Zero Fuel Weight

[bigD]

I'm not quite sure what you're getting at, since Zero Fuel Weight is a term that has a definition, not a limit. If it were MAX ZFW or MIN ZFW, it would be a limit, and we might discuss why.

Zero Fuel Weight is the sum of the weights of the empty airplane, the crew, hydraulic fluid, flight attendants, passengers, bags, cargo, and other furnishings. Basically, it's the weight of everything but the Usable Fuel.

.

Heh - this is really pedantic, even for you, Tony!

 

[pilotmiketx]

Don't forget floor limits...

 

[USMCmech]

Basically it is the structural weight limit for the wing roots.

That is it in a nutshell.

Basicly the zero fuel weight stops you from loading all the load in the center of the span. Since the load is spread across the span somewhat more evenly, the wing attach fittings and hardware can be be smaller and lighter.

By placing the load of fuel in the wings the wing attach fittings do not have to cary that load, just the load of the fueslage and it's contents. When you are talking about airliners, and even buisness jets that adds up to several tons. Multiply that by the design load factor, and then the enginers fudge factor, and you are talking about some serious weight.

As stated any fuel in the fuselage tanks is included in the "zero" fuel weight, since it is adding to the load in the center.



FYI the wingroot of the 747 is attached by hundreds of 1 inch bolts streching from the front spar to the rear spar. I had to X-ray every single one back in July. After crawling into and out of the center tank 8 hours a day for 5 days I was a walking bruise.

Anybody want to consider a career in aircraft maint?

 

[TonyC]

Heh - this is really pedantic, even for you, Tony!

I guess it depends on how you use it every day. I look at Zero Fuel Weight every time I fly, but I never think of it as a limit. In fact, the only thing remotely related to a limit and Zero Fuel Weight for me and the 727 is the Min Flight Weight for some of them. If the Min Flt Wt is 100,000# and the Zero Fuel Weight is 95,000#, I must designate 5,000# of fuel as Min Flt Weight Fuel to comply with the FAA mandated restriction (something about floor loading & flexing).

Other than that, my dealings with ZFW are brief. My Flight Plan / Release is predicated on a predicted ZFW. If the actual ZFW varies from that, I have to consider how it will affect my fuel burn, and determine if I have enough fuel aboard.

In all of that, the ZFW is just a number, as the definition would imply. While there might BE a Max ZFW, I'm not aware of it, for it does not come into play in our operations. OR, I guess it would be more accurate if I were to admit that IF it comes into play, the ramp-provided Weight & Balance will have already taken that into consideration.

Let's save pedantic for something like the "with you" thread.





.

 

[Donsa320]

In all of that, the ZFW is just a number, as the definition would imply. While there might BE a Max ZFW, I'm not aware of it, for it does not come into play in our operations. OR, I guess it would be more accurate if I were to admit that IF it comes into play, the ramp-provided Weight & Balance will have already taken that into consideration.

Let's save pedantic for something like the "with you" thread.


TonyC

The Maximum Zero Fuel Weights for our 727s were 140,000lbs for the B-727-2S7 and 141,000lbs for the B-727-2M7. In the manual under "Limitations".

As you say, the loading programs should have that built in. (I hope) <grin>

DC





.[/quote]

 

[TonyC]

The Maximum Zero Fuel Weights for our 727s were 140,000lbs for the B-727-2S7 and 141,000lbs for the B-727-2M7. In the manual under "Limitations".

They gave you a MANUAL!

Man, do I feel ripped off!











.

 

[Donsa320]

They gave you a MANUAL!

Man, do I feel ripped off!











.

Ha, I know what you mean...it was a different world back then. The bad part was...we were supposed to know what was in it.

 

[CutEmUp]

Don't you use your ZFW to figure your gross weight?

ZFW + Fuel on board = gross weight

 

[TonyC]

Don't you use your ZFW to figure your gross weight?

ZFW + Fuel on board = gross weight

The formula is correct, but I don't do it. The Ramp Agent plugs the numbers in the computer (the computer handles all the limits automatically) and the Weight & Balance manifest is printed out for me. We plug the TOCG and TOGW into the performance computer along with the environmental variables, and it spits out Takeoff Performance data. I sign it, and we close the door.




.

 

[CutEmUp]

Wouldn't you need it if you get a hold or something and got to figure holding speed/epr/fuel flow? You never know