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Optimum Landing Fuel Reserves

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Just curious

 

I have read many posts about fuel calculation. Topics mainly discuss how to calculate the quantity of fuel to add to the aircraft inclusive of reserves etc etc. Due to this, I would assume there would be an optimum quantity of fuel remaining at arrival or shut down, providing the sorte was flown as per plan and with no adverse wind conditions or diverts. I would immagine this quantity would differ from individual airline policy, but would expect there to be a ball park figure ?

 

I would like to confirm my fuel calculations within reason, post flight ?

 

Cheers

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As I understand it, reserves include as a minimum:

Fuel to fly from your destination to your divert plus

30 minutes legal reserves (local laws may differ from country to country) plus

Any potential holding for traffic requirements at the divert (depends on the airport and time of day)

 

On top of that are any airline reserve requirements.

 

So, 'it depends'. The ultimate 'right' quantity is enough...

 

Hope that helps.

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Due to this, I would assume there would be an optimum quantity of fuel remaining at arrival or shut down, providing the sorte was flown as per plan and with no adverse wind conditions or diverts. I would immagine this quantity would differ from individual airline policy, but would expect there to be a ball park figure ?

 

No.  There is no ballpark figure.  Aviation is not black and white.  A "good" figure for me when I fly into IAD is nearly full tanks because 100LL is about $9 a gallon there.  When I fly to BCB, on the other hand, it's about $5, so it's more economical for me to land with the FAA (planned - VFR) minimum of 30 min.  I don't personally like arriving anywhere with only 30 min of fuel, though, so my personal figure is more like an hour.  That's a compromise of my own view of safety, combined with the economics of being able to fill more of the tanks with cheaper gas than where the plane is based.  This concept is called tankering.  Some simmers choose to incorporate this aspect into the sim.

 

Additionally, there's no true safety risk if you run out of fuel, so some simmers choose to eliminiate all of the alternate planning requirements.

 

The optimum amount of landing fuel is enough to get you to the gate, and no more.  If I'm carrying around fuel for that flight that I'm not going to use, I'm burning more of that fuel to get where I'm going.  Since aviation (and life) isn't that cut and dry, and planning isn't 100% exact, you wouldn't want to do that.  So the optimal is going to be based on your personal (or operator) mix of priorities and acceptable risks.

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Just curious

 

I have read many posts about fuel calculation. Topics mainly discuss how to calculate the quantity of fuel to add to the aircraft inclusive of reserves etc etc. Due to this, I would assume there would be an optimum quantity of fuel remaining at arrival or shut down, providing the sorte was flown as per plan and with no adverse wind conditions or diverts. I would immagine this quantity would differ from individual airline policy, but would expect there to be a ball park figure ?

 

I would like to confirm my fuel calculations within reason, post flight ?

 

Cheers

You should specify which country you are wanting regulations for. I'm guessing since you use the word "sorte," you're looking for ICAO-type regs.

 

At my company, when we touch down, we often get a "Using Res Fuel" message in the FMC. That means that the dispatchers did a good job and we flew it right to the plan. (Our company includes ALT fuel in the FMC RES fuel entry.)

 

So, when you touch down, you'd want to have Alternate fuel, Contingency, Holding, and any ETOPS add, or Refile.

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Here is a build up of how fuel is calculated at (most) airlines:

 

Taxi fuel (company)

APU fuel (if applicable)

Trip fuel (calculated company)

Alternate fuel (Includes: Missed approach at dest, flight to alternate. and app at alternate.)

Contingency fuel (the greater of 5 mins at holding speed at 1500 AGL or 5% of en-route fuel)

Final reserve (turbine: 30 mins at holding speed at 1500 AGL, Props: 45 mins)

Additional fuel (depending on ops & company standards)

Extra fuel (up to the captain, for instance not sure about weather as it has changed, or anticipating last minute ATC delays)

 

So, when we land at our planned destination and we get an inspection, in order not to brake the law, we need to have at the very least:

Alternate fuel

Final reserve fuel

 

To give you an idea, in Europe, if we get into using our final reserve or think we will get into it, we MUST declare an emergency. 

 

There are some cases when the requirements change, IE, ETOPS or flying to isolated destinations, but you should have a good enough idea with the above.

 

Hope this helps a bit.

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Thanks for the responses.

 

I am sure Boeing tested the 737 many times, full fuel, full passengers, full cargo landings. Just wondering weather Boeing specify a recommended maximum landing weight to preserve structural integrity ? I have only just come to terms with handling the basic flight characteristics of the 737, my next challenge is fuel calculations, hence the silly questions. I then intend to move on to the advance take off and and landing calculations. love the variety of challenges available with this add on. Once I have the fundamentals under my belt, I'll give Vatsim a go.

 

Thanks for your time.

No.  There is no ballpark figure.  Aviation is not black and white.  A "good" figure for me when I fly into IAD is nearly full tanks because 100LL is about $9 a gallon there.  When I fly to BCB, on the other hand, it's about $5, so it's more economical for me to land with the FAA (planned - VFR) minimum of 30 min.  I don't personally like arriving anywhere with only 30 min of fuel, though, so my personal figure is more like an hour.  That's a compromise of my own view of safety, combined with the economics of being able to fill more of the tanks with cheaper gas than where the plane is based.  This concept is called tankering.  Some simmers choose to incorporate this aspect into the sim.

 

Additionally, there's no true safety risk if you run out of fuel, so some simmers choose to eliminiate all of the alternate planning requirements.

 

The optimum amount of landing fuel is enough to get you to the gate, and no more.  If I'm carrying around fuel for that flight that I'm not going to use, I'm burning more of that fuel to get where I'm going.  Since aviation (and life) isn't that cut and dry, and planning isn't 100% exact, you wouldn't want to do that.  So the optimal is going to be based on your personal (or operator) mix of priorities and acceptable risks.

I assume you use some kind of add on software to be so concerned with fuel cost ?

 

Landing with near full fuel tanks, does the PMDG have progressive wear and tear modeled into the sim ? I would immagine there would be e few undercarriage replacements over short periods, adopting this technique lol

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Just wondering weather Boeing specify a recommended maximum landing weight to preserve structural integrity
Yes, it's called the Maximum Landing Weight. You can often be landing just at MLW.

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Yes, it's called the Maximum Landing Weight. You can often be landing just at MLW.

Pardon my ignorance, what would be the MLW, or where could I find it ? Can you dump fuel in the NGX ?

 

Cheers

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MLW is in the limitations section of the AFM and it's usually placarded in the plane, too.

 

No fuel dumping in a 737.

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A 45 minute reserve at typical weights is around 3700-ish pounds.  If you have an alternate add that burn to your 45 minute reserve.  Most captains I fly with start to get antsy if the planned arrival fuel is anything less than 5000 pounds.

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Hi,

Example of fuel plan (taken by a my EDDM-LIMC PFPX flightplan)

TRIP FUEL= 2667 KG (55 MINUTES FL270)+ CONTINGENCY FUEL (5%= 190 KG)+ALTERNATE AIRPORT FUEL (LIMF= 1305KG 26 MIN)+FINAL RESERVE (HOLDING FUEL= 1141 KG = 30 MIN HOLDING) TAXI= 200 KG; SUMMARIZING:

 

TRIP= 2670

CONT= 190

ALTN=1305

FINAL=1140

TAXI=    200

TOTAL=5505 KG (MINIMUM)

Naturally minimum diversion fuel to go to the alternate will be 1305+1140=2445 kg so I input 2.5 (in this case) into RES FUEL box of my CDU.

(I got a ZFW of 57,8 tons and C.I.=30)

Best Regards

Andrea

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Hi,

Example of fuel plan (taken by a my EDDM-LIMC PFPX flightplan)

TRIP FUEL= 2667 KG (55 MINUTES FL270)+ CONTINGENCY FUEL (5%= 190 KG)+ALTERNATE AIRPORT FUEL (LIMF= 1305KG 26 MIN)+FINAL RESERVE (HOLDING FUEL= 1141 KG = 30 MIN HOLDING) TAXI= 200 KG; SUMMARIZING:

 

TRIP= 2670

CONT= 190

ALTN=1305

FINAL=1140

TAXI= 200

TOTAL=5505 KG (MINIMUM)

Naturally minimum diversion fuel to go to the alternate will be 1305+1140=2445 kg so I input 2.5 (in this case) into RES FUEL box of my CDU.

(I got a ZFW of 57,8 tons and C.I.=30)

Best Regards

Andrea

Thank you all kindly for your reply's. If someone has the time to put together one of these for YBTL to YBCS ( which has just been smashed. By cyclone Ita), with full passengers, no cargo and no alternative, would be greatly appreciated. My calcs put me at 5700 Kgs ?

 

Cheers

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If I put that quickly into FSBuild, I get 4008kg.

Reserve 900 and extra 1000kg.

 

 

That is with no weather included.

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I use simbrief to calculate my fuel and routes and such. http://www.simbrief.com/home/  I usually land with about 3000kgs to 6000 depending on the distance to the alternate, weather, traffic expected, and my gut feel. 

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Thanks guys

 

I appear to be on the money, or close anyway.

 

Thanks for your time.

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An excellent solution is PFPX............it does all these tedious calculations for you.

 

There is a learning curve, but once you master this application, you will not believe how easy flight planning can be!

 

Bill Clark

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An excellent solution is PFPX............it does all these tedious calculations for you.

 

There is a learning curve, but once you master this application, you will not believe how easy flight planning can be!

 

Bill Clark

Yes, I have been looking at PFPX. I am sure it is a valuable tool, but quite expensive. There's a few freebies out there that seem to do the job quite well, so I may stick with them for a little while longer.

 

Thanks for the suggestion, I have PFPX in second position on my want list :-)

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Yes, I have been looking at PFPX. I am sure it is a valuable tool, but quite expensive. There's a few freebies out there that seem to do the job quite well, so I may stick with them for a little while longer.

 

SimBrief is kind of PFPX lite in my book. It doesn't have all you would want, but it gets the job done, and all for free.  :lol:

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SimBrief is kind of PFPX lite in my book. It doesn't have all you would want, but it gets the job done, and all for free.  :lol:

Thanks, got it.

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