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allrounder99
31st Oct 2011, 10:04
To all pilots of jet aircraft, old and new.

Typically (scratch that, lets say exclusively) in ATC if we want to vector and aircraft, we give you a heading. Perhaps it is Turn left 5 degrees or fly heading 345 or whatever.

Small problem is, headings are just a guess. So in an ever increasing search for efficiency, it would be better from time to time,to have aircraft fly tracks, or is this just transfering the guesswork to the crew?

Will the FMS of your aircraft, auto compensate for wind and speed, and fly an accurate track?

Thanks.

atila_101
31st Oct 2011, 10:10
On Airbus, by pushing the "TRK/FPV" you are able to steer tracks rather than headings.

Type1106
31st Oct 2011, 10:54
If ATC said something along the lines of 'From present position fly track of *** until advised' it should not pose a problem for the FMS. These days there must be very few aircraft flying under IFR that do not have the ability to display wind/drift/groundspeed and, therefore, the ability to fly a given track. Whether you can connect this to the automatics, and do it quickly, will depend on the sophistication of the equipment.

Tu.114
31st Oct 2011, 12:06
The DH8 is one of the planes fitting Type1106s description. It has a FMS that is able to calculate tracks, winds aloft and all that. It also has a LNAV heading mode in which You enter the heading to be flown into the FMS and let it take care of this instead of using the heading bug (forbidden in a few, optional in most, compulsory in other cases).

But this mode does exactly that - it follows a heading without corrrecting for drift, let alone changing drift due to wind changes coming with altitude changes. While it would be possible to chase the track bug on the ND by using any of the heading modes, it would drastically increase workload in a situation not low on it by itself (approach or climb) and also possibly be a bit inaccurate.

What can be done (although it takes some serious FMS programming; I estimate 30 seconds at least) is leaving a fix on a designated track or intercepting a track from a fix to follow it.

A question for my understanding: I am not an ATCO, but I would expect a heading to work all right, as drift is pretty much the same for all aircraft at an altitude within a not-too-large area?

C212-100
31st Oct 2011, 12:53
The Bus does exactly what you want. We can fly a track as easily as we fly an heading. Just a push in a button before the track selection.

Waterskier
31st Oct 2011, 12:58
Last time I ran into this with a controller... he gave me direct to a waypoint just clear of the military airspace followed by direct destination. There's less confusion that way.

Tu.114
31st Oct 2011, 14:25
Allrounder,
thank You - that explanation makes perfect sense.

FlightPathOBN
31st Oct 2011, 14:46
its as simple as turning the dial.....

Mach Tuck
31st Oct 2011, 15:08
Depends on the aircraft manufacturer's brief to the FMS manufacturer.

I've flown different types both with Honeywell equipment and one of them will automatically fly a track, the other won't. The latter does display the track made good though so one could navigate a track but it'd require manual heading inputs to the autopilot.

MT

5LY
31st Oct 2011, 21:54
To give you a simple answer: yes for most modern a/c it's a simple button push to fly a track as opposed to a heading. No, it's no extra work!

Denti
1st Nov 2011, 06:43
737s can't fly a track directly, sure we see track and wind information but we only can follow a heading, not a track. We can of course twiddle the heading bug to follow a selected track, but that increases workload and one has to actively realize in which kind of ND configuration you fly on this particular plane, track up or heading up.

cosmo kramer
1st Nov 2011, 10:25
737 can fly a track automaticly, but it takes some fiddling.

You go to position page, copy the present position to the scratch pad, insert the position as the first waypoint on the legs page. Copy the new waypoint to the scratch pad, write the desired track after the waypoint and a forward slash and with an arbitrary distance (or if ATC will be so kind to inform for how many miles to maintain the track). Insert the scratch pad entry as a waypoint and you are good to go.
Takes 10 seconds if you are familiar with the way of doing it. It's a trick and not a documented procedure, hence not something everyone knows.

Denti
1st Nov 2011, 11:09
It is actually teached during type rating, but honestly not used on the line much, easier to fly the track using the heading bug.

However, not an easy way to fly tracks directly like for example on an airbus.

Crankshaft
1st Nov 2011, 13:52
Cosmo, I think that the fmc trick won't actually give you a constant track, but rather a great circle. If you fly it long enough you will see a slightly changing track reading on your ND.
A constant track will actually be a rhumb line.
For short distances it's probably good enough for ATC purposes, but it's still a different thing.

raraa
2nd Nov 2011, 20:18
Ive flown all of the A320-A330-A340 families and I can tell you its simply a push of a button from HDG/V-S to TRK/FPA which is what you asking. Ive had a controller in the Middle East ask me to fly a track around a prohibited area, it went like this:

ATC-Fly Track 270

Pilot-Confirm you mean heading 270?

ATC-Confirm you type is A319

Pilot-track 270 it is.

We had a good laugh that day especially when he reminded me to contact our handling on our second box to get our parking position, because it was some heavy season and if I don't remind them they will throw us in a remote area!

Capt Claret
2nd Nov 2011, 20:21
In the B717, toggle HDG/TRK selector to TRK, select desired track direction, pull.