take-off distances
 

I need enlightening over the definitions and differences between TODR,TORR,TODA,TORA for my ATPL Performance exam. The text that I am using contains conflicting information.

Any help gratefully received.

IMHO, try reading book called Aircraft Performance Theory for Pilots by P J Swatton, an instructor on the subject at good old PPSC. He puts all the technical stuff into pilot's language without over-simplification. Hope it helps.

Sorry Lumpy, I should have added that the book is published by Blackwell Science,ISBN No. 0-632-05569-3. Website www.blackwell-science.com

TORA: The distance available for rolling your wheels along the surface during the take-off run.

TORR: The distance required to roll your wheels along the surface during the take-off run - or you roll of the end of the runway before getting airborne.

TODA: The distance available for rolling your wheels along the runway surface during the take-off run and and then climb to a specified height (eg 50') above the runway the surface.

TODR: The distance required to roll your wheels along the runway surface during the take-off run and and then climb to a specified height (eg 50') above the runway the surface.

Just to clarify what Tinny has so ably explained -

We need also to consider ASDA (Accelerate-Stop Distance Available).

TORA is the basis - the hard stuff your a/c can roll on with no restriction.

ASDA is TORA plus stopway (stuff your a/c can roll on during a RTO) The excess past TORA (stopway) may well be damaged by the a/c, but is used only in emergency.

TODA is not necessarily all stuff your a/c can roll on. TODA often exceeds TORA - it cannot be less. It includes stopway and may include clearway (an obstacle free plane over which an a/c may fly while making screen height). Clearway is often water.

Muchas gracias - very clear and helpful.

An additional point to clarify ...

TORR includes a portion of the airborne distance to 35 ft .. either one half or one third depending on the rule set. This ensures that there is a margin to protect against the aircraft's running past the end of the declared distance available.