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brou0040 View Drop Down
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    Posted: 11 Dec 2014 at 11:16pm
OBS functionality is not totally clear to me and I'm not sure the sim is capable of testing this out because the OBS functionality is not simulated.

I was wondering how to add modified missed approach instructions that are issued that are different than the published.  Typically they start out with turn to heading xyz and climb to 1234 or climb to 1234 then turn to xyz then climb to 5678.  Maybe I'm thinking about this wrong, but I thought the way to do this would be to put the 540 into OBS mode at the MAP with an altitude restriction.  I'd like to add this to the flight plan prior to flying the approach.

It looks like once the MAP is the active waypoint, I could enter OBS mode and select the course, but OBS mode is not allowed insde the FAF.  It also looks like I can't add an OBS course as a future leg in the flight plan and that it can only be used with the current active waypoint.

Even if I could add an OBS course to the MAP in the flight plan, would it be a direct course from the MAP and not include the curve that is typically shown when changing course to account for the turn radius?  The instructions never say track xyz outbound from the MAP, they expect you to turn to xyz then maintain that heading.

What would be the best way to add modified missed approach instructions?
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oskrypuch View Drop Down
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You can't directly enter a heading + altitude restriction into the IFD540. But then, you can't enter that into a 737 FMS either.

You could create a user waypoint for a track to approximate a heading, and then set an altitude restriction, but strictly speaking that is not a heading. Further that would not sequence you to a second leg on achieving that altitude, but rather on reaching that waypoint. Getting all that set up during a busy approach phase doesn't seem ideal.

I would just set the heading bug, flick to heading mode after the MAP, use an altitude preset, and more than likely just fly it by hand. Sometimes dialing down the level of automation is the more efficient thing to do.


Semi-related, I sure hope we get our HEADING mode back in the IFD540 (HDG -> GPS/VLOC) for some release in the future, it was removed during the certification phase as it would have delayed cert. too much.

* Orest





Edited by oskrypuch - 12 Dec 2014 at 12:03am
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brou0040 View Drop Down
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Points: 720 		Post Options Post Options   Thanks (0) Thanks(0)   Quote brou0040 Quote  Post ReplyReply Direct Link To This Post Posted: 12 Dec 2014 at 12:37am
I was wondering if this was beyond what the 540 offered, but it seems like many of the components are there so it seemed like it could be possible, but I just haven't figure it out.  Not everything needs to be automated, but it would be easy to remember if it was dialed into the 540.

The figure on 2-12 sure looks like you can enter a heading with an altitude restriction.  Are those fields not modifiable?  I can't access these fields on the sim to test their behavior.

I was thinking that the main limitation is that you can't program the nav indicator to be dialed to a given course at some point in the future, it could only be set to it's current value, but headings are already available in published missed procedures so I'd think that somehow this could be programmed.

I guess it would be more similar to dialing in a heading as if you didn't have an external nav indicator integrated with the 540 and then adding an altitude restriction to create a leg similar to that shown at the top of 5-19.  Press the bottom right button to add a waypoint, press the OBS button to put it into OBS mode, dial the CDI knob to program the course, then add the altitude restriction.

Could this be a future feature?
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oskrypuch View Drop Down
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Points: 3061 		Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 12 Dec 2014 at 9:07am
Also, please note that altitude terminated segments (fly 320* to 1200 then ...) in departures are available on the IFD540, but these are as part of published data. 

You can't create these on the fly.

* Orest
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brou0040 View Drop Down
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Points: 720 		Post Options Post Options   Thanks (0) Thanks(0)   Quote brou0040 Quote  Post ReplyReply Direct Link To This Post Posted: 12 Dec 2014 at 3:33pm
Maybe not currently, but I don't see any limitation to why what I described could be a future feature candidate.  The unit has the knobs and buttons to be able to input the data and it is capable of flying these legs for the published missed/departures.
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brou0040 View Drop Down
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Points: 720 		Post Options Post Options   Thanks (0) Thanks(0)   Quote brou0040 Quote  Post ReplyReply Direct Link To This Post Posted: 27 Dec 2014 at 2:32am
Originally posted by oskrypuch oskrypuch wrote:

I would just set the heading bug, flick to heading mode after the MAP, use an altitude preset, and more than likely just fly it by hand. Sometimes dialing down the level of automation is the more efficient thing to do.

This defeats the purpose of having an FMS and flying the flight plan.  Since we all have different equipment, what works for you may not work for others.  I would venture a guess that most people don't have an autopilot with altitude preselect.  Also, I haven't totally figured out how this will work yet with a GPS, but I assume my AP will work the same as it does currently flying VORs.  My AP requires me to have my heading bug set to the intended heading when in NAV mode (Navomatic 300A) so I can't dial the heading bug to a heading for an alternate missed approach while still flying the final approach.

I know you said you'd more likely just fly it by hand and I don't disagree with dialing back automation, but I don't think this capability would increase automation at the expense of additional complication.  The same automation argument could be made for hand flying a hold, but the IFD540 was specifically designed to reduce single pilot IFR workload. Being able to add an entry or two to the flight plan prior to reaching the IAF before things get busy so that I have the proper guidance at the MAP, I think this is exactly inline with the design goals of the 540.


Edited by brou0040 - 27 Dec 2014 at 2:34am
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oskrypuch View Drop Down
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Points: 3061 		Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 27 Dec 2014 at 4:21pm
Well, perhaps it will be added as a candidate feature.

* Orest
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