I have a question about fuel burn

[Lonnie]

To start off I love the game. Everything is well done and I bet it will even get better, but I a have had a fuel burning problem or at least I
think it was.

I flew an ATR 72-500 not Flight1 thought. I flew from SF to an Airport an hour away. I placed 40% fuel on board that I estimated to make a
quick flight and was fined -300 points at the end for not having my 45 min. reserve. I then calculated it through FSbuild 2.2 which is my
normal routine, I went to flightpln.com to get my winds forecast which came to -10 input that into fsbuild, along with: 15 taxi, :45 reserve
and :%5 extra and came up with I believe 1925 lbs of fuel that would be needed, which came to 20%, which would not have been enough
to make it since estimating it landed me with 11%. Fsbuild is really good at that giveing you the needed fuel. It seemed to burn the fuel
really fast and I had no leak. Fsbuild allows you to input your reserve so that it is included in you’re your report so not to make a mistake,
is there something I need to consider with FSpassenger that I’m missing in my calculations? I ask because it should not take 60% fuel
to fly an hour away, it really should take about 40%. That is more then enough fuel; I think around 2 and half hours worth.

Anyway, any help would be great; I don’t want to be fined again.

Also just a suggestion but having an input box to type your lbs of fuel in along side the slider to place the exact amount in would be great
for future versions, and another cool thing would be to simulating the off boarding of your passengers like you do when they board so that
they can be getting off during your shut down checklist. I would love to see that in future as well, again just ideas I thought I might throw
out to an already great add on.

LB

[pagir]

It only a long shot, but maybe you want to try the same flight unloaded to see if it's not weight related...

About unboarding plane, it's already there: after setting your parking brakes, open the door. They will unboard the plane.

Pagir

[omarza]

I will quickly tell you my opiniun in what happened in my limited time I used FS Passengers. I might be wrong and Dan or SWAFO might confirm. While
flying you can pull an In-Flight report and experiment a bit if you want to as well.

Its diffuclt to explain but I will try to do my best. The shorter the flight the greater the margin of error becomes in calculating the amount of
fuel left. The reason for this is roughly the following...

Take the 3 basic phases of your flight.
- Climb
- Cruise
- Decent

No matter how long your flight, your fuel burn for the climb and decent will roughly stay the same given similar accent, cruise altitiude, decent
rates, wind condition etc etc. With staying the same I mean you should burn roughly the same amount of fuel in the accent (climb) for a 1 hour
flight as for a 4 hour flight... IF you use the same weights, Rate of Climb, Weather conditions etc etc.

Now in the cruise you use much less fuel than climbing... thats in fuel used per NM. This will result in the longer the flight the lower your
avergae fuel burn per NM will become... the shorter the flight the higher the average fuel burn per NM will be. Now IF FS Passengers does not
distinguish between the climb, cruise and decent stages of the flight the remaining time calculated for fuel left will be incorrent as it will take
the climb into account as well and calculate incorrectly... as the 45min left should in fact be ONLY calculated taking into account fuel burn during
the cruise stage of a flight disregarding the climb and decent really... and that is very difficult to do in my opiniun due to FS Passengers being an
addon. Therefore I can see your problem actually happening on a low QTY of fuel even with a good reserve.... on short flights I will thus make 100%
sure to calculate my reserves taking all 3 stages of flight into account... not only calculating reserves on Cruise. ALSO keep in mind on very short
flights to use a lower cruise altitute as that in fact might result in a more accurate calculation from FS Passenegrs due to climb stage being very
short and cruise longer.

Didnt know if that helped and please keep in mind im totally new to FS Passenger and might be totally wrong in my assesment altho thats the way it
looked to me checking on my inflight reports in the little time I used this great addon.

[Sovek]

tip, find the gas pump before ending the flight, you wont get docked, the only problem is it really screws up your gas stats. so try to do that as
least as possible.

[Lonnie]

Thanks guys,

I think omarza made a great point, I think part of the biggest issue is that lower altitude, that changes the burn and I had that in mind
when thinking about the problem. Flying at cruise level of FL190 which is where I went to I think makes a huge difference with the burn
then say FL290 because the aircraft seals up at high alt, thus needing less to burn but still placeing a full tank for an hour flight is not
what is done in the real world and with this thought of as real as it gets (not with this add on but in FS community in general) it would bug
me not to do it the way it needs to be done.

I also thought that what pagir said about cargo might be an added calculation that I am overlooking but if I add that to the overall payload it
should take that into account but I still think it burns heavy.

Maybe this is something the team should look at or if you have a go around not involving filling it up on short flights or hitting the tank on
the way into the gate because neither is what I would like to do that would be cool too. I know that it all can't be perfect but if the idea is to
train us on the things that FS does not and make us accountable for our actions then this is an issue that I see needing a fix.

Also I didn't know that they unloaded like that, I hit end flight and it was the end. If I wait till they all get off the aircraft will it effect my in
time? Or is end time recorded as soon as I put my emerg brakes on?

And again, please don't take my thoughts here the wrong way, I just know that fuel costs and even my VA I fly for, they want me in the
habbit of conserving my fuel.

LB

[SE-TMA]

Lonnie wrote:
Also I didn't know that they unloaded like that, I hit end flight and it was the end. If I wait till they all get off the aircraft will it effect my in
time? Or is end time recorded as soon as I put my emerg brakes on?

The unboarding time is added to your total flight time, so if you are a bit early, you could always let the passengers disembark .

[SWAFO]

Omarza,
For the most part, you're right! If you do a very short flight, your fuel figures are likely to be off. Basically, FSP takes a collective
average of your fuel flow, and if you spend most of the flight time at high thrust settings, your averages will be quite a way off. It'd be the
opposite for a long flight; your averages would be nearly dead on.

It's always a good rule of thumb to carry MORE than the minimum reserve amount of fuel. Yes, the FAA requires that all aircraft
operating under FAR121 regulations carry at least a 45 minute reserve. I fly 737's, so I'm referencing that type of aircraft in all of my
replies. Basically, I'll never takeoff without enough fuel to complete a go-around at my intended landing airport, and land on the 2nd
attempt with at least 5500LBS of fuel on board. Typically, I'll land with around 6-6.5k lbs of fuel on board during a standard VMC day.
When you're flying in IMC condition, expect to land with as much as 12K lbs of fuel on board (again, this is specifically geared towards the
737.) I believe I've posted some rough fuel planning figures on here previously, so a search of the forum may turn them up.

Let me know if you have any more questions.

[Lonnie]

So should I reserve say an hours worth to be on the safe side on all my flights, short and long halls? I do full thrust when flying the atr
because even at cruis I'm lucky to get over 200 kts and it doesn't auto my speed because for some reason wheneer I do, my speed
slowly drops to a stall iff I let it.

again this is with the ATR but I do fly other caircraft, like 737 NG, PMDG

[SWAFO]

I don't know much about the ATR. I don't think you should keep the aircraft at full thrust (unless this is how it's MEANT to be flown, which I
highly doubt). At FULL thrust, you will have VERY HIGH fuel flow.

If you fly the PMDG 737, I can be of more help. There's an excellent fuel planning utility available at their website
(http://www.precisionmanuals.com). You've just got to search for it, as I don't have a direct link.

BELOW IS HOW I'LL PLAN FUEL REQUIREMENTS FOR A FLIGHT WITH THE PMDG FUEL PLANNER
First, I'll enter 5500LBS for the "Minimum Landing Fuel", and 500LBS for "Taxi Fuel". Then, in the area where you can set the forecast
winds for your cruise altitude, select a HEADWIND of 100KTS (this will plan for any headwind condition at or below 100KTS... you should
ALWAYS plan for a headwind, never a tailwind). Next, enter your trip distance (rounded to the nearest 100NM), and the distance to your
PRIMARY alternate (again, rounded to the nearest 100NM); followed by an approximate cruise altitude.

Selecting an alternate airport is usually a complex matter, however it's best to select a MAJOR airport within 200-400NM for simplified
purposes in FS9.

The resulting figures will be mostly accurate fuel quantities for your wing, and center tanks. The numbers this fuel planner gives you are
the quantities of fuel you'd use IF you need to fly with the possibility of an alternate airport. To get the amount of fuel you need on a
standard VMC day, divide the number in the grey "Alternate Fuel" box by two, and subtract the result from each of the wingtanks.

Let me give you an example, since by this time I've even confused myself:

SITUATION: I'm going to fly a 300NM flight, with an alternate that's 200NM away. I'll be cruising at FL310 in a 737-700.

SETUP: First, I make sure that my minimum landing fuel is 5500LBS. Next, I make sure that the taxi fuel is set to 500LBS. Also, I check
to make sure the forecast calls for a headwind of 100KTS. Now, I set the trip distance to 300NM, the extra distance to alternate to 200NM,
and the cruising altitude to FL310. I've found that the "weights" section doesn't matter with the PMDG aircraft for the most part, so just
ignore it. Now, we're ready to copy down some numbers.

RESULT: We now have our final fuel requirements. The numbers in the respective "tank areas" are 6988LBS in the wings, and
1000LBS in the center. These are my fuel requirements IF I need an alternate. For simulation purposes, assume you need an alternate
when you have a headwind at cruise level that is greater than 100KTS, or IMC conditions at your arrival airport. Naturally, alternate
planning is much more complex than that, but let's keep it simple . Okay, back to the topic. I don't know much about the ATR. I don't
think you should keep the aircraft at full thrust (unless this is how it's MEANT to be flown, which I highly doubt). At FULL thrust, you will
have VERY HIGH fuel flow.

If you fly the PMDG 737, I can be of more help. There's an excellent fuel planning utility available at their website
(http://www.precisionmanuals.com). You've just got to search for it, as I don't have a direct link.

BELOW IS HOW I'LL PLAN FUEL REQUIREMENTS FOR A FLIGHT WITH THE PMDG FUEL PLANNER
First, I'll enter 5500LBS for the "Minimum Landing Fuel", and 500LBS for "Taxi Fuel". Then, in the area where you can set the forecast
winds for your cruise altitude, select a HEADWIND of 100KTS (this will plan for any headwind condition at or below 100KTS... you should
ALWAYS plan for a headwind, never a tailwind). Next, enter your trip distance (rounded to the nearest 100NM), and the distance to your
PRIMARY alternate (again, rounded to the nearest 100NM); followed by an approximate cruise altitude.

Selecting an alternate airport is usually a complex matter, however it's best to select a MAJOR airport within 200-400NM for simplified
purposes in FS9.

The resulting figures will be mostly accurate fuel quantities for your wing, and center tanks. The numbers this fuel planner gives you are
the quantities of fuel you'd use IF you need to fly with the possibility of an alternate airport. To get the amount of fuel you need on a
standard VMC day, divide the number in the grey "Alternate Fuel" box by two, and subtract the result from each of the wingtanks.

Let me give you an example, since by this time I've even confused myself:

SITUATION: I'm going to fly a 300NM flight, with an alternate that's 200NM away. I'll be cruising at FL310 in a 737-700.

SETUP: First, I make sure that my minimum landing fuel is 5500LBS. Next, I make sure that the taxi fuel is set to 500LBS. Also, I check
to make sure the forecast calls for a headwind of 100KTS. Now, I set the trip distance to 300NM, the extra distance to alternate to 200NM,
and the cruising altitude to FL310. I've found that the "weights" section doesn't matter with the PMDG aircraft for the most part, so just
ignore it. Now, we're ready to copy down some numbers.

RESULT: We now have our final fuel requirements. The numbers in the respective "tank areas" are 6988LBS in the wings, and
1000LBS in the center. These are my fuel requirements IF I need an alternate. For simulation purposes, assume you need an alternate
when you have a headwind at cruise level that is greater than 100KTS, or IMC conditions at your arrival airport. Naturally, alternate
planning is much more complex than that, but let's keep it simple Okay, back to the topic: I'll round the 6988LBS in the wing tanks up to
a simple figure of "7.0". I'll keep the center tank figure as "1.0" (note that these are written down somewhere so that I can set the correct
fuel amount when I get in the sim.)

Now, we need to figure out our fuel that we'd depart with on a standard VMC day, with no alternate required (95% of the time). If you
notice, the grey alternate fuel box reads 3300LBS. What I'll do is divide this in half (3300/2=1650), then I'll round the resulting number up
or down appropriately (1650=1700LBS). Next, I'll convert it to decimal form (1.7), and subtract this number from each of the wing tanks
(7.0-1.7=5.3). There we have it!

Our fuel required on a VMC day with no alternate is 5300LBS in the wing tanks, and 1000LBS in the center tank. If we require an
alternate, we'll load up 7000LBS in the wing tanks, and 1000LBS in the center tank. With 5.3 in the wings, and 1.0 in the center, we
should touchdown with ~6000lbs of fuel on board.

This is how I compute fuel for the PMDG 737, and it should work fine for everyone else. It's pretty "dumbed-down" from real life
calculations, yet it simplifies it quite a bit, and gives a number that is similiar to real world numbers.

I hope this makes sense, as I've already started the last day of celebration before returning to work as a CAPTAIN!

If anything needs to be cleared up, or you've got any further questions, just let me know!

[omarza]

Very nice detailed information SWAFO... thanks for that as I'm sure it will help many.

May I make a suggestion to maybe make that a sticky post as im sure many can benefit from that information

[SWAFO]

I didn't think I presented the information in a very easy to understand method... lol. Let's see what other people think.

Perhaps I will make a post in the future detailing specifics of real world fuel planning, and the many variables that apply to it. I could also
tie it in with FS9, and explain different methods (or did I do an ok job above with the FS9 half of it?) Let me know.

This would be an excellent post for the forum I recommended Dan create some time ago... read about it and show your support here:

http://www.fspassengers.com/forum/showth...99#pid4199

[lightrail]

I always calculate my fuel burn as follows:

1. Climb - decide on a cimb rate and figure out how long to cruise altitude. Do some math to figure out FS fuel burn per minute, then for the climb I
times it by three. So if FS Navlog says 3.3 lbs per minute fuel burn, then on climb I allow 9.9 lbs per minute and times that by the lengh of time to
get to cruise altitude.

2. Cruise - if on IFR, I add 15 minutes for approach vectors, for VFR, I add about 10 percent as I never fly at optimum speed for some reason

3. Descent - I don't bother working out fuel - just leave it as cruise - so I burn less.

4. Reserves - I work out and add fuel for diverison or missed approach plus another 45 minutes reserve - so for missed approach add 20 minutes (if
IFR, less if VFR) plus 45 minutes reserve.

5. taxi - add a fuel to allow for taxi at both ends - more important for big jets.

The above then provides me with my fuel estimate.

You want to make sure you have 45 minutes after landing, even if diverted or missed approach

[Lonnie]

I'm glad that the thread has become what it has because I think our fuel is an important factor that some forget about. A lot of options
have been posted that I am going to now use along with the steps I take. For example I have not taken into consideration that I might end
up with a missed approach, it doesn't happen much but it doesn't mean that it might not and I need to be ready for that and really 20
minutes is a good number, but sometimes it takes me twenty or more just on my approach.

Anyway great ideas and I think a fuel formula sticky note would be good, one that works acrros the board because I fly many aircraft.

LB

[bdlong]

I've been flying the Beach 1900 and have been learning how to regulate the fuel. I used to have to load three times as much as the flight planner
required. I just figured they FS9 flight planner wasn't grabbing the correct configuration for the plane. After playing with FSPassenger, it became
clear that I needed to make better planning if I wanted to make money.

Previously, I would run full throttle from take-off until turning for final and burn a huge amount of fuel. Now, after reaching cruise altitude, I
reduce to 50-65% throttle. I arrive within a couple of minutes of what the flight planner called for, (instead of several minutes <15), and my total
fuel burn is very close to what the planner calls for. I don't think the flight planner takes into consideration your climb burn. Each of the legs
now show an equal or less fuel burn than proposed with the airspeed within a couple of knots.

Dean

[pegase]

I use a quite simplist method but which do the job.

First get the data about fuel buened by your planes

Before take off, at the gate, note time and fuel reserve.

Take off and climb to the max cruise altitude you go for this plane.
Mark time and reserve at fl 100.
Mark time and reserve at lowest cruise alt
----------------------------------average cruise alt
----------------------------------Max cruise alt.

Reach cruise speed, mark the amount used within 5 minutes

do the same for average and min cruise altitude. and then calculate the lb/h

Mark time and reserve before descent to your destination. and check when parked.

You have now all relevant data.

Before the flight, estimate the block time.
Take the amount necessary for climb to your cruise altitude and descent.
Substract to the block time the time for climb and descent to get the cruise time.
from the cruise time,and the lb/h you got on the corresponding altitude you have the amount

Add the amount you marked at FL 100 it barely covers the missed approach.

Add one hour.

In summary

Total = Climb fuel amount + Cruise fuel amount+descent ... + Climb at fl 100 + 1 hour at cruise