They give you a heading to make you fly a track. I only have (reliable) ground track info displayed in my plane and fly from a class C. I get vectors all the time and fly them as ground track vectors. I rarely get vector corrections like I hear other traffic get fairly often on windy days (on Sunday they even called out one guy's vector changes as required because of wind drift).

So do you ask to be given track vectors not heading vectors?

Nope. They say fly 240 and I turn to 240 ground track. I do have a compass but it's terribly inaccurate, so I consider it more decoration than anything else.

Pilots have always flown mag heading because there never used to be a ground track indicator in the cockpit. ATC had to give the pilots information they could usefully manage with the equipment in the aircraft. The national airspace system is anchored on the ground, and other than vectors for traffic, every turning instruction ATC gives you is based on ground track for them and converted (if necessary) for the pilots so they can use a magnetic compass.

ATC is calling for no-wind vectors, which are the same as ground track. They have to give you corrections if there's wind, since you can't correct yourself like you would an NDB or VOR, or even a magenta GPS line. If we all were able to fly ground track, it'd free up some of the controllers' time from having to look and see if they need to give the pilots a wind correction to the vectors they want the aircraft on.

I agree with your reasoning but unless the controller knows you are flying a track when he expected you to fly a heading you will not be going where he is expecting you to go.

Karmutzen wrote:....Do I really care where the aircraft is pointed or would I prefer my track over ground? Track is what counts, heading is something nominal always needing correction for wind drift, unreliable in the far north, always being massaged with forecasts, charts, as you struggle to determine track over ground. ....we were stuck with compasses, stabilized compasses, flux-valve ahrs, E6-B computers and little wind drift corrections, but now....

My point exactly.

mtv wrote:

hotrod180 wrote:

mtv wrote: It's worthy of note that the turn coordinator is not a required instrument for IFR certification. MTV

Check 91.205 instrument & equipment requirements
(d) IFR, (3) gyroscopic rate of turn indicator, and (4) slip/skid indicator.

Hmm, yep, you're right. That's changed in the last couple years. I obviously don't read the FARs as much as I used to.....

MTV

Keeping up with the FARs is a bitch! That, plus interpretations from the General Counsel's office and various ACs can change things significantly, too.

FWIW, AC 91-75 allows the T&B or TC to be removed and replaced with a backup AI. The requirement for a slip/skid indicator wasn't changed. The justification within the AC is that a backup AI will provide all of the necessary information that a T&B or TC can provide, and as long as its power source is different from the primary AI, it is therefore a safer alternative.

Of course, that's why the G5 configured as the only AI should have a backup battery--same reason I had my Quattro installed (STC'd to replace the AI), because it does away with the concerns of a failed vacuum pump and even a failed electrical system with its backup battery capable of running the AI for well more than long enough to get on the ground.

Cary

Cary wrote:....FWIW, AC 91-75 allows the T&B or TC to be removed and replaced with a backup AI. The requirement for a slip/skid indicator wasn't changed. The justification within the AC is that a backup AI will provide all of the necessary information that a T&B or TC can provide, and as long as its power source is different from the primary AI, it is therefore a safer alternative.....

I disagree with that rationale, an attitude indicator doesn't generally include a rate-of-turn indicator.
As in helping you make a standard rate (aka two-minute) turn.

hotrod180 wrote:

Cary wrote:....FWIW, AC 91-75 allows the T&B or TC to be removed and replaced with a backup AI. The requirement for a slip/skid indicator wasn't changed. The justification within the AC is that a backup AI will provide all of the necessary information that a T&B or TC can provide, and as long as its power source is different from the primary AI, it is therefore a safer alternative.....

I disagree with that rationale, an attitude indicator doesn't generally include a rate-of-turn indicator.
As in helping you make a standard rate (aka two-minute) turn.

On the other hand, in over 42 years of IR flying, I've never made a 2 minute/standard rate turn for real, only in periodic training, typically for partial panel purposes. Most of the time, I pretty much ignore the T&B (that's what my airplane has, probably OEM in the airplane, the only OEM gyro instrument remaining). So maybe their rationale is correct.

Cary

a3holerman wrote:I agree with your reasoning but unless the controller knows you are flying a track when he expected you to fly a heading you will not be going where he is expecting you to go.

I think they expect to see your ground track match your assigned vector, and then they check to see if they need to give you a wind drift correction - but I'm not a controller so that's just a educated guess based on my experience. Either way, I've never been given a vector adjustment when on long vectors. We have a few restricted areas here so it's not uncommon to get vectored around them once you get inside the C airspace.

Cary wrote:On the other hand, in over 42 years of IR flying, I've never made a 2 minute/standard rate turn for real, only in periodic training, typically for partial panel purposes. Most of the time, I pretty much ignore the T&B (that's what my airplane has, probably OEM in the airplane, the only OEM gyro instrument remaining). So maybe their rationale is correct.

Cary

That's true in my much lesser experience as well. A decent rule of thumb if you don't have a T&B (I don't) is 15% of your TAS in knots. Or you can do 10% and then half again the correction for easier mental math.

Ex: 120 kn TAS: 120*10%= 12, 12/2=6, 12+6=18 degrees for a standard rate turn.

CamTom12 wrote:I think they expect to see your ground track match your assigned vector, and then they check to see if they need to give you a wind drift correction - but I'm not a controller so that's just a educated guess based on my experience. Either way, I've never been given a vector adjustment when on long vectors. We have a few restricted areas here so it's not uncommon to get vectored around them once you get inside the C airspace.

ATC will issue vectors relative to magnetic heading, not track.

One role of air traffic control is to separate aircraft.

If a controller issues two aircraft (in the same relative air mass) the same heading vector and one flies the assigned heading and one flies the corresponding track, the two aircraft may actually be converging. The controller has no way of knowing which aircraft is complying with the heading vector, as all the controller can see on the scope is the wind affected ground track.

In your situation, while other aircraft may be receiving vector corrections and you are not, it could be that they are receiving those corrections because your airplane isn't going where the controller expects it to go based on similar heading vectors issued to the surrounding aircraft. The controller doesn't know, he or she is simply trying to keep the aircraft from coming together.

I've watched numerous pilots incorrectly set their magnetic DG to the GPS track while operating IFR. Depending on the relative bearing and velocity of the wind, the difference between the heading vector and track could be negligible, but a 90 degree turn could make it significant.

In practice, if you are receiving heading vectors, you should be flying those vectors with respect to magnetic heading. Let the controller sort out the track.

Slippery Wing wrote:

CamTom12 wrote:I think they expect to see your ground track match your assigned vector, and then they check to see if they need to give you a wind drift correction - but I'm not a controller so that's just a educated guess based on my experience. Either way, I've never been given a vector adjustment when on long vectors. We have a few restricted areas here so it's not uncommon to get vectored around them once you get inside the C airspace.

ATC will issue vectors relative to magnetic heading, not track.

One role of air traffic control is to separate aircraft.

If a controller issues two aircraft (in the same relative air mass) the same heading vector and one flies the assigned heading and one flies the corresponding track, the two aircraft may actually be converging. The controller has no way of knowing which aircraft is complying with the heading vector, as all the controller can see on the scope is the wind affected ground track.

In your situation, while other aircraft may be receiving vector corrections and you are not, it could be that they are receiving those corrections because your airplane isn't going where the controller expects it to go based on similar heading vectors issued to the surrounding aircraft. The controller doesn't know, he or she is simply trying to keep the aircraft from coming together.

I've watched numerous pilots incorrectly set their magnetic DG to the GPS track while operating IFR. Depending on the relative bearing and velocity of the wind, the difference between the heading vector and track could be negligible, but a 90 degree turn could make it significant.

In practice, if you are receiving heading vectors, you should be flying those vectors with respect to magnetic heading. Let the controller sort out the track.

That's fair.

I don't have an accurate compass except in one direction, thanks to my tube frame aircraft and terrible compass mounting location, so I'm stuck with ground track if I'm going to be any sort of precise. I'll get a hold of my departure controllers on the phone and ask them if I need to announce that I fly ground track for vectors.

To caveat your supposition about other aircraft getting vectored around me because I'm not heading where they think I should - my airplane is VFR only so I can see all the traffic around me. Most usually the guys getting vector corrections are nowhere near me (as in, on the other side of the airspace. Way far.), and the very few times I've seen it happen near me it's been a #1 / #2 aircraft on the same flight path (separated by lateral space, on the same path through the sky sort of thing). As in the other guy is in front of or behind me and we're getting vectors on the same path, but I don't get corrections. Weird.

CamTom12 wrote:
That's fair.

I don't have an accurate compass except in one direction, thanks to my tube frame aircraft and terrible compass mounting location, so I'm stuck with ground track if I'm going to be any sort of precise. I'll get a hold of my departure controllers on the phone and ask them if I need to announce that I fly ground track for vectors.

To caveat your supposition about other aircraft getting vectored around me because I'm not heading where they think I should - my airplane is VFR only so I can see all the traffic around me. Most usually the guys getting vector corrections are nowhere near me (as in, on the other side of the airspace. Way far.), and the very few times I've seen it happen near me it's been a #1 / #2 aircraft on the same flight path (separated by lateral space, on the same path through the sky sort of thing). As in the other guy is in front of or behind me and we're getting vectors on the same path, but I don't get corrections. Weird.

A traditional whisky compass can be adjusted to account for installation and other ferrous metal influences normally found in the airplane. The procedure to adjust the compass is relatively straight forward depending on the compass you have installed.

As an aside, FAR 23.1327 allows for up to 10 degrees of error in the compass compared to a known heading (i.e. reference a compass rose), and even more if there are electrical components that, when turned on, cause deviations greater than 10 degrees provided the correction is documented for those systems.

Regarding controller vectors, keep in mind they will also issue vectors if they need more lateral separation between airplanes. So two traffic targets could be tracking in parallel, but the controller needs more lateral separation between them. In that case they may issue the faster aircraft the vector correction because that aircraft can generate the separation needed in a shorter amount of time than the slower airplane.

I'll disengage now since this wasn't really the intended topic of this thread.

Back on the topic -- sort of...

A friend who is at Sun-N-Fun got one of the Garmin people aside at an "after hours" event, and was told that they are expecting to have the G5 DG/HSI approved to drive an autopilot (presumably their own from the experimental world) in the near future. He was told to look for it at AirVenture... Then the guy realized what he had said, and shut up without answering any more questions.

Here's hoping it's true!