W & B question

[CaptainKiwi]

Kiwi,

There are basically two concerns regarding fuel at the end of the runway:

The first is that you cannot begin your take-off roll without at least the minimum (min fuel) required in the dispatch release (this is the minimum fuel you can depart with).

The second concern is that you cannot begin your take-off roll if you (after subtracting out the calculated fuel burn of the flight plan) will land overweight (this is the maximum fuel you can depart with).

Taxi fuel that is put in by dispatch is just a wag based on historical data. The two items above keep you in compliance with the FARs.

S

Am I missing something? That is my point but others are saying taxi fuel is not a wag. It is still on the airplane. Others above are saying you must burn off the fuel before you takeoff.

Btw, this doesn't come up much on my current airplane but when I was on the crj-200, it came up alot. I did talk to a fed about it on one of my jumpseats. Albeit was just one fed's oppinion, he said his main concerns were that you had enough fuel and that no structural limits were exceeded.

 

[CaptainKiwi]

Let me flip a coin... How much taxi fuel can dispatch add?? I had one put on 4 times the standard taxi fuel. I quickly called cause it flagged me to find out what was going on?? A VIP arrival or weather, ect. Her response was we were departing a big airport. I'd rather just call it extra fuel rather than taxi fuel to keep you from getting in these situations but it does restrict payload. So back to my question... How much taxi fuel can a dispatcher add without justification. Btw, that day she put on 4 times the normal taxi fuel we only taxied for 10 minutes to takeoff and we didn't have enough payload to get into this corner. So it wasn't an issue that day but could easily have pushed into it if the airplane was full.

 

[tzskipper]

Am I missing something? That is my point but others are saying taxi fuel is not a wag. It is still on the airplane. Others above are saying you must burn off the fuel before you takeoff.

Btw, this doesn't come up much on my current airplane but when I was on the crj-200, it came up alot. I did talk to a fed about it on one of my jumpseats. Albeit was just one fed's oppinion, he said his main concerns were that you had enough fuel and that no structural limits were exceeded.

Hi Kiwi,

The only amount of taxi fuel that is required to be "burned off" during taxi, is enough so that the amount of total fuel that you have on board when you take-off, less the en-route planned burn allows you to remain under max landing weight (actual t/o weight less flight plan burn) at your destination (while still departing with at least "min fuel" as required by your release - this is the departure to destination to alternate + 45 minutes...).

For example; if your taxi fuel on the release is 500 lbs. and you only burn 300 lbs., you can take-off with the additional 200 lbs. of fuel on-board, so long as the additional 200 lbs. will not put you in a position of taking off, knowing that you will be overweight for landing at your destination (ZFW + fuel remaining at take-off - en-route burn = estimated landing weight).

I hope this helps.

S

 

[CaptainKiwi]

Skipper.

Max landing wt is 47000lbs
enroute fuel is 3000lbs
taxi fuel is 1000lbs

47000 + 3000 + 1000 = 51000
per the dispatch release you are legal to dispatch but the question is can you takeoff if you only burn 200lbs and now weigh 50800?

The fuel onboard is minfuel + the 1000lb taxi fuel. Min fuel including enroute + reserve + alternate. So in this example, dispatched legally the only time to legally takeoff is the exact moment when taxi fuel is completly used up to be under the max takeoff weight and just enough fuel to legally complete the flight. It just seems silly. I'd rather takeoff. What would be worse is if you needed that fuel later and wished you had it but now you don't because you burnt off your taxi fuel.

 

[tzskipper]

Skipper.

Max landing wt is 47000lbs
enroute fuel is 3000lbs
taxi fuel is 1000lbs

47000 + 3000 + 1000 = 51000
per the dispatch release you are legal to dispatch but the question is can you takeoff if you only burn 200lbs and now weigh 50800?

The fuel onboard is minfuel + the 1000lb taxi fuel. Min fuel including enroute + reserve + alternate. So in this example, dispatched legally the only time to legally takeoff is the exact moment when taxi fuel is completly used up to be under the max takeoff weight and just enough fuel to legally complete the flight. It just seems silly. I'd rather takeoff. What would be worse is if you needed that fuel later and wished you had it but now you don't because you burnt off your taxi fuel.

You are right in this scenario. To be legal (by definition), when you push the throttles up for take-off, you have to have exactly 3000 lbs. of fuel on-board. One pound less and you do not meet the min fuel requirement, one pound more and you take-off knowing that (by definition) you will land overweight.

It is "silly", and (imo) this would be a good time to talk to the dispatcher about getting a closer alternate, or if an alternate is not needed, removing it completely, so you have a little extra fuel.

S

 

[asayankee]

Why do you people continue the over-complicate the hell out of this crap??? This job is not that hard. Stop over thinking it. Dont' take off overwright, make sure you can get where you're going and land.

 

[GuppyWN]

So much for experience and judgement! After reading this thread I agree that you cannot takeoff if the exact profile numbers will put you overweight at landing. I still feel like I should be able to level off 2k lower or drop the gear early but I agree the feds don't like that answer.

Gup

 

[CaptainKiwi]

Let's try this one...

Can you takeoff using a runway intersection with data you don't have? You are taking off runway 17. You have data for RW 17 full length and RW 17 at intersection K3. Can you takeoff using intersection K2 allowing more runway to takeoff than the K3 but use the K3 runway data? Common sense says sure, you have more runway but really you are taking off without out proper takeoff data. I think you can takeoff but I had an f/o challenge me because we didn't have data for K2 when we were taking off from there. I told him when we go past our intersection K3 at 80 knots that he can start the takeoff data then. Again good judgement has to come in at some point...

 

[tzskipper]

Let's try this one...

Can you takeoff using a runway intersection with data you don't have? You are taking off runway 17. You have data for RW 17 full length and RW 17 at intersection K3. Can you takeoff using intersection K2 allowing more runway to takeoff than the K3 but use the K3 runway data? Common sense says sure, you have more runway but really you are taking off without out proper takeoff data. I think you can takeoff but I had an f/o challenge me because we didn't have data for K2 when we were taking off from there. I told him when we go past our intersection K3 at 80 knots that he can start the takeoff data then. Again good judgement has to come in at some point...

You can do whatever you want, until something goes wrong.

No data, no departure...

Common sense does not apply to most regulations.

S

 

[TWA Dude]

So by that logic you can take off above MGTOW or below MIN Fuel.

Not at all. I just think that common sense prevails rather than being caught in FAR minutia. This is how I see it working in the real world.