While studying FAA's Instrument Procedure Handbook, I noticed these minimum performance requirements for obstacle clearance, when a SID or ODP is absent for a particular runway:

-- Cross the departure end of the runway (DER) at least 35ft AGL.

-- Climb to 400ft above the DER before turning.

-- Maintain a climb of at least 200ft per nautical mile (FPNM) until reaching minimum IFR altitude.

The minimum IFR altitude is 1000ft above obstacles, or 2000ft in mountainous areas.

I was wondering if the last rule, regarding a constant climb with a minimum climb gradient of 200 ft/NM (if no other is specified) until reaching minimum IFR altitude, applies also in case of SIDs, or it is up to pilot's or ATC's judgement to establish a minimum climb gradient for a particular, arbitrary portion of the SID route.

In other words, if for a particular SID it is mentioned "climb gradient of X ft/NM until Y altitude", then after reaching Y altitude is the pilot allowed to fly with whatever climb gradient he deems necessary, even if it is less than 200 ft/NM?

p.s. I have to give some credit to this question, though it is not a duplicate since it asks if a minimum performance applies in case of the absence of a SID or ODP. I am asking if a minimum performance (especially the last rule regarding the minimum IFR altitude) applies when the pilot is following a SID.


1 Answer 1


I believe that now I am able to provide an answer to my own question.

I think that the "minimum of 200 ft/NM" rule applies during the whole climb phase. In other words, until the end of the SID, where either the enroute phase begins or the SID itself provides some enroute transitions as a passageway to the enroute phase.

FAA's TERPS manual clearly states:

Chapter 2, "Sloping OCS" 2-1-4b. The concept of providing obstacle clearance in the climb segment of an IFP is based on the aircraft maintaining a minimum climb gradient. [...] The minimum climb gradient that will provide adequate ROC in the climb segment is 200 ft/nautical mile (NM), unless a higher gradient is specified.

In addition, the rule is also repeated in the PBN manual:

Chapter 1, "Common Criteria" 1-3-1g(2). Climb Gradient (CG). Obstacle clearance in a climb segment is dependent on the aircraft maintaining a minimum CG to a specified altitude. The minimum CG (also referred to as standard CG) is 200 ft/NM.


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