How do you determine Effective Runway Length?
§ 135.361:
(b) For the purpose of this subpart, "effective length of the runway," for landing means the distance from the point at which the obstruction clearance plane associated with the approach end of the runway intersects the centerline of the runway to the far end of the runway.
(c) For the purpose of this subpart, "obstruction clearance plane" means a plane sloping upward from the runway at a slope of 1:20 to the horizontal, and tangent to or clearing all obstructions within a specified area surrounding the runway as shown in a profile view of that area…
§ 135.385:
(b) Except as provided in paragraph (c), (d), or (e) of this section, no person operating a turbine engine powered large transport category airplane may takeoff that airplane unless its weight on arrival, allowing for normal consumption of fuel and oil in flight (in accordance with the landing distance in the Airplane Flight Manual for the elevation of the destination airport and the wind conditions anticipated there at the time of landing), would allow a full stop landing at the intended destination airport within 60 percent of the “effective length of each runway” described below from a point 50 feet above the intersection of the obstruction clearance plane and the runway.
The Question is:
If the only information available is the information given on an approach chart or the A/FD, how does a (normal) pilot determine the effective runway length at various different airports for practical day-to-day operations?
Effective runway length is absolutely essential for calculating the 60% (destination) or 70% (alternate) landing distance requirement, but there does not seem to be any way of calculating it from the information available.
Thanks