How to determine what flight level to input into CDU when planning a IFR flight?

[captain420 3,099]

I want to know what method everyone use to determine what FL to input into the CDU when flying heavy jets like 737/777 A318-A321, etc.

 

Do you use the value that PFPX provides you with, or do you find it from a real world route using websites such as flightaware.com?

[Sesquashtoo 2,846]

Well, you can be assigned as low as FL180.

 

But mostly for the norm,

 

East heading flight plan, odd thousands

 

 

West heading flight plan even thousands

[richie894 45]

I go by flightaware.

[Orlaam 306]

Flightaware, and then I will alter if needed depending on winds or other factors.  RW commercial traffic will go up or down often enough, especially for turbulence.

[twharrell 38]

Aaron, I typically check flightaware.com, which typically gives altitudes fir most flights. I use whatever PFPX or Simbrief recommends but I sometimes crosscheck it with flightware, because you may get an unrealistic altitude. For exampke, when flying from KLAS to KLAX (a 40 min flight), FL380 is not very realistic since you'll reach top of descent well before you ever hit FL380.

[Orlaam 306]

Aaron, I typically check flightaware.com, which typically gives altitudes fir most flights. I use whatever PFPX or Simbrief recommends but I sometimes crosscheck it with flightware, because you may get an unrealistic altitude. For exampke, when flying from KLAS to KLAX (a 40 min flight), FL380 is not very realistic since you'll reach top of descent well before you ever hit FL380.

 

LOL, yeah more like FL220,  FL280 tops.  My last flight was this route in the NGX.  I was at 280 for about 30 miles, maybe 40. 

[spearmint_flyer 579]

It's mostly tied to fuel economy which translates into which level has the most favorable winds.

 

Then you add aircraft performance into the mix. What is the highest the aircraft can fly under that weight configuration. Many long haul flights change altitudes several times to a higher in some occasions because they get lighter the more fuel they burn.

 

The best starting point is using a flight planing tool like PFPX or FSbuild that tells you automatically what the best altitude for the flight is and in the navlog it also shows you where to step climb.

 

Hope that it explains and helps b

[cmpbellsjc 2,960]

I also use the briefing page in ASN to check to see what the altitude the most favorable winds will be for my route.

[Orlaam 306]

I also use the briefing page in ASN to check to see what the altitude the most favorable winds will be for my route.

 

I do this as well.  Then adjust based on other factors.

 

I did have a FP from FlightAware the other day that called for FL410.  No problem I thought.  Well, despite being a short route, the weight was too much.  Could only hit 380.  I was full of PAX though.

[captain420 3,099]

Thanks guys. I will check flightaware to see what they use and base it off that. I have been using PFPX and sometimes it's given me an unrealistic FL... such as FL380 for a 45 minute flight.