INTRODUCTION :

Obstacle limitation surfaces are intended to define the airspace around aerodrome and limits to which the objects may project into this airspace around airports. International Civil Aviation Organization (ICAO) provides guidelines through Annex-14 in controlling the obstacles, whereas States may also establish their own legislation according to their requirements.

In Pakistan, the control of obstacles around the airport is governed under Rule-68 of Civil Aviation Rules-1994(Safe-Guarding at Aerodromes). It requires restricted height of 500 feet within a radius of 15 Km from the airport. As such construction of high rise buildings/structures and erection of antennas/ poles/ masts/ chimneys within abovementioned areas requires Height Clearance from CAA.

The Policy :

Civil Aviation Rules 1994

Issued by Government of Pakistan, MINISTRY OF DEFENCE (Defence Division) AVIATION WING Rawalpindi, under Statutory Notifications (S.R.O.) S.R.O. 961(I)/94 dated 3rd October, 1994

Section 3 - SAFE-GUARDING AT AERODROMES

68. Limitation of obstructions (1) No person shall erect any temporary or permanent structure, nor position a vehicle or other mobile object on or in the vicinity of an aerodrome to which these rules are applicable, that will be within the clearance area, or will protrude through an obstacle limitation surface, at that aerodrome.

(2) For the purpose of this rule:

1. a clearance area at an aerodrome:
   1. in respect of a runway, is an area 457 meters wide located symmetrically about the runway and extending the full length of the runway and for a distance of 274 meters beyond each end, plus an area at each end with a length of 914 meters and widening over its length from 457 meters to a width of 646 meters;
   2. in respect of a taxiway, is an area 137 meters wide, centered on the taxiway and extending the full length of the taxiway;
   3. in respect of an apron, is an area enclosing an apron with a perimeter which is 38 meters outside its edges;
2. an obstacle limitation surface at an aerodrome is:
   1. a funnel area being a sloping surface at each end of a runway, which originates at the end of the runway clearance area at the elevation of the runway threshold, located symmetrically about the produced center line of the runway and rising 1 meter vertically in each 50 meters horizontally over its length of 2773 meters, to a height of 55 meters, and with a width of 457 meters adjacent to the clearance area, widening to 1219 meters at its far end; and
   2. an area of restricted height being a horizontal surface 55 meters above the elevation of the runway at the end of each funnel area, located symmetrically above the produced center line of the runway, having a width of 1229 meters and a length of 4572 meters; and
   3. an inner horizontal surface being a surface 45.7 meters above the aerodrome elevation within a radius of 3962 meters from the aerodrome reference point; and
   4. an inner conical surface being a surface extending outwards and upwards from the periphery of the inner horizontal surface, and from the edges of the funnel area and the area of restricted height, with a gradient rising 1 meter vertically in 20 meters horizontally measured radially from the aerodrome reference point, to a height of 151 meters above the aerodrome elevation; and
   5. an outer horizontal surface being a surface 151 meters above the aerodrome elevation within a radius of 15,240 meters from the aerodrome reference point; and
   6. a transition surface being a surface extending outwards and upwards from the runway clearance area and the funnel area with a gradient rising 1 meter vertically in 7 meters horizontally, measured at right angles to the runway axis, until it intersects the inner horizontal surface, and extending outwards and upwards from the edges of the area of restricted height with a gradient rising 1 meter vertically in 7 meters horizontally until it intersects the inner conical surface and the outer horizontal surface, the gradient being measured from the sides of the area at right angles to the runway axis, and parallel to the axis at the end.

   (3) Notwithstanding the provisions of this rule, the Director- General may specify in Air Navigation Orders or by other means other dimensions of clearance areas and obstacle limitation surfaces for particular aerodromes.

   (4) In the event that a person erects a structure, or positions a vehicle or other mobile object in contravention of this rule, the Director-

   General shall take such action as he considers fit to cause the infringing object to be removed, and shall not be liable for damage so caused. Any costs incurred by the Director-General in taking such action shall be borne by the person causing the infringement.

   DOCUMENTS REQUIRED FOR BUILDING NOC FROM HQCAA

   Following information / documents are required to evaluate the site Under Rule-68, Part-VIII, Section 3 of Civil Aviation Rules-1994 for the issuance of NOC.

   1. WGS-84 Geographical coordinates in degrees, Minutes and 1/100 of seconds of the proposed site where building is to be constructed from Survey of Pakistan duly authenticated.
      
   2. Guide map of Survey of Pakistan showing the proposed site duly authenticated.
   3. Map scale 1:500,000 of Survey of Pakistan showing the proposed site duly authenticated.
   4. Height of the proposed site (i.e. elevation) from mean sea level duly authenticated by Survey of Pakistan.
   5. Total height of the proposed building (including all types of installations on roof top) above ground level.Site Plan issued from issuing authority.
   6. Site Plan of the property issued by competent authority.
   7. Any other document required by CAA.

   3. The documents are required to be submitted on the address given below 30 days to process the case. Without the above documents case will not be entertained.

   4. Application should be addressed to:
   The Director General
   Headquarters, Civil Aviation Authority,
   Terminal-1, Jinnah International Airport,
   Karachi.

   Address: Survey of Pakistan Director Southern Circle, 38th P.N.H. Lines, 22nd Central Street, Phase-II, DHA Karachi. Ph. No. 021-9266381, Fax. No. 021- 9266382. Director of Map Publication, Survey of Pakistan Rawalpindi. Director of Eastern Circle, Survey of Pakistan , Lahore. Ph. No. 042-9220377 Fax.No. 042-9220783