GM1 CAT.OP.MPA.115 Approach flight technique — aeroplanes

CAA ORS9 Decision No. 47

Text in magenta in force from 30 October 2025

CONTINUOUS DESCENT FINAL APPROACH (CDFA)

(a) Introduction

    (1) Controlled flight into terrain (CFIT) is a major hazard in aviation. Most CFIT accidents occur in the final approach segment of non-precision approaches; the use of stabilised- approach criteria on a continuous descent with a constant, predetermined vertical path is seen as a major improvement in safety during the conduct of such approaches. Operators should ensure that the following techniques are adopted as widely as possible, for all approaches.

    (2) The elimination of level flight segments at MDA close to the ground during approaches, and the avoidance of major changes in attitude and power/thrust close to the runway that can destabilise approaches, are seen as ways to reduce operational risks significantly.

    (3) The term CDFA has been selected to cover a flight technique for any type of NPA operation.

    (4) The advantages of CDFA are as follows:

(i) the technique enhances safe approach operations by the utilisation of standard operating practices;

(ii) the technique is similar to that used when flying an ILS approach, including when executing the missed approach and the associated missed approach procedure manoeuvre;

(iii) the aeroplane attitude may enable better acquisition of visual cues;

(iv) the technique may reduce pilot workload;

(v) the approach profile is fuel-efficient;

(vi) the approach profile affords reduced noise levels;

(vii) the technique affords procedural integration with APV operations; and

(viii) when used and the approach is flown in a stabilised manner, CDFA is the safest approach technique for all NPA operations.

(b) CDFA

    (1) Continuous descent final approach is defined in Annex I to this Regulation.

    (2) An approach is only suitable for application of a CDFA technique when it is flown along a nominal vertical profile: a nominal vertical profile is not forming part of the approach procedure design, but 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:

      (i) NDB, NDB/DME;

      (ii) VOR, VOR/DME;

      (iii) LOC, LOC/DME;

      (iv) VDF, SRA; or

      (v) GNSS/LNAV.

    (3) Stabilised approach (SAp) is defined in Annex I to this Regulation.

      (i) The control of the descent path is not the only consideration when using the CDFA technique. Control of the aeroplane’s configuration and energy is also vital to the safe conduct of an approach.

      (ii) The control of the flight path, described above as one of the specifications for conducting an SAp, should not be confused with the path specifications for using the CDFA technique. The predetermined path specification for conducting an SAp are established by the operator and published in the operations manual part B.

      (iii) The predetermined approach slope specifications for applying the CDFA technique are established by the following:

        (A) the published ‘nominal’ slope information when the approach has a nominal vertical profile; and

        (B) the designated final-approach segment minimum of 3 NM, and maximum, when using timing techniques, of 8 NM.

      (iv) An SAp will never have any level segment of flight at DA/H or MDA/H as applicable. This enhances safety by mandating a prompt missed approach procedure manoeuvre at DA/H or MDA/H.

      (v) An approach using the CDFA technique will always be flown as an SAp, since this is a specification for applying CDFA. However, an SAp does not have to be flown using the CDFA technique, for example, a visual approach.

The title text below will replace the title and text above on 30 October 2025:

GM1 CAT.OP.MPA.115(b) Approach flight technique — aeroplanes

CONTINUOUS DESCENT FINAL APPROACH (CDFA)

  1. Introduction

    1. Controlled flight into terrain (CFIT) is a major hazard in aviation. Most CFIT accidents occur in the FAS of approach operations flown using NPA procedures. The use of stabilised-approach criteria on a continuous descent with a constant, predetermined vertical path is seen as a major improvement in safety during the conduct of such approaches.

    2. The elimination of level flight segments at MDA close to the ground during approaches, and the avoidance of major changes in attitude and power/thrust close to the runway that can destabilise approaches, are seen as ways to reduce operational risks significantly.

    3. The term CDFA has been selected to cover a flight technique for instrument approach operations using NPA procedures.

    4. The advantages of CDFA are as follows:

      1. the technique enhances safe approach operations by the utilisation of standard operating practices;

      2. the technique is similar to that used when flying an ILS approach, including when executing the missed approach and the associated missed approach procedure manoeuvre;

      3. the aeroplane attitude may enable better acquisition of visual cues;

      4. the technique may reduce pilot workload;

      5. the approach profile is fuel-efficient;

      6. the approach profile affords reduced noise levels;

      7. the technique affords procedural integration with 3D approach operations; and

      8. when used and the approach is flown in a stabilised manner, CDFA is the safest approach technique for all instrument approach operations using NPA procedures.

  2. Stabilised approach (SAp)

    1. The control of the descent path is not the only consideration when using the CDFA technique. Control of the aeroplane’s configuration and energy is also vital to the safe conduct of an approach.

    2. The control of the flight path, described above as one of the specifications for conducting an SAp, should not be confused with the path specifications for using the CDFA technique. The predetermined path specifications for conducting an SAp are established by the operator and published in the OM.

    3. The appropriate descent path for applying the CDFA technique is established by the following:

      1. the published ‘nominal’ slope information when the approach has a nominal vertical profile; and

      2. the designated final-approach segment minimum of 3 NM, and maximum, when using timing techniques, of 8 NM.

    4. Straight-in approach operations using CDFA do not have a level segment of flight at MDA/H. This enhances safety by mandating a prompt missed approach procedure manoeuvre at DA/H.

    5. An approach using the CDFA technique is always flown as an SAp, since this is a specification for applying CDFA. However, an SAp does not have to be flown using the CDFA technique, for example, a visual approach.

  3. Circling approach operations using the CDFA technique

    Circling approach operations using the CDFA technique require a continuous descent from an altitude/height at or above the FAF altitude/height until MDA/H or visual flight manoeuvre altitude/height. This does not preclude level flight at or above the MDA/H. This level flight may be at MDA/H while following the IAP or after visual reference has been established as the aircraft is aligned with the final approach track. The conditions for descent from level flight are described in AMC7 CAT.OP.MPA.110.