Looking for help on ATPL - Equal time point to alternates.
Thread Starter
Joined: Oct 2010
Posts: 4
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From: NZ
Looking for help on ATPL - Equal time point to alternates.
The basics I have:
Flying from point A to point B, where is the equal time point to get to A or B?
I can do that in still air and with wind using the formula:
Dist to ETP = (total Dist X GS Home) divided by (GS out + GS Home)
Where I am having problems and can’t find the information is
Flying from point A to point B, where is the equal time point to return to A or diver to the Alternate at point C or what is the equal time point to 2 different alternates when flying along route A to B I need to be able to this in both still air and wind.
Is there a way of working this into the above formula or does it need to be done via plotting and if so how?
Any help would be greatly appreciated
Flying from point A to point B, where is the equal time point to get to A or B?
I can do that in still air and with wind using the formula:
Dist to ETP = (total Dist X GS Home) divided by (GS out + GS Home)
Where I am having problems and can’t find the information is
Flying from point A to point B, where is the equal time point to return to A or diver to the Alternate at point C or what is the equal time point to 2 different alternates when flying along route A to B I need to be able to this in both still air and wind.
Is there a way of working this into the above formula or does it need to be done via plotting and if so how?
Any help would be greatly appreciated
Joined: Aug 2001
Posts: 775
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From: Dorset
The answer to your question depends upon your reason for asking it.
This question also appears in the Tech Log Forum. As stated by BOAC in that forum by, in the real-world the solution of this type of problem is quite complex.
If you are preparing to take ATPL exams the question becomes a bit easier. Complex questions of this type are rare in the JAR ATPL exams but quite common in some others such as the Indian DGCA ATPL and CPL exams.
The questions include the distances between the various locations plus the wind speed/direction and the TAS or the ground speed for each leg of the flight. With this information you can apply the formula in the usual way using the appropriate speeds and distances.
Pass rates for JAR ATPL exams are usual better than 90%. Pass rates for the Indian DGCA exams are usually closer to 5%.
This question also appears in the Tech Log Forum. As stated by BOAC in that forum by, in the real-world the solution of this type of problem is quite complex.
If you are preparing to take ATPL exams the question becomes a bit easier. Complex questions of this type are rare in the JAR ATPL exams but quite common in some others such as the Indian DGCA ATPL and CPL exams.
The questions include the distances between the various locations plus the wind speed/direction and the TAS or the ground speed for each leg of the flight. With this information you can apply the formula in the usual way using the appropriate speeds and distances.
Pass rates for JAR ATPL exams are usual better than 90%. Pass rates for the Indian DGCA exams are usually closer to 5%.
Joined: Aug 1998
Aviation Qualifications: ATPL
Posts: 6,623
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From: Ex-pat Aussie in the UK
As stated by BOAC in that forum by, in the real-world the solution of this type of problem is quite complex.
Thread Starter
Joined: Oct 2010
Posts: 4
Likes: 0
From: NZ
Thankyou for the help
Apologies for double posting, I needed a quick answer so was trying to get more people to read it by copying the post into the tech forum as well. Checkboard seems to have covered everything I need in his post there.
Greeny
Greeny
Last edited by Greeny989; 15th October 2010 at 09:50. Reason: Spelling
