Takeoff obstacle avoidance & runway analysis
Ok, here is the scenario, on an 800XP, FAR 135 recurrent ride; the check pilot presented this situation: VMC departure (clear and 20) from RWY 15 from Addison, TX (KADS).
In front of me I have the Obstacle Departure Procedure (HUBBARD Departure), the computer generated runway analysis and a made up NOTAM indicating that the first 2000 feet of the runway is closed leaving 5205 ft. available for takeoff. The current runway analysis indicates an obstacle limiting weight of 26,990 lbs (NOTAM obstacle limiting weight). After going through the charts in the AFM I found that the runway limiting weight is 27990 lbs., with 5202 ft. of runway.
This is where it becomes gray. Do I takeoff using the obstacle limiting weight of 26,990 lbs. or because it is VMC and I can see and avoid the “multiple building beginning 1085’ from departure end of runway, 21’ left of centerline, up to 321’AGL/956’MSL” and go with the runway limiting weight of 27990 lbs. and make my destination without a fuel stop.
My answer was the more conservative, and to make the fuel stop. This was accepted, however after vast research and looking at several closed threads that never really addressed this precise issue (of obstacle clearance analysis and VMC departures), the question still lurks in the back of my mind. It would probably be acceptable for FAR 91 operations to takeoff with the heavier weight, but for 135 and 121, I don’t see a definitive regulation as to why this cannot be done.
Additionally, looking into the Instrument flying handbook, it say’s to see and avoid obstacles thus eliminating the need for an obstacle restrictive runway. (does this only apply for FAR 91?) Then it talks about escape route procedures and so forth. Also looked into the FAA instrument Check Pilots handbook and came up short there as well.
So where is the definitive answer as to why you cannot see and avoid obstacles under FAR 135 and 121?