Hi.

 

It depends on where you at. I saw you mentioned FAA regulations. Part 91 flights are usually charters or ferry flights even if those are passenger aircraft. If you carry passengers and any revenue payload, then you have to comply with Part 121 Ops, not part 91. Part 121 has a bit different fuel requirements and those are not the same for Domestic and Flag Ops.

Flag Ops:

• To fly to and land at the airport to which it is released;
  
• After that, to fly for a period of 10 percent of the total time required to fly from the airport of departure to, and land at, the airport to which it was released;
  
• After that, to fly to and land at the most distant alternate airport specified in the flight release, if an alternate is required; and
  
• After that, to fly for 30 minutes at holding speed at 1,500 feet above the alternate airport (or the destination airport if no alternate is required) under standard temperature conditions.
  

Domestic

• To fly to the airport to which it is dispatched;
  
• Thereafter, to fly to and land at the most distant alternate airport (where
  
• required) for the airport to which dispatched; and
  
• Thereafter, to fly for 45 minutes at normal cruising fuel consumption
  

You don't have to have any Contingency and/or extra fuel per regulations but some company may require Contingency fuel and those 5% of "C" fuel you mentioned came from nowhere. Like I said, some airlines may require it but it is in their Ops Specs but not in FAA regs. It is good to have it both for weather deviations or ATC delays... But there are time you are tank limited and do not have a room for any extra fuel at all. We dispatch B777 from LLBG to KEWR and or on Polar routes VIDP to KEWR, the same story. You have about 20-30 mins of holding fuel in order to take every one on board. That's why we do some crazy things like FAA Exemptions to reduce en route reserve 10% to 5% and/or Re-dispatch to put more gas. And dispatcher is not a magician. If we have a room, we'll put more gas, if not, sorry, we have to deal with it.

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Just to add it could also be Part 135 as well for pax carrying. And at least in our Opspec the alternate fuel is only required if the weather at destination is less than 1500 feet above the lowest authorized circle or strait in mins or 2000 whchvr is higher and 2 miles over the lowest vis or 3 miles wchvr is higher. Any better than that and you are legal for just destination and 45 mins. Legal but not smart. If VFR and the airport has more than 1 "seperate" usable runway which is actually more than 2 runways and usually 4 and above than I am ok with 1 hour but short of that or for me if there is a cloud in the sky and am not weight restricted or only 1 runway at uncontrolled field I allways have an alternate but I am a lover of fuel. I have had to many friends that have run out of gas because they were all big on the "Costs fuel to carry fuel" stuff. There is legitimacy in this in cases where you are flying a big jet but dont be like "Fuel Lights Dan" who thinks a good flight in the Citation is when the fuel lights come on on 1/4 mile final or like the crazy King Air jump pilot who dead sticked it into my airport and cut off my friend on short final unnanounce and had to get towed to the fuel island!

 

I had one guy tell me when I said I routinely land with 2 hours plus say you are landing with way to much gas. Well whatever. There are guys who are running out of gas and there are guys who never run out of gas. In the flight sim however it's fun to think like an airline pilot and pretend the boss will fire you if you land with to much fuel. :Loser:

 

My NGX reserves follow the regulations stricktyl and never any more and if I ever have to dead stick it into an airport after a few unforseen go arounds than I will prove myself correct w/o anyone getting hurt.

 

So I do 3.3 in the 800 for landing reserve and add alternate only if required by 91 or 135 regs which I am familiar with and 1-2 for holding (I get them in Radar Contact periodically)and .7 for maneuvering and approach and shortcommings of the FMS. In real life I would probably throw on another 1.0 for sanity but this aint real life so it is fun to push the envelope a little.

Hello all and sorry, just three questions?

 

1-Is fuel consumption figures used at operating the aircraft under flaps & gear down, taxiing, holding, base fuel and extra.... are applicable for the 900,700 & 600 as well ? I understand that the trip fuel is calculated by the FMC so it must be different from various airplanes

2-I couldn't see any compensation for winds ?? does it takes place in real world calculations?

3-The wiglets should save 5% of fuel as I believe I read somewhere? should this considered while applying the fueling model on none wiglets aircraft.

 

Thanks and sorry if it was mentioned somewhere.

 

 

Thanks & sorry

The FMC knows which variant you are flying (ie. 600/700/800/). You can either put average winds on perf init page or a more detailed wind/waypoint as pointed out in tutorial 2 (too much work for me). The FMC knows the plane best and does a great job so long as you give it good route information. Another tip, if you are making a long flight to an airport where you are not sure which runways will be used for landing, plan for the longest trip around the airport at the gate before departure. Like KSEA for instance, coming in from LA or phoenix from the south, plan your flight as if you will land on 16L/C/R. This way the FMC calculates fuel use on this possible flight path, you can always edit in the air later.

 

Eric W

 

The FMC knows which variant you are flying (ie. 600/700/800/). You can either put average winds on perf init page or a more detailed wind/waypoint as pointed out in tutorial 2 (too much work for me). The FMC knows the plane best and does a great job so long as you give it good route information. Another tip, if you are making a long flight to an airport where you are not sure which runways will be used for landing, plan for the longest trip around the airport at the gate before departure. Like KSEA for instance, coming in from LA or phoenix from the south, plan your flight as if you will land on 16L/C/R. This way the FMC calculates fuel use on this possible flight path, you can always edit in the air later.

 

Eric W

You want to put top of climb winds on the perf init, not average.

Flag Ops:

• To fly to and land at the airport to which it is released;
  
• After that, to fly for a period of 10 percent of the total time required to fly from the airport of departure to, and land at, the airport to which it was released;
  
• After that, to fly to and land at the most distant alternate airport specified in the flight release, if an alternate is required; and
  
• After that, to fly for 30 minutes at holding speed at 1,500 feet above the alternate airport (or the destination airport if no alternate is required) under standard temperature conditions.
  

 

Just to point out one important thing you forgot there, final reserve fuel of 30 mins should be added in there, you don't want to burn your 10% route reserve en-route, hold for 30 mins then divert, only for the engines to cut out on touchdown at your alternate. Off the top of my head, a figure of 1200kg should be about 30 mins in a B738. A lot of simmers seem to forget final reserve fuel for some bizarre reason....

 

Rónán.

Just to point out one important thing you forgot there, final reserve fuel of 30 mins should be added in there, you don't want to burn your 10% route reserve en-route, hold for 30 mins then divert, only for the engines to cut out on touchdown at your alternate. Off the top of my head, a figure of 1200kg should be about 30 mins in a B738. A lot of simmers seem to forget final reserve fuel for some bizarre reason....

 

Rónán.

 

Hi Ronan.

Thanks for the reply.

"final reserve fuel of 30 mins should be added in there, you don't want to burn your 10% route reserve en-route.."

Well, actually this is not a part of FAA regulations for a Flag flight. I am not arguing you, but that is what written on the stone. We, dispatchers, are not supposed to plan to burn reserve, but! if for some reason ATC went crazy or weather went south and such and such, that's what the reserve for. There is no determination of "Final reserve". Reserve is reserve. Use it if needed.

"you don't want to burn your 10% route reserve en-route". In this case we use exemption B44- Re-dispatch. It is confusing. Sometimes I spent 30 minutes on the phone with my pilots to explain them this. Even most experienced pilots get confused because there is too much going on behind the scene.

 

Bman2006.

 

If you want to plan fuel exactly or close how it works in real life, make a decision who do you fly for. If you are "FAA fan", plan you FOB based on FAA regulation part 121, 91 or 135. (Actually I have never heard someone was dispatching under part 135, it is basically pilot's chapter, not dispatch!!!) If you fly for virtual airline, ask those people, who rule that airline and under what regulation they want you to fly and then stick with that. If you just fly on your own, pick anything you want. Every country has their own requirements. I'd say there is no correct or wrong answer here. People in this community reside all around the world and they have to obey the rules where they live.

 

Thanks to all. We have a nice family here.

 

 

#1

Hi Ronan.

Thanks for the reply.

"final reserve fuel of 30 mins should be added in there, you don't want to burn your 10% route reserve en-route.."

Well, actually this is not a part of FAA regulations for a Flag flight. I am not arguing you, but that is what written on the stone. We, dispatchers, are not supposed to plan to burn reserve, but! if for some reason ATC went crazy or weather went south and such and such, that's what the reserve for. There is no determination of "Final reserve". Reserve is reserve. Use it if needed.

"you don't want to burn your 10% route reserve en-route".

 

Well, we operate under JAR-Ops, but I'm pretty sure that the Final fuel reserve, [aka minimum landing fuel] is also a part of FAA regs. Though that fuel is never supposed to be touched, you are allowed burn off your route reserve and holding fuel, but if you estimate you'll burn some of your final reserve fuel you have to declare a fuel PAN situation to ATC. AFAIK it's a manufacturers requirement to have this fuel on board.

 

Capt. Rónán O Cadhain.

Well, we operate under JAR-Ops, but I'm pretty sure that the Final fuel reserve, [aka minimum landing fuel] is also a part of FAA regs. Though that fuel is never supposed to be touched, you are allowed burn off your route reserve and holding fuel, but if you estimate you'll burn some of your final reserve fuel you have to declare a fuel PAN situation to ATC. AFAIK it's a manufacturers requirement to have this fuel on board.

 

Capt. Rónán O Cadhain.

 

Well this is what I found in the FARs for international ops:

 

121.645:

(B) For any certificate holder conducting flag or supplemental operations outside the 48 contiguous United States and the District of Columbia, unless authorized by the Administrator in the operations specifications, no person may release for flight or takeoff a turbine-engine powered airplane (other than a turbo-propeller powered airplane) unless, considering wind and other weather conditions expected, it has enough fuel—

(1) To fly to and land at the airport to which it is released;

(2) After that, to fly for a period of 10 percent of the total time required to fly from the airport of departure to, and land at, the airport to which it was released;

(3) After that, to fly to and land at the most distant alternate airport specified in the flight release, if an alternate is required; and

(4) After that, to fly for 30 minutes at holding speed at 1,500 feet above the alternate airport (or the destination airport if no alternate is required) under standard temperature conditions.

 

No mention of final reserve, though 121.647 does require the dispatcher to consider various factors like weather, anticipated delays and at least one instrument approach plus go-around.

 

A manufacturer's requirement sounds like unusable fuel to me (i.e. fuel that you can't reliably drain from your tanks). It's up to the regulator to determine what is a sufficient fuel reserve, not the manufacturer.

Oh I see where the confusion is arising here, what the FAA regs refer to as holding fuel, JAR-ops refers to as Final reserve. A bit confusing really, as holding fuel implies that it's alright to hold, where as final reserve sounds a bit more serious, which it is. What I consider holding fuel is contained within your 10% route reserve.

 

Sorry for the confusion guys,

Rónán.