For JAR performance and a two engined aircraft landing from an instrument approach, the aircraft needs to be able to comply with both the following conditions:
1 With both engines running and in the landing configuration, achieve a climb gradient of 3.2% This is essentially a baulked landing and go - around.
2 With the critical engine inoperative and gear up with missed approach flaps, the aircraft needs to achieve a climb gradient of 2.1% from CAT 1 or 2.5% if decision height is below 200 feet.
In the design of instrument approaches PANs ops requires the missed approach phase provides 30m obstacle protection based on a 2.5% gradient.
So worst case and heaviest landing weight, on a cat1 approach with one engine inoperative, at the missed approach point the aeroplane if handled correctly will achieve at least a 2.1% climb gradient. If following the published missed approach you would be converging towards the 2.5% obstacle plane considered in the missed approach design, but the minimum obstacle clearance being provided is 30m on the intermediate part.
This is not to be confused with take of requirements which have a lower obstacle clearance limit, as low as 15 feet when launching from a wet runway and based on a 2.4% gradient.
All very boring I hear you say so whats the answer. Each airfields missed approach climb gradient needs to be considered if contemplating a single engine missed approach at max landing weight from minimums. I would suggest you land !
ref: JAR Ops 1 510 Landing Destination and alternate aerodromes
PANS Ops 1 volume 1 section 3.6, missed approach