Instrument Rating Drift Allowances???
Rather than flying a non-parallel outbound, you could just use a shallow bank angle turning outbound so that your parallel track is further away and allows for an easier intercept of the inbound.
b. execute a 180 turn in the direction specified , SO AS TO FLY
OUT-BOUND A TRACK PARALLEL TO THE INBOUND TRACK
OUT-BOUND A TRACK PARALLEL TO THE INBOUND TRACK
Aerocat S2A. Just watch the "shallow" bank angle theory. With some gyro systems running the weather radar and also ADI, any prolonged angle of bank less than six degrees can give rise to marked errors in the vertical gyro system. This shows as false ADI wings level and/or pitch attitude and in turn the weather radar stabilisation system will go ape and paint echoes only on one side or the other. Stick to minimim rate one turns and the gyros are happy.
Join Date: Feb 2000
Location: Gate 69
Posts: 210
Likes: 0
Received 0 Likes
on
0 Posts
Talk about ask a simple question….. 
If you are just doing your IR in a Be76, a
PA30 (god help you), or even a PA28, just use these: If you’re holding 10 degrees of drift to maintain inbound track, then hold 3 times (ie 30 degrees) outbound (1 min pattern) or 2 times (ie 20 degrees) outbound (2 min pattern). At the speeds you’ll be doing you won’t “stray” too far. 
As for your 80/260 problem try this one: If your outbound is 360, right turn 80/260, wind from the right, hold the heading of 080 for 1 second longer for each knot of x-wind. If the wind is from the left, start the turn back to the left 1 degree earlier for each knot of x-wind. You won’t be far out.
As for adding or subtracting seconds to the outbound try this: For each 10 knots of wind add or subtract 10 sec (head or tail). You’ll find the distance travelled is pretty close to what it would have been in nil wind. We are talking 100 to 120 knots here. If you want to get
add/subtract 10% for each 10 knots of wind. So a 1 min hold becomes 66 seconds. Works really well for a aircraft doing around 120kts and works regardless of the holding time. But really, who cares??? Just make some allowance, especially if you are pushing into a big headwind outbound, as you won’t be back on track when you cross the aid again. Which is a problem if you want to actually commence the approach and not just continue holding.
Another useful rule of thumb is: Half the x-wind to work out your drift. Say taking off and you want to maintain runway centreline (QDM 360), 10 knots from the right, turn onto a heading of 005, and you will be pretty close.
Like it has been said before, unless you want to go beyond Rate One (or 25o AOB), then correct for the drift. Unless the Checkie has a data-logger like we used to have on the ag machines (you got to love SatLoc), he isn’t going to be able to say you are not paralleling the inbound.
Now if the big jets do it so “right”, then tell me why does the FMS on my aircraft adjust the timing to give me 1.5 min inbound, and not outbound like the regs say?
Must admit leaving it in LNAV, and letting it do the work, is pretty cool. 
If you are just doing your IR in a Be76, a
PA30 (god help you), or even a PA28, just use these: If you’re holding 10 degrees of drift to maintain inbound track, then hold 3 times (ie 30 degrees) outbound (1 min pattern) or 2 times (ie 20 degrees) outbound (2 min pattern). At the speeds you’ll be doing you won’t “stray” too far. As for your 80/260 problem try this one: If your outbound is 360, right turn 80/260, wind from the right, hold the heading of 080 for 1 second longer for each knot of x-wind. If the wind is from the left, start the turn back to the left 1 degree earlier for each knot of x-wind. You won’t be far out.
As for adding or subtracting seconds to the outbound try this: For each 10 knots of wind add or subtract 10 sec (head or tail). You’ll find the distance travelled is pretty close to what it would have been in nil wind. We are talking 100 to 120 knots here. If you want to get
add/subtract 10% for each 10 knots of wind. So a 1 min hold becomes 66 seconds. Works really well for a aircraft doing around 120kts and works regardless of the holding time. But really, who cares??? Just make some allowance, especially if you are pushing into a big headwind outbound, as you won’t be back on track when you cross the aid again. Which is a problem if you want to actually commence the approach and not just continue holding.Another useful rule of thumb is: Half the x-wind to work out your drift. Say taking off and you want to maintain runway centreline (QDM 360), 10 knots from the right, turn onto a heading of 005, and you will be pretty close.
Like it has been said before, unless you want to go beyond Rate One (or 25o AOB), then correct for the drift. Unless the Checkie has a data-logger like we used to have on the ag machines (you got to love SatLoc), he isn’t going to be able to say you are not paralleling the inbound.
Now if the big jets do it so “right”, then tell me why does the FMS on my aircraft adjust the timing to give me 1.5 min inbound, and not outbound like the regs say?
Must admit leaving it in LNAV, and letting it do the work, is pretty cool.
Join Date: Feb 2000
Location: Euroland
Posts: 959
Likes: 0
Received 0 Likes
on
0 Posts
AerocatS2A
And exactly how do you work out what that bank angle should be?
Centaurus
Actually it isn't OK. Leaving aside for a minute the fact that the wording assumes still air, the rule for holds - in the rest of the world, anyway - is that you should regain the inbound track as soon as is practicable after turning inbound. As for straying outside the protected area, there is absolutely no chance of that happening if you fly a drift-corrected outbound leg which subsequently allows a rate one turn to place you back on the inbound track. If your guy believes that is not the case, he needs to have a look at the construction of a PANS OPS II hold. The clearance surfaces are well outside any possible deviation that is purely to correct drift. The holds (and the protected area around them) are designed with exactly this purpose in mind.
That, anyway, is true for PANS OPS II holds, which your government says it abides by for these purposes.
Having said that, it would be just like Australia to try and do it differently to the rest of the world...
And exactly how do you work out what that bank angle should be?
Centaurus
If you overshoot the inbound leg that's OK - just ensure you are back on track to the aid before reaching overhead. I also knew the bloke in DCA who confirmed multiple drift angle corrections was not on because of the danger of straying outside the protected area
That, anyway, is true for PANS OPS II holds, which your government says it abides by for these purposes.
Having said that, it would be just like Australia to try and do it differently to the rest of the world...
the rule for holds - in the rest of the world, anyway - is that you should regain the inbound track as soon as is practicable after turning inbound.
Aerocat and Centaurus are both on the right track (no pun intended) there is no mention that I can find of how wide a holding pattern should be. It is sensible to ensure that the outbound leg is far enough away from the inbound leg to give you a fighting chance of getting back on to the inbound track prior to the aid. Although as mentioned, this is not required as often once overhead the aid another different outbound track must be intercepted. Sure it makes you feel warm and fuzzy to be on track inbound to the aid prior to station passage and then turning to intercept the outbound but it is not required. Following a change to the wording in the mid 1990's the descent can be commenced once on an intercept heading rather than the previous requirement to be within five degrees.
I think the 'how wide' question is pretty straightforward - as wide as a rate 1 turn at the maximum speed for holding.
Naturally the designers will have allowed for any reasonable crosswind component when considering the protected area.
If the wind's blowing toward the inbound track then you'll overshoot it a bit on the inbound turn, but they will have allowed for that - so, fly rate 1 turns and allow only for know or forecast wind and you'll be complying with the regs, I reckon.
Naturally the designers will have allowed for any reasonable crosswind component when considering the protected area.
If the wind's blowing toward the inbound track then you'll overshoot it a bit on the inbound turn, but they will have allowed for that - so, fly rate 1 turns and allow only for know or forecast wind and you'll be complying with the regs, I reckon.
Join Date: Feb 2000
Location: Euroland
Posts: 959
Likes: 0
Received 0 Likes
on
0 Posts
Do you have a reference for that or is that just the way that you have always done it?
An interesting point comes from the UK AIP, which is based on the same PANS OPS criteria:
3.5 These procedures have been established in accordance with the ICAO PANS-OPS, except for those UK differences shown
at GEN 1.7. While certain specified allowances for wind effect have been made in determining the areas which will contain the various
procedures, it is emphasized that these Holding and Approach to Land procedures are based on still air conditions and in practice due
allowances must be made for wind.
at GEN 1.7. While certain specified allowances for wind effect have been made in determining the areas which will contain the various
procedures, it is emphasized that these Holding and Approach to Land procedures are based on still air conditions and in practice due
allowances must be made for wind.
It doesn't say HOW allowance should be made.
there is no mention that I can find of how wide a holding pattern should be. It is sensible to ensure that the outbound leg is far enough away from the inbound leg to give you a fighting chance of getting back on to the inbound track prior to the aid.
Can anyone please explain how a holding pattern with two (widely spaced) parallel tracks consumes less airspace than one with two divergent tracks? It DOESN'T. The only issue here is the point that you end up at, from where you commence your turn inbound. That point will be exactly the same whether you choose to use a divergent outbound track, or a lower rate turn when turning downwind. The difference is that you have a much greater chance of achieving the correct turn-in point by using a drift correction, that you do by trying to guesstimate a bank angle. More to the point, you will drift a lot further whilst carrying out a shallow turn downwind that you will if you just make a rate one turn and apply a drift correction.
Sure it makes you feel warm and fuzzy to be on track inbound to the aid prior to station passage and then turning to intercept the outbound but it is not required.
I am amazed that any pilot with any experience at all, could advocate not only being off-track, but not making an immediate attempt to regain it.
As the parallel-but-widely-spaced hold profile actually uses more airspace than the divergent method, I fail to see how it could possibly be safer - even if lateral protection was an issue, which it isn't at any promulgated holding speed or conceivable crosswind.
As I said before, the only important point (and the point that takes all the skill that a instrument pilot develops), is the point at which you commence your inbound turn. If you have done it properly, you will end up on your inbound track. If you haven't, you are now playing catch-up. That may be OK in Oz, but nobody else thinks like that. In fact, in two or three airlines I have worked for, that sort of thinking would get you a nice big "fail" against the holding item on the LPC check form.
Last edited by MOR; 15th Jun 2006 at 05:57.
Join Date: Mar 2006
Location: Sydney
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
why do people assume 25 degrees is the maximum bank angle allowed?
AIP ENR 1.5 p3.2.1 page 21
we are obviously not talking about a nil wind situation.
whether or not anyone thinks the AIP is wrong the fact is it says you must fly the outbound leg parallel to the inbound track. people who violate written procedures or regulations because they think their method is better are asking for trouble IMHO....
there are methods to help vary the AoB to be on TR when you roll out.
with 90 degrees to run, the RB should lead the TR by 10 degrees. with 45 to run, the RB should lead the TR by 5. you can check again at 30, 20 and 10, where the RB should be pretty close to the TR.
shouldn't people be using a similar method to ensure they roll out on track during the base turn of an NPA? if you don't, then you're not really very appreciative of the wind effect there either.
as to the wider holding patterns for faster aircraft, in cases where it matters wouldn't they have a higher minimum altitude for the hold for faster speeds, check the holding pattern at CCK on the Canberra plate.
to say that
is ridiculous in my opinion. the important point is to comply with the written procedures that you are required to comply with. in the absence of particular directions in your ops manual, it would have to be the AIP in this case wouldn't it?
AIP ENR 1.5 p3.2.1 page 21
All turns in nil wind should be at a bank angle of 25 degrees or Rate One.....
whether or not anyone thinks the AIP is wrong the fact is it says you must fly the outbound leg parallel to the inbound track. people who violate written procedures or regulations because they think their method is better are asking for trouble IMHO....
there are methods to help vary the AoB to be on TR when you roll out.
with 90 degrees to run, the RB should lead the TR by 10 degrees. with 45 to run, the RB should lead the TR by 5. you can check again at 30, 20 and 10, where the RB should be pretty close to the TR.
shouldn't people be using a similar method to ensure they roll out on track during the base turn of an NPA? if you don't, then you're not really very appreciative of the wind effect there either.
as to the wider holding patterns for faster aircraft, in cases where it matters wouldn't they have a higher minimum altitude for the hold for faster speeds, check the holding pattern at CCK on the Canberra plate.
to say that
the only important point (and the point that takes all the skill that a instrument pilot develops), is the point at which you commence your inbound turn
Last edited by wdn; 15th Jun 2006 at 07:46.
Join Date: Feb 2000
Location: Euroland
Posts: 959
Likes: 0
Received 0 Likes
on
0 Posts
why do people assume 25 degrees is the maximum bank angle allowed?
http://www.airservicesaustralia.com/.../enr/15739.pdf
it says you must fly the outbound leg parallel to the inbound track.
important point is to comply with the written procedures that you are required to comply with.
17.4.2 The pilot in command must, at all times, take positive action to regain
track as soon as a deviation from the correct track is recognised.
... which also applies to holding patterns, when half way round, after a parallel outbound leg in a crosswind, you suddenly realise you about to overshoot the inbound track by quite a lot...
but no, you just carry on with your slavish obedience to a misinterpretation of a single phrase...
Join Date: Jun 2001
Location: Australia
Posts: 889
Likes: 0
Received 0 Likes
on
0 Posts
Just one post I think...
This from the NZ AIP, which follows PANS-OPS quite closely these days.
Turns
3.3.6 All turns are to be made at a bank angle of 25°, or at a rate of 3° per second, whichever requires the lesser bank.
Wind Allowance
3.3.7 All procedures depict tracks and pilots should attempt to maintain track by making allowance for known wind by applying corrections both to heading and timing during entry and while flying in the holding pattern.
It seems clear to me that, in wind, you can either comply with 3.3.6 or 3.3.7, but not both. Some pilots prefer to obey the one and ignore the other, other pilots vice versa.
Isn't there a minimum five nm buffer between the nominal pattern and the nearest critical terrain? This would be enough to take account of single, double, triple drift variations would it not?
You must have quite a headache by now MOR, what with all that head-banging. Try this one instead
- it's easier.
Turns
3.3.6 All turns are to be made at a bank angle of 25°, or at a rate of 3° per second, whichever requires the lesser bank.
Wind Allowance
3.3.7 All procedures depict tracks and pilots should attempt to maintain track by making allowance for known wind by applying corrections both to heading and timing during entry and while flying in the holding pattern.
It seems clear to me that, in wind, you can either comply with 3.3.6 or 3.3.7, but not both. Some pilots prefer to obey the one and ignore the other, other pilots vice versa.
Isn't there a minimum five nm buffer between the nominal pattern and the nearest critical terrain? This would be enough to take account of single, double, triple drift variations would it not?
You must have quite a headache by now MOR, what with all that head-banging. Try this one instead
- it's easier.
Join Date: Feb 2000
Location: Euroland
Posts: 959
Likes: 0
Received 0 Likes
on
0 Posts
Yeah, really! I give up. The Ozmates can fly holds however they like, if they want to be different to the rest of the world, I suppose we shouldn't be surprised.
They'll look a pack of prize charlies trying it in non-Oz airspace though... you know, in countries where track-keeping and accuracy are important...!
They'll look a pack of prize charlies trying it in non-Oz airspace though... you know, in countries where track-keeping and accuracy are important...!
Nocivef, you won't get a question about drift in a holding pattern in your IREX. But you will most likely get taught a method such as holding 2 or 3 times the drift on the outbound leg in you flight training. If that is what you are taught, and that is what your testing officer expects, then that is what you do, regardless of the strict interpretation of the AIP.
Join Date: Jun 2003
Location: Awstraya
Posts: 197
Likes: 0
Received 0 Likes
on
0 Posts
MOR:
"Quote: why do people assume 25 degrees is the maximum bank angle allowed?
AIP ENR 1.22.1"
This refers to IAL procedures. IAL means Instrument Approach to Land, not Holding.
As the radius of turn for Class C & D aircraft is so much larger than the Class A & B aircraft most do their ratings in, then the rules of thumb outlined above will not not exceed the protected area. In holds above the area LSALT there is little practical problem anyway.
I've received few actual holds - and the majority of these have been requested by ATC based on GPSRNAV capability - unpublished random holds or unpublished holds based on a GPS Waypoint at altitudes and locations where "protected area" doesn't apply.
A great way to see how you go with holds is to borrow a portable GPS (e.g. GPSIII Pilot) which keeps a track log and fly a few entries/holds and NDB approaches and look at the shape of what you've done - very instructive!
"Quote: why do people assume 25 degrees is the maximum bank angle allowed?
AIP ENR 1.22.1"
This refers to IAL procedures. IAL means Instrument Approach to Land, not Holding.
As the radius of turn for Class C & D aircraft is so much larger than the Class A & B aircraft most do their ratings in, then the rules of thumb outlined above will not not exceed the protected area. In holds above the area LSALT there is little practical problem anyway.
I've received few actual holds - and the majority of these have been requested by ATC based on GPSRNAV capability - unpublished random holds or unpublished holds based on a GPS Waypoint at altitudes and locations where "protected area" doesn't apply.
A great way to see how you go with holds is to borrow a portable GPS (e.g. GPSIII Pilot) which keeps a track log and fly a few entries/holds and NDB approaches and look at the shape of what you've done - very instructive!
Join Date: Feb 2000
Location: Euroland
Posts: 959
Likes: 0
Received 0 Likes
on
0 Posts
This refers to IAL procedures.
I have had to hold virtually every day (at LHR, CDG, MAN and BHX usually).
Another point that nobody seems to get, is that if you fly a parallel outbound and accept that you will fly through the inbound as a result of a crosswind and the AoB limitation quoted above, two things happen. Firstly, you cannot possibly fly a parallel inbound leg, as you have to re-intercept it; and secondly, the amount (ie distance from the still-air track) you would have flown upwind to end up back on the inbound, is the same distance that you will end up displaced out the other side of the hold if you attempt to fly a parallel outbound leg. Think about it.
Crayon drawings available for those who still don't get it...
Originally Posted by MOR
Firstly, you cannot possibly fly a parallel inbound leg, as you have to re-intercept it; and secondly, the amount (ie distance from the still-air track) you would have flown upwind to end up back on the inbound, is the same distance that you will end up displaced out the other side of the hold if you attempt to fly a parallel outbound leg. Think about it.
Crayon drawings available for those who still don't get it...
Crayon drawings available for those who still don't get it...
Join Date: Jun 2003
Location: Awstraya
Posts: 197
Likes: 0
Received 0 Likes
on
0 Posts
MOR
Now we (nearly) agree: the correct reference for bank angle: 3.2.1.d.
novicef
For the purposes of your question, in an initial IFR issue or renewal in Australia in a cat A or B ACFT you shouldn't run into any significant problem using freek flyers pretty pic. For the purposes of flying a cat A or B ACFT generally you will not exceed the protected area using the methods described, either. For the faster stuff I bow to higher authorities on the forum.
Now we (nearly) agree: the correct reference for bank angle: 3.2.1.d.
novicef
For the purposes of your question, in an initial IFR issue or renewal in Australia in a cat A or B ACFT you shouldn't run into any significant problem using freek flyers pretty pic. For the purposes of flying a cat A or B ACFT generally you will not exceed the protected area using the methods described, either. For the faster stuff I bow to higher authorities on the forum.
Join Date: Feb 2000
Location: Euroland
Posts: 959
Likes: 0
Received 0 Likes
on
0 Posts
NOtimTAMs
OK I'll give you that one...
BTW why do they give you enroute holds, and not just a bit of speed control?
AerocatS2A
Yes it is semantics. However, if you have to spend time intercepting the inbound, and you only have a minute to do it, your actual track is not going to be parallel to the outbound, apart from the last bit!
OK I'll give you that one...
BTW why do they give you enroute holds, and not just a bit of speed control?
AerocatS2A
Yes it is semantics. However, if you have to spend time intercepting the inbound, and you only have a minute to do it, your actual track is not going to be parallel to the outbound, apart from the last bit!
Join Date: Mar 2000
Location: Melbourne, VIC, Australia
Posts: 73
Likes: 0
Received 0 Likes
on
0 Posts
This debate has been going on for many years... I once remember having it out with a Deputy CFI once (nicely of course)... I don't have an AIP with me to reference at the moment, from memory doesn't it state something along the lines of "Adjust outbound heading so that you can intercept the inbound track" my interpretation is that you don't necesarilly fly a parrallel outbound track, but thats just it, its all about interpretation of the rules... For instance I now fly cat D aircraft, holds are flown using a FMC. The FMC will reduce angle of bank on the outbound turn, thence fly a parrallel track followed by a 25 degree AOB turn to intercept the incound track, this is effecectively the same as 3x drift as it trakes you wider than the nil wind parrallel track...
And just to note, remember that you are in fact adjusting track INTO WIND, this coupled with the required hold speeds should always keep you inside the protected area...edit spelling
And just to note, remember that you are in fact adjusting track INTO WIND, this coupled with the required hold speeds should always keep you inside the protected area...edit spelling