Alternate routing
Thread Starter
Joined: Feb 2025
Posts: 8
Likes: 1
From: France
Alternate routing
Hello, I mainly talk about A320 but I think it’s valid for every aircraft.
I’m quite the only one inserting the alternate routing on MCDU in order to have a valid route and some fuel predictions but I’m the only one that finds with little sense using some SIDs?
for example from MXP the alternate is many times LIN and our FPlans normally have as first point SRN, thus a SID going to the right, so generally people put this sid in the alternate routing. What I do is generally copy the final wpt of the missed approach and create the route from there…. In MXP means from 35L going to the left and this means a bit more consumption… Is it wrong ? Do you do something different?
I’m quite the only one inserting the alternate routing on MCDU in order to have a valid route and some fuel predictions but I’m the only one that finds with little sense using some SIDs?
for example from MXP the alternate is many times LIN and our FPlans normally have as first point SRN, thus a SID going to the right, so generally people put this sid in the alternate routing. What I do is generally copy the final wpt of the missed approach and create the route from there…. In MXP means from 35L going to the left and this means a bit more consumption… Is it wrong ? Do you do something different?
Joined: Apr 2010
Posts: 1,320
Likes: 102
From: IRS NAV ONLY
Personally, I only bother with alternate routing in case a diversion is very likely (weather close to, or below limits). I think it's a bit overkill to do in CAVOK weather on an airport with two or more runways (e.g. MXP). In reality, you're probably likely get radar vectors, especially if the alternate is very close by (MXP-LIN is a great example), or radar vectors and then at some point a direct to STAR/IAF for the alternate airport.
KISS principle works great with these things.
KISS principle works great with these things.
Joined: Apr 2003
Aviation Qualifications: ATPL
Posts: 3,652
Likes: 491
From: Europe
Exactly. In the busy European airspace it is extremely unlikely that you will fly the OFP alternate route or any other programmed route. It just will not happen. All diversions I have done went something like ‘eehhh…fly heading 180 for now’, or a direct to some waypoint in the general direction of the alternate. Followed later on by more sensible direct routing once the controllers have finished coordinating amongst themselves.
Of course, for planning purposes I rely on the OFP figures (if sensible) and take it from there as things happen, using the MCDU as guidance as the situation develops. For example, the decision to divert is just as likely made from a holding waypoint or position well before the approach.That’s a whole different proposition all together in terms of required fuel and routing. For example, the only time I came close to diverting from MXP to LIN was in the hold over VERCE, well south of SRN. In that case I’m far more interested in the fuel required from VERCE and that’s where the MCDU comes in hadny! For that I will use the secondary..
Of course, for planning purposes I rely on the OFP figures (if sensible) and take it from there as things happen, using the MCDU as guidance as the situation develops. For example, the decision to divert is just as likely made from a holding waypoint or position well before the approach.That’s a whole different proposition all together in terms of required fuel and routing. For example, the only time I came close to diverting from MXP to LIN was in the hold over VERCE, well south of SRN. In that case I’m far more interested in the fuel required from VERCE and that’s where the MCDU comes in hadny! For that I will use the secondary..
Joined: Mar 2012
Posts: 2,605
Likes: 154
From: Having a margarita on the beach
Hello, I mainly talk about A320 but I think it’s valid for every aircraft.
I’m quite the only one inserting the alternate routing on MCDU in order to have a valid route and some fuel predictions but I’m the only one that finds with little sense using some SIDs?
for example from MXP the alternate is many times LIN and our FPlans normally have as first point SRN, thus a SID going to the right, so generally people put this sid in the alternate routing. What I do is generally copy the final wpt of the missed approach and create the route from there…. In MXP means from 35L going to the left and this means a bit more consumption… Is it wrong ? Do you do something different?
I’m quite the only one inserting the alternate routing on MCDU in order to have a valid route and some fuel predictions but I’m the only one that finds with little sense using some SIDs?
for example from MXP the alternate is many times LIN and our FPlans normally have as first point SRN, thus a SID going to the right, so generally people put this sid in the alternate routing. What I do is generally copy the final wpt of the missed approach and create the route from there…. In MXP means from 35L going to the left and this means a bit more consumption… Is it wrong ? Do you do something different?
When using the secondary to plan for an alternate routing, just use it as a reference for the distance to go and then use the Flysmart (or paper QRH/FCOM data if you're not no paper cockpit yet) to find official alternate fuel values. I mean, the secondary flight plan works perfectly fine, but the FMGC values are advisory in nature, hence for legality purposes you need a crosscheck with an approved piece of documentation.
Joined: Dec 2013
Posts: 133
Likes: 72
From: Milan
Mostly agree with the above comments. Just keep in mind that if your Operator SOPs do require to insert the routing to the alternate then you'd better be in the position of actually doing it. For example we do that, as we crosscheck the difference in the FMGC alternate fuel predictions vs OFP (Lido) for gross error checks.
When using the secondary to plan for an alternate routing, just use it as a reference for the distance to go and then use the Flysmart (or paper QRH/FCOM data if you're not no paper cockpit yet) to find official alternate fuel values. I mean, the secondary flight plan works perfectly fine, but the FMGC values are advisory in nature, hence for legality purposes you need a crosscheck with an approved piece of documentation.
When using the secondary to plan for an alternate routing, just use it as a reference for the distance to go and then use the Flysmart (or paper QRH/FCOM data if you're not no paper cockpit yet) to find official alternate fuel values. I mean, the secondary flight plan works perfectly fine, but the FMGC values are advisory in nature, hence for legality purposes you need a crosscheck with an approved piece of documentation.
