Getting rid of the vacuum pump , and Garmin G5

Why not just get one of those portable dynon things?

Certainly cheaper

Alex

You can certainly do that and simply replace the Attitude indicator with a G5 and use a portable Dynon as backup.However I am.not sure if a fully installed backup horizon is not required in any efis install for IFR. Another question will also be if the G5 can deal with the Flight Director signal off the Autopilot. I think it should but it’s worth investigating.

Alex, if you have a TB20 you most likely have a KI256 vacuum AI, and a Kind autopilot which uses the KI256 as an attitude source.

If you search here for “vacuum” you will find a few bits which may be of interest. If the G5 can emulate the KI256 as a pitch and roll source certified for the job, that is new and I would like to know about it. Otherwise, the only solutions are as they have always been for years

• G500+GAD43
• G600
• EFD1000+EA100

The Sandel EHSI is not relevant to this issue.

Peter wrote:

Unfortunately there is a fair bit of detail involved in this and I wish I knew it all.

The IM for the G5 can be downloaded from Garmin’s web site and it has quite a lot of information about connectivity options.

Mooney_Driver wrote:

Another question will also be if the G5 can deal with the Flight Director signal off the Autopilot.

It can’t. From the G5 IM: “[The G5] cannot replace a primary attitude indicator that includes a flight director or is part of an
autopilot system (an existing attitude indicator in the primary location that is part of an autopilot but without flight director may be moved to the turn coordinator location and a G5 installed in the primary location)”

Neil wrote:

G5 or Aspen will do the job.

The Aspen solutions currently fall on their face (stop indicating attitude) with loss of air data (e.g. a blocked pitot). This is documented in the Aspen documentation, and one reason Aspens need another AI as backup. (Maybe the backup is only legally required for IFR, not sure.) At Friedrichshafen, their representative told me that by the end of the year, there would be a software upgrade so that they fall on their face only on loss of air data and GPS (like the Garmin G500/600/1000 do).

I’ve looked into what it would take to get rid of my mechanical backup instruments (I have a Garmin G500 as primary instrument). Hereunder are my conclusions. Possibly all of those are acceptable as primary indicators, I didn’t specifically check. Also I have no info on the autopilot interface questions earlier on this thread.

• Mid-Continent MD302: falls on its face with loss of air data (and disqualified for this reason). Expensive.
• L3 Aviation ESI-500: Great package of features (attitude, HSI, ILS/LPV GS, synthetic vision with therrain and obstacles, TAS, OAT, …). Expensive. Enters “degraded mode” on air data loss; degraded mode specifications are less tight (more error) than with Sandia SAI-340, the static case is OK-ish, the dynamic one frankly scary if I have to hang my life on it. No turn rate / standard rate turn indicator.
• Sandia SAI-340 Quattro: Enters “degraded mode” on air data loss. Best performance in degraded mode. Needs significant warm-up time on ground when very cold-soaked (up to 15 min at -20°C). No navigation features (no HSI, no glideslope), no TAS/OAT, … No turn rate / standard rate turn indicator.
• Garmin G5: On the one hand, it will cease to function normally only on simultaneous GPS and air data loss, so it is more robust. On the other hand, what happens then is not tested by Garmin. Will it fall on its face (stop displaying attitude)? Will it show attitude with degraded accuracy? Garmin won’t tell. Also, is not yet a legal backup to Garmin G500/600 PFD, but is expected to become in the future. Has turn rate / standard rate turn indicator.

Note that for less than the price of an ESI-500, one can get both one Sandia SAI-340 and a Garmin G5. So if space on panel allows, I think that’s a good solution.

How much of my conclusions are transferable to use as primary instrument is your research to find out :)

lionel wrote:

Garmin G5: On the one hand, it will cease to function normally only on simultaneous GPS and air data loss, so it is more robust. On the other hand, what happens then is not tested by Garmin. Will it fall on its face (stop displaying attitude)?

I haven’t installed my G5 yet, but I have played with it on the bench and can confirm it does not need air data or GPS to display attitude. Upon power-up it says “ALIGNING” for a few seconds and then shows a fully functional AI.

lionel wrote:

* Garmin G5: On the one hand, it will cease to function normally only on simultaneous GPS and air data loss, so it is more robust.

Small correction: According to Garmin, the G5 enters “degraded mode” on GPS loss, while it still has air data. Which means it will function, but with less accuracy. That degraded mode is compliant with DO-334, but I don’t have exact figures on what this means, so cannot compare to the other ones in my list. Garmin wrote me that it is not tested whether DO-334 degraded mode requirements are met in the event of GPS and air data loss. To minimise GPS loss scenarios, Garmin suggested: dedicated GPS antenna for each G5 (in a dual installation), using the G5 internal GPS receiver instead of (or in addition to) relying on an external GNS/GTN. Which does nothing for the “GPS space segment not available or jammed” scenarios :)

Ultranomad wrote:

I haven’t installed my G5 yet, but I have played with it on the bench and can confirm it does not need air data or GPS to display attitude. Upon power-up it says “ALIGNING” for a few seconds and then shows a fully functional AI.

I assume that test is done in a situation where the G5’s internal GPS receiver cannot get a GPS signal?

lionel wrote:

L3 Aviation ESI-500: (…) Enters “degraded mode” on air data loss;

According to my notes, also enters degraded mode if you do tight turns for a long time: more than 35° bank (or pitch) for 3 minutes.