Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

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

Tech Log The very best in practical technical discussion on the web

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

Old 28th Aug 2014, 05:57
  #21 (permalink)  
 
Join Date: Aug 2014
Location: moon
Posts: 5
There is a note in the PBN manual which talks about not clearing wpts derived from nav db when doing sid/star even if they are not overflow, under radar vectors or clearing weather.
Sorry I do not have the manual handy for exact ref.
A360 is offline  
Old 30th Aug 2014, 14:07
  #22 (permalink)  
 
Join Date: Jun 2007
Location: Wanderlust
Posts: 2,237
A360
We were discussing sequencing FLTPLN for approach because you won't get NAV mode for GA. Even during departure or clearing weather if you do not overfly way points and leave them in flight plan when you are asked to join the departure or wished to get back in NAV you won't get it. NAV can only be engaged when MCDU FROM and TO way points match ND way points.
vilas is offline  
Old 30th Aug 2014, 23:11
  #23 (permalink)  
 
Join Date: Aug 2014
Location: moon
Posts: 5
Hello Vilas,


During the STARs (or SIDs), if U wish not to fly the STAR's waypoints for any reason (radar vectors, weather) you can do so but do not clear the STAR's waypoints until you are on final intercept heading. After that either to perform DIR TO or clear the waypoints behind you.


This is applicable for RNAV APPs as per the PBN manual.


Thanks
A360 is offline  
Old 31st Aug 2014, 07:51
  #24 (permalink)  
 
Join Date: Jan 2000
Location: Asia
Posts: 2,378
Lateral Revision and type in the next waypoint may be quicker than clearing.

Having the original route in the secondary can be useful if you get cleared to a way point you thought didn't apply anymore.

Remember you can't activate the Secondary Flight Plan in NAV without going into heading first, unless it is sequenced with the active. Direct To will stop the sequencing of the secondary.

Extending the centreline and having NAV armed whilst in heading will prevent you from flying through your final course and possibly infringing on a parallel runway. I do this if cleared for ILS approach whilst outside the 25nm protected area.

The FMS is a tool box and there are differences in how people use it.
Metro man is offline  
Old 31st Aug 2014, 12:39
  #25 (permalink)  
 
Join Date: Jun 2007
Location: Wanderlust
Posts: 2,237
A360
There was never any doubt about that. You need to do it before intercepting final track.
vilas is offline  
Old 31st Aug 2014, 13:40
  #26 (permalink)  
 
Join Date: Apr 2004
Location: United States of Europe
Age: 36
Posts: 446
Toptip

If despite all best intents you have messed up the flightplan sequencing and you discover this late on final approach:

Below 700ft RA (MCDU datalock):
-Direct to ¨Runway¨
-LOC - G/S remain engaged and flightplan is sequenced correctly for G/A

Obviously, before someone will jump at me, there are cons to going heads down at this height.
OPEN DES is offline  
Old 1st Sep 2014, 00:57
  #27 (permalink)  
 
Join Date: Aug 2014
Location: moon
Posts: 5
OPN DES


If you perform DIR TO after you are locked on the ILS, the APPR (LOC & GS) will disengage and NAV will engage.
A360 is offline  
Old 1st Sep 2014, 05:04
  #28 (permalink)  
 
Join Date: Mar 2005
Location: Uh... Where was I?
Posts: 1,342
There are several ways to achieve the same target, which is to have a "correct" waypoint TO.

Some like sequencing by clearing the waypoint from, or a couple of waypoints.
If there is a lot of waypoints to clear perhaps is better the next method:

make a DIR TO to the desired WPT TO and then pull HDG.

make a DIR TO with radial in to a suitable waypoint in final (if your FMGS standard allows it) and then pull HDG

In some cases I think it would be OK not to pull HDG. That would give better VDEV (if you pull HDG the FMGS computes direct distance from a/c to the WPT TO.)
Microburst2002 is offline  
Old 1st Sep 2014, 14:02
  #29 (permalink)  
 
Join Date: Jun 2007
Location: Wanderlust
Posts: 2,237
A360
Refer to my post 19. This thread going round in circles.
vilas is offline  
Old 2nd Sep 2014, 00:26
  #30 (permalink)  
 
Join Date: May 2006
Location: brisbane
Posts: 14
Vilas,maybe if we did a lateral revision on post #19 and inserted this post we would end up with a proper sequenced flight plan...
b215 is offline  
Old 2nd Sep 2014, 07:29
  #31 (permalink)  
 
Join Date: Apr 2004
Location: United States of Europe
Age: 36
Posts: 446
A320 MCDU "Sequence the flight plan" instead of DIR to?

A360 read mypost again. Not if done below700ft ra! Mcdu datalock....
OPEN DES is offline  
Old 10th Jul 2019, 11:41
  #32 (permalink)  
 
Join Date: Nov 2004
Location: Here, there, and everywhere
Posts: 698
Originally Posted by Microburst2002 View Post

In some cases I think it would be OK not to pull HDG. That would give better VDEV (if you pull HDG the FMGS computes direct distance from a/c to the WPT TO.)
The FCOM does talk about using the Direct To function with one reason given being "The VDEV to be computed on reasonable distance assumptions".
Anybody have a good explanation for this?
punkalouver is offline  
Old 10th Jul 2019, 12:06
  #33 (permalink)  
 
Join Date: May 2014
Location: LGW
Posts: 740
Originally Posted by vilas View Post
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.
This is why you ask to sequence the FPLAN BEFORE the approach is armed.
Quite logical.
a350pilots is offline  
Old 10th Jul 2019, 12:13
  #34 (permalink)  
 
Join Date: May 2014
Location: LGW
Posts: 740
Thumbs down

Originally Posted by OPEN DES View Post
Toptip

If despite all best intents you have messed up the flightplan sequencing and you discover this late on final approach:

Below 700ft RA (MCDU datalock):
-Direct to ¨Runway¨
-LOC - G/S remain engaged and flightplan is sequenced correctly for G/A

Obviously, before someone will jump at me, there are cons to going heads down at this height.
???

Seriously?
I rather fly the MAP by RAW Data selected, unless it is REALLY complicated to fly, but then I should not be flying.
a350pilots is offline  
Old 10th Jul 2019, 15:34
  #35 (permalink)  
 
Join Date: Mar 2012
Location: Having a margarita on the beach
Age: 100
Posts: 1,290
Originally Posted by a350pilots View Post
???

Seriously?
I rather fly the MAP by RAW Data selected, unless it is REALLY complicated to fly, but then I should not be flying.
Fly an RNP1 go around raw data and let us know how it worked.
sonicbum is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.