February 26, 201511 yr I don't know if some of you have noticed but I have found weight discrepancies, for example, with the PMDG 737 and the PMDG MD-11. I'll use the PMDG MD-11 as an example. In the MD-11 aircraft.cfg. file, it shows the maximum gross weight is 633,500 lbs, In the PMDG MD-11 Load Manager, it shows that the maximum weight is 630,500 lbs - marked in blue. That is a difference of 3,000 lbs. I don't think the max gross weight shown in the aircraft.cfg means the maximum ramp weight and it would have stated that. You'll notice that the load manager assumes 1,500 lbs for taxi fuel so using the 630,500 lbs as the max for take-off, the max ramp weight would be 632,000 lbs, or 635,000 lbs using the max weight in the cfg file. So that being the case, why is it that the maximum weight is 630,500 lbs in the load manager and the maximum weight is 633,500 lbs in the aircraft.cfg? Is the max gross weight in the aircraft.cfg file the same reference weight as the load manager? if so, they should be exactly the same. Also, how do I go about editing the the max weight in the load manager program? Ken.
February 26, 201511 yr I don't know if some of you have noticed but I have found weight discrepancies, for example, with the PMDG 737 and the PMDG MD-11. I'll use the PMDG MD-11 as an example. In the MD-11 aircraft.cfg. file, it shows the maximum gross weight is 633,500 lbs, In the PMDG MD-11 Load Manager, it shows that the maximum weight is 630,500 lbs - marked in blue. That is a difference of 3,000 lbs. I don't think the max gross weight shown in the aircraft.cfg means the maximum ramp weight and it would have stated that. You'll notice that the load manager assumes 1,500 lbs for taxi fuel so using the 630,500 lbs as the max for take-off, the max ramp weight would be 632,000 lbs, or 635,000 lbs using the max weight in the cfg file. So that being the case, why is it that the maximum weight is 630,500 lbs in the load manager and the maximum weight is 633,500 lbs in the aircraft.cfg? Is the max gross weight in the aircraft.cfg file the same reference weight as the load manager? if so, they should be exactly the same. Also, how do I go about editing the the max weight in the load manager program? Ken. The load manager says 1500lbs taxi assumed but it doesn't mean you can't have more. You're making it more complicated than it is. 633500 is listed in the cfg because you can load it with fuel all the way to that weight. However, the MTOW is 630500 so you can't take off till you reach that weight. And no, you can't edit the coded values of the load manager. ~William Genovese~
February 27, 201511 yr Author Okay. I think I understand it better now. I've always interpreted the maximum gross weight as the maximum take-off weight of the aircraft. I've noticed right next to this, it says max ramp weight but there's no value listed. So, is the 633,500 lbs the max ramp weight of the aircraft? I figure it must be since during taxi, the fuel is burn down to the maximum take-off weight of 630,500 lbs. That's quite of bit of fuel to burn during taxi, and I guess the MD-11 would burn about 3,000 lbs if it had to wait in line at busy airports. Am I understanding it correctly now? The reason I ask about editing the PMDG MD-11 load manager is because since there are different weight specifications for a variety of MD-11s and different ZFW values, one could edit that. Ken.
February 27, 201511 yr Yes, you understand correctly now. Yes, there are different mzfw for different versions, but you cannot edit them within the coding. Each Mzfw, 430k for passenger, 461.5(?) For the freighter, is the max weight option one could receive from McDonnell Douglas for each type. http://www.boeing.com/boeing/commercial/airports/plan_manuals.page Click on md-11 and you can see the options yourself. It doesn't list the 461.5 zfw option for some reason, but I know it exists and at least Lufthansa and UPS have that option on at least some of their fleet. What's cool about having the max option modeled, it's that you can pretend to have a less capable option if you want. ~William Genovese~
February 28, 201511 yr Author Hi William, Here's another one that's strange to me why they would list these weights differently. Is the principal here still the same? These weights are from the Wilco PIC 737-300: Aircraft maximum weights from the aircraft.cfg file: Max Taxi Weight: 135,500 lbsl Max Take-Off Weight: 135,000 lbs Max Landing Weight: 114,000 lbs Max Zero Fuel Weight: 106,500 lbs Aircraft Maximum Weights from the Manual: Max Taxi Weight: 131,000 lbs Max Take-Off Weight: 130,000 lbs Max Landing Weight: 114,000 lbs Max Zero Fuel Weight: 105,000 lbs Ken.
February 28, 201511 yr This is a PMDG forum and I don't want to guess why their manual differs from the aircraft.cfg file. Each aircraft will have slightly different dry operating weight for a multitude of reasons. Why the 5000 lb difference in MTOW can only be answered by Wilco. Dan Downs KCRP
February 28, 201511 yr Hi William, Here's another one that's strange to me why they would list these weights differently. Is the principal here still the same? These weights are from the Wilco PIC 737-300: Aircraft maximum weights from the aircraft.cfg file: Max Taxi Weight: 135,500 lbsl Max Take-Off Weight: 135,000 lbs Max Landing Weight: 114,000 lbs Max Zero Fuel Weight: 106,500 lbs Aircraft Maximum Weights from the Manual: Max Taxi Weight: 131,000 lbs Max Take-Off Weight: 130,000 lbs Max Landing Weight: 114,000 lbs Max Zero Fuel Weight: 105,000 lbs Ken. Wouldn't know about Wilco either as I don't own them. However, when you look at the pmdg 737ngx manuals (not the intro, but the ones that are basically Boeing's manuals like the fcom) they mention the -800 having a MTOW in the 150's. However, it is understood that there are higher weight customer options. Maybe wilco could only get info on the 131k version, but knew it was capable of 135k so they put that in the cfg ~William Genovese~
February 28, 201511 yr It's worth bearing in mind that there is a difference between maximum structural weights and maximum certified weights. DOWs will vary between airlines (and even between aircraft of the same airline) dependent on the specific equipment etc that is fitted. MTOWs are quite frequently 'written down' to reduce en-route navigation charges (for instance, Ryanair have different MTOWs for their NGs that they write up or down depending on the routes they're flying, and BA's short-haul 767s have artificially low MTOWs (three aircraft at 158T, another set at 172.3T and only the long-haul airframes at the full 181.4T) for the same reason -- the DOWs and MZFWs vary between airframes as well. I would guess that the cfg file represents the structural limits whereas the load manager reflects the certification limits which is what matters to the flight crew. Simon Kelsey
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