Altitude Reference: Stratus 2 WAAS or Altimeter?

[3Dreaming]

Retired ATC here. If you are assigned a heading, you fly the heading. I wouldn't put too much stock in what a controller might say in a casual conversation.

You could get yourself into trouble. For example, say you were instructed to fly heading 270 and you cranked in 20 degrees of wind correction and flew 290. If a loss of required separation occurred and the controller asked what your heading was and you replied "290", you just earned a Pilot Deviation.

The debate is not over the heading assigned. The debate is over HOW to fly and maintain the heading assigned. If there is cross wind at the altitude being flown the 'ground track' will be different than the magnetic heading.

Guys that do not have glass and/or GPS may not have a way to readily fly a ground track to make sure the plane flys along the heading assigned.

And I am willing to bet that a lot of guys are not correcting for the wind. As was noted in the ATC conversation above. the controller admits that when pilots deviate from the headings assigned, they call and give them corrections.

Just because you have the ability to fly ground track instead of heading, and that is what you have been doing doesn't make it right.

[SportPilot]

.......

[BrianL99]

I'm reminded of the old saw ...

When you wrestle with a pig, you both come out smelling like $h_t and only the pig likes it.

[drseti]

As I've said already, each of us has expressed pretty much the same opinion, several times over. If that input hasn't been heard yet, it never will be. So, let's move on. If this thread is prolonged much longer, I'll be forced to lock it.

[Jack Tyler]

Except let's thank Charlie Tango and especially Bruce, in their last posts, for clarifying what I've always felt has been our failure to fully communicate the different contexts in which a 'heading' is flown.

Cecil, where are you based? Do you fly in/out of the LA Basin? Knowing that might help us picture your view of the world a bit better.

[CharlieTango]

As I've said already, each of us has expressed pretty much the same opinion, several times over. If that input hasn't been heard yet, it never will be. So, let's move on. If this thread is prolonged much longer, I'll be forced to lock it.

It would be a shame to put this to rest in a state where the anonymous lurker, trying to learn potentially comes away with the impression that there is ambiguity here. The claims made by CTLSi coupled with the cross post with answers by a controller could certainly accomplish that.

[drseti]

Locking a thread will not hide it, CharlieTango. It will just block further posts to it, keeping us from prolonging a pointless argument. But, I'm hoping that won't be necessary.

[CharlieTango]

If the argument appears unsettled (to the Lurker) and you lock the thread than erroneous safety information is disseminated.

CTLSi advocates protecting new pilots from erroneous safety info, he actually wants to be corrected, he's a bit challenging to convince though.

[FastEddieB]

Before it gets locked, one more observation.

I spent decades as an instrument instructor, preparing many pilots for their instrument checkrides - with a 100% pass rate, by the way.

During much of the training, I would serve as a "faux" air traffic controller, giving headings to intercept VOR and NDB courses, approach courses, or just to get us to and from the practice area.

My observation? I do not recall a single student ever doing anything other than simply flying my assigned headings to the best of his or her ability. Not one ever thought they should apply a wind correction angle to an assigned heading. Not one. Ever.

I wonder if the experiences of other instrument instructors here parallel mine.

Just putting that out there to reinforce how unusual this particular "misunderstanding" of a very simple concept is.

[3Dreaming]

I can see where the problem he is having is coming from. Most of us learned to fly in a time when you only had 1 or 2 heading sources. The magnetic compass and heading indicator. To figure a wind correction angle when given a heading to fly just wasn't going to happen.

I have a CTLS that is set up like a bunch of the new light sport aircraft. It has a Dynon D100/120 combo, a Garmin 496 GPS, and a autopilot. When you are setting in the cockpit you now have 4 places you can pick up a heading. The magnetic compass, the Dynon, the GPS, and the autopilot. The heading on the autopilot comes from the GPS. One aircraft I owned also had an ADI, attitude direction indicator. The headings displayed on the GPS, autopilot, and ADI are all GPS based headings. The GPS based headings will provide a heading with wind correction already built in, so there is no figuring.

The thing to remember is not all aircraft flying out there have all this new equipment. When a controller provides a heading he isn't thinking about whether you can fly a ground track or only a heading. The system was set up before pilots had the equipment to fly a ground track instead of a heading. When assigned a heading you should be flying a magnetic based heading and not a ground track, so you will fit in with all the other traffic that is out there.

[CharlieTango]

I can see where the problem he is having is coming from. Most of us learned to fly in a time when you only had 1 or 2 heading sources. The magnetic compass and heading indicator. To figure a wind correction angle when given a heading to fly just wasn't going to happen.

I have a CTLS that is set up like a bunch of the new light sport aircraft. It has a Dynon D100/120 combo, a Garmin 496 GPS, and a autopilot. When you are setting in the cockpit you now have 4 places you can pick up a heading. The magnetic compass, the Dynon, the GPS, and the autopilot. The heading on the autopilot comes from the GPS. One aircraft I owned also had an ADI, attitude direction indicator. The headings displayed on the GPS, autopilot, and ADI are all GPS based headings. The GPS based headings will provide a heading with wind correction already built in, so there is no figuring.

The thing to remember is not all aircraft flying out there have all this new equipment. When a controller provides a heading he isn't thinking about whether you can fly a ground track or only a heading. The system was set up before pilots had the equipment to fly a ground track instead of a heading. When assigned a heading you should be flying a magnetic based heading and not a ground track, so you will fit in with all the other traffic that is out there.

Are you sure? The source where headings are displayed should be your magnetometer not a dumb GPS.

I have heading reading out in a few places, Like on my Whiskey Compas, EFIS, HSI and 496. The 496 doesn't know actual heading but my other indications do. My Big GPS depicts crab angle because it uses the magnetometer too. On a windy day my course line on my 496 will be strait up and on my big GPS it will be at an angle.

[FastEddieB]

When you are setting in the cockpit you now have 4 places you can pick up a heading. The magnetic compass, the Dynon, the GPS, and the autopilot. The heading on the autopilot comes from the GPS.

Not so sure about the GPS (and maybe autopilot) and heading.

I don't believe my 496 has the ability to show heading. Proof of this is when you go the the E6B page. In order to calculate wind, one of the fields you have to input is HEADING. The other is IAS. Also OAT and altimeter setting, but that's for other calculations.

Admittedly, some of the more advanced glass may have a remote compass input. In that case it could show heading, but only that magnetically derived from the remote compass.

Edited to add: I see Charlie Tango visited some of the same ground. Hopefully my post just reinforces what he observed.

[FastEddieB]

Even on the relatively advanced (for the time) Avidyne PFD in the Cirrus, heading was sourced by a remote compass in the wing - NOT by either of the two Garmin 430's or any other gadgetry.

That heading is the 303 indicated below, and also on the faux HSI:



That, and only that, is the reference when assigned a heading.

As far as the autopilot, only the HEADING mode is relevant to this discussion. Obviously, if navigating to a waypoint, it will adjust the heading to achieve the desired ground track. But when being vectored, the autopilot needs to be in HEADING mode, with the heading bug set to whatever ATC assigns.

[MrMorden]

When you are setting in the cockpit you now have 4 places you can pick up a heading. The magnetic compass, the Dynon, the GPS, and the autopilot. The heading on the autopilot comes from the GPS.

Not so sure about the GPS (and maybe autopilot) and heading.

My autopilot definitely uses GPS for heading. I kept thinking my AP was having some error, as I would set a heading in the AP and it was close but never matched 100% what the EFIS showed. Then I noticed that the heading in the AP was DEAD ON the heading shown in my 496. That makes sense because there is an interface cable from the AP to 496 for nav data, but there is no need for a connection to the EFIS, though the GPS does talk to the EFIS to display the HSI, etc. It's certainly possible the GPS/AP is flying a ground track and not a heading.

The GPS and EFIS magnetometer are usually within 1°-3° of each other, but I have observed errors up to 6°. If I had to set a heading and wanted to use the AP, I'd set it in the AP then observe what the EFIS showed me and adjust the heading on the AP as needed to make the directed heading match the EFIS.

[3Dreaming]

OK, I guess the point I was trying to make didn't come across the way that I intended. Substitute direction for heading, and you will get the idea.
The point was in the old days you only had 1 or 2 places to pick up information, and now you might have as many as 5 different directions displayed on the panel.