ADDITIONAL FACILITIES AND REQUIREMENTS FOR PRECISION APPROACH AND LANDING OPERATIONS (CAT ll/lll)
Approach, threshold, touchdown zone, runway edge, centre line, runway end and other aerodrome lights are required in compliance with Annex 14, Volume I, appropriate to the category of operation for which a runway is intended. Where the runway may in future be upgraded so as to be suitable for Category II and III operations, it is advantageous to provide the necessary improved lighting during the initial construction or resurfacing of precision approach runways. This would eliminate the need for extensive future modifications.
For daylight operations, experience has shown that surface markings are an effective means of indicating the centre lines of taxiways and holding positions. A holding position sign is required at all Category II and III holding positions.
Signs may also be needed to identify taxiways. Taxiway centre line lights or taxiway edge lights and centre line markings providing adequate guidance are required for Category II and III operations. The conspicuity of runway markings and taxiway markings deteriorates rapidly, particularly at airports with higher movement rates. Frequent inspection and maintenance of markings cannot be over- emphasised, especially for Category II and III operations.
Stop bars can also make a valuable contribution to safety and ground traffic flow control in low visibility operations. The primary safety function of the stop bar is the prevention of inadvertent penetrations of active runways and Obstacle Free Zones by aircraft and vehicles in such conditions. Stop bars when provided should be used at least in visibility conditions corresponding to RVRs to less than 350 metres (CAT III). They also may contribute, in conjunction with other elements of the SMGCS, to effective traffic flow when low visibility prevents ATC from effecting optimum flow and ground separation by visual reference.
It may also be advantageous to partly automate the operation of selected stop bars so that the air traffic controller will not be required to operate them manually every time, thus avoiding possible human errors. For example, manual switch-off of a stop bar after issuance of a movement clearance would be followed by an automatic re-illumination by the crossing aeroplane. Or a 'limited visibility' setting on the control panel would automatically illuminate stop bars across taxiways which are not to be used in limited visibilities.
It will be possible that some lights in a particular system may fail, but if such failures are distributed in a manner that does not confuse the lighting pattern, the system may be regarded as serviceable. It is both difficult and expensive to provide monitoring of individual lights, except by regular inspection of all sections of the lighting system, and consideration may, therefore, be given to monitoring only the lighting circuits. To help safeguard recognisable patterns in the event of failure of a single circuit, iit hld b itld tht th fil f djt liht lt f liht ill b
IATA Airport Flight Operations Issues
241
G2.5 VISUAL DOCKING GUIDANCE SYSTEMS
With the adoption of nose-in parking and use of aircraft loading bridges, it is necessary to provide a guidance system to assist the pilot in positioning his aircraft accurately. The Civil Aviation Publication (CAP) 637 entitled Visual Aids Handbook, produced by the Civil Aviation Authority in the United Kingdom, should be referred to as current best industry practice on AGNIS/PAPA installations and their subsequent usefulness.
The following are topics which must be addressed during the planning and development of visual docking guidance systems:
Pilot Responsibility
The pilot should be provided with a system which guides him accurately to the final parking position for his aircraft without ambiguity, and indicates to him his rate of closure with the desired stopping position.
Accuracy
The system must provide the accuracy of parking which is required on the particular airport or apron, and this should be established by airport authorities and airlines jointly. Points to be considered include:
• The clearances involved. For some aircraft this includes distances between the pitot tube probes and the forward edge of the passenger door when open (i.e. B737).
• The performance of the loading bridges.
• The positions of fuelling hydrants and dispenser hose lengths available.
• The space required for all apron servicing activities including ULD loading/unloading.
When fixed loading bridges are installed, the docking guidance system must be particularly reliable as the accuracy of this system must match the tolerance of the proposed fixed bridge. On aprons serviced by apron-drive loading bridges, parking accuracy requirements may be less stringent.
Multi-Aircraft Type Capability
The system must accommodate as many different aircraft types as are likely to operate and this factor should be established by airport authorities and airlines in joint consultation. In a multi- aircraft system the problem of providing stopping guidance is more difficult and it is important that the correct stopping position for the specific aircraft type using the stand should be clearly identifiable by the pilot, irrespective of his height above apron