Velocity Vector, a better way to fly IFR?

[B25Flyer]

I want to start a discussion about how we fly IFR. This is not about anybody's brand of box, only about how we should present information.

I have flown a Tru Trak EFIS prototype and I've had several conversations with Jim Younkin about the human machine interface of how we fly IFR. I am pondering an article for IFR magazine so I would like to hear some opinions on the subject.

For those who may not be aware, The TT system Displays GPS ground track instead of heading, and gyrostabilized instantanous VSI instead of pitch. I am not positive what the roll display is, I am not sure if it is bank angle or turn rate.

I don't care whether or not people agree with way the TT EFIS derives the information, only the human machine interface HMI.

TT is chasing the LSA market with this unit, and some pilots have a problem with the unconventional HMI. Lets call it the velocity vector or VVHMI

If the LSA market is VFR only, then the reason for an EFIS in an LSA is to resolve an inadvertant IFR encounter. If that is the reason then the logical question is, which HMI would most likely result in a successful outcome.

I mentioned that I have flown the unit, and I can say without any doubt that a VFR only pilot could more easily fly IMC with VVHMI.

Some units no display both VV and traditional information. The military jets use VV information. ATC could start the trend by doing something as simple as adding a new word to their glossary, TRACK. Instead of "Fly Heading XXX" the could tell /G airplanes to "Track XXX" That would be a great first step.

Anyone with an EFIS hand flying the approach puts the track carrot in the course notch and the needle stays in the middle. Why not have the Track as the primary display with the mag heading as a carrot?

Same with pitch, AOA or a secondary indicator for actual pitch with IVSI as the primary indication. Isn't that what we really care about?

With that background, the question is this, If the VVHMI is easier to fly for a VFR pilot, why don't we abandon the traditional heading, and Pitch HMI and begin a transition to a VVHMI on all makes of EFISes?

For the record, I can argue both sides of some aspects of this argument, but with the proliferation of GPS and EFIS, flying the the old HMI just because we always have, is not a good enough answer.

Tailwinds,
Doug Rozendaal
F-1 EVO with traditional HMI

[John Collier]

Doug,
I do not have any experience with the new VV EFIS systems but I do fly with a HUD velocity vector in the Air Force and I wouldn't want to give it up. In my opinion, it rapidly speeds up your instrument crosscheck. Set the VV level and cross check the VVI and Altimeter - done. Want to set 3 degrees on an ILS...set three degrees on the VV and cross check - you are now descending on a 3 degree glidepath and 300ft per mile. I agree that a VV would benefit a VFR pilot who encounters IFR.

Two caveats:
1) I do not rely exclusively on the VV...I also cross-check a standard attitude indicator in the process. I would consider it very poor form to only have a VV type instrument with no backup. I'm not sure about FAR requirements here...maybe others can address this? In your scenario, what happens if the required GPS goes TU?
2) Its easy to become reliant on the technology and lose basic skills. Similar to turning off a GPS and trying to read a map, turning off your VV and forcing yourself to fly standard instruments (or just maneuver VFR) can be a humbling experience for someone "addicted" to a VV - ask me how I know

I'm tossing around the idea of having a Dynon EFIS and a Tru-trak in my RV8...so thanks for the thread and I look forward to your article.

[penguin]

Doug,

About the same time I was going through my basic instrument training during my private I also got to fly a military avionics development simulator regularly at work. I found the VV presentation completely intuitive to fly with very little training (put the VV where you want to go ...). I think Garmin et al have significantly missed a trick by simply replicating steam gauges on glass. Chelton and GRT, as well as Trutrak, seem to have thought about how to get the most out of the new technology. So I am a huge fan of the VV type presentation. As very few GA pilots have flown with a VV most are unlikely to realize what they are missing! Once the enlightened start to make VV based systems more prevalent their popularity will increase as more people understand the benefits its brings.

I have recently finished my IR (after many years of VFR only flying), the airplane I did most of my training in did not have a GPS. Transitioning into an IFR GPS equipped airplane made tracking localizers (and VOR radials) so much easier - intercept and get the needle centered, then make the track number the same as the inbound course - easy (right!), but certainly better than trying to guess the wind. As for glide slope, I had never thought how a VV could be of benefit until John pointed it out above.

IMHO a VV equipped system is the way ahead, once pilots brought up on steam gauges realize what they are missing everyone will want one.

Pete

[Ironflight]

Great topic Doug!

I have been flying with VV guidance for many years in a certain "Heavy Glider", and use it almost exclusively (with pitch/roll cross-check for situational awareness). In my RV, I have it on the GRT, and use it for approach guidance all the time, as well as for quickly nailing a level-off. I've flown experimental VV guidance systems in many different simulations, and they are all easier to fly than raw data.

I have flown the TT ADI quite a bit in Louise's -6, and find it equally as easy for nailing altitude. I'm not sure I'd want to be without a true attitude reference as a backup, but yup - VV is a far easier way to fly IFR, based on my experience.

Paul

[hevansrv7a]

I agree with Paul and the others that the indicator that shows what the aircraft is doing in three dimensional space without lag and without requiring the mental integration of a VSI to an AI is a big plus. That said, I still want to know the airplanes attitude. GRT has both at once if you turn on the appropriate indicators.

Both in reaching/holding altitude and in the synthetic approach (HITS), the path indicator is a wonderful thing. In the GRT it also shows where you are going while crabbed, with the airport drawn on the brown/lower side of the screen right where it is if you look out the window and can see it. I'm sure others have this, too, but I'm only familiar with the GRT.

I know I don't have to explain it to this crowd, but it does matter what the aircraft's attitude is especially when it does not agree with the path!

BTW - these features are very helpful in poor VMC, too.

[REHughes]

At its little functional heart, the TT is a Turn Coordinator with a VSI in the middle. It is a stretch to use the term Velocity Vector (or Flight Path Marker) when describing the VSI function, and indeed, even the term CDA (Climb-Dive Angle) is not appropriate since no angular information is available without integrating an airspeed term.

The TT roll display likewise does not yield angular information. A steady-heading sideslip with a wing down 20 degrees will result in a wings-level TT display.

This is not to say that the instrument is not useful. It is a better global information-processing display than a separate iVSI and Turn Needle or Coordinator, but the control capabilities are basically the same.

Doug raises some interesting points in terms of future training. As more and more people are exposed to VV systems, I would hope that training will emphasize the obvious benefits. One of the interesting results to come out of the polling of several groups of HUD-experienced Carrier pilots at PAX River concerned the utility and necessity of displaying raw pitch-angle data as a Waterline symbol in the HUD. Other than the obvious role in providing attitude information when the VV system failed, the only time when pilots envisioned a clear need for a raw pitch-angle reference was to initially set and hold the nose attitude at liftoff when carrying heavy high drag stores (like mines) on cat shots or land takeoffs until the VV and AOA settled down.

[B25Flyer]

First of all, I would like to say again, I am not interested in a discussion about TT ADI or EFIS. It is a discussion about choosing a different paradigm in instrument flying.

Experimental aircraft have been leading the charge in many areas, and I think the industry needs to have a discussion about what the HMI looks like in the future.

Jimmy Doolittle and Sperry developed a great system with the available technology, but I think we can, and it is time to do better...... What better place than all the new EFIS technology that is arriving in the EXP market.

I don't know what "better" means, it maybe synthetic vision coupled with Velocity vector, but again based on the synthetic vision systems I have seen, the pitch gets lost in teh pretty picture, the horizon is far below the center of the instrument and the perspective of pitch gets lost in the perception of altitude.

Tailwinds,
Doug

[Rainier Lamers]

Yes, your comments are on the money !
With our synthetic vision you "see" where you are going - but you are right, the vertical is difficult to do this way with any sort of meaning. I am very open to ideas and will be keenly watching this thread...

Of course I've been looking at how other systems try to do it - but to be honest, I don't really like any of them - there has to be a better way. Little abstract pointers and things don't do it for me. I'm stupid - I need the EFIS to be "loud and clear".

Rainier
CEO MGL Avionics

Originally Posted by B25Flyer

First of all, I would like to say again, I am not interested in a discussion about TT ADI or EFIS. It is a discussion about choosing a different paradigm in instrument flying.

Experimental aircraft have been leading the charge in many areas, and I think the industry needs to have a discussion about what the HMI looks like in the future.

Jimmy Doolittle and Sperry developed a great system with the available technology, but I think we can, and it is time to do better...... What better place than all the new EFIS technology that is arriving in the EXP market.

I don't know what "better" means, it maybe synthetic vision coupled with Velocity vector, but again based on the synthetic vision systems I have seen, the pitch gets lost in teh pretty picture, the horizon is far below the center of the instrument and the perspective of pitch gets lost in the perception of altitude.

Tailwinds,
Doug

[Steve Brown]

I have found flying the ground track based HSI on my GPS496 is much more intuitive and precise than flying a magnetic heading on a standard HSI.

Approaches & airways all want a ground track. ATC also wants a ground track, which is why they sometimes hunt for the right heading in strong winds.

Bottom line is than it is always better to know what direction you are going than what direction you wish you were going.

What I would like is GPS track merged with magnetic heading, such that below the velocity suitable for GPS track, magnetic heading took over (ground ops). That could be done in a relatively seamless way via software. Also, magnetic heading should seamlessly back up the GPS in case of failure.

As far as pitch I don't have a strong opinion yet. I have and ADI pilot I use for AP functions and I guess it provides a backup AI function. I'm going to try flying it a bit and see how it works.

I think some people get nervous betting their lives on GPS. Its important to remember the number of people who have bought the farm because of vacuum system failure in IFR. All systems can fail. The key to long life (IMO) as an IFR pilot is heterogeneous backup systems.

I have 2x Dynon D10s, both with backup batteries. One I use for everything but heading. The other configured as an HSI, one button away from being a backup AI.

The problem is that both units rely on the pitot system to make the AI work properly. I would strongly prefer that one or the other unit be configured to use GPS ground speed for AI solution rather than air speed.

If I have a pitot failure IMC, I'm going to have a very bad day. I don't know if the ADI pilot needs airspeed or directly reads rate of turn (If you know, let me know)

[AlexPeterson]

Sorry for being so dumb, but can someone describe how the VV is depicted on one or more of the systems? I've studied the displays shown on various manufacturers' websites, for example, but it doesn't jump out or maybe it isn't displayed.

I am very interested in the human/machine interface, and appreciate Doug's starting this thread.