I think I'll take a stab at this one.
Originally Posted by
BIRDIE
...clearance to fly a SID with non-standard climb gradient, no ODP. Does the standard climb gradient of 3.3% keep you clear of obstacles? In other words, can it be assumed that the non-standard climb gradient on the SID serves a purpose other than obstacle clearance since there is no obstacle departure procedure?
No. Reference the Bob2 Departure at UZA and the take off minimums information for the airport (from the front of the book):
http://www.airnav.com/depart?http://...5361BOBCAT.PDF
http://www.airnav.com/depart?http://...0909/SE2TO.PDF
You'll notice that the greater than standard climb gradient for a runway 2 departure is dictated by trees off the DER. At 100 ft tall and a quarter mile from DER, assuming you use more than 3800 ft for take-off, 200 ft per nm is gonna put you in the trees (or too close to them, at least). No ODP is necessary at UZA because the obstacle threat is right there at the airport, and the only thing that is going to get you safely over it is a greater than standard climb.
Not doubting anyone, but I've never seen the daggers either. However, on a NACO SID chart, it is my understanding that the "Takeoff Minimums" section lists the
minimum climb gradient allowed for a safe departure. ATC preferred climb gradients will be specified elsewhere in the procedure. Reference the LGA2 departure:
http://www.airnav.com/depart?http://...AGUARDIA_C.PDF
So, I think my answer is not what you wanted to hear. Perhaps I am wrong. My opinion is however; if the SID has a greater than standard climb gradient published in the "Takeoff Minimums" section of the NACO chart, then you
must comply. Maybe that is not always the case, but that has been my experience. Certainly you cannot always assume that no ODP equals some reason other than an obstacle for the greater than standard climb. Hope this helps.