Lecture Minimum safe flight altitude Calculate of minimum safe flight altitude, safe flight altitude in approach zone, in circle zone (circle altitude), minimum safe flight altitude in aerodrome area, minimum obstacle clearance air route altitude (in rescue operation area)
Guidance Materials ICAO
Minimum heights Except when necessary for take-off or landing, or except by permission from the appropriate authority, aircraft shall not be flown over the congested areas of cities, towns or settlements or over an open-air assembly of persons, unless at such a height as will permit, in the event of an emergency arising, a landing to be made without undue hazard to persons or property on the surface. Note see for minimum heights for VFR flights and for minimum levels for IFR flights.
VFR Except when necessary for take-off or landing, or except by permission from the appropriate authority, a VFR flight shall not be flown: a) over the congested areas of cities, towns or settlements or over an open-air assembly of persons at a height less than 300 m (1 000 ft) above the highest obstacle within a radius of 600 m from the aircraft; b) elsewhere than as specified in a), at a height less than 150 m (500 ft) above the ground or water.
Minimum levels for IFR Except when necessary for take-off or landing, or except when specifically authorized by the appropriate authority, an IFR flight shall be flown at a level which is not below the minimum flight altitude established by the State whose territory is overflow, or, where no such minimum flight altitude has been established: a) over high terrain or in mountainous areas, at a level which is at least 600 m (2 000 ft) above the highest obstacle located within 8 km of the estimated position of the aircraft; b) elsewhere than as specified in a), at a level which is at least 300 m (1 000 ft) above the highest obstacle located within 8 km of the estimated position of the aircraft. Note The estimated position of the aircraft will take account of the navigational accuracy which can be achieved on the relevant route segment, having regard to the navigational facilities available on the ground and in the aircraft.
Minimum levels Minimum descent altitude (MDA) or minimum descent height (MDH). A specified altitude or height in a nonprecision approach or circling approach below which descent must not be made without the required visual reference. Note 1. Minimum descent altitude (MDA) is referenced to mean sea level and minimum descent height (MDH) is referenced to the aerodrome elevation or to the threshold elevation if that is more than 2 m (7 ft) below the aerodrome elevation. A minimum descent height for a circling approach is referenced to the aerodrome elevation. Note 2. The required visual reference means that section of the visual aids or of the approach area which should have been in view for sufficient time for the pilot to have made an assessment of the aircraft position and rate of change of position, in relation to the desired flight path. In the case of a circling approach the required visual reference is the runway environment. Note 3. For convenience when both expressions are used they may be written in the form minimum descent altitude/height and abbreviated MDA/H.
Minimum levels MCA Minimum Crossing Altitude MDA(H) Minimum Descent Altitude (Heigh) MEA Minimum En-route Altitude MEHT Minimum Eye Height Over Threshold MFA Minimum Flight Altitude MHA Minimum Holding Altitude MOCA Minimum Obstruction Clearance Altitude MORA Minimum Off-Route Altitude (Grid or Route) MRA Minimum Reception Altitude MSA Minimum Safe/Sector Altitude MTCA Minimum Terrain Clearance Altitude MVA Minimum Vectoring Altitude
Minimum levels Minimum en-route altitude (MEA). The altitude for an en-route segment that provides adequate reception of relevant navigation facilities and ATS communications, complies with the airspace structure and provides the required obstacle clearance. Minimum obstacle clearance altitude (MOCA). The minimum altitude for a defined segment that provides the required obstacle clearance. Minimum sector altitude (MSA). The lowest altitude which may be used which will provide a minimum clearance of 300 m (1 000 ft) above all objects located in an area contained within a sector of a circle of 46 km (25 NM) radius centred on a radio aid to navigation.
Minimum levels Obstacle clearance altitude (OCA) or obstacle clearance height (OCH). OCA/H is the lowest altitude or the lowest height above the elevation of the relevant runway threshold or the aerodrome elevation as applicable, used in establishing compliance with appropriate obstacle clearance criteria. Note 1. Obstacle clearance altitude is referenced to mean sea level and obstacle clearance height is referenced to the threshold elevation or in the case of non-precision approaches to the aerodrome elevation or the threshold elevation if that is more than 2 m (7 ft) below the aerodrome elevation. An obstacle clearance height for a circling approach is referenced to the aerodrome elevation. Note2. See Part IV, Chapter 1 for Area navigation (RNAV) point-in-space (PinS) approach procedures for helicopters using basic GNSS receivers, Part IV, Chapter 1. The general criteria for OCA/H apply (Part I, Section 4, Chapter 5, 5.4) with the addition that the OCH is above the highest terrain/surface within 1.6 km (0.86 NM) of the MAPt. Obstacle free zone (OFZ). The airspace above the inner approach surface, inner transitional surfaces, and balked landing surface and that portion of the strip bounded by these surfaces, which is not penetrated by any fixed obstacle other than a low-mass and frangibly mounted one required for air navigation purposes.
MEA and MORA Grid MORA MORA MEA MOCA 86 265 4000a 6180 STD FL 140 2000т Н QNH min H SAFE H MOC obst H obst H rel QNH reduced QNH MSL QNH MSL QNE
Mountainous area. An area of changing terrain profile where the changes of terrain elevation exceed 900 m (3 000 ft) within a distance of 18.5 km (10.0 NM). Significant obstacle. Any natural terrain feature or man-made fixed object, permanent or temporary, which has vertical significance in relation to adjacent and surrounding features and which is considered a potential hazard to the safe passage of aircraft in the type of operation for which the individual procedure is designed.
Width of secondary area
Terminal area fixes include, but are not limited to: a) the initial approach fix (IAF); b) the intermediate approach fix (IF); c) the final approach fix (FAF); and d) the holding fix, and when necessary, a fix to mark the missed approach point (MAPt), or the turning point (TP). Terminal area fixes should be based on similar navigation systems. The use of mixed type (as VHF/LF) fixes should be limited to those intersections where no satisfactory alternative exists.
Height loss altimeter setting vs. speed
Final approach fix defined by descend fix
Surface equations basic ILS surfaces
OAS output data generated by PANS-OPS OAS software
Measurement units The results of the size zones calculation are not linked with ILS or MLS must be rounded to 0,01 km (0,01 nm). The dimension of ILS and MLS zones must be rounded to1,0 m (1,0 ft). ОСА/H value must be rounded to : - 50 m for MSA; - 5 m for NPA; - 1 m for PA. Slope gradients are expressed in percents and angels are expressed in degrees. 22