Hey guys,

Quick question on the ground part of the CPL flight test.

Is it required to do the interpolation for things like the FD winds, cruise performance and take-off and landing distances? Or is it acceptable to just go to the higher (more conservative) value in the POH?

Example: Lets say I need to plug in the winds for 4500ft in my nav log and the FD is 3000 at 360@12 and 6000 at 050@27 Do I need to interpolate? Same thing for take-off and landing distances, interpolate or I can use the higher PA and temp value in the book for the airport in question?

I know the method of interpolation but I just find that I am running out of time for that 1hr prep time with plotting the course, doing the nav log, the fuel calculation, weight and balance and t/o and landing distances... Any tips would be greatly appreciated!

Thank you,
Radar

I would suggest interpolating half-way between two wind forecasts is a useful skill and yes, you should be willing and able to do it, if you want to earn a CPL.

I wouldn't go into much more detail than "split the difference", not because of the difficulty but since the forecasts aren't that accurate, there isn't a lot of point.

Alternatively you can find another website that gives you wind forecasts on a continent-wide 20km grid every couple of hundred feet altitude at hourly intervals.

i do suggest the FD interpolation, but i definitely suggest the t/o and landing distance interpolation.

i did my flight test a month or so ago, but i used winds from before the "hour", i used the 5 am winds when my flight test was at 9 am. just print them off before hand. all of my other weather was from 8 am but it saved me a whole bunch of time, got my weather package on the hour and finished with time to spare.