Originally Posted by
fsuskypilot
FATboy,
When calculating climb performance OEI, the AF actually allows us to scrape paint...provided the first two options listed below aren't feasible.
11-202V3 (Of course your MAJCOM or 11-MDS may restrict it further)
8.7.2.2.1 The following methods are authorized for computing engine-out climb performance on departure. Methods may not be combined. These are in priority order
8.7.2.2.1.1. Meet or exceed the published climb gradient, or 200 ft/nm (whichever is higher) for the selected departure, with one-engine inoperative, or;
8.7.2.2.1.2. Special Departure Procedure (SDP) (if available), or;
8.7.2.2.1.3. Vertically clear all obstacles along the planned departure path with one engine inoperative, or;
So if you are down to using the third option, the only acceptable technique to calculate required OEI CG is to subtract .8% (48 ft/nm) from the published CG. This is regardless of whether the published CG was calculated using the old 48 ft/nm required obstacle clearance (ROC) or the current 24% ROC. (fully detailed in 11-217V1 chpt 9)
So with a standard climb of 3.3% (200 ft/nm) your OEI climb requirement is 2.5% (152 ft/nm)
I fully understand what the USAF allows and requires us to do.
The big question I have is, the FAA saying that TERPs IS NOT to be used for OEI analysis. That creates a lot of WTFs for me. We've all flown FAA TERPs departure procedures ... and used those published climb graidients to calculate OEI TOLD. So the question I have is, why? What is wrong with the 200'/NM and why isn't it always good? Additionally, why doesn't USAF TOLD take into account the horizontal separation requirements?
SDPs, when they came out, were a vast improvement over the way we used to do TOLD (KC-10 guys can definitely relate). But SDPs initially were designed to get you 35 feet above the obstacles (not sure about the horizontal). But the USAF in their infinite wisdom decided to reduce this down to 0 feet ... as normally required. I think this was a big mistake. But then again, we've not hit anything so who cares?
I hear the SDPs aren't very popular up at HQAMC / HQUSAF ... and they intend to make them go away. BIG mistake -- especally after reading the Advisory Circular. Something just doesn't jive.