You're quite correct, departures are different. In addition to meeting the IFR departure climb gradient requirements, an air operator has to meet the aircraft performance requirements. In many cases, the IFR departure is more onerous than the aircraft performance as the captured area is larger and the obstacle requirements are less stringent. Aircraft performance gradients deal with things like second segment, etc. whereas IFR gradients are the average climb gradient to clear the obstacle with a very healthy obstacle clearance safety factor.iflyforpie wrote: ↑Sat Aug 08, 2020 8:47 am Departures are different. Quite possibly since you are entering them from a static environment vs a dynamic one and the actual risk is less since most aircraft pass well above 35 above the departure end of the runways vs below DH or at MDA at the MAP.
They used to have missed approaches in the RCAP well in excess of 425ft per nautical mile (I want to say 460 or 500 ft in some cases) before the Advisory Circular or whatever came out restricting them to under 425. But lots of departures have 500ft/nm requirements which is pretty insane when you thing about it—especially if you’re dealing with an engine failure.
Until a few years ago, any non-standard missed approach gradients (>200 ft/nm) need at TC exemption; this changed to allow up to 425 ft/nm without exemption. Anything above that would need an exemption, which, as you point out, is a pretty healthy climb gradient particularly if one loses a fan.
