Are you saying at MGTOW and +15 all the way up, the 850XP (winglets) will go straight to 410 without a step climb? If that is is case, WOW! Not your father's Hawker. That would open up a lot of places for the Hawker, mainly PHNL without the pucker factor or possibly having to turn around if the winds are stronger than 50-60 Knots on the nose.
As for the PERF calculations, are you entering the winds as well in the computer or are you just putting the FLxxx and cruise speed, letting it figure out the rest? I found that if you enter the winds (Duats or FLTPLAN), the #s work out really well. Try entering the winds at every fix, as +300-600lbs is quite a difference.
Something is not working/being programmed correctly if you are seeing 0 fuel at landing during the climb out. On FMSs
without perf computers, you'll see that if you are going within 20-30% of the aircraft's endurance limit, or planning on landing with less than 25% of mission fuel: 1500lbs = 225 US Gallons. NON-Perfs use
current fuel burns and speed only, then does the math, giving you your destination fuel, ETE, and ETA as if you were to continue at your current fuel burn and speed. As you climb thus becoming more efficient, especially once at altitude and on speed, the FMS will "create" fuel to give you a better and more accurate ETE, ETA, and idea of what you are going to have upon landing in terms of fuel.
On units
with PERF computers, it takes into account things that non-Perf computers do not, such at 250 below 10, enroute winds (some), VNAV data, fuel burns based upon altitude and speeds down the road, etc, then computes all that data taking those factors into account and spits out a fairly accurate #, typically within 2-7 percent. It's good enough to calculate ref speeds/weights during any regime of flight without having to do the math in your head.
Also, I'm thinking the API winglets are aftermarket, so have you adjusted the default setting of your PERF computer to reflect the change in performance? For example, do you still need 1500lbs as a reserve, or can you plan for less? What are you telling it you are going to use for a climb schedule, cruise speed, and decent speed? To keep it simple, tell the FMS as much as you possibly can and the #s will be spot on. Try telling it winds at every fix, and
winds and aircraft speed at every fix below 10. Don't forget the approach segment. Tell it at the FAF you'll be at whatever the plate says you should be at and REF+10 (if that is what you use). Create a fix at the Threshold, and tell it you'll be at REF and 50ft above it when you ge there.
Finally, if you typically cruise at 400 or 410, there is not a lot of traffic up there, so you're more likely to get Direct more often than you would if you were down with all the Airline traffic. Could that be where you are getting the fuel saings?
g159av8tor said:
Thanks for the info.
With the API winglets, the 800XP2 accelerates nicely under hot and heavy conditions and will straight to FL400/410, 2000 to 4000 feet above the standard 800XP charts for max cruise altitude for temp and weight. The PERF landing fuel calcualtion is always 300-600 pounds lighter than actual reserve amounts, about a 100lbs per flight hour increase in reserve gas. The shorter the flight, the more accuarate it is. Less variables I guess. We've gone from having 0 reserve to 1500lbs during a transcon flight westbound as calculated by the ProLine cruising at M.75. For us, that speed gives us the best FF for the speed, usually 4-6 longer than MAX speed and up to 700lbs of fuel savings, depending on the length of the flight.
Again, thanks for the reply.
tailwinds....
