pucker factor the pilot is comfortable with. I fly with dual fully redundant main display systems with backup batteries on both and a standby. I have a low pucker factor tolerance.

 

[airguy]

Hi, I have had this very same conversation with more experienced pilots in my hangar. I asked the same question when I took my check ride with my DPE, so please correct me if I’m wrong.

FAR 91.205 specifies required instruments and equipment for (a) VFR day, (b) VFR night, and (c) IFR. For part 91 operations where does it say that ANY backup instruments are REQUIRED?

See post #4 this thread. Not required, possibly desired.

 

[penguin]

What Airguy said, nothing is required.
Just because the rules allow you to build a system that could allow you to kill yourself at the first sign of a failure doesn't mean it is a good idea.
Given the amount of opinion on this subject at least an AC and 23-1309 & 1311 provides a sound basis to design a system.

 

[PilotjohnS]

Expanding this discussion, for EAB, is it RequireD to have all fuses accessible in flight, or is that a certified world rule?

 

[gmcjetpilot]

Expanding this discussion, for EAB, is it RequireD to have all fuses accessible in flight, or is that a certified world rule?

I think you are referring to FAR 23.1357 Circuit protective devices. We are not Part 23, GA planes. Not going to debate that, but it is like having IFR back up, there is good guidance, standards and practice.

Almost every, car, motorcycle, small boat uses ATC blade fuses. The use of ATC fuses in Kit Planes, not necessarily easily accessed or replaced, was popularized by AeroElectric Connection Bob Nuckolls, who has strong opinions. You can look up some of his published works on subject and his logic.

Personally I have a bunch of Klixon Pullout Circuit Breakers. Why? Easy to access, easy to reset, easy to see what tripped, and they can be pulled, used to remove power like an alternative switch. Fuses work, lighter, cheaper. Nothing says you can't use both. Non critical items on fuses and critical items on CB's you can access and reset easily. Like back up for a panel intended for IFR in IMC, up to you. Since many panels have transitioned to rely only on electricity for flight instruments and ignition, circuit protection is even more critical.

http://www.aeroelectric.com/articles.html​

. .

 

[PilotjohnS]

I think you are referring to FAR 23.1357 Circuit protective devices. We are not Part 23, GA planes. Not going to debate that, but it is like having IFR back up, there is good guidance, standards and practice.

Almost every, car, motorcycle, small boat uses ATC blade fuses. The use of ATC fuses in Kit Planes, not necessarily easily accessed or replaced, was popularized by AeroElectric Connection Bob Nuckolls, who has strong opinions. You can look up some of his published works on subject and his logic.

Personally I have a bunch of Klixon Pullout Circuit Breakers. Why? Easy to access, easy to reset, easy to see what tripped, and they can be pulled, used to remove power like an alternative switch. Fuses work, lighter, cheaper. Nothing says you can't use both. Non critical items on fuses and critical items on CB's you can access and reset easily. Like back up for a panel intended for IFR in IMC, up to you. Since many panels have transitioned to rely only on electricity for flight instruments and ignition, circuit protection is even more critical.

http://www.aeroelectric.com/articles.html​

. .

Thanks for your reply.
I uses circuit breakers for everything except stuff I could live without or wouldn’t cause an immediate diversion. So I used fuses for stuff like taxi lights, landing lights, strobes, defrost fan, etc. And those fuses are not accessible in flight.

 

[avrojockey]

Definitely take the time to try it out under real world conditions. During my little evening adventure, I discovered that at a “half battery” power level, my Yaesu 750 would die when you pressed the transmit button. Which meant I couldn’t turn on pilot-controlled runway lighting, much less talk to ATC. Sort of defeated the whole purpose of having the thing.

I have a 750 as an emergency backup and it gets charged for every flight, but it also comes with a AA battery pack and 12V dc cord for backup. As long as I could get a couple transmissions to ATC with my intentions, I would be good. Afterwords, I would be in receive mode only which requires a fraction of the power.

 

[avrojockey]

I really like the "light" IFR panel, but have enough redundancy to be comfortable with low IFR. I have the following...

2x G3X GDU370/375 Displays
2x GSU25 ADHRS
1x GPS175 WAAS GPS
1x GTR200 Com
1x GMC307 Autopilot
iPad with ForeFlight (backup attitude from GPS175, and backup GPS)
Yaesu 750 connected to external antenna.

I think a redundant electrical system is more important for an all electric airplane. GDUs and GSUs are wired on independent buses with the ability to isolate by the pilot, and essential bus off hot battery bus. Additionally, everything but the COM and AP servos (FD still works) can be powered for 1 hour by TCW backup battery. The autopilot/FD is important because it relieves the pilot to be able to recognize any issue, and bandwidth to resolve it.

Things I live without and why...

VOR/ILS - not needed for CAT I most places these days, and Yaesu 750 works in an emergency
Standby compass - Watch and phone both have a compass app which is probably more accurate than a whisky compass bouncing around
A separate clock - GTX335 has one built in

 

[bigmo]

I really like the "light" IFR panel, but have enough redundancy to be comfortable with low IFR. I have the following...

2x G3X GDU370/375 Displays
2x GSU25 ADHRS
1x GPS175 WAAS GPS
1x GTR200 Com
1x GMC307 Autopilot
iPad with ForeFlight (backup attitude from GPS175, and backup GPS)
Yaesu 750 connected to external antenna.

I think a redundant electrical system is more important for an all electric airplane. GDUs and GSUs are wired on independent buses with the ability to isolate by the pilot, and essential bus off hot battery bus. Additionally, everything but the COM and AP servos (FD still works) can be powered for 1 hour by TCW backup battery. The autopilot/FD is important because it relieves the pilot to be able to recognize any issue, and bandwidth to resolve it.

Things I live without and why...

VOR/ILS - not needed for CAT I most places these days, and Yaesu 750 works in an emergency
Standby compass - Watch and phone both have a compass app which is probably more accurate than a whisky compass bouncing around
A separate clock - GTX335 has one built in

We have literally the *exact* same setup (except I have the 460/465 EFIS).

The only other item I'd comment on is a GDL52 adds yet another layer of battery backed security providing reliable attitude information to your iPad. I do practice approaches every now and then using nothing but the iPad and it's really not that much different than following my G3X.

I'm not sure which Yaesu I have (maybe the 550) - mine's the lowest entry point that has the ILS. I change my batteries like clockwork every 4 months and turn it on to check ATIS each flight just to make sure it's working. I've also used it, coupled with just the iPad to fly an approach - that forced me to add a little velcro to the panel so I could watch the localizer and glideslope and not be fumbling around holding it.

I feel I've done my part to be as safe as possible. My other personal part of this is never going under 1 hour fuel. Climb and relocate is a final layer of protection.

I do try to keep this all balanced with all the 50+ year old part 23 a/c out there with a hodgepodge of outdated technology and a rats nest of wiring.

 

[avrojockey]

The only other item I'd comment on is a GDL52 adds yet another layer of battery backed security providing reliable attitude information to your iPad. I do practice approaches every now and then using nothing but the iPad and it's really not that much different than following my G3X.

I have a 39 but thought about upgrade to 52 for this exact reason

 

[PilotjohnS]

I have a G5 instead of a backup GSU25

 

[bigmo]

I have a G5 instead of a backup GSU25

I think that makes sense if one doesn't have the second screen already, and for sure saves money. But if one has the screen already, the GSU25 is more affordable.

I've seen discussion about the logic of the backup system having completely different code etc.. I've been combating this by not being an early adopter of new G3X software releases. I wait a full cycle, if not two to make sure the bugs are FULLY worked out.

I do very much like the G5. I flew a pretty old Mooney recently with a terribly outdate panel, but they just added twin G5's. Coupled to the autopilot, one has to work hard to find fault with that setup. I can't believe I am typing this, but the G5s seem underpriced for what they offer.

 

[Dugaru]

I have a 750 as an emergency backup and it gets charged for every flight, but it also comes with a AA battery pack and 12V dc cord for backup. As long as I could get a couple transmissions to ATC with my intentions, I would be good. Afterwords, I would be in receive mode only which requires a fraction of the power.

If I had been smart, I would have left it on receive on 121.5 and waited to hear from them. I couldn’t have idented or responded, but perhaps they could have asked me to acknowledge with a course change. Not really sure what ATC procedure is for lost comms.

 

[Dugaru]

I've been combating this by not being an early adopter of new G3X software releases. I wait a full cycle, if not two to make sure the bugs are FULLY worked out.

Makes sense. Waiting for others to act as involuntary beta testers is also the recommendation of at least one Garmin customer service rep.

I can't believe I am typing this, but the G5s seem underpriced for what they offer.

I agree completely, and I’m equally shocked! They are superb gadgets.

 

[PilotjohnS]

Makes sense. Waiting for others to act as involuntary beta testers is also the recommendation of at least one Garmin customer service rep.


I agree completely, and I’m equally shocked! They are superb gadgets.

G3X software version 9.33 released. fixes a problem with 9.32 that was released a week ago.
I download the latest. it is not hard to roll back a version. But I have never had to roll back because of them, only due to my fat fingers turning off power while downloading.

 

[Foghorn]

If I had been smart, I would have left it on receive on 121.5 and waited to hear from them. I couldn’t have idented or responded, but perhaps they could have asked me to acknowledge with a course change. Not really sure what ATC procedure is for lost comms.

If VFR stay VFR.
If IFR:

 

[BobTurner]

The "lost com" IFR procedures are pretty much common sense and straightforward, with one exception: I've spoken with several controllers, and they all agree - if you arrive earlier than your ETA, they really don't want you holding somewhere. Just go ahead, shoot the approach (any approach, your choice) and land.

 

[Dugaru]

If VFR stay VFR.
If IFR:
View attachment 57036

Yup, I knew that part. I meant I didn’t know exactly how they try to contact you.

 

[Dugaru]

G3X software version 9.33 released. fixes a problem with 9.32 that was released a week ago.

This is sort of making my point. Much easier to just wait a while.

 

[PilotjohnS]

This is sort of making my point. Much easier to just wait a while.

Ya I wrote this for you. We all need a little humor now and then.

 

[jcarne]

The "lost com" IFR procedures are pretty much common sense and straightforward, with one exception: I've spoken with several controllers, and they all agree - if you arrive earlier than your ETA, they really don't want you holding somewhere. Just go ahead, shoot the approach (any approach, your choice) and land.

Not to mention full loss of coms IFR is quite logically an emergency. Personally I'm squawking 7700 and doing what I need to do. Controllers I have talked to want you on the ground asap. haha Even if you are VFR and follow 91.185 they are going to be clearing everyone out of your way.

There is a great Opposing Bases podcast where they discuss how bad the NAS could get screwed up if one follows 91.185 blindly. Legal yes, but so is declaring. Very interesting to hear their side of the story.

Now that being said, I'll be teaching my students 91.185 with a caveat.

Funny enough, on my CFII checkride last week the DPE gave me a lost coms scenario and asked what I would do on a nice clear day like today. Gave him the answer he wanted (troubleshoot, stay VFR and land) and he said "you have no idea how many people go straight into MEA and AVEF without thinking first".

 

[Dugaru]

Not to mention full loss of coms IFR is quite logically an emergency. Personally I'm squawking 7700 and doing what I need to do. Controllers I have talked to want you on the ground asap.

Makes sense. What I never had thought about is how much more complicated this scenario gets at night, even VMC. No comm = no pilot controlled lighting. If you proceed to your filed airport, they (likely) know where to turn the lights on for you. Otherwise I guess it’s (a) hope they figure out where you’re going, and are able to turn the lights on there, (b) land in the dark, or (c) bomb into a towered airport unannounced and look for light gun signals?

 

[gmcjetpilot]

Not to mention full loss of coms IFR is quite logically an emergency.

Funny enough, on my CFII checkride last week the DPE gave me a lost coms scenario and asked what I would do on a nice clear day like today. Gave him the answer he wanted (troubleshoot, stay VFR and land) and he said "you have no idea how many people go straight into MEA and AVEF without thinking first".

If VFR it is assumed you will land, and it's in the FAR's. I would hope you would get that right.

FAR 91.185 (b) says: "VFR conditions. If the failure occurs in VFR conditions, or if VFR conditions are encountered after the failure, each pilot shall continue the flight under VFR and land as soon as practicable."

But if IMC and you lose your radios, can't divert under VFR, SQUAWK 7600.
Then fly your route and altitudes based in the following order.

I teach my students the well known mnemonic memorization aids. Students have to recite this.

AVE-F (Lost Com Route Clearance)

1. Assigned
2. Vectored
3. Expected
4. Filed

MEA (Lost Com Altitude Clearance)​

Fly the highest altitude of:

1. Minimum IFR Altitude (Often Charted)
2. Expected Altitude
3. Assigned Altitude

However if an emergency you can deviate. What if you just took off. The Airport is 3 miles, 2000 ft and you are now climbing through 5000 ft, solid IMC, at the start of 4 hour flight to a busy airport. I might consider landing back at departure airport, e.g., shooting approach back at departure airport. Technically you should fly to destination if solid IMC the whole time. Not an official by the book answer but...

Not suggesting you or anyone do this (my lawyer told me to say this). I am saying emergency PIC can deviate. You just have to explain it later to the FEDS. What if NAV radio is dead? Well I guess that is the case for iPad/Tablet with built in GPS/Battery and EFB software with aviation maps/IAP charts. My EFB has that and it does work in plane. If I connect to ADS-B in via WiFi I can get weather and traffic. Technology is great.

What if your transponder is dead as well? There is primary return, meaning ARTCC can see traffic with raw data, radar reflection off plane, but it depends on coverage. Low sector and terrain may be not, but high up yes likely they can see raw data, meaning a plane with no transponder. If there is weather may be not?

Good news you will come down eventually Com or No Com /NORDO/.... No plane has ever been left up in the sky.

 

[blaplante]

Some thoughts on the 'single big screen does everything'.
Many are touch screens. It is common on commercial touch screens to provide the touch data via USB to the computer.
USB is a serial interface... so break one wire and the touch screen stops working.

Maybe the big avionics vendors don't use serial interfaces for touch. Or maybe they do.

But losing all data input capability, while not as bad a losing the display, would still be uncomfortable if that's the only way you can tune the radio, or even put in the lost-com squawk code.

 

[jcarne]

Makes sense. What I never had thought about is how much more complicated this scenario gets at night, even VMC. No comm = no pilot controlled lighting. If you proceed to your filed airport, they (likely) know where to turn the lights on for you. Otherwise I guess it’s (a) hope they figure out where you’re going, and are able to turn the lights on there, (b) land in the dark, or (c) bomb into a towered airport unannounced and look for light gun signals?

All good points! That is why I live by the saying IFR, Terrain, Night. Choose 1 haha

If VFR it is assumed you will land, and it's in the FAR's. I would hope you would get that right.

FAR 91.185 (b) says: "VFR conditions. If the failure occurs in VFR conditions, or if VFR conditions are encountered after the failure, each pilot shall continue the flight under VFR and land as soon as practicable."

But if IMC and you lose your radios, can't divert under VFR, SQUAWK 7600.
Then fly your route and altitudes based in the following order.

I teach my students the well known mnemonic memorization aids. Students have to recite this.

AVE-F (Lost Com Route Clearance)

1. Assigned
2. Vectored
3. Expected
4. Filed

MEA (Lost Com Altitude Clearance)​

Fly the highest altitude of:

1. Minimum IFR Altitude (Often Charted)
2. Expected Altitude
3. Assigned Altitude

However if an emergency you can deviate. What if you just took off. The Airport is 3 miles, 2000 ft and you are now climbing through 5000 ft, solid IMC, at the start of 4 hour flight to a busy airport. I might consider landing back at departure airport, e.g., shooting approach back at departure airport. Technically you should fly to destination if solid IMC the whole time. Not an official by the book answer but...

Not suggesting you or anyone do this (my lawyer told me to say this). I am saying emergency PIC can deviate. You just have to explain it later to the FEDS. What if NAV radio is dead? Well I guess that is the case for iPad/Tablet with built in GPS/Battery and EFB software with aviation maps/IAP charts. My EFB has that and it does work in plane. If I connect to ADS-B in via WiFi I can get weather and traffic. Technology is great.

What if your transponder is dead as well? There is primary return, meaning ARTCC can see traffic with raw data, radar reflection off plane, but it depends on coverage. Low sector and terrain may be not, but high up yes likely they can see raw data, meaning a plane with no transponder. If there is weather may be not?

Good news you will come down eventually Com or No Com /NORDO/.... No plane has ever been left up in the sky.

Yep, all good points George, I just thought it was funny my DPE said that because he sees a lot of people who forget about the VFR part when asked on a checkride thinking the examiner is looking for the full procedure.

 

[Dugaru]

I live by the saying IFR, Terrain, Night. Choose 1

Literally words to “live” by!