OPERATING MINIMA FOR AEROPLANES AND HELICOPTER OPERATIONS PURPOSE REFERENCE 4.0 DEFINITION

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1 ORDER TCAA-O-OPS034A March 2013 OPERATING MINIMA FOR AEROPLANES AND HELICOPTER OPERATIONS PURPOSE 1. This Order gives guidance to the Authority s Operations Inspector on the procedures for approval of the methods used by the Operator on determining operating minima for aeroplanes and helicopters as described under Regulation 85, 86 and 87 of The Civil Aviation (Operation of Aircraft) Regulations. 2. The responsibility of the State for ensuring the safe conduct of operations is implicit in its acceptance of the International Standards and Recommended Practices for the safety of air navigation to which Article 37 of the Convention on International Civil Aviation refers. REFERENCE 3.1 Regulations 85, 86 and 87 of the Civil Aviation (Operation of Aircraft) Regulations, 3.2 AIP 3.3 Manual of All Weather Operations ICAO Doc AN/ ICAO Annex 6, Aerodrome Operating Minima ICAO Doc Vol DEFINITION 4.1 aerodrome operating minima means the limits of usability of an aerodrome for- (a) take-off, expressed in terms of runway visual range and visibility and, if necessary, cloud conditions; (b) landing in precision approach and landing operations, expressed in terms of visibility and runway visual range and decision altitude or height (DA or DH) as appropriate to the category of the operation; (c) landing in approach and landing operations with vertical guidance, expressed in terms of visibility and runway visual range and decision altitude or height (DA or DH); and TCAA-O-OPS034A March 2013 Page 1 of 7

2 (d) landing in non-precision approach and landing operations, expressed in terms of visibility and runway visual range, minimum descent altitude or height (MDA or MDH) and, if necessary, cloud conditions; 5.0 OBJECTIVE 5.1 Aerodrome operating minima are established in order to ensure a desired level of safety for aeroplane operations at an aerodrome by limiting these operations in specified weather conditions. Such minima are generally expressed differently for take-off and for landing. For take-off, which commences with the aeroplane at rest, limitations are usually stated in terms of horizontal visibility and in some instances by both horizontal visibility and cloud base. For the approach to landing where the aeroplane is already in flight, generally a limit on the instrument approach is established, called decision altitude/height (DA/H) or minimum descent altitude/height (MDA/H) together with a horizontal visibility limitation. 5.2 The values of aerodrome operating minima for a particular operation must ensure that at all times the combination of information available from external sources and the aeroplane instruments and equipment is sufficient to enable the aeroplane to be operated along the required flight path. In determining the values of aerodrome operating minima, a large number of factors are involved which fall primarily into three groups as follows: a) the ground environment and the design, maintenance and operation of ground equipment; b) the characteristics of the aeroplane/helicopter and its equipment; and c) the operator s procedures, flight crew training and experience The flight phases to be considered in the determination of aerodrome operating minima are: a) take-off and initial climb; b) final approach and landing; and c) ground movement from the aeroplane stand to the start of take-off, and from the end of the landing roll to the aeroplane stand. 6.0 REQUIREMENTS 6.1 The basic information required by the pilot must enable the pilot to judge the aeroplane lateral position and rate of change of position. This is normally provided by external visual cues but these may be supplemented by instrument derived information. In establishing take-off minima due consideration must be given to the need for the pilot to continue to have adequate information in the event of abnormal situations or malfunctions of the aeroplane systems. It is also necessary to ensure that once the aeroplane is airborne, sufficient visual or instrument information is available to enable a flight path to be maintained clear of obstacles. 6.2 In the take-off case, the information available must be sufficient to enable the pilot to keep the aeroplane within acceptable limits relative to the runway centre line throughout the take-off roll until it is either airborne or has been brought to a stop following discontinuation of the take-off. TCAA-O-OPS034A March 2013 Page 2 of 7

3 6.3 For approach and landing the specific considerations involved in the determination of aerodrome operating minima are: a) the accuracy with which the aeroplane can be controlled along its desired approach path, by reference to the instrumentation and use of the equipment provided on board, and by utilization of the guidance provided by ground based navigation aids; b) the characteristics of the aeroplane (e.g. size, speed, missed approach performance, etc.) and of the ground environment (e.g. obstacles in the approach or missed approach areas, safeguarding of ILS/MLS critical and sensitive areas and lighting aids, etc.); c) the proficiency of the flight crew in the operation of the aeroplane; d) the extent to which external visual information is required for use by the pilot in controlling the aircraft; and e) the interaction of all these factors in demonstrating satisfactory total system performance. 6.4 The accuracy of the airborne and ground based guidance and control systems generally determines the size of the area in which obstacles need to be considered. Where obstacles are not limiting, the minimum height to which an approach may be continued without external visual reference will be determined by the accuracy and the reliability of the total system. 6.5 The visibility element in minima for approach and landing is determined by the task the pilot is required to carry out at and below DA/H or MDA/H in order to complete the landing. As a general rule, the higher the aeroplane or the more the pilot needs to see as a visual reference the greater will be the visibility/rvr required. 6.7 Aeroplane operating Minima are based on aircraft categories as follows:: Category A: less than 169 km/h (91 kt) indicated airspeed (IAS) Category B: 169 km/h (91 kt) or more but less than 224 km/h (121 kt) IAS Category C: 224 km/h (121 kt) or more but less than 261 km/h (141 kt) IAS Category D: 261 km/h (141 kt) or more but less than 307 km/h (166 kt) IAS Category E: 307 km/h (166 kt) or more but less than 391 km/h (211 kt) IAS Category H: see 14, Helicopters. 13 FACTORS AFFECTING OPERATIONAL MINIMA 13.1 In general, minima are developed by adding the effect of a number of operational factors to OCA/H to produce, in the case of precision approaches, decision altitude (DA) or decision height (DH) and, in the case of non-precision approaches, minimum descent altitude (MDA) or minimum descent height (MDH). The general operational factors to be considered are specified in Annex 6. The detailed criteria and methods for determining operating minima are currently under development for this document. The relationship of OCA/H to operating minima (landing) 13.2 Operators may specify two types of approach procedures for non-precision approaches. The first is that described as: descend immediately to not below the minimum stepdown fix altitude/height or MDA/H as appropriate. This method is acceptable as long as the achieved descent gradient remains below 15 per cent and the missed approach is initiated at or before the MAPt. Alternatively, operators are encouraged to use a stabilized approach technique for nonprecision approaches. This technique requires a continuous descent with a rate of descent adjusted to achieve a constant descent gradient to a point at a nominal height of 15 m (50 ft) above threshold, taking due regard of the minimum crossing altitudes/heights specified for the FAF and any prescribed stepdown fix. If the required visual reference approaching MDA/H is TCAA-O-OPS034A March 2013 Page 3 of 7

4 not achieved, or if the MAPt is reached before reaching the MDA/H, the missed approach must be initiated. In either case, aircraft are not permitted to go below the MDA/H at any time 13.3 Circling minima The following circling minima are applicable to all aerodromes. Aeroplane category A B C D MDH 400 ft 500 ft 600 ft 700ft (120m) (150m) (180m) (210m) Visibility 1600m 1600m 2400m 3600m The circling minima for wide bodied aeroplanes are MDH 300m and visibility 5 km HELICOPTERS Categorization Helicopters may be classified as Category A aeroplanes for the purpose of designing instrument approach procedures and specifications (including the height loss/altimeter margins in Table I-4-5-2). When helicopters use procedures designed for Category A aeroplanes, and when no special helicopter procedure has been promulgated, the following operational constraints must be considered: a) Range of final approach speeds. The minimum final approach speed considered for a Category A aeroplane is 130 km/h (70 kt). This is only critical when the MAPt is specified by a distance from the FAF (e.g. an off aerodrome NDB or VOR procedure). In these cases (if the FAF to MAPt distance exceeds certain values dependent on aerodrome elevation), a slower speed when combined with a tailwind may cause the helicopter to reach start of climb (SOC) after the point calculated for Category A aeroplanes. This will reduce the obstacle clearance in the missed approach phase. Conversely, a slower speed combined with a headwind could cause the helicopter to reach the MAPt and any subsequent turn altitude before the point calculated for Category A aeroplanes, and hence depart outside the protected area. Therefore, for helicopters, speed should be reduced below 130 km/h (70 kt) only after the visual references necessary for landing have been acquired and the decision has been made that an instrument missed approach procedure will not be performed. b) Rate of descent after fixes. When obstacles are close to final approach or stepdown fixes, they are discounted for Category A aircraft if they lie below a 15 per cent plane relative to the earliest point defined by the fix tolerance area and minimum obstacle clearance (MOC). Helicopters are capable of nominal descent gradients which could penetrate this plane. Therefore, for helicopters, rates of descent after crossing the final approach and any stepdown fix should be limited accordingly TCAA-O-OPS034A March 2013 Page 4 of 7

5 PROCEDURES SPECIFIED FOR USE BY HELICOPTERS ONLY GENERAL For flight operations and procedures based on helicopter-only criteria, Table I provides a comparison between selected Category H helicopter criteria and the corresponding Category A aeroplane criteria. Awareness of the differences between the two criteria is essential to the safety of helicopter IFR operations. Table I Comparison between selected helicopter-only criteria and the corresponding aeroplane criteria PANS-OPS, Volume II reference Criteria CAT H CAT A Part I Section 2 General principles Chapter 2 Terminal area fixes Stepdown fix gradient (per cent) 15 to Section 3 Departure procedures Chapter 2 General concepts 2.3 Minimum height to initiate a turn 90 m (over the 120 m (over the DER elevation) DER elevation) 2.7 Procedure design gradient 5% 3.3% Chapter 3 Departure routes 3.2 Straight departures Track adjustments will take place no further than a point corresponding to above the DER, or at a specified track adjustment 90 m 120 m point 3.3 Turning departures Straight flight assumed until reaching a height of at least 90 m (295 ft) 120 m (394 ft) I Procedures Aircraft Operations Volume I PANS-OPS, TCAA-O-OPS034A March 2013 Page 5 of 7

6 Volume II reference Criteria CAT H CAT A Turn initiation area start point See earliest limit for 600 m from beginning DER of runway Turn parameters, max speed 165 km/h (90 kt) 225 km/h (121 kt) Reduced speed limitation for obstacle avoidance (from Table I-4-1-2) 130 km/h (70 kt) 204 km/h (110 kt) Chapter 4 Omnidirectional departures 4.1 Initial straight ahead climb 90 m (295 ft) 120 m (394 ft) Turn initiation area beginning of the FATO Chapter 5 Published information 5.1 Procedure design gradient 5% 3.3% Section 4 Arrival and approach procedures Chapter 1 General information Table I Speeds (kt) Initial approach a) general 70/120* 90/150 b) reversal, racetrack below ft MSL c) reversal, racetrack above ft MSL Final approach 60/90* 70/100 Circling N/A 100 Intermediate missed approach Final missed approach Chapter 5 Final approach segment 600 m from beginning of runway Maximum descent gradient 10% 6.5% Origin of descent gradient (above the beginning (above the threshold) of the LDAH) Chapter 6 Missed approach segment Final phase MOC 40 m (130 ft) 50 m (164 ft) Reduced turning speed 130 km/h (70 kt) 185 km/h (100 kt) PANS-OPS, Volume II Reference Criteria CAT H CAT A TCAA-O-OPS034A March 2013 Page 6 of 7

7 Part II Conventional procedures Section 4 Holding criteria Chapter 1 Holding criteria Table II-4- Holding 1-2 Maximum speed up to m ( km/h (100 kt) 315 km/h (170 kt) ft) Maximum speed above m ( km/h (170 kt) 315 km/h (170 kt) ft) Buffer area 3.7 km (2 NM) 9km (5 NM) (only below m (6000 ft)) Table II MOC (ft) Linear from 0 to full Steps MOC * Helicopter point-in-space procedures based on basic GNSS may be designed using maximum speeds of 120 KIAS for initial and intermediate segments and 90 KIAS on final and missed approach segments, or 90 KIAS for initial and intermediate segments and 70 KIAS on final and missed approach segments based on operational need. Refer to Part IV, Chapter 1. Tanzania Civil Aviation Authority TCAA-O-OPS034A March 2013 Page 7 of 7