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)

http://img62.imageshack.us/img62/1376/axlp.jpg

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

Are you located in the US? How do you manage to fly from there to Cochin in a 737?:hmm:

Outbound track 281 when passing the VOR. Where is the confusion or problem?

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.

:ok:

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.....:uhoh:

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.

Agree. Instrument rated candidates from a certain 'sausage machine" flying school were being checked for basic instrument flying ability prior to being considered for a job. A 737 simulator was used. It was noticed that each one would deliberately fly for 15 seconds into the non-holding side of the holding pattern before turning to track parallel to the outbound leg of the holding pattern. Seems that was the way they had been taught by their flying instructors who themselves were just about as inexperienced as their students.

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.

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.

It´s a nice appch.
If you are for instance, FL 100 (max.hld.) you have time to descend to 3000 ft to intercept GS.

gameover:

What about the 185 max note on the chart?

185 kts is the max speed for the teardrop approach
 

Max holding speed is 220 kts as also listed on the chart.

- while, as you post, one should turn AT THE FIX, it is perhaps worth observing that the (ICAO) protected airspace extends 5nm outside the holding area.

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.

Sorry to rain on your parade, but if you are following PANS-OPS, you have to apply corrections for known wind: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.

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.