Cant fly 737NG Higher than Flt340

[nhagag 26]

Hello thereI see many comercial flight routes by American, Continental and others flying the 737-800 at flt400 and even flt410.When I try to re-enact these flights I get an FMC error stating that my maximum flight is 343. When I request flt380 or higher I am usually more than half way through the route and my fuel tanks are not even half full.Any reason why?Thanks Bill

[Guest Pilot533]

I always have this problem, I think it is a bug.

[falcon999 24]

What cost index are you using?

[downscc 1,327]

Not a common bug.. unless you are very heavy. For example, SWA flys 737-700 from KSAT to KBWI everyday at FL410. However, the ETE is 2:44 and a PMDG Fuel Planner fuel load is less than 26,000 lb allowing for plently left over. If your tanks are full you'll never make it FL410. OBTW SWA uses cost index of 33 (maybe).

[Tabs 2,790]

Check your fuel load - you probably have way too much loaded for the route...

[nhagag 26]

Hi GuysI usually use Fsbuild fuel estimate with approximately 5-6000 lb reserve at landing. Cost index is 70-80%.I see that some of you are thinking it is the cost index and some are thinking it is too much fuel. Shold I lower the cost index?Bill

[downscc 1,327]

What is your GTOW (gross takeoff weight)? A cost index of 70-80 is normal.

[monnie 1]

I agree with you. I fly some of those routes and i find that it is important to calculate the fuel and weight using whatever tools or devices you might have.Using Flightaware I have often attempted to immulate the aircrafts progress to include altititudes. What I see is that sometimes the plane has to cruise at a certain step before it is able to climb to its final cruising altitude.Fuel weight is an issue. a couple of examples are SWA from KMDW to KDEN flies at 40000,with around 135 pax, 11866 lbs cargo, and uses 14100.76 lbs of fuel not counting extra fuel needed. I fly with 18608 lbs for the 781 mile trip. KSTL to KSLC uses close to the same amount for a 1014 mile trip. Monnie CrenshawBest regardsJan1,KINDWhen I push the button and it works, I'm happy:-)HP Media CenterPentium D 2.80 GHz Duel core2.00 GB RAMNVIDIA GeForce 6200SEConexant Falcon II NTSCXP SP2