PPRuNe Forums - View Single Post - JAA ATPL Training Questions - CAP698 from UK CAA
Old 17th Nov 2014, 15:04
  #4 (permalink)  
keith williams
 
Join Date: Jan 2011
Location: England
Posts: 661
Received 20 Likes on 13 Posts
You are correct up to the point where you included the term "balanced field".

The CAP says the following


a) When no stopway or clearway is available the take-off distance when multiplied by 1.25 must not exceed TORA.

b) When a stopway and/or clearway is available the take-off distance must:
i) not exceed TORA
ii) when multiplied by 1.3, not exceed ASDA
iii) when multiplied by 1.15, not exceed TODA

A balanced field is simply one in which the TODA is equal to the ASDA.
A field with identical stopway and clearway is a balanced field. A field with no stopway and no clearway is also a balanced field.

The 1.25 factor applies where there is no stopway and no clearway.
The 1.15 factor applies when there is a stopway and/or a clearway.

If it is a question of ASDR, then the regulatory factor is 1.3
Not quite. In all of the cases above we are comparing the TODR with the TORA, ASDA and TODA.

So for example if we have a stopway and/or a clearway we must ensure that

i) The TOD is not longer than the TORA
ii) 1.3 x the TOD is not longer than the ASDA
iii) 1.15 x the TOD is not longer than the TODA

If have no stopway and no clearway we simply need to ensure that 1.25 x TOD is not longer than the TORA.


Curiously although you will find the terms TORR, TODR and LDR, you will not find the term ASDR anywhere in the EASA regulations. Although you may find that it comes up frequently in perf related conversation.

Later in the course you will come across the terms "balanced take-off" and "balanced V1 take-off) These relate to the distance required and not to the distances available.
keith williams is offline