Aircraft weights

BarryTheAviator · Post by **BarryTheAviator** » Tue Nov 23, 2004 9:30 am

"I'm just playing around doing some forward flight planning for my Bid Flights for December and am getting quite confused about the various weights of the 747-200 for Globe Cargo. To resolve this I looked up my last flight as recorded by ACARS and got even more confused, here is the problem (all figures from FSACARS Log on flight from EHAM to KORD:- Take off:- Cargo = 135,000 lbs ZFW = 428,470 lbs Fuel = 338,153 lbs If I deduct cargo weight from ZFW I get 293,470 lbs for the nett weight empty of cargo and fuel. Now the landing figures are:- Fuel left = 48,159 lbs (OK a bit much but I allowed a bit extra for head winds) Landing weight = 538,738 lbs If I deduct my fuel left from my landing weight and then deduct my cargo weight I now get an empty weight of 355,579 lbs. So somewhere along the route I appear to have gained an extra 62,109 lbs - I may have collected a few bugs on the windscreen but they weren't that big. [img]style_emoticons/<#EMO_DIR#>/ohmy.gif[/img] I am obviously doing something wrong in my calculations, can someone tell me (defintively) what is the weight of the 747-200 with no cargo and zero fuel to be used in my loading calculations and also tell me what I am doing wrong with what appear to be simple arithmetic calculations? Your help would be greatly appreciated before I throw all my toys out of my pram and stamp on my calculator <!--emo&

-->[img]style_emoticons/<#EMO_DIR#>/mad.gif[/img]"

CraigM · Post by **CraigM** » Tue Nov 23, 2004 2:44 pm

"Empty weight should be 342,000 lbs. By the way: <span style='font-family:Courier'>15:00 Zero fuel Weight: 452159 Lbs, Fuel Weight: 247888 Lbs 15:00 NOAA:RKSI 230230Z 15010KT 8000 NSC 11/05 Q1029 NOSIG 15:00 NOAA:PANC 230153Z 33005KT 10SM FEW035 BKN090 OVC140 M01/M03 A2977 RMK AO2 SLP081 VIRGA S-W/ SH DSNT SE T10111028 15:03 Zero fuel Weight: 452161 Lb, Fuel Weight: 247179 Lb</span> Mine gained 711 lbs. last night, if you factor in spent fuel. Those METARs must weigh more than I thought.

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Tsuru · Post by **Tsuru** » Tue Nov 23, 2004 7:52 pm

"On the topic of weights, I use the maximum of 112 tons of payload on all my flights (246400lbs), because it allows for a safe margin when regarding the MLW of 630000lbs and the reserve fuel carried on flights that allow for the maximum tonnage worth of knickers (and some contraband [img]style_emoticons/<#EMO_DIR#>/tongue.gif[/img] ). 342000+246400+~22000=~610400lbs Also, what MTOW do you use? As far as I know, the real N924FT is certified for 820000lbs, or 371.9 tons. I suppose I could use the 840000lbs limit prescribed in the manuals, but I think that would put me in an awkward position when one of the -7Q engines decides to take an early retirement shortly after V1. [img]style_emoticons/<#EMO_DIR#>/unsure.gif[/img] So what maxima (payload, MLW, MTOW) do you guys stick to? [img]style_emoticons/<#EMO_DIR#>/huh.gif[/img]"

Tsuru · Post by **Tsuru** » Tue Nov 23, 2004 9:24 pm

"I got bored and made myself a payload vs. range diagram for the RFP V2, Useful for establishing how much stuff you can bring along on those long flights.

Made using the RFP fuel planner. Prerequisites: 35000 feet No wind 30 min total contingency (holdings and taxi time) 100NM to alternate Limit points: 3100NM @ 118T 3450NM @ 112T 6550NM @ 0T

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BarryTheAviator · Post by **BarryTheAviator** » Wed Nov 24, 2004 4:16 am

"<div class='quotetop'>QUOTE(Tsuru @ Nov 24 2004, 01:24 AM)</div><div class='quotemain'>I got bored and made myself a payload vs. range diagram for the RFP V2, Useful for establishing how much stuff you can bring along on those long flights. [img]style_emoticons/<#EMO_DIR#>/smile.gif[/img] Made using the RFP fuel planner. [right][snapback]2250[/snapback][/right] </div> Yannic, Just the job - I'll use this for my loading, many thanks [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img] "

Tsuru · Post by **Tsuru** » Wed Nov 24, 2004 5:12 am

"<div class='quotetop'>QUOTE(BarryTheAviator @ Nov 24 2004, 09:16 AM)</div><div class='quotemain'>Yannic, Just the job - I'll use this for my loading, many thanks [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img] [right][snapback]2253[/snapback][/right] </div>Remember that it is only correct for an MTOW of 820000lb [img]style_emoticons/<#EMO_DIR#>/wink.gif[/img]"

BarryTheAviator · Post by **BarryTheAviator** » Wed Nov 24, 2004 10:00 am

"<div class='quotetop'>QUOTE(Tsuru @ Nov 24 2004, 09:12 AM)</div><div class='quotemain'>Remember that it is only correct for an MTOW of 820000lb [img]style_emoticons/<#EMO_DIR#>/wink.gif[/img] [right][snapback]2257[/snapback][/right] </div> Yep thanks for that - but basically anywhere under the curve is good to go and anything outside the curve is a non-starter. Gives a good working ""envelope"" for planning. Really useful. [img]style_emoticons/<#EMO_DIR#>/rolleyes.gif[/img]"