HSI: Track up vs Heading up

[LEM]

I've never used a Track up oriented HSI.
I'm told it can be disorientating if you are not used to it.
When you turn to a heading in Heading mode, will you have the selected heading at 12 o'clock?
I don't understand:confused: :confused: :confused:

[Notso Fantastic]

Yes, the compass is bang on your heading with current heading bang on 12 o'clock. That's the way nature intended it! Never flown track up.

[LEM]

I agree, that's why I'm asking...
Check this page :
http://www.b737.org.uk/flightinsts.htm
You can notice a TRK UP HSI on a 737 classic.

[BOAC]

I cannot recall why the option is there - I was told once (Tempus fugit) but I'm sure there is a good reason and someone will offer it soon!

I'm confused enough as it is :p

[4Greens]

Heading is not at 12 the track is. It will only be at 12 if there is zero drift. Track makes instrument approach procedures extremely sensible, as track is what you are supposed to fly. Have never known anyone not like it. There is no disorientation.

[Notso Fantastic]

I see the confusion! I don't like it. To me, compasses are to tell you which way you are looking. Hence HDG. Tye explanation under 'Map Mode' explains that the diagram is to represent that some people may want an oddball representation of TRK up and it takes a software change to allow TRK up. I would give it no more thought. I shall have a play tonight on the 747-400 and see if it is possible to have it that way but I'm fairly certain it can't even be done (not that you would want to- you have a very effective white TRK line). I reckon that diagram is just to show you that it can be accomplished (with software changes). Give it no more thought other than to the option of HDG (True) (long overwater/polar flights) and HDG (Mag).

[KingoftheRoad]

bmi(baby) 737's are indeed 'track up', but their Airbus fleet is all 'hdg up'.

When converting from one to the other, nobody even thinks to mention it - you just set the hdg. req'd. & read the trk., or set the trk. and the hdg. is what it is, depending on the wind.

Much easier on the 'bus using the 'flight path vector', then you can fly any trk.you wish, and forget about the drift.,much more useful, v.clever.


Roger Miller.

[QAVION]

"I shall have a play tonight on the 747-400 and see if it is possible to have it that way but I'm fairly certain it can't even be done (not that you would want to- you have a very effective white TRK line). "

There is no pilot selection for this feature. It is, however, selectable through a combination of wiring (pin programming) and software changes on aircraft like the 747-400. Some simulators which are used by a number of airlines may allow this selection with a push of a button (not found in a normal aircraft).

Our 747-400 and 767 fleet has "TRACK UP" for whatever reason (perhaps because we are generally a long haul airline where most of the time we are following an LNAV track). Most airlines, I believe have a HDG UP display. KLM, I seem to remember, switched from one to the other.

Regards.
Q.

[john_tullamarine]

For the 733 etc, flying track up on the EHSI makes letdowns a doddle .. one does the normal brain strain nav solution guesswork and starts out with a best guess heading on the heading bug and the track display tells you the TMG ... corrections to track are a breeze and flying an ILS to the ground was never so easy ....

Being the dinosaur that I am, I resisted it for a while .. but it didn't take too long before the simplicity seduced me ...

At the end of the day it is still a preference sort of thing, subject to a particular operator's SOP directions, of course ...

[Intruder]

On our 744s the Nav Display is Track Up, but the compass card on the Primary Flight Display is Heading Up. Neither are selectable in the cockpit (only True/Magnetic is selectable).

As with virtually all airborne systems that have a couple primary options, there are good and bad points about either one.

When "following the magenta line" with an FMS, Track Up makes all kinds of sense, because you can reference the wind-corrected heading at a glance (it's at the top!). No mental gymnastics are required to manually fly a complicated Departure Procedure (SID), even without a Flight Director.

OTOH, the Heading Up display is a good quick reference in high crosswinds to get a mental picture of your drift, and subsequently align your eyeballs to find traffic or the approach lights.

[planecrazi]

In our fleet of A340's, only one has track up. This you cannot select and comes with the software. Others are all Hdg up. Unusual to have one black sheep in the fleet when they all come from the factory.
Track up:-green line in twelve o' clock position on ND with nose off centre due to drift. (if drfit)
Hdg up: Heading in twelve o' clock with green line running off centre due to drift.(if drift)

[Barbers Pole]

All our 733 are track up.. Once you get used to it hand flown dep/app's are a piece of p#ss. eg, "airbourne turn left trk 115" so take off roll left until the trk line says 115, no drift guess's req'd. :ok:

NDB app, "cross" the beacon turn the until the trk line is the same as the FNA crse check raw data on RMI :ok:

Holding patterns the same.

[LEM]

Yes, but I can imagine your track changes when the wind changes, so it's a half step forward.
The real one is on the 777, where you can select to command a certain track with the heading knob , which then becomes a true track knob .
Am I wrong? ;)

[Bundi Gap]

Generally Boeing aircraft have nav displays with track up and Airbus aircraft have NDs with heading up. I have flown both - once you get used to the different display methods they both seem to work ok.

[Notso Fantastic]

Seems to me all the advantages stated for 'Track-up' are on a 'Hdg-up' display too. On the 747-400 fit, with 'Hdg-up', you have a white track line which will usually be offset to the left or right (depending on drift) of your Hdg-up line. Therefore to fly approaches or go direct anywhere, just put the white line on the final approach line or place it on your direct-to position, and Bob's your uncle.
Compasses are meant to show where you are facing. Any nautical type will know that, and try and allow for drift (tide) mentally. 'Twas how it was meant to be. Track-up is a mite too clever for itself- for instance, when you stop taxiing, what does the compass display do? Does it swing out of control because essentially, by definition, you have no track and it is not telling you anything then, or does it default to something sensible-ie. Hdg-up? Breaking out of cloud near 2 airfields with similar runways, Hdg-up will immediately tell you which is the wrong one-Track-up could actually confuse you as the Runway nomination may not match the way the compass says you are Heading.

[dvt]

Track up is an excellent situation awareness tool. If you're proceeding direct, "screw the heading bug", simply roll out with your Track Line over you fix point. The drift is automatically killed. Can it get any easier?!

Hell, roll out on final and put your track line through the runway symbol and you're done with wind adjustments for a non-precision approach. Can it get any easier?! In heavy x-winds, in the weather, with your bug on runway heading you can train yourself to where to look for the runway when you pop out of the clouds. ie Your eyes need to go in the same direction you need to go to place the heading bug over the Track Line. This is why, I believe, Boeing has the heading bug jump to runway heading at LOC Capture. Their actually helping pilots out, by designing systems that think like like pilots. Can it get any easier?!

Also when manuevering for thunderstorms, simply displace your Track Line relative to the storm. It's a snap. The Track Line has range gates or tick marks that make displacement a no-brainer. You can use your fingers as dividers, or just WAG it. Can it get any easier?! It's a bit funny to watching former Airbus guys dogging T-storms with the heading bug. They're not clued into the fact that their Track Line is going directly through that big Red Cell up ahead. Look out the window and tell me what's wrong with this picture.