Originally Posted by
JammedStab
Here is a document with page highlighted explaining how far there is an analysis for terrain after which point, there could be a tall mountain...like Calgary or Denver don't go straight out forever.
or google faa ocs 25/46 miles to get to the exact page on the appropriate link provided.
U.S. TERPS is
only for all engines operating. In non-mountainous areas the IFR obstacle departure procedure (ODP) is assessed out to 25 miles. In regulatory Designated Mountainous Areas (DMAs) the assessment is to 46 miles. If a 40:1 performance surface cannot be maintained in all directions, then a route ODP must be developed for publication.
The assumption: with all engines operating you will be level at a legal IFR altitude within those distances.
With OEI it becomes the operator's responsibility to assess the takeoff and en route-climb flight path. At a places such as Calgary or Denver the operator's performance department needs to design OEI routes that don't go straight-out into high terrain..