Thanks, I missed the question on required gradients entirely. That's what I get for leaving my bifocals upstairs....
On the topic of required gradient by segment, something to add here is that there are really two aspects to these gradients. One is basic WAT certification, (the gross percents indicated) which, as OS indicates, do not reference ground effect, but also don't reference obstacles. The second requirement is to degrade the gross climb performance before using it in obstacle clearance calculations (net takeoff flight path).
When a student asks me what the required climb gradient is for an operational exercise, I normally respond first with 'whatever it takes to miss the rock'. The net-to gross decremenents vary with the number of engines, OS provided the data for a twin. Depending on the obstacle analysis method used, there may be other additives. 35 feet is standard, however when departing from a wet or contaminated runway, there are tricks played with this. If a turn is involved, the margin generally is increased.
When providing min altitudes for turns or acceleration, operators are required to identify the gross altitude (i.e. what the crew will see on the altimeter) for the maneuver. Depending where in the world this is done, there may be yet further additives for altimeter error and cold temperatures. On occasion these themselves can back-drive an increased climb requirement and associated weight decrement.
I see a related question on climb gradients on all engines on another thread. I'll wander over there shortly. There is a common belief that analysing a departure for the one engine inoperative case guarantees SID climb gradient compliance. Not actually true.
I've probably gone from too little all the way over to too much, now that I'm armed with my glasses AND too many coffees....
I should ask what region you are considering. Beyond the basic stuff discussed here, there are differences between ICAO, Europe, US and Canada.
Cheers
Vs