Parallel Entry in hold
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Parallel Entry in hold
I am not sure about how parallel entry into hold is done in bigger aircrafts like 737 in raw data mode (VOR mode on Nav Display)
Take example of Cochin Intl Airport ILS-Z via overhead (as shown in attachment)
suppose aircraft is approaching overhead on radial 040. Now once overhead Do we turn right immediately or after certain time (like 15 seconds so that we parallel)? on heading 281 (+- wind correction) and then fly for one minute or less? Then fly direct to VOR following the VOR Bearing Pointer shown on ND. Then turn left overhead and enter out-bound. Fly for one minute. Thus continue hold. When cleared for approach on inbound leg approaching overhead arm VOR LOC and turn so that you proceed outbound on 101 radial.
Is there any thumb rule as to how many miles before overhead we need to turn to take care of aircraft momentum. Typically people follow 10% of Ground Speed. But my observation is it doesn't really work out every time
Take example of Cochin Intl Airport ILS-Z via overhead (as shown in attachment)
suppose aircraft is approaching overhead on radial 040. Now once overhead Do we turn right immediately or after certain time (like 15 seconds so that we parallel)? on heading 281 (+- wind correction) and then fly for one minute or less? Then fly direct to VOR following the VOR Bearing Pointer shown on ND. Then turn left overhead and enter out-bound. Fly for one minute. Thus continue hold. When cleared for approach on inbound leg approaching overhead arm VOR LOC and turn so that you proceed outbound on 101 radial.
Is there any thumb rule as to how many miles before overhead we need to turn to take care of aircraft momentum. Typically people follow 10% of Ground Speed. But my observation is it doesn't really work out every time
You don't want to delay the turn overhead to track outbound. Furthermore, you should TRACK, not simply fly a heading.
Otherwise, what often happens is that pilots 'lose the plot' as they turn inbound and end up holding on the wrong side of the station. Seen it not once, but dozens of times.
Otherwise, what often happens is that pilots 'lose the plot' as they turn inbound and end up holding on the wrong side of the station. Seen it not once, but dozens of times.
Outbound track 281 when passing the VOR. Where is the confusion or problem?
I know to some holding is an art form but, and I'll get flamed for this, IMHO there's sometimes a danger of trying to finesse it too much and in doing so miss the essentials...which are, fundamentally, that you need to stay in the holding area, hold in the correct sense, try to get the timing roughly right...and, err, that's it.....
In the Cochin case you're holding "at" the VOR, so wait until overhead then immediately turn to make good the outbound track..certainly don't delay otherwise there's a danger of putting yourself outside the holding area and/or as Mach has pointed out, utterly confusing yourself.
Last edited by wiggy; 2nd Aug 2013 at 08:39.
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In the Cochin case you're holding "at" the VOR, so wait until overhead then immediately turn to make good the outbound track..certainly don't delay otherwise there's a danger of putting yourself outside the holding area and/or as Mach has pointed out, utterly confusing yourself
When asked why the magic 15 seconds more or less at 90 degrees to the inbound leg of the holding pattern (Sector One entry or parallel entry), the reason given was that it was easier to intercept the inbound track of the holding pattern; thus avoiding the over-turn that was normally necessary with a parallel entry, to intercept the inbound track to the holding aid.
The fact they were operating in the non-holding airspace with its various ramifications, had never occurred to them. They simply accepted blindly what their instructors told them - which was naive of them.
Last edited by A37575; 2nd Aug 2013 at 12:35.
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You can check Doc 8168 (ICAO) so...,
1.2.1.2 Sector 1 procedure (parallel entry)
a) Overhead the fix, the aircraft is turned onto an outbound heading (to a track parallel to the inbound track) for
the appropriate period of time or distance; then
b) turned right onto the holding side to intercept the inbound track or to return to the fix.
...so, TIME, when wings are leveled and for a period dependening on wind.
...Bear in mind that 220 kt is max. so, you could reduce your speed for instance 210, 200, 190 (keeping clean configuration.)
...If you are not able to intercept the inbound track you MUST return to the fix.
Itīs a nice appch.
If you are for instance, FL 100 (max.hld.) you have time to descend to 3000 ft to intercept GS.
1.2.1.2 Sector 1 procedure (parallel entry)
a) Overhead the fix, the aircraft is turned onto an outbound heading (to a track parallel to the inbound track) for
the appropriate period of time or distance; then
b) turned right onto the holding side to intercept the inbound track or to return to the fix.
...so, TIME, when wings are leveled and for a period dependening on wind.
...Bear in mind that 220 kt is max. so, you could reduce your speed for instance 210, 200, 190 (keeping clean configuration.)
...If you are not able to intercept the inbound track you MUST return to the fix.
Itīs a nice appch.
If you are for instance, FL 100 (max.hld.) you have time to descend to 3000 ft to intercept GS.
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gameover:
What about the 185 max note on the chart?
...Bear in mind that 220 kt is max. so, you could reduce your speed for instance 210, 200, 190 (keeping clean configuration.)
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Originally Posted by A37575
The fact they were operating in the non-holding airspace with its various ramifications
Parallel entry doesn't *require* one to track the outbound but to hold a heading to parallel the outbound track, prior to turning inbound. Although, I agree, you're not likely to get into trouble if you intercept the reciprocal of the hold's inbound track prior to turning inbound. On reflection, I'm surprised that wasn't specified as the procedure when the procedure was originally designed, instead of the no-track-guidance parallel heading procedure.
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1.3.3 Allowance for known wind
[...] Pilots should attempt to maintain the track by making allowance for known wind by applying corrections both to heading and timing. This should be done during entry and while flying in the holding pattern.
(PANS-OPS, Volume I, Part I, Section 6, Chapter 1)
Edit: Sorry, Tinstaafl, I misunderstood your post. I just see you wrote "heading to parallel the outbound track". I thought you had suggested a heading parallel to the outbound track. Your parade is still fine.
[...] Pilots should attempt to maintain the track by making allowance for known wind by applying corrections both to heading and timing. This should be done during entry and while flying in the holding pattern.
(PANS-OPS, Volume I, Part I, Section 6, Chapter 1)
Last edited by hvogt; 3rd Aug 2013 at 08:48.
Well, in hindsight I could have written '...a heading to make good a track that parallels the reciprocal of the inbound track...' which would have been a bit clearer.