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All glass cockpit redundancy

But my take is that a loss blocked pitot tube means that you lose the AI.

Well found… this is going to surprise a lot of people

I have demonstrated to the satisfaction of several students (under the hood in VMC, I might add) that it is perfectly possible in extremis to get down to 200’ using SkyDemon, by locking onto the RoD from 500’ (where the glideslope goes off) to 200’. I wouldn’t recommend it to a VFR airfield (unless there really were no alternative) but if you are reduced to standby AI plus iPad, it would be a reasonable way into a low lying, flat airport with an ILS.

A far far better way is to carry a Yaesu 750 and then you can do it properly. Everybody flying anywhere for real should carry a handheld radio (and a handheld GPS, maybe a phone with a VFR moving map app) and this is the obvious choice. The 750 is really great; see my writeup on it. Anybody who can hand fly an ILS can hand fly an ILS with this thing. And the lithium battery lasts something well over a year – unlike the old “CAA approved” Icoms with their NICD batteries which are always flat when you pull them out of the bag, unless you recharge them every 1-2 months.

Administrator
Shoreham EGKA, United Kingdom

I have bought a separate battery pack for my Icom which takes AA batteries, which are dated to 2021.

EGKB Biggin Hill

I sent an e-mail question to the producer, just to be sure. I hope Dave Phillips will also share his source.

LPFR, Poland

I have bought a separate battery pack for my Icom which takes AA batteries, which are dated to 2021.

Yes; so did I. But the Yaesu is a no-brainer choice over the Icom. It does 8.33 too and it flies the real ILS using its properly surveyed and monitored radio signal, not some hacked glideslope which is likely to be hard work especially when under pressure.

Administrator
Shoreham EGKA, United Kingdom

Interesting that the GH-3100 Goodrich glass standby that appears in many Citations can lose pitot static instruments and attitude/heading continues to work.

EGTK Oxford

The successor GH-3900 instrument is described here: http://www.l3aviationproducts.com/products/gh-3900/#1466626132544-78bcfc6c-05ed

It appears that after 3 minutes of no airdata, it would show “CROSS CHECK ATTITUDE” but not turn off the AI. This is probably better than what Aspen and others do — immediately turn off the AI when they don’t like something. The AI will be subject to errors pretty quickly unless you fly straight and level for the majority of the time. How dangerous this condition would be is hard to say.

Vref wrote:

from a separate power generating source and NAV/COM radio

BTW As Peter, I also carry Yaesu 750 and I confirmed in real weather I can hand-fly ILS approach using it.

LDZA LDVA, Croatia

achimha wrote:

It appears that after 3 minutes of no airdata, it would show “CROSS CHECK ATTITUDE” but not turn off the AI. This is probably better than what Aspen and others do — immediately turn off the AI when they don’t like something. The AI will be subject to errors pretty quickly unless you fly straight and level for the majority of the time. How dangerous this condition would be is hard to say.

Let’s face it, the only circumstance when you will need the standby is when there is no other choice. A gradually erroneous standby AI is better than none.

Last Edited by JasonC at 25 Oct 12:11
EGTK Oxford

The battery driven mechanical AI has no such failure mode.

A total electric failure followed by an iced up pitot is a very valid scenario. The answers that the GA all-glass cockpits provide to that are not really great. I would be very worried about the Piper M600 with the Aspen backup instrument.

Air France 447 is partly caused by sensor failure and partial panel with the crew not understanding the fine details. GA pilots don’t understand it either. I have learned a lot from this thread (prompted by the Aspen failure) and so have most other readers I believe. It’s something that pilots and instructors should deal with.

Last Edited by achimha at 25 Oct 12:36

achimha wrote:

Air France 447 is partly caused by sensor failure and partial panel with the crew not understanding the fine details. GA pilots don’t understand it either. I have learned a lot from this thread (prompted by the Aspen failure) and so have most other readers I believe. It’s something that pilots and instructors should deal with.

To one of the other threads, it is exactly the sort of thing which is covered in type rating training at places like Flightsafety.

EGTK Oxford
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