On Monday, April 27, 2015 at 7:32:13 PM UTC-5, son_of_flubber wrote:
I understand that an AHRS, compared to a Truetrak, is going to produce more consistent results in the hands of a trained and current pilot.

Some definitions are in order:

AHRS stands for Attitude Heading Reference System. In the big expensive iron, it's the suite of expensive sensors (gyros, accelerometers, magnetic heading sensor) that provide data to the attitude displays.

Nowadays there are tons of inexpensive solidstate devices that have been developed for cars, RC helos, UAVs etc that can provide basically the same data: real time attitude (pitch, roll, yaw).

Using this data to drive a big, modern attitude display makes flying IMC a LOT easier, as it comes closer to "a window on the real world", instead of a pictorial representation of what your aircraft is doing. Old school instruments such as a turn and bank, turn coordinator, Tru-Track, or even a mechanical attitude indicator are really just mechanical ways to present attitude information, and require lots of training and practice to use safely. A good attitude display, on something like an Oudie or equivalent, would be easier to use, IMO. It would still need training to use, and it's really tough to simulate the feeling of vertigo that can result from flying in real IMC, but it would sure beat not having anything!


But will the AHRS require more training to use and stay current compared to the Truetrak? And not being a power pilot, I've zero experience with a panel mounted attitude indicator. My tactile attitude indicator is stick position fore-aft.

I would say the opposite. A modern glass cockpit attitude indicator is pretty intuitive, while a Trutrak is an old-school instrument. A PC simulator could be used to show how to interpret and use an attitude display - but if you have never flown under the hood or in real IMC that kind of training would be HIGHLY recommended! Vertigo is nothing to be sneezed at!


Seems like (after a few hours of IFR training) I could practice using the Truetrak and ASI in my routine VFR thermaling. And Kirk mentioned the desirability of a large AHRS display... I only have space for a 57mm display in my panel.

Forget the small instrument display - get a cheap PNA and have a big 5 in color display! That's what I want!

Seems like the Truetrak would be the clear best bet for me. The visual simplicity is intuitively appealing. Am I missing something?

Yes. Truetraks are meant to be backup, emergency instruments. My idea is to provide a modern attitude display, available instantly, on our pretty much ubiquitous moving map displays. Trust me, the difference is night and day! Or more likely, life or death!!

I understand that an IFR-rated pilot would want an AHRS in a glider, but that is not me.

Take some time to look at all the latest cockpit display coming out for airplanes - they are all going to big screen attitude displays - for a good reason! As far as cost, solid state AHRS sensors combined with a good display is cheaper and more reliable than ANY hardware attitude indicator, and provides so much more situational and attitude awareness that there is really no comparison. The only thing better is a wide angle HUD, but those get a bit heavy and use a lot of power ;^).

Cheers,

Kirk
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