Determining WCA on the Garmin G1000
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Determining WCA on the Garmin G1000
Hi all
I'm really stuck with this and I would appreciate some help, this is an easy question if you have experience with the Garmin. I’m currently IFR training and was practising holds today with a 40 Knot crosswind. So obviously need to correct on the outbound leg.
My instructor was talking about doubling the WCA on the outbound leg, but I'm 100% not sure how to work it out when I'm looking at the instrument tbh.
I understand you can see the difference on the inbound leg when aligned on the CRS and fly the diamond, but I struggled to line up the A/C properly before the fix today and could not use that method to work out WCA for the outbound.
Help guys I'm back at it Monday 9am
I'm really stuck with this and I would appreciate some help, this is an easy question if you have experience with the Garmin. I’m currently IFR training and was practising holds today with a 40 Knot crosswind. So obviously need to correct on the outbound leg.
My instructor was talking about doubling the WCA on the outbound leg, but I'm 100% not sure how to work it out when I'm looking at the instrument tbh.
I understand you can see the difference on the inbound leg when aligned on the CRS and fly the diamond, but I struggled to line up the A/C properly before the fix today and could not use that method to work out WCA for the outbound.
Help guys I'm back at it Monday 9am
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Difference between track and heading = single drift
Fly single drift when you fly up the hold axis towards the beacon
Fly double drift when going outbound if the wind is from the non holding side (For example, hold axis is 360 degrees, this would wind be from the west, from the left)
Fly triple drift when going outbound if the wind is from the holding side
Your track on the G1000 is the magenta diamond on the pfd
Flying inbound to the beacon, adjust your heading so the blue nav aid needle is on the green course bar, i.e. on the hold axis, and the magenta diamond is on top of that. You have now found your single drift value aka the WCA. Mentally double or triple that value to come up with the heading you need to fly outbound on.
For example, let's say hold axis is 360 degrees, right hand hold, wind is 270/20 knots. You are flying directly to the beacon on the 360 QDM, bang on the hold axis, the needle is nicely aligned with the green course bar, the magenta track diamond is nicely aligned too.
20 knots crosswind from the left, at light aircraft speeds, basically gives max drift of 10 degrees.
The wind is 90 degrees off the hold axis so you use all of it. All crosswind, no head or tailwind.
So to maintain that nicely aligned hold axis, your WCA is going to be 10 degrees into wind. Which will be 350 degrees.
You're about to turn outbound over the beacon. Wind is from the non-holding side so double drift. Single is 10 so that's 20 degrees.
Recall that wind correction must be into wind. This is simple enough but is frequently an awkward concept to mentally calculate when your capacity is being squeezed in flight. You'll get there with practice.
With the hold axis being 360 degrees, that means the outbound track you want is 180 degrees.
With double drift, with the correction being applied into wind, that means you want an outbound heading of 200 degrees. So you'll turn past the outbound axis of due south 180 degrees, further to the right, to the south west, with the theory being that the crosswind from the west will not push you towards the east and thus miles out of the hold protection area because you've accounted for it by turning into it with the double drift.
Wind was all crosswind, so no time correction required, after 1 minute outbound you should be perfectly located, neither wide or narrow, ready to turn inbound directly on the hold axis, remembering to now hold single drift (350 degrees heading) inbound to the beacon again.
Is your instructor teaching you the gate method where at the 1 minute outbound point you should be at the imaginary 'gate', 30 degrees off the hold axis?
Holding is a flying technique that unfortunately can't be brute-forced. It has to click in your head. Once it does it will be easy but until it does it is a big capacity drain. Especially in those 40kt winds.
The golden rules with the G1000 are get the needle in the course bar and get the magenta diamond on top of that when tracking inbound, and to trust in the techniques like time correction and the curve of pursuit for parallel entries. Remember, it's not a problem to fly a hold and end up wide or narrow, you just correct for it with a heading change and will hopefully be spot on with the next lap. Once you've got single drift worked out you should be ok.
What will help you is to draw lots of diagrams on paper, make up various hold axis and wind scenarios and have a good think of what the EHSI should look like. Consider what changes you'd make to your outbound heading if you were hypothetically narrow or wide when turning inbound to the beacon, or at the gate if you're using that method.
If you have a USB joystick there are G1000 simulation products available you can practice at home with. Using Garmin's G1000 trainer at home, making myself deliberately wide and narrow to understand how the needles would then look, is how I got holding to click in my head.
Fly single drift when you fly up the hold axis towards the beacon
Fly double drift when going outbound if the wind is from the non holding side (For example, hold axis is 360 degrees, this would wind be from the west, from the left)
Fly triple drift when going outbound if the wind is from the holding side
Your track on the G1000 is the magenta diamond on the pfd
Flying inbound to the beacon, adjust your heading so the blue nav aid needle is on the green course bar, i.e. on the hold axis, and the magenta diamond is on top of that. You have now found your single drift value aka the WCA. Mentally double or triple that value to come up with the heading you need to fly outbound on.
For example, let's say hold axis is 360 degrees, right hand hold, wind is 270/20 knots. You are flying directly to the beacon on the 360 QDM, bang on the hold axis, the needle is nicely aligned with the green course bar, the magenta track diamond is nicely aligned too.
20 knots crosswind from the left, at light aircraft speeds, basically gives max drift of 10 degrees.
The wind is 90 degrees off the hold axis so you use all of it. All crosswind, no head or tailwind.
So to maintain that nicely aligned hold axis, your WCA is going to be 10 degrees into wind. Which will be 350 degrees.
You're about to turn outbound over the beacon. Wind is from the non-holding side so double drift. Single is 10 so that's 20 degrees.
Recall that wind correction must be into wind. This is simple enough but is frequently an awkward concept to mentally calculate when your capacity is being squeezed in flight. You'll get there with practice.
With the hold axis being 360 degrees, that means the outbound track you want is 180 degrees.
With double drift, with the correction being applied into wind, that means you want an outbound heading of 200 degrees. So you'll turn past the outbound axis of due south 180 degrees, further to the right, to the south west, with the theory being that the crosswind from the west will not push you towards the east and thus miles out of the hold protection area because you've accounted for it by turning into it with the double drift.
Wind was all crosswind, so no time correction required, after 1 minute outbound you should be perfectly located, neither wide or narrow, ready to turn inbound directly on the hold axis, remembering to now hold single drift (350 degrees heading) inbound to the beacon again.
Is your instructor teaching you the gate method where at the 1 minute outbound point you should be at the imaginary 'gate', 30 degrees off the hold axis?
Holding is a flying technique that unfortunately can't be brute-forced. It has to click in your head. Once it does it will be easy but until it does it is a big capacity drain. Especially in those 40kt winds.
The golden rules with the G1000 are get the needle in the course bar and get the magenta diamond on top of that when tracking inbound, and to trust in the techniques like time correction and the curve of pursuit for parallel entries. Remember, it's not a problem to fly a hold and end up wide or narrow, you just correct for it with a heading change and will hopefully be spot on with the next lap. Once you've got single drift worked out you should be ok.
What will help you is to draw lots of diagrams on paper, make up various hold axis and wind scenarios and have a good think of what the EHSI should look like. Consider what changes you'd make to your outbound heading if you were hypothetically narrow or wide when turning inbound to the beacon, or at the gate if you're using that method.
If you have a USB joystick there are G1000 simulation products available you can practice at home with. Using Garmin's G1000 trainer at home, making myself deliberately wide and narrow to understand how the needles would then look, is how I got holding to click in my head.
Last edited by tech log; 7th Jan 2017 at 01:40.
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Thank you for taking the time to reply with such a detailed and comprehensive answer, it's really cleared up my uncertain.
I 'get it' now and am looking forward to putting into practice on Monday.
My Instructor hasn't mentioned anything about gates yet, tbh I think he knew I was struggling as it was and didn't want to overload me even more.
I did a search on various sites to try and find the information I required before I posted this question and noticed the gate method being discussed. I will look into it
Thanks again I have nine hours of flying left before my ME/CPL/IR skill tests, so was concerned I would struggle, but feel less anxious now
I 'get it' now and am looking forward to putting into practice on Monday.
My Instructor hasn't mentioned anything about gates yet, tbh I think he knew I was struggling as it was and didn't want to overload me even more.
I did a search on various sites to try and find the information I required before I posted this question and noticed the gate method being discussed. I will look into it
Thanks again I have nine hours of flying left before my ME/CPL/IR skill tests, so was concerned I would struggle, but feel less anxious now
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This has really got me thinking about training on glass vs steam dials. Some of that went over my head as a steam gauges chap - and I suspect the opposite would also be true.
New world!
New world!
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Thinking about it all now I have such a lack of continuity in my instructors teachings, every one of them has a different method and it's confusing, the simulator instructor was useless and teaches different procedures when entering the hold to my current instructor, so I'm now having to change how I do things late on
When I ask a question it seems to annoy him, his reply is to look it up in the SOP's, but sometimes it's much easier to have a discussion about a particular aspect of an approach than read a couple of paragraphs in book.
I think he forgets I'm paying for him and the aircraft
When I ask a question it seems to annoy him
The only stupid question is the one that you didn't ask!
Great advice from tech log. I taught holding for 100s of hours (many years ago on steam gauges) and agree with pretty much everything he says.
I'm not sure what the modern test requirements are regarding timing, but you may need to remember that in the example given you will actually have a headwind component on the outbound leg. Heading 200 degrees with a wind from 270.
A small effect in this case but one which could be significant for larger correction angles.
Good luck, fly sensible steady headings and don't chase the needle too much!
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I had more Garmin issues today, couldn't remember how to setup the FP up on the PFD, specifically flight levels for certain points. Instructor wouldn't show me again" as I should know this".
He's really getting on my tits now, I'm on the verge of reminding him who is paying for him to be sat with me
I'm paying , he knows the system inside out and there's a unit right in front of us for him to demo on, what's is the problem ??
He's really getting on my tits now, I'm on the verge of reminding him who is paying for him to be sat with me
I'm paying , he knows the system inside out and there's a unit right in front of us for him to demo on, what's is the problem ??
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Do you mean you are using the VNAV function and inputting altitude/flight level constraints on flight plan waypoints?
The Garmin PC software might be able to help you with that. I'll just quickly reinstall it and see what Flight Plan functionality it has, and report back.
The Garmin PC software might be able to help you with that. I'll just quickly reinstall it and see what Flight Plan functionality it has, and report back.
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I had more Garmin issues today, couldn't remember how to setup the FP up on the PFD, specifically flight levels for certain points. Instructor wouldn't show me again" as I should know this".
He's really getting on my tits now, I'm on the verge of reminding him who is paying for him to be sat with me
I'm paying , he knows the system inside out and there's a unit right in front of us for him to demo on, what's is the problem ??
He's really getting on my tits now, I'm on the verge of reminding him who is paying for him to be sat with me
I'm paying , he knows the system inside out and there's a unit right in front of us for him to demo on, what's is the problem ??
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I had more Garmin issues today, couldn't remember how to setup the FP up on the PFD, specifically flight levels for certain points. Instructor wouldn't show me again" as I should know this".
He's really getting on my tits now, I'm on the verge of reminding him who is paying for him to be sat with me
I'm paying , he knows the system inside out and there's a unit right in front of us for him to demo on, what's is the problem ??
He's really getting on my tits now, I'm on the verge of reminding him who is paying for him to be sat with me
I'm paying , he knows the system inside out and there's a unit right in front of us for him to demo on, what's is the problem ??
Flying inbound to the beacon, adjust your heading so the blue nav aid needle is on the green course bar, i.e. on the hold axis, and the magenta diamond is on top of that. You have now found your single drift value aka the WCA. Mentally double or triple that value to come up with the heading you need to fly outbound on.
Using your example, outbound track 180:
Lubber line on 150, magenta diamond on 160, course pointer on 180 is spot on.
Lubber line on 160, magenta diamond on 170, course pointer on 180, turn (left) away from the course pointer.
Lubber line on 140, magenta diamond on 150, course pointer on 180, turn (right) towards the course pointer.
I wish I'd had a magenta diamond when I was learning to do this!
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Yes it does. Reports of an extremely aggressive and unhelpful sim instructor on the one hand, together with a CPL (Not IR) skill test being conducted in less than marginal VFR conditions in 40 minutes because the Examiner had a long way to travel, and was running out of time!! The test was written up as passed and the candidate told to annotate his log book for a much longer flight. May not be the same place, but sounds awfully similar........ Still, if you get the ticket so be it.
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Yes it does. Reports of an extremely aggressive and unhelpful sim instructor on the one hand, together with a CPL (Not IR) skill test being conducted in less than marginal VFR conditions in 40 minutes because the Examiner had a long way to travel, and was running out of time!! The test was written up as passed and the candidate told to annotate his log book for a much longer flight. May not be the same place, but sounds awfully similar........ Still, if you get the ticket so be it.
On the other hand I haven't heard or seen any short cuts on the tests, in fact it's strict regarding minima, procedures and attention to detail. The amount of information and regulations one is expected to know/understand are huge, it certainly not easy and it's continues to be very challenging in terms of knowledge and flying skills
