The new EU Ops should provide excellent bedside reading -
AMC 2 OPS.GEN.150:
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3. All non-precision approaches should be flown using the Continuous Descent Final Approach (CDFA) technique. Different procedures may be used for a particular approach to a particular runway
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AMC 4 OPS.GEN.150:
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4. The DH to be used for an approach should be the highest of: a. the minimum height to which the approach aid can be used without the required visual reference; b. the Obstacle Clearance Height (OCH) for the category of aircraft; c. the published approach procedure DH, where applicable; d. 200 ft for Category I approach operations; e. the system minimum in Table 1 of AMC4 OPS.GEN.150; or f. the lowest decision height specified in the AFM or equivalent document, if stated.
(Table 1 sets a minimum of 300ft for VOR, NDB/DME, LNAV and SRA terminating at 1NM; 250ft for VOR/DME, LLZ with or without DME and SRA terminating at 0.5NM)
AMC 5 OPS.GEN.150:
1. In order to qualify for the lowest allowable values of RVR/CMV detailed in Table 3 of AMC6 OPS.GEN.150.A (applicable to each approach grouping), the instrument approach should meet at least the following facility requirements and associated conditions:
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b. Instrument approaches flown using the CDFA technique with a nominal vertical profile, up to and including 4.5 degrees for Category A and B aeroplanes and 3.77 degrees for Category C and D aeroplanes, where the facilities are NDB, NDB/DME, VOR, VOR/DME, LLZ, LLZ/DME, VDF, SRA or RNAV/LNAV, with a final approach segment of at least 3 Nautical Miles (nm), which also fulfil the following criteria: i. The final approach track is offset by not more than 15 degrees for Category A and B aeroplanes and by not more than 5 degrees for Category C and D aeroplanes; ii. The Final Approach Fix (FAF), or another appropriate fix where descent is initiated is available, or distance to THR is available by FMS/RNAV or DME
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GM2. OPS.GEN.150A (Some 10+ pages on the topic of CDFA) including:
An approach is only suitable for application of CDFA technique when it is flown along a pre-determined vertical approach slope which follows a: i. Designated Vertical Profile: A continuous vertical approach profile which forms part of the approach procedure design. APV is considered to be an approach with a designated vertical profile; or a ii. Nominal Vertical Profile: A vertical profile not forming part of the approach procedure design, but which can be flown as a continuous descent. The nominal vertical profile information may be published or displayed (on the approach chart) to the pilot by depicting the nominal slope or range/distance vs height. Approaches with a nominal vertical profile are considered to be: A. NDB, NDB/DME; B. VOR, VOR/DME; C. LLZ, LLZ/DME; D. VDF, SRA or E. RNAV/LNAV;
Oh yes, and
GM OPS.GEN.150
Additional increments to the published minima may be imposed by the competent authorities to take into account special operations, such as downwind approaches and single-pilot operations.
So, if you fly CDFA, MDA=DA which may = OCA. This is beginning to be reflected in Jeppesen charts where they are publishing DA instead of MDA on NPAs for some European States.