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Guest Pilot53

ZFW

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What is the correct max ZFW for the 744? The manual shows 535,000lbs, but the load manager shows 542,500lbs.

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Hi Pilot 53,I checked with the Boeing specs and they're both correct. The 542,500lbs ZFW is optional. Ken.

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I came across this as well, but how could a limitation figure such as MZFW be optional?

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>I came across this as well, but how could a limitation figure>such as MZFW be optional?I'm not sure but it could be the differences in the three class configurations, single class, dual class, and tri class configurations. 747-400s do have small differences in operating limitations and performances. This probably plays the role. Maybe Jon knows. He flies the real thing. Ken.

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ZFW means exactly that, Zero Fuel Weight. It is totally dependent on your passenger and cargo load. When all of that is factored in, then you will your true ZFW (the total aircraft weight minus fuel). Sounds like you were referring to empty weight. You will have to consult with the manuals and experts to get that data

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I believe the 'MAXimum Zero Fuel Weight' of the 747-400 is 535,000 lbs or 242,400 kgs.Regards,noullet

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When there excists a difference in ZFW, it will be a difference in the CERTIFIED zero fuel weight and not the structural zero fuel weight, which is for each aircraft equal.The reason for a difference in the actual and certified ZFW can be found in the fact that airlines may not want a fully certified 747 and in order to pay less, they can lower the certified ZFW.AZFW = CZFW ==> full capacity ==> most expensiveAZFW > CZFW ==> less then full capacity ==> less expensiveConsequences:When buying a 747 with a lower than actual ZFW, you will pay less for the same aircraft, but you are not allowed to take the full AZFW, but a lower limit (altough the aircraft won't crash)Example:Manual: 535 000 lbs (certified)Load manager: 542 000 lbs (structural)==> same aircraft, but different ZFW. when loading the aircraft to a full 542 000 lbs, it won't crash (as the lower limit of 535 000 lbs is just for regulations/price)The same practice is found in the engine ratings... but I don't think you will be interested in that :(Kind regardsNick

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If i want to buy an aircraft that can take (hypothetical) 10 tons or an aircraft that can take 20 tons (so YOUR revenue increases too) the price for the last aircraft will be higher then the first one.As ZFW is an indication for the amount of payload, and your revenue, it is logical that a higher MZFW implies a higher price for the aircraft (as you can earn more with the same tool).Kind regards,Nick

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>I believe the 'MAXimum Zero Fuel Weight' of the 747-400 is>535,000 lbs or 242,400 kgs.>>Regards,>noulletOhhh well, those pax-planes... wait till the -400F comes, and hopefully the "Extended Zero-Fuel-Weight" will be available.. Then we talk weight ;-)Cheers,Norbert - CLX001CEO Virtual Cargoluxwww.virtualcargolux.orgCLX_banner_grey.jpg

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OK,but how is an airplane with a lower MZFW different? Is it that the gear assembly is different or something? What's to stop me from filling my plane to the structural max zfw?Paul

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the fact that your are not allowed, you are not certified, to load your aircraft fully. If you do, you are in breach of your certification.

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Who's there to check? Are you saying that all i have to do to get a particular aircraft certified to have a certain MZFW is pay some money?

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in fact, yes. Weight is also an option just like if you want red or blue seats. Of course not every weight is an option: there is a range in between you can choose: the lower your requested MZFW, the less you will pay to the producer.Concerning the checks: ever seen a load sheet of a B747? It is CLEARLY printed what your MZFW is. Those papers are checked by autorities before you are allowed to use them (crosscheck with the actual aircraft certificate).So, before the calculation sheets can be used, they have to be approved (and the autorities are not going to allow a higher ZFW than allowed by the certificate).When they are in use: it is practically impossible to load the aircraft more then allowed: it will be clearly seen by the pilot on the documents and he will refuse to take off. And when we change some figures? That's fraud ;)A real-life incident which proves how relative the maxima are (and also indicates what I say is true): a few years ago, there was a singapore airlines flight bound for singapore, departing from brussels (cargo) and the take off roll was largely extended, just a few hundred yards before the end of the runway, the aircraft finally took of. Of course, dispatch was warned immediatly by the captain that something was wrong, as the aircraft didn't go in the air at Vr. The aircraft was placed in a holding in the neighborhood of Brussels while dispatch was running all the documents and calculations again. After a few minutes it was clear what the error was: the aircraft weighted 10 tons more then was declared (10 tons above the certified MZFW, as the aircraft was fully loaded) but did take off, and calculations (based on manuals for higher weight classes) showed the aircraft could continue the trip to singapore, remaining within CG limits and having enough fuel. The aircraft arrived safely in singapore without any further incidents.I think this makes my point well clear: the certified ZFW is just a commercial instrument for the producers: "you want us (the producers) to allow you (the airline) to take more on board? Fine, just pay more and we will increase the certified maximum weight" (Of course keeping in mind that ZFW+Fuel has a direct effect on maximum T/O weight and is therefor also influenced by commercial thinking by the producers)Nick

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