Under PANS-OPS the standard Procedure Design Gradient for a missed approach is 2.5%. Approach chart minima are published based on that. If a higher gradient can be achieved then the approach chart can show lower minima based on a higher gradient such as 5%. From memory, an example would be the Runway 01R ILS minima at Dalaman in Turkey (LTBS) which give minima of around 850 feet for 2.5% missed approach gradient and 210 feet for 5% as you can start the missed approach from closer to obstacles with the better gradient.
For Departures under PANS OPS the “standard “ initial Procedure Design Gradient is also 2.5% above the Obstacle Identification Surface (OIS) which is then increased by 0.8% to give 3.3%. Should a higher gradient be required to achieve obstacle clearance then this too is published on the Departure chart with a required gradient to an altitude. Again Dalaman is a good example where the BENEM 1R SID is annotated as requiring a 5% gradient until 7500 feet again from memory. (I retired 4 years ago!) DOC 8168 Vol 1 refers.
Last edited by Matey; 4th Dec 2021 at 23:05.