GM1 ADR-DSN.H.405 Applicability

(a)The obstacle limitation surfaces define the limits to which objects may project into the airspace. Each surface is related to one or more phases of a flight, and provides protection to aircraft during that phase.

(b)The OLS also help to prevent the aerodromes from becoming unusable by the growth of obstacles around the aerodromes.

(c)The effective utilisation of an aerodrome may be considerably influenced by natural features and man-made constructions outside its boundary. These may result in limitations on the distance available for take-off and landing and on the range of meteorological conditions in which take-off and landing can be undertaken. For these reasons, certain areas of the local airspace should be regarded as integral parts of the aerodrome environment.

(d)Objects which penetrate the obstacle limitation surfaces may in certain circumstances cause an increase in the obstacle clearance altitude/height for an instrument approach procedure or any associated visual circling procedure or have other operational impact on flight procedure design. Criteria for flight procedure design are contained in the Procedures for Air Navigation Services — Aircraft Operations (ICAO, PANS-OPS, Doc 8168).

(e)In ideal circumstances all the surfaces should be free from obstacles but when a surface is infringed, any safety measures required should have regard to:

(1)the nature of the obstacle and its location relative to the surface origin, to the extended centre line of the runway or normal approach and departure paths, and to existing obstructions;

(2)the amount by which the surface is infringed;

(3)the gradient presented by the obstacle to the surface origin;

(4)the type of air traffic at the aerodrome; and

(5)the instrument approach procedures published for the aerodrome.

(f)Safety measures could be as follows:

(1)promulgation in the AIP of appropriate information;

(2)marking and/or lighting of the obstacle;

(3)variation of the runway distances declared as available;

(4)limitation of the use of the runway to visual approaches only;

(5)restrictions on the type of traffic.

(g)In addition to the requirements described in the certification specifications of Chapter H, it may be necessary to call for other restrictions to development and construction on and in the vicinity of the aerodrome in order to protect the performance of visual and electronic aids to navigation and to ensure that such development does not adversely affect instrument approach procedures and the associated obstacle clearance limits.

[Issue: ADR-DSN/5]