Hey folks, 

Simple question in the sim... is there any real point (apart form adding to the authenticity of a flight) in making a secondary flight plan and viewing alternates just in case? 

Just wondering as nothing seems to happen in sim that requires these... or have i missed something?

Cheers

Dug

Only if you might need to divert I would think?

No RW pilot here, but this topic has always intrigued me.

For my airliner flying (especially long-haul), I always pre-program an ALTN airport on the active F-PLN page.

However, this post made me look up a bit just now for scenarios where a Secondary flight plan may be called upon, instead of just programming an ALTN airport; one scenario, I noted, being last-minute weather-related emergency re-routing.

In this context, one memorable, in fact, my longest ever RW travel, from a decade or so ago, comes to my mind. It was a non-stop (AA) B777 flight from KORD/Chicago to VIDP/Delhi. After 16+ hours, as we neared VIDP, into stormy weather and poor visibility conditions, as I recall, we had to do a hold above VIDP, without a clear indication whether we could land there, or divert to an unknown alternate destination airport that could handle the 777 (I wouldn’t know what was the pre-programmed ALTN).

So, I was just wondering if the pilots might have then taken recourse to a Secondary flight plan, without impacting the primary flight plan.

Anyway, after about 19 hours, we finally landed in another airport hours away, not in so much better weather conditions, but we did land safely. To this day, I remember rather vividly that nerve wracking flight, thinking that we must have been running low on fuel at the end of it.

I’m interested in hearing from the experts, on this topic.

Occasionally if there’s an airport with complicated arrivals and approaches that need manual entries for height or speed constrains and an uncertainty about the runway or approach in use it’s sometimes handy to have something pre programmed in route 2. 
Then if there’s a last minute change of plan it’s easy to activate your route 2.

Nowadays with digital ATIS there are less surprises as you can monitor what’s happening from the other side of the world.

The other use would be to have your diversion airport arrival and approach all set up ready to go.

To be honest once you’re familiar and confident at FMC programming it’s just as quick and more accurate to just amend route 1 on the fly with your actual clearance.

Thanks, jon.

I recently replicated my (KORD->VIDP) flight with the PMDG 777 in MSFS2024, for fun, without, of course, the tension…🙂…including a hold pattern over VIDP.

Having never programmed a secondary flight plan for actual use in the SIM, I did what you indicated in your last paragraph.

I just amended the primary route, added a new destination (for what I thought the RW diversion was to), and then did a Dir-To to that airport.

I believe 10-12 years ago, there were probably not any 777 suitable airports within an hour or two of VIDP, which, as I recall, was practically the primary (and the only) hub for 777s in that region, though things may have changed since. Plus, the weather pattern may have ruled out alternates in close proximity…I’m thinking now.

Appreciated your notes…for (possible) later use in my (virtual) flights …🙂…

Edited February 10Feb 10 by P_7878

From the point of departure, unless you’ve enabled failures, no, there’s no point at all.

If you’re flying on VATSIM at a busy event, then yes, there’s more scope to use the feature. But, ultimately, fuel accordingly. 

If you fly with failures switched off then there is no need for a secondary flightplan. If you do have them switched on though, you want the secondary flightplan programmed with your Engine Out Sid, so that you have it read should you lose an engine on take off.

Your fuel planning should take into account what you set for an alternate.  Weather changes and TFRs are some reason why you may need to divert to alternate.  I don’t think MSFS 2024 implements runway closure and I’m not sure if it’s even an option thru the SDK.

Edited February 11Feb 11 by SayAgain

2 hours ago, MikeV1 said:

unless you’ve enabled failures,

Ah yes... i guess the 'random' element is what is missing here... i haven't enabled failures but may well try that to spice things up!

Retired airline pilot here... Making a secondary flight plan for a possible diversion (or using RTE 2 for this in the FMS) is fine, not a mistake by any means, but operationally, diversions are often reconsidered enroute because the facts change mid-flight. Perhaps the alternate picked by the dispatchers isn't the best one; maybe another airport has good weather and better company ops; perhaps another airport has good weather and easier connections for the passengers. Or perhaps, given the inevitability of a diversion, the decision is made well before you get to the actual destination.

The choice of alternate airport while flight planning is to guarantee that you have enough fuel to make it to a place with a better weather forecast. However, in real world ops, you may end up starting your diversion early, and/or picking a totally different airport to land at based on all kinds of different reasons. So be prepared for some flexibility. A pre-entered route to the flight-planned diversion airport is often overruled by practical considerations in the moment.

Edited February 11Feb 11 by prolixindec

1 hour ago, prolixindec said:

Retired airline pilot here... Making a secondary flight plan for a possible diversion (or using RTE 2 for this in the FMS) is fine, not a mistake by any means, but operationally, diversions are often reconsidered enroute because the facts change mid-flight. Perhaps the alternate picked by the dispatchers isn't the best one; maybe another airport has good weather and better company ops; perhaps another airport has good weather and easier connections for the passengers. Or perhaps, given the inevitability of a diversion, the decision is made well before you get to the actual destination.

The choice of alternate airport while flight planning is to guarantee that you have enough fuel to make it to a place with a better weather forecast. However, in real world ops, you may end up starting your diversion early, and/or picking a totally different airport to land at based on all kinds of different reasons. So be prepared for some flexibility. A pre-entered route to the flight-planned diversion airport is often overruled by practical considerations in the moment.

Fascinating expert answers to OP's original question...!

Clearly, lots of human judgement and prevailing considerations have to be factored in the final decision-making in RW. From the above explanation, two points particularly touched my own personal experience that I've cited above:

1. "...perhaps another airport has good weather and easier connections for the passengers..." [My note: In my case, it was an international long-haul into a major airport, surely with (connecting) legs expected forward, either international or domestic.]
2. "...The choice of alternate airport while flight planning is to guarantee that you have enough fuel to make it to a place with a better weather forecast. However, in real world ops, you may end up starting your diversion early, and/or picking a totally different airport to land at based on all kinds of different reasons...." [My note: I have a feeling that the original ALTN airport had to be (eventually) ruled out under the un-expected (and widespread) prevailing weather patterns.]

I was checking now a bit with AI, and it provided 5 simple scenarios, as below. Engine failure tops the list, and my (weather-related) diversion is 2nd on this list.

Key Scenarios for Using a Secondary Flight Plan:

• Emergency/Immediate Return: If an engine failure or urgent issue occurs shortly after takeoff, the secondary plan is activated to route the aircraft back to the departure airport.
• Diversions: En route, it is used to plan a new route to an alternate destination due to adverse weather or operational changes.
• Runway/Approach Changes: Used to set up a new landing runway and approach procedure (e.g., unexpected wind change).
• Operational Contingencies: It allows pilots to prepare for specific terrain escape maneuvers or to pre-plan the flight path for the next leg during quick turnaround times.
• Missed Approach/Alternative Destination: If a missed approach occurs, the secondary plan can be activated to navigate directly to an alternate airport. 

This video from a real world pilot clearly explains the various scenarios where you might use it (first 5 mins).

 

 

11 hours ago, P_7878 said:

I just amended the primary route, added a new destination (for what I thought the RW diversion was to), and then did a Dir-To to that airport

ATC in India like to issue spontaneous hold present position instructions or make a 360 degree orbit instruction rather than using their published holds.

If diverting in the 777 you can use the FMC keys as a simple aide memoir.

Starting top left and moving to the right..

INIT REF- select your current Vref (if diverting enroute you probably won’t have one entered)

RTE - enter your diversion airfield as the destination 

DEP/ARR- build up your STAR and expected approach 

Moving down to the next line..

FIX - put in your destination airport for orientation and instant direct to mileage 

LEGS- check and tidy up the arrival

Finally NAV RAD enter something appropriate for the destination.

Then moving on to communications you can use the radio panel in a similar fashion , starting on the left and moving right…

VHF L-ATC inform ATC of your intentions 

VHF R- Inform the company of your intentions ( the right VHF is usually tuned to company ops if in range, but maybe replaced by a SATCOM call if far away. Also for a diversion that isn’t immediate and urgent it’s best to discuss options with operations first before making a decision)

CAB -inform the cabin crew supervisor what’s going off using a NITS briefing-Nature, Intentions, Time to landing, Special instructions.

PA- Finally once you’ve go everything else sorted tell the pax what is going off, using your best Captain’s voice.

 

Well that’s the way we used to do things, there’s a written aide memoir or checklist in the QRH for diverting nowadays, younger pilots of today can’t scratch their nose without using a checklist, but it’s good to have a simple technique like above in your head.

 

Edited February 11Feb 11 by jon b

 

3 hours ago, jon b said:

...Well that’s the way we used to do things,...

Thanks, jon. Yes, as I should handle diversions. Appreciated the detailed steps. I'll run it once; just lifting off VIDP, enter a HOLD, then Exit the HOLD, and follow through with the steps outlined.

BTW, I am now told by my better-half, with slightly better memory of such happenings...🙂... from 10-15 years ago... that the diversion airport was likely Lucknow (VILK), about 270 miles southeast of Delhi. See the SimBrief F-PLN Screenshot #1 below, with ALTN=VILK.

That sounds right. In my previous replication (in MSFS2024/PMDG777), I'd diverted further north to VICG/Chandigarh (also can be seen in MAP below), which is only about an hour or so away, and what I recall, the diversion flight had lasted more than 2-hours, though after nearly 18 hours, in uncertain conditions, every hour had seemed like an eternity.

I've also shown the SimBrief F-PLN for the (KORD->VIDP) non-stop leg, that I'd replicated a month or two ago. I understand that AA no longer flies this direct route from O'Hare, but Air India does. However, that was my only ~19-hour flight, and I intend to keep it that way...🙂...not much of a (travel) fan of ultra-long-haul flights...

Cheers...!

12 hours ago, vonduck said:

Ah yes... i guess the 'random' element is what is missing here... i haven't enabled failures but may well try that to spice things up!

Sounds like something worth practicing...

Good luck, and thanks for originating this discussion here...🙂...

Edited February 11Feb 11 by P_7878