tamsini

What would happen if you add fuel to FMS mid-flight

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Hi all, just wondering, in the real-world, what would happen on a real-world flight if you try to add fuel in the FMS of a Boeing or Airbus? Obviously, there wouldn't be any fuel added to the aircraft (😁 ) so I assume it would wreak havoc on fuel calculations.

I just find it a bit silly that you can do so in our sim-world. Why can't the developers (especially the big guys) disable this feature once a flight begins?

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Why does it need to be disabled?  if you think it shouldn't be used inflight, then don't.

Sometimes folks either get the fuel planning wrong, or maybe the winds used by a fickle flight planner are way off.  No need in a simulator to force them to crash once they see there's a problem.  Of course if you want to be held accountable...leave the fuel load alone and take your lumps.

Also, the ability to set a fuel load mid-flight makes it possible to warp ahead on long legs, and then reduce the fuel load at the other end accordingly...in this case changing the fuel load means reducing it rather than adding fuel.

Regards

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13 minutes ago, bean_sprout said:

Hardly anything.  Just do it - its a simulator.

 

Cheers
bs

Hey Bean, what I'm saying is, I know we can do it in the sim but shouldn't it be made so we CANNOT do it?

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1 hour ago, tamsini said:

Hey Bean, what I'm saying is, I know we can do it in the sim but shouldn't it be made so we CANNOT do it?

I think Bob’s answer below is the best choice. Just because you can do it doesn’t mean you have to or should. Just pretend the option isn’t there to do it. After all, we’re pretending to be flying.

 

1 hour ago, w6kd said:

Why does it need to be disabled?  if you think it shouldn't be used inflight, then don't.

 

 

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Agreed.  Freedom.  If you run out of gas, and just because you CAN refuel along the way, there is no pressure in doing so.  Let your poor calculations play out and crash and restart the flight from scratch with better planning.   It's simply a self-control issue.  I've suffered this myself, hey it happens...most of us didn't go to flight school.  I choose to die and restart each time.

Mark

 

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4 hours ago, toucanair said:

.....or Divert... it happens in the real world..

Exactly, its a fun challenge as well

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I did it once when I really didn't pay attention to my planning.  

Nothing really happens - the aircraft balks a little form the added weight, but settles down pretty quickly.  The weights are readjusted.   Clearly you wouldn't go from near empty to near full.  I assume the only situation where you would want to add additional fuel is if you just want to add an extra margin which is no big deal.

Or,  the best option as @toucanairmentioned, it to play the part for real -  and divert.  Much more interesting

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I mean that you somehow compare apples to oranges here. Real world planes don't have the same FMC Omption like a PMDG (or any other) plane. This part is only for the simulator to fill your payload and fuel.

If you enter something in the "real" part of the FMC, I expect the same results as in the real world, which is a wrong calculation.

I can't recall a payware aircraft where fuel and weight are controlled over the "normal" FMC.

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Or you can consider the option to add fuel as a way to replicate in-flight refuel. B737 has that ability (the navy variant called Poseidon) and A330s can do it too (the tanker version). 

No harm in enlarging the scope of the simulation. As others have said it's all about the user freedom. Use it or leave it. But even if an option seems unrealistic today (10 years ago no 737 or A330 could refuel in-flight) it doesn't mean that we have to forbid the user to do it. Sometimes reality catches up!

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Interesting array of responses. I would have thought, for a full immersion experience, having the freedom to add fuel at FL360 would be a no-no.

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3 minutes ago, tamsini said:

Interesting array of responses. I would have thought, for a full immersion experience, having the freedom to add fuel at FL360 would be a no-no.

Your plane, your sim, your rules.    

Pausing the sim is also possible mid-flight.  Completely immersion shattering, but doesn't mean it is a used option.  Where would one draw the line?

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11 minutes ago, ErichB said:

Your plane, your sim, your rules.    

Pausing the sim is also possible mid-flight.  Completely immersion shattering, but doesn't mean it is a used option.  Where would one draw the line?

Good point. 

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In the aircraft I fly, throughout the flight I am updating the FMS with the current fuel on board. The fuel flow sensors within the FMS and the analog gauges we have in the engine stack can be off sometimes and I will update the fuel with the actual fuel on board to get a better idea of how much I will have at my destination. 

 

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1 hour ago, ErichB said:

Pausing the sim is also possible mid-flight.  Completely immersion shattering, but doesn't mean it is a used option.  Where would one draw the line?

Good point!

Also we’re able to set the time and date we want to fly which is not realistic. Maybe we should only be able fly at the current date and time when we start the sim to maintain the most realism, lol.

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1 hour ago, cmpbellsjc said:

Good point!

Also we’re able to set the time and date we want to fly which is not realistic. Maybe we should only be able fly at the current date and time when we start the sim to maintain the most realism, lol.

Now, now, let's not get carried away 😁

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1 hour ago, cmpbellsjc said:

Good point!

Also we’re able to set the time and date we want to fly which is not realistic. Maybe we should only be able fly at the current date and time when we start the sim to maintain the most realism, lol.

I tend to fly like that actually... I mean, only fly at the current date and time 😇 I find that this gives me a nice variety in conditions, and I enjoy the continuity between what I see out my window and in my sim.

Unless I'm testing something specific, in which case I do whatever I please 😉

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27 minutes ago, Benjamin J said:

I tend to fly like that actually...

me too

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10 hours ago, ErichB said:

I did it once when I really didn't pay attention to my planning.  

Hehe. I actually pulled a Gimli Glider once. Didn't notice that Simbrief had reverted to kgs when I have it set to lbs. Happily loaded the block fuel and then wondered 2/3ds through my flight why I was so low on fuel.

Learned a few things that day, including how important the prog screen on your FMS is. Had I bothered to pay attention to it I'd have noticed it predicting 0 fuel at my destination and would have figured out something was wrong much earlier.

 

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1 hour ago, eslader said:

Didn't notice that Simbrief had reverted to kgs when I have it set to lbs.

Ha ha, yeah, I did that too a couple of times early on! Easy mistake to make when you're learning, so it's nice to have the option to correct it without having to end up banging your head on the desk!! 😂

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Ok, but now I am curious.. on a real airplane, can you change the figure on the FMS? so the computer allows you to change it while you are on cruise?

S.

 

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