CAPTAIN SIM FORUM - Max fuel issue (Pounds / LBS same)

fowler Full Member Offline Posts: 72 Joined: Oct 31^st, 2009	Max fuel issue (Pounds / LBS same) Feb 10^th, 2013 at 2:57pm	Print Post
	Guys help me understand the pounds issue I can see in Flight Manual Part 3 Normal OPS under limitations the MTOW is listed at 220'000 POUNDS yet in FSX I can see a MTOW is 255'000 LBS ? (Same limit in FMC) Are we speaking about the same pounds here ? If it was me I would do all in KGS anyway... ;.) This lead to the real problem below : Also something is wrong in the payload and fuel as you wouldn't be able in any airplane to load full pax & cargo AND full fuel and still be under MTOW. Yet you can do it with CS 757 so something must be wrong here. Checking real data for 752 it appears that max fuel is more like 94'000 LBS than 75'000 LBS so this would explain why you can do it as in reality you would never be at full fuel. I checked all other weights and they seem to match except the full fuel is way off.


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Markoz

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Re: Max fuel issue (Pounds / LBS same)
Reply #1 - Feb 10^th, 2013 at 4:00pm

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On the Wikipedia page for the Boeing 757, it says this about the MTOW:

Maximum takeoff weight (MTOW): 255,000 lb (115,680 kg)

So my guess is that the normal procedures manual might be off. Especially when you consider that the aircraft.cfg has this:

[WEIGHT_AND_BALANCE]
max_gross_weight = 256000 � � � � � � � � � � �// (pounds)

Which is possibly the Maximum Taxi Weight, which, like it shows in the manual, is 1000 pounds more than the MTOW:

Weights	Pounds
Maximum Taxi Weight (MTW)	221,000
Maximum Take Off Weight (MTOW)	220,000

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fowler Full Member Offline Posts: 72 Joined: Oct 31^st, 2009	Re: Max fuel issue (Pounds / LBS same) Reply #2 - Feb 11^th, 2013 at 11:35am	Print Post
	Hi Markoz, yes I think also the manual is wrong. No big deal anyway. What bothers me is the max fuel load, I feel really wrong to be able to load full pax & cargo and full fuel. Too good to be true. I don't fly long distance but if doing so it might be an inconvenience if I miss about 20'000 LBS of fuel. Any chance to change that in the cfg file ? But then also in the FMS ? Weird.


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Markoz

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Re: Max fuel issue (Pounds / LBS same)
Reply #3 - Feb 11^th, 2013 at 4:48pm

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fowler wrote on Feb 11^th, 2013 at 11:35am:

Hi Markoz, yes I think also the manual is wrong. No big deal anyway. What bothers me is the max fuel load, I feel really wrong to be able to load full pax & cargo and full fuel. Too good to be true. I don't fly long distance but if doing so it might be an inconvenience if I miss about 20'000 LBS of fuel. Any chance to change that in the cfg file ? But then also in the FMS ? �Weird.

If I want to fly with "full" passengers, cargo and fuel, I generally lower the weight of the cargo in the "ULD's".

So my setup for the Captain Sim 757-200 would be:

Empty Weight	130875
Captain & FO	340
Crew	510
172 Passengers @150 lbs each	25800
Cargo (9 x ULD's @2545 lbs each)	22905
Maximum Fuel	75549
Maximum Weight	255979

If I was to change the Max Gross weight in the aircraft.cfg for the 757-200 to 255000, instead of it being 256000, then I would simply reduce the ULD weight to 2433 lbs ea. so I would still have it close to MTOW. Looking at the data for the B757-200 on wikipedia (which looks the same as what you can get from Boeing.com), it has the capacity (after adding the EW + Max Fuel) to carry a payload of 50,503 lbs. My payload from above, is only 49,555 (almost 1000 lbs less), so it's pretty close IMO.

The truth is that the passengers probably should weigh more than 150 lbs each. Say about 180 lbs each?

Edited:

If I wanted to change it from 150 to 180, I would change it in the aircraft.cfg using Edit > Replace (CTRL+H) and start it at the [WEIGHT_AND_BALANCE] line.

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fowler Full Member Offline Posts: 72 Joined: Oct 31^st, 2009	Re: Max fuel issue (Pounds / LBS same) Reply #4 - Jul 28^th, 2015 at 3:00pm	Print Post
	Hi Markoz, that is precisely the issue that bothers me. You shouldn't be allowed to fill all pax and cargo and at the same time take full fuel. Is it possible that CS reduced the max fuel of 752 from approx. 95'000 LBS in reality to 75'000 LBS ? So as to avoid this issue of beeing possibly over MTOW when taking full pax and cargo ? I don't know but it sure looks very unrealistic. Also this would reduce the range if modelled 75k LBS instead of 95k LBS in real life. I know some US airline use the 752 for transatlantic crossing. (Say east coast to LHR) I tried GVA to JFK no way you could do it with the RR version, but the GE version can barely do it without any reserve left at JFK.


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