Originally Posted by
AKASHA
135.379 is totally relevant to tracer997's scenario. And nothing was said about losing an engine, which is off-subject. As I read it, the question is simply...
"If I am too heavy to meet the climb gradient on the ODP, can I still take-off at the heavier weight and maneuver visually to avoid obstacles under Part 135... where is the reg??"
135.379 states obstacle clearance requirents both within and outside of the airport boundary. And AC 120-91 reminds us that "operators MUST COMPLY with 14 CFR requirements regarding the development of takeoff performance data and procedures." That is, 135.379.
Thus, 135.379 and AC 120-91, which apply only to OEI, are totally irrelevant to his question.
The issue is, "where is the controlling obstacle along the ODP route?" Answer: It is not published.
There may be many obstacles along an ODP path that penetrate the basic 40:1 path, but only one that dictates the charted climb gradient.
If the controlling obstacle is within 3 miles of the departure end of the runway then an alternative ceiling and visibility will be charted, which can be used in conjunction with the ODP (but usually not with any SIDs). The problem is, if there is an optional ceiling and visibility published in the takeoff minimums, it has little use unless a VCOA (visual climb over airport) procedure is also charted (those are fairly new, thus most airports don't have them). And, a VCOA itself is fraught with hazards unless the pilot is provided a good plan on how to use it safely.