EFB as sole approach option

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Rich
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EFB as sole approach option

Post by Rich »

I've been wondering over the years about fallback in IMC for total electrical system failure. Just how good could, say, Foreflight do in a pinch. Next time out I'll give it a try, with the assumption that all panel-mounted avionics are gone, as well as the AI and TC.

Here's the display I would be using.
IAP display.jpg
FF doesn't display a GS, but I should be able to execute the plain-jane LP approach. Note the display for the altitudes for the checkpoints right on the chart. They're quite readable in reality.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Tim H
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Re: EFB as sole approach option

Post by Tim H »

Years ago I acted as safety pilot while by buddy shot a practice instrument approach (in VMC conditions) using a Garmin handheld GPS (don't recall which model) as his sole reference. He actually did a reasonably good job and I believe he could have landed safely.
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Boatguy
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Re: EFB as sole approach option

Post by Boatguy »

Your scenario still has the standby AI, TC, airspeed and altimeter, correct? FF is just providing the moving map. In that scenario you've also notified ATC of your loss of nav instruments.

I normally have the plate displayed in FF during an approach and it shows my position in the plan view. But there is no CDI so no guarantee of staying in the LNAV lane. I don't trust the blue dot on the plate as a CDI.

It seems like it would really depend on the terrain and ceiling. Certainly FF would be useful for situational awareness, but I wouldn't use it for primary navigation on an approach if there were any other options. My DA40NG has about an hour of backup electricity before it becomes a glider. If I could get vectors to an airport with more friendly terrain and/or higher ceilings that was say half an hour away that would be my preference. Ideally an airport not in IMC, or a nice big military airport with precision approach radar. But upon arriving there, I might still have to use FF for the approach.
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chili4way
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Re: EFB as sole approach option

Post by chili4way »

I recall reading that Gary Reeves has his "ForeFlight IFR Mastery" students fly a practice approach under the hood using only ForeFlight, primarily as a demonstration of capability.
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Rich
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Re: EFB as sole approach option

Post by Rich »

Boatguy wrote: Tue Dec 08, 2020 10:07 pm Your scenario still has the standby AI, TC, airspeed and altimeter, correct? FF is just providing the moving map. In that scenario you've also notified ATC of your loss of nav instruments.

I normally have the plate displayed in FF during an approach and it shows my position in the plan view. But there is no CDI so no guarantee of staying in the LNAV lane. I don't trust the blue dot on the plate as a CDI.

It seems like it would really depend on the terrain and ceiling. Certainly FF would be useful for situational awareness, but I wouldn't use it for primary navigation on an approach if there were any other options. My DA40NG has about an hour of backup electricity before it becomes a glider. If I could get vectors to an airport with more friendly terrain and/or higher ceilings that was say half an hour away that would be my preference. Ideally an airport not in IMC, or a nice big military airport with precision approach radar. But upon arriving there, I might still have to use FF for the approach.
There is no standby AI or TC in my steam gauge plane and wouldn't have TC with loss of electrical system. But I still have AS, Alt, VS, as they are non-electric. I'm talking emergency use, here. The AHARS does provide CDI function and it reacts to the course you see on the moving map.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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dmloftus
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Re: EFB as sole approach option

Post by dmloftus »

I've tested Foreflight many times against the G1000 and KLN-94's in many C172's for IFR approaches. Foreflight is highly capable on an iPad with GPS, but beware many lower end iPad's do NOT have built in GPS unless they are cellular capable. Apple made a marketing decision not to include a GPS receiver in many of their base wifi models. So if you lose your GTX345R or other panel GPS source that is driving your Foreflight, your iPad will lose it's position when you lose your primary nav. Flying IFR, I like to have backups. I fly with an iPad Mini cellular model with native GPS plus a Stratus 2 to provide backup GPS, FIS-B weather, and AHRS. I'm also running Foreflight on my iPhone to backup the iPad Mini. I usually slave the iPad to the GTX345R via Bluetooth and have wifi connected to the Stratus 2. Belts and suspenders ;-) I am highly confident that I could execute a highly accurate approach to any normal airport if I lost primary nav, but I would be a bit more concerned trying to do it in someplace like Tahoe, etc. As most of you know, it's actually not legal to use your Foreflight as primary, but invaluable in an emergency.
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Rich
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Re: EFB as sole approach option

Post by Rich »

I should probably mention that there is a Stratus 3 in the mix. Normally AHRS is being driven by my 530W + Flightstream. But the Stratus is always running and FF will seamlessly start using that if necessary.

This scenario would likely be more than just an alternator failure. Something like smoke in the cockpit where I kill the master.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Rich
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Re: EFB as sole approach option

Post by Rich »

I also should mention this is an iPad Pro 11. The display you see is equivalent in size to 2 iPad minis side by side.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Rich
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Re: EFB as sole approach option

Post by Rich »

One other caution I need to resolve is the scale of the off-track error markings. In "real" GPS operations, the lateral scale gets tighter as you transition to the approach and even tighter as the approach progresses. An LP or LPV approach brings the scale down to 350 ft. either side. I suspect the CDI in FF might not behave this way.

Of course, it's an emergency, and as one gets closer the runway also comes into view in the synth vision, so lateral guidance gets augmented that way.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Rich
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Re: EFB as sole approach option

Post by Rich »

As I work through the nuances of this, something else came to mind - the loss of engine instruments in an electrical system failure.

To get a stabilized path in an instrument approach, I know that something like 11 inches MAP gets me pretty close to a 90 KIAS, 500 FPM descent, depending somewhat on weight. So just minor adjustments from there keeps things reasonably unexciting. It's also true I need to continue to move the throttle lever very slowly rearward during descent to maintain the same MAP and thus keep things constant. In this no-engine-instrument scenario I'd be guessing the whole way so I can expect to be chasing the airspeed and descent rate and things would be ragged. An example: The LNAV approach to RWY 28 here at S39 traverses about 4,300 vertical feet, so that throttle adjustment is not something to ignore.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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