ADF and Drift
Thread Starter
Join Date: Jan 2008
Location: Australia
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
ADF and Drift
Ive just started my IR, all was going very well in the sim untill the dreaded WIND came in! anyone got any rules of thumb or general hints for applying drift and keeping the needles where they are suppose to be.
thanks
thanks
Put the heading bug on the wind direction. Have the course bar on your required track. Pick a heading of half the wind speed +/- your track if the wind is within 45 degrees of your track, or if 90 degrees use the whole windspeed +/- your heading.
To adjust your course when tracking via the ADF/RMI drop the head of the needle onto your track or let the tail rise onto your track if tracking outbound.
If tracking via a VOR follow the command indications of the instrument.
On the outbound leg of a holding pattern double the wind speed as your heading adjustment. When turning inbound check if you are undershooting or overshooting at 45 degrees to the inbound track and adjust your turn as required.
Once you are switched on with instrument flying you just fly the dials and the tracking takes care of itself.
KISS
To adjust your course when tracking via the ADF/RMI drop the head of the needle onto your track or let the tail rise onto your track if tracking outbound.
If tracking via a VOR follow the command indications of the instrument.
On the outbound leg of a holding pattern double the wind speed as your heading adjustment. When turning inbound check if you are undershooting or overshooting at 45 degrees to the inbound track and adjust your turn as required.
Once you are switched on with instrument flying you just fly the dials and the tracking takes care of itself.
KISS
Guest
Posts: n/a
TGG's suggestions sound good
For drift, I generally use 1/2 if the wind component for drift angle if the wind is between 60 and 90 degrees left/right of my track, 1/3 for 30 to 60, and 1/4 for 0 to 30.
Double that drift angle outbound in the hold.
Wind will cause the head of the ADF needle to do opposite of what it normally does....if it's rising, wind is the issue.
For drift, I generally use 1/2 if the wind component for drift angle if the wind is between 60 and 90 degrees left/right of my track, 1/3 for 30 to 60, and 1/4 for 0 to 30.
Double that drift angle outbound in the hold.
Wind will cause the head of the ADF needle to do opposite of what it normally does....if it's rising, wind is the issue.
Join Date: Dec 2009
Location: Melbourne
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
wind from rough 30 deg- 1/5 wind strength= drift angle
45 deg- 1/3 wind strength= drift angle
90 deg- 1/2 wind strength= drift angle
examples-
with an abeam wind, take half of the wind speed and call it drift
-a 20kt abeam wind requires drift allowane of 10 deg
wind from 45 deg, use one third (round to the nearest 5 deg) call it drift
-a 20kt wind at 45 deg would require a dift allowance of 6 or 7 deg-call it 5 deg
you kind of get it. i dont know if that was the information you were after, but i hope it helps. then you will need to watch the needle. if it is falling left, you will need to turn left to intercept, or falling right, you will turn right to intercept. if you are holding those drift allowances i have stated, and its not working, you will need to adjust the drift more.
hope that helps and good luck on your instrument rating
45 deg- 1/3 wind strength= drift angle
90 deg- 1/2 wind strength= drift angle
examples-
with an abeam wind, take half of the wind speed and call it drift
-a 20kt abeam wind requires drift allowane of 10 deg
wind from 45 deg, use one third (round to the nearest 5 deg) call it drift
-a 20kt wind at 45 deg would require a dift allowance of 6 or 7 deg-call it 5 deg
you kind of get it. i dont know if that was the information you were after, but i hope it helps. then you will need to watch the needle. if it is falling left, you will need to turn left to intercept, or falling right, you will turn right to intercept. if you are holding those drift allowances i have stated, and its not working, you will need to adjust the drift more.
hope that helps and good luck on your instrument rating
Join Date: Jan 2010
Location: The place to be
Posts: 96
Likes: 0
Received 0 Likes
on
0 Posts
I'm with Roxy - shouldn't your instructor give you some help with this?
Of course it's wise to use the wealth of knowledge on PPRune.
Depending on how you memorise things, I find that remembering what public speakers might call subheadings is a better way to regurg material you need in the heat of the moment. Eg - figures might be 30, 60, 90 and you will know which wind speed ratio it pertains to.
Furthermore, try different methods as everyones memory recall is different!
Of course it's wise to use the wealth of knowledge on PPRune.
Depending on how you memorise things, I find that remembering what public speakers might call subheadings is a better way to regurg material you need in the heat of the moment. Eg - figures might be 30, 60, 90 and you will know which wind speed ratio it pertains to.
Furthermore, try different methods as everyones memory recall is different!
Yeah these days I don't even calculate the heading, I just do what is required to maintain the correct tracking.
As long as you know where the wind is coming from you have a rough idea where to point the nose. Most of the time the wind is different at a few thousand feet up to what the AWIS is indicating anyway.
As long as you know where the wind is coming from you have a rough idea where to point the nose. Most of the time the wind is different at a few thousand feet up to what the AWIS is indicating anyway.
Just to throw another one into the mix, try holding 3x the drift outbound in a 1 minute holding pattern, 2x the drift in a 2 minute pattern and 1x drift for a three minute pattern. May seem excessive, but it will allow for the wind effects during the inbound turn. For the 3 minute pattern you will be far enough out to easily regain and maintain the inbound track by the aid.
For a 1 minute pattern the needle should be leading the bug by 10 deg (080RB) at 90deg to go inbound and should have reduced to 5 deg lead (040 RB) by 45deg to go. (Yes I know... right hand turns, mirror for left turns)
Definitely agree this sort of thing is what you SHOULD be getting taught by your training provider.
Get onto a java program on the net (free) called Tim's navaid trainer. Fantastic for practising these techniques to see what works.
For a 1 minute pattern the needle should be leading the bug by 10 deg (080RB) at 90deg to go inbound and should have reduced to 5 deg lead (040 RB) by 45deg to go. (Yes I know... right hand turns, mirror for left turns)
Definitely agree this sort of thing is what you SHOULD be getting taught by your training provider.
Get onto a java program on the net (free) called Tim's navaid trainer. Fantastic for practising these techniques to see what works.
Join Date: Apr 2005
Location: Australia
Posts: 1,414
Likes: 0
Received 0 Likes
on
0 Posts
try holding 3x the drift outbound in a 1 minute holding pattern,
Some years ago, a CASA instrument approach chart designer published an article in the then CASA safety magazine which stated that adding or subtracting more than the required drift to parallel the inbound leg was incorrect and under some circumstances it could result in the aircraft going beyond the protected area surrounding the holding pattern.
With some aircraft where a change of configuration takes place half-way through the holding pattern (flap and speed changes for example) the drift angle may change. My understanding is the outbound leg should always parallel the inbound leg (normal single track drift allowance to maintain parallel) and the turn towards the inbound leg adjusted by squaring if heading into wind or increasing to an appropriate angle of bank if a tailwind. There is no chart requirement to have a steady rate one turn angle of bank from outbound to inbound legs.
Join Date: Dec 2000
Location: On the equator
Posts: 1,291
Likes: 0
Received 0 Likes
on
0 Posts
Tim's Air Navigation Simulator
You can set the wind vector by simply pressing the 'W' key and then dragging your mouse over the area where the airplane flies.
Another good tool to use is RANT XL. Although it's rather expensive, there is a free demo that works for a few minutes .. probably enough time to do a 1 minute holding pattern just to see how the wind affects your flight path with the above 'rules of thumb'.
You can download the RANT XL demo from here;
Oddsoft Ltd
..and if I remember correctly, RANT also simulates the annoying ADF Dip error as well.
Originally Posted by The Green Goblin
Yeah these days I don't even calculate the heading, I just do what is required to maintain the correct tracking.
As long as you know where the wind is coming from you have a rough idea where to point the nose. Most of the time the wind is different at a few thousand feet up to what the AWIS is indicating anyway.
As long as you know where the wind is coming from you have a rough idea where to point the nose. Most of the time the wind is different at a few thousand feet up to what the AWIS is indicating anyway.
Brendan,
The rules of thumb will help for a bit, but you will probably find after a bit that yoyu can judge it. Good luck with it! TGG's tips are gold.
j3
The rules of thumb will help for a bit, but you will probably find after a bit that yoyu can judge it. Good luck with it! TGG's tips are gold.
j3
The rules of thumb give you an initial heading to try, after which you need to adjust as required. The "suck it and see" method is really just the same except that the initial heading is derived from experience (pulled out of back passage.) Either way, as long as you make positive corrections in the right direction it should work pretty well. You'll often find that there are wind changes on the descent so the drift correction that worked at 5000' over the top heading outbound, might not work at 2500' heading inbound.
Folks,
It would be a good idea to actually read the rules for a holding patter, and consequently the actual shape of the obstacle protected area -- and the design rules for flying to remain inside --- PANS/RAC Doc.8136 from memory, in the Jepp. "100s" pages???
I well remember the CASA article alluded to in one post, the author could have seriously benefited from doing his homework before he wrote the article.
When you do your homework, you will find that there is no way (short of grossly exceeding maximum holding IAS) that applying the "traditional" drift corrections outbound (three times for one minute, two for a two minute pattern - because of the relative effects of the drift in the two turns --- versus the time outbound) will get you into trouble with cumulus granitis.
What he was trying to say is that procedure design does not require drift correction to stay withing the protected area.
As some of you will be aware, we have had several recent incidents, where a pilot had tried to track the pretty little "racetrack" on their screen (not required) with some interesting results, when the bank angle limit was overridden to try and stay on the pink ( Sorry, "magenta") line in the turn.
I gather it got a tad exciting for a few minutes, the stick shaker is not really supposed to be a early morning wakeup alarm.
Tootle pip!!
It would be a good idea to actually read the rules for a holding patter, and consequently the actual shape of the obstacle protected area -- and the design rules for flying to remain inside --- PANS/RAC Doc.8136 from memory, in the Jepp. "100s" pages???
I well remember the CASA article alluded to in one post, the author could have seriously benefited from doing his homework before he wrote the article.
When you do your homework, you will find that there is no way (short of grossly exceeding maximum holding IAS) that applying the "traditional" drift corrections outbound (three times for one minute, two for a two minute pattern - because of the relative effects of the drift in the two turns --- versus the time outbound) will get you into trouble with cumulus granitis.
What he was trying to say is that procedure design does not require drift correction to stay withing the protected area.
As some of you will be aware, we have had several recent incidents, where a pilot had tried to track the pretty little "racetrack" on their screen (not required) with some interesting results, when the bank angle limit was overridden to try and stay on the pink ( Sorry, "magenta") line in the turn.
I gather it got a tad exciting for a few minutes, the stick shaker is not really supposed to be a early morning wakeup alarm.
Tootle pip!!
Last edited by LeadSled; 27th Feb 2010 at 06:55.
Join Date: Jul 2007
Location: I fly because it releases my mind from the tyranny of petty things
Age: 52
Posts: 187
Likes: 0
Received 0 Likes
on
0 Posts
So what you are trying to say Leadsled is that you do not need to apply wind correction in the hold? Is that what you are saying?
av8etc,
All I am saying is: Go read the rules, the actual rules, not some training course notes
As Sgt. Joe Friday would have said:"The facts, man, just the facts".
Tootle pip!!
PS1: Hint: The "racetrack" is a charting depiction of a holding pattern, not a track to fly.
PS2: FTDK: Amazing, for once I agree with you.
All I am saying is: Go read the rules, the actual rules, not some training course notes
As Sgt. Joe Friday would have said:"The facts, man, just the facts".
Tootle pip!!
PS1: Hint: The "racetrack" is a charting depiction of a holding pattern, not a track to fly.
PS2: FTDK: Amazing, for once I agree with you.
Last edited by LeadSled; 27th Feb 2010 at 07:08.
Yeah, don't worry. Apparently you can't catch some things twice.
Seriously, how much of a "protected area" are we talking about and how far out are you actually going to end up?
You can expect circling outside the specified circling area to result in CFIT, but are holding patterns set up below terrain? What about 10nm MSA if holding over the aid?
If a Cat D/E can safely operate within the specified holding pattern, I'm sure a Cat A/B is going to have to be pretty far out of whack to be in trouble.
Seriously, how much of a "protected area" are we talking about and how far out are you actually going to end up?
You can expect circling outside the specified circling area to result in CFIT, but are holding patterns set up below terrain? What about 10nm MSA if holding over the aid?
If a Cat D/E can safely operate within the specified holding pattern, I'm sure a Cat A/B is going to have to be pretty far out of whack to be in trouble.
Join Date: May 2006
Location: Canberra
Posts: 71
Likes: 0
Received 0 Likes
on
0 Posts
Firstly find x wind component.
90 deg off track take all of it
60 deg = all of it
45 deg = 3/4
30 deg = 1/2
then...Drift angle = component / groundspeed in nm per min
This is the standard mental dead reckoning (MDR) technique taught to RAAF trainee pilots (for what it's worth)
90 deg off track take all of it
60 deg = all of it
45 deg = 3/4
30 deg = 1/2
then...Drift angle = component / groundspeed in nm per min
This is the standard mental dead reckoning (MDR) technique taught to RAAF trainee pilots (for what it's worth)