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A320 MCDU "Sequence the flight plan" instead of DIR to?

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A320 MCDU "Sequence the flight plan" instead of DIR to?

Old 23rd Jul 2014, 08:47
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A320 MCDU "Sequence the flight plan" instead of DIR to?

Why do some pilots insist on sequencing the flight plan instead of a DIR to? I fly with some skippers who will quite happily tell me to manually clear 10 way points in busy airspace below transition knowing full well they are on a radar heading to intercept final. Only once have I ever been in a situation where after initially being given a radar heading I was told to go to another waypoint which I had just cleared. No big deal, just type it! 5 years flying the bus, I've still not managed to comprehend why you would do this as a rule. Can anybody offer me an alternative viewpoint?
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Old 23rd Jul 2014, 09:14
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Yup - the people who insist on this sort of activity will tell you that this sort of thing is illegal and you might be arrested by the Air Police on arrival. I believe it is due to a lack of confidence. The only real explanation for their reluctance to delete superfluous waypoints is that they'd like them to remain in the FMS "Just in case." My personal preference is to have a what I'm most likely to do punched into the box. If ATC add extra waypoints, we'll put those in on an "as and when basis".
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Old 23rd Jul 2014, 14:16
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I fly with some skippers who will quite happily tell me to manually clear 10 way points in busy airspace
Why not type the 11th way point in the scratch pad, place it on line 3L and clear line 2? You'll have PPos, discontinuity and your desired way point without engaging NAV.
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Old 23rd Jul 2014, 16:20
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I hear you, some people have been on the airplane for decades and still don't know how to use the mcdu to their advantage.
once on vectors it is most helpful to have track miles to touchdown to calculate an immaculate descent, and this is achieved by doing what goldenrivet suggests, though having PPOS will not give you accurate track miles, I'd have a From-To leg on the final approach course making sure the TO waypoint will be overflown (FAF) so typically ill have the FAF as the To way point and anything else on the centerline right behind it, you can also achieve this with a radial TO intercept to the FAF or equivalent.
just copy the active before you do this if you need to recall what was there.

and always ready to learn something new.
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Old 28th Jul 2014, 06:58
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A common action in our company (not SOP as far as I know), is to set the reciprocal radial in to the localiser on the DIR page, and then pull heading (so that it won't turn onto finals if you haven't been cleared yet) to get a good visual representation of the extended centreline. Of course this is only at the very end of the approach, and I'm quite happy to get rid of those superfluous waypoints at other times.
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Old 28th Jul 2014, 07:57
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In my company it's actually quite opposite.

'Do you want an extended centerline, sir?' (=you moron, how can you fly an ILS without extending the Airbus centerline!)

Ehh...now I don't!

But seriously, I think this is a case of 'give the guy what he wants' and be done with it. If he wants his waypoints, then that's the way it is. Maybe one of the waypoints passes over his grandma's house, or maybe he really does not expect straight in radar vectors, in which case an extended center line will give you way too optimistic track miles. The extended centerline has its merits, but it is not at all compulsory.
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Old 28th Jul 2014, 09:10
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PENKO
There is no function to extend the centre line in Airbus FMGS except if you select the RW only. This is a radial in function. It extends the radial. On some NPAs the RW heading and inbound final approach track is different and you need to extend the inbound track. Extend centre line is a misleading term. Some tend to think that it is done to help turn inbound and not to get NAV during GA. No Airbus document uses this term.
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Old 28th Jul 2014, 10:24
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What are you trying to say vilas?
Radial in, extended centreline...the end result is the same if you pull HDG
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Old 28th Jul 2014, 11:26
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Not when inbound course is different. You do not put RW you put FAF and radial gets extended.
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Old 28th Jul 2014, 13:52
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In our company we extend the RW centerline ( sequence the flight plan is the command) only in case of radar vector ILS approach..or in case of a visual approach and its done by using the direct to radial in on the mcdu. Gives better prediction on the prog page and better situational awareness as well.
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Old 28th Jul 2014, 14:06
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If you do not sequence the flight plan correctly nav will not engage in the event of a Go-around.
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Old 28th Jul 2014, 20:40
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pfff, as long as the flightplan is sequenced when you start the approach. Otherwise you might have a surprise for the go-around.

For the rest why is this a discussion?
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Old 31st Jul 2014, 07:09
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I agree with Vilas that "extend the centre line" is a misleading term. Maybe it should be called "extend the final approach course" instead (except if making a visual approach, in which case RW centre line would be appropriate).
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Old 31st Jul 2014, 07:58
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Sometimes it is good to use radial in to the FAF or CI..... Other times it is good to leave the waypoints in.. We should not be prescriptive, we must allow for different thought processes, and as PNF/PM accept the wishes of the PF unless it is unsafe.
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Old 31st Jul 2014, 13:43
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To get the GA procedure in NAV you have to sequence the FPL before intercepting inbound track/ LOC/ILS. You need the TO way point that is on final track generally FAF , either you use radial in or clear each way point. Extend centre line become so routine that it gets used even when RW centre line is different than inbound track and people start misunderstanding the purpose of doing it. What is centre line for Canarsie approach at JFK or Kai Tak HK ILS?
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Old 31st Jul 2014, 13:51
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vilas

You must be a Time Lord if you can still fly the Kai Tak HK IGS.
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Old 31st Jul 2014, 14:01
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vilas, you can sequence the flightplan after the intercept as well.
If the extended centreline is different from the inbound track, as with most of our VOR approaches, every idiot will understand that you want the final approach track extended and not the runway QDM.

But I agree with you, technically speaking it is not the centerline. Try to change this habit in 2000 pilots who have been saying 'extend the centerline' for more than a decade.
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Old 31st Jul 2014, 14:32
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PENKO
Quoted below from FCTM NO-110 P4/10


The flight crew should sequence the F-PLN first, and then press the APPR pb. When the LOC mode is armed or engaged, the flight crew should not perform a DIR TO, in order to sequence the F-PLN as this will result in the FMGS to revert to the NAV mode. In this case, the LOC mode will have to be re-armed and re-engaged, increasing workload unduly.
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Old 31st Jul 2014, 14:50
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vilas,

Eee by hecky thump you are pedantic.

Nobody said perform a DIR TO, simply deleting the way points which are uselessly behind you will sequence the flight plan without engaging NAV.

If you want to be really picky - then it was the IGS at Kai Tak HK (not the ILS) which was 48 degree off set.
The ILS 32 was in line with the runway.
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Old 31st Jul 2014, 15:22
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I don't see a situation when you leave sequencing until after intercepting ILS unless off course you had forgotten. If you start doing things differently you allow Mr Murphy to sneak in. I feel since we have no instincts in the air we need to follow procedures. Theoretically there may be many ways of doing a thing but under pressure we may do something inappropriate for that situation and I meant the IGS at Kai Tak.
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