Cosmo, before dismissing other people's knowledge, maybe a further read of manuals may be prudent.
CS-25.119 and CS-25.121 refer:
CS 25.119 Landing climb: all-engines- operating
In the landing configuration, the steady gradient of climb may not be less than 3·2%, with –
(a) The engines at the power or thrust that is available 8 seconds after initiation of movement of the power or thrust controls from the minimum flight idle to the go-around power or thrust setting (see AMC 25.119(a)); and
(b) A climb speed which is – (1) Not less than –
(i) 1·08 VSR for aeroplanes with four engines on which the application of power results in a significant reduction in stall speed; or
(ii) 1·13 VSR for all other aeroplanes;
(2) Not less than VMCL; and
(3) Not greater than VREF.
CS 25.121 Climb: one-engine- inoperative
(See AMC 25.121)
(a) Take-off; landing gear extended. (See AMC 25.121(a).) In the critical take-off configuration existing along the flight path (between the points at which the aeroplane reaches VLOF and at which the landing gear is fully retracted) and in the configuration used in CS 25.111 but without ground effect, the steady gradient of climb must be positive for two-engined aeroplanes, and not less than 0·3% for three-engined aeroplanes or 0·5% for four- engined aeroplanes, at VLOF and with –
(1) The critical engine inoperative and the remaining engines at the power or thrust available when retraction of the landing gear is begun in accordance with CS 25.111 unless there is a more critical power operating condition existing later along the flight path but before the point at which the landing gear is fully retracted (see AMC 25.121(a)(1)); and
(2) The weight equal to the weight existing when retraction of the landing gear is begun determined under CS 25.111.
(b) Take-off; landing gear retracted. In the take-off configuration existing at the point of the flight path at which the landing gear is fully retracted, and in the configuration used in CS25.111 but without ground effect, the steady gradient of climb may not be less than 2·4% for two-engined aeroplanes, 2·7% for three-engined aeroplanes and 3·0% for four-engined aeroplanes, at V2 and with –
(1) The critical engine inoperative, the remaining engines at the take-off power or thrust available at the time the landing gear is fully retracted, determined under CS 25.111, unless there is a more critical power operating condition existing later along the flight path but before the point where the aeroplane reaches a height of 122 m (400 ft) above the take-off surface (see AMC 25.121(b)(1)) ; and
(2) The weight equal to the weight existing when the aeroplane’s landing gear is fully retracted, determined under CS 25.111.
(c) Final take-off. In the en-route configuration at the end of the take-off path determined in accordance with CS 25.111, the steady gradient of climb may not be less than 1·2% for two-engined aeroplanes, 1·5% for three-engined aeroplanes, and 1·7% for four-engined aeroplanes, at VFTO and with –
(1) The critical engine inoperative and the remaining engines at the available maximum continuous power or thrust; and
(2) The weight equal to the weight existing at the end of the take-off path, determined under CS 25.111.
(d) Approach. In a configuration corresponding to the normal all-engines-operating procedure in which VSR for this configuration does not exceed 110% of the VSR for the related all-engines-operating landing configuration, the steady gradient of climb may not be less than 2·1% for two-engined aeroplanes, 2·4% for three-engined aeroplanes and 2·7% for four-engined aeroplanes, with –
(1) The critical engine inoperative, the remaining engines at the go-around power or thrust setting;
(2) The maximum landing weight;
(3) A climb speed established in connection with normal landing procedures, but not more than 1·4 VSR; and
(4) Landing gear retracted.
Chapter 6 in 8168 Vol. II for instance refers:
6.1.1 Requirements
6.1.1.1 A missed approach procedure shall be established for each instrument approach and shall specify a point where the procedure begins and a point where it ends. The missed approach procedure is initiated:
a) at the decision altitude height (DA/H) in precision approach procedures or approach with vertical guidance (APV); or
b) at the missed approach point (MAPt) in non-precision approach procedures.
6.1.1.2 The missed approach procedure shall terminate at an altitude/height sufficient to permit:
a) initiation of another approach; or
b) return to a designated holding pattern; or
c) resumption of en-route flight.
Only one missed approach procedure shall be established for each approach procedure.
Note.— This chapter contains general criteria which apply to all types of instrument landing procedures, as well as criteria specific to non-precision procedures. For the details regarding precision approaches and approaches with vertical guidance, see the applicable chapters.
6.1.2 Phases of missed approach segment
In principle the missed approach segment starts at the MAPt and includes the following three phases (see Figure I-4-6-4):
a) initial phase — begins at the earliest MAPt, and extends until the Start of Climb (SOC);
b) intermediate phase — extends from the SOC to the point where 50 m (164 ft) (Cat H, 40 m (132 ft)) obstacle clearance is first obtained and can be maintained; and
c) final phase — extends to the point at which a new approach, holding or return to en-route flight is initiated. Turns may be carried out during this phase.
6.1.3 Types of missed approach
There are two types of missed approach:
a) straight missed approach (includes turns less than or equal to 15 degrees); and
b) turning missed approach.
6.1.4 Missed approach area
The area considered for the missed approach shall start at the earliest MAPt tolerance, with a width equal to that of the final approach segment at that point. The subsequent size and shape of the area depends on the missed approach procedure, including the point at which a turn is initiated, if applicable, and the extent of the turn.
6.2 CLIMB GRADIENT AND MOC
6.2.1 Initial phase
6.2.1.1 The initial phase begins at the earliest missed approach point (MAPt) and ends at the start of climb point (SOC). The manoeuvre during this phase requires the concentrated attention of the pilot, especially when establishing the climb and the changes in configuration, and it is assumed that guidance equipment is not utilized during these manoeuvres. No turns may be specified during this phase.
6.2.1.2 Climb gradient in the initial phase. In the initial phase the flight track is horizontal.
6.2.1.3 Obstacle clearance in the initial phase. In the initial missed approach area, the minimum obstacle clearance shall be the same as for the last part of the final approach area except where the extension of the intermediate missed approach surface backwards towards the missed approach point requires less clearance. (See Figures I-4-6-4 and I-4-6-5.)
6.2.2 Intermediate phase
6.2.2.1 The intermediate phase begins at the SOC. The climb is continued at stabilized speeds up to the first point where 50 m (164 ft) (Cat H, 40 m (132 ft)) obstacle clearance is obtained and can be maintained. In the construction of this phase it is assumed that advantage may be taken of available navigation guidance. During the intermediate phase, the missed approach track may be changed from that of the initial phase by a maximum of 15°.
6.2.2.2 Climb gradient in the intermediate phase. The nominal climb gradient (tan Z) of the missed approach surface is 2.5 per cent. A gradient of 2 per cent may be used if the necessary survey and safeguarding can be provided. Additional climb gradients of 3, 4 or 5 per cent may also be specified. These may be used by aircraft whose climb performance permits the operational advantage of the lower OCA/H associated with these gradients, with the approval of the competent authority.
Note.— In case of non-precision approach, any intermediate values (e.g. 3.4 per cent) between 2 and 5 per cent may be considered.
6.2.2.3 Obstacle clearance in the intermediate phase
6.2.2.3.1 In the intermediate missed approach phase, the minimum obstacle clearance shall be 30 m (98 ft) in the primary area, and in the secondary area the minimum obstacle clearance shall be 30 m (98 ft) at the inner edge, reducing linearly to zero at the outer edge. See Section 2, Chapter 1, 1.3, “Obstacle clearance”.
6.2.2.3.2 The OCA/H for the nominal 2.5 per cent must always be published on the instrument approach chart. If additional gradients are specified in the construction of the missed approach procedure, they and their associated OCA/H values must be published as alternative options.
Note.— MOC may be obtained by increasing the OCA/H or by a longitudinal adjustment of the MAPt or both.
6.2.3 Final phase
The final phase begins at the point where 50 m (164 ft) (Cat H, 40 m (132 ft)) obstacle clearance is first obtained and can be maintained. It ends at the point at which a new approach, holding or return to en-route flight is initiated. Turns may be carried out during this phase.
6.2.3.1 Climb gradient in the final phase. The criteria of the intermediate phase apply. 6.2.3.2 Obstacle clearance in the final phase
6.2.3.2.1 In the final missed approach phase of a straight missed approach the minimum obstacle clearance shall be 50 m (164 ft) (Cat H, 40 m (132 ft)) in the primary area, reducing linearly to zero at the outer edge of the secondary area. See Figure I-4-6-4.
6.2.3.2.2 Turning missed approaches have specific criteria for MOC and for the arrangement and extent of secondary areas (see 6.4, “Turning missed approach”).
Note.— MOC may be obtained by increasing the OCA/H or by a longitudinal adjustment of the MAPt or both. In addition, obstacles may be excluded from consideration by defining a turn.
In ALL cases the performance criteria must be achieved.
Approach Segment is one engine out and take-off thrust. Gear is up. Flaps are retracted a bit to increase stall speed by 10% above the stall speed with landing flap deflection. With this flap setting the airplane is flown at V = 1.5 Vs at the landing weight.
Landing Segment is the only case with all engines operating. Gear is extended, flaps in landing position, V = 1.3 Vs and thrust that is available 8 secs. after the throttle is moved from idle to take-off thrust position.
EASA CAT.POL.A.225 refers
AMC2 CAT.POL.A.225 Landing – destination and alternate aerodromes
MISSED APPROACH
(a) For instrument approaches with a missed approach climb gradient greater than 2.5 %, the operator should verify that the expected landing mass of the aeroplane allows for a missed approach with a climb gradient equal to or greater than the applicable missed approach gradient in the OEI missed approach configuration and at the associated speed.
(b) For instrument approaches with DH below 200 ft, the operator should verify that the expected landing mass of the aeroplane allows a missed approach gradient of climb, with the critical engine failed and with the speed and configuration used for a missed approach of at least 2.5 %, or the published gradient, whichever is greater.
MISSED APPROACH GRADIENT
(a) Where an aeroplane cannot achieve the missed approach gradient specified in AMC2 CAT.POL.A.225, when operating at or near maximum certificated landing mass and in engine-out conditions, the operator has the opportunity to propose an alternative means of compliance to the competent authority demonstrating that a missed approach can be executed safely taking into account appropriate mitigating measures.