Hi there ,
Can anyone confirm when calculating etas we need to take into more than 5degrees of drift consideration from the whizwheel for GS calculations? Or still it is 10 degrees or more for etas ?
Have casa changed the requirement in recently ?
Just bit worried for my upcoming exam questions on PNR and ETP calculations
This is a near universal point of confusion when using the Jepp CR.
The correct solution is to run the ETAS calculation ALL the time.
However, if you look at the trigonometry, as the drift angle gets closer to zero, the effect of the trigonometry gets closer and closer to having no effect. If you REALLY want to, you can start thinking about not considering it as you get to angles much less than 15 degrees and, by the time you are down to 5 degrees or less it is negligible.
However, you are still going to set up the sum for the rest of the solution so why not just include the correction ?
CASA is on record saying they won't worry about ETAS below 5 degrees. Take your pick.
Engineering specialist in aircraft performance and weight control.
