‘Ground-based systems are the way to go’
AIRFIELD-BASED systems represent the ‘best opportunity’ to extend low visibility landing to the greatest number of operators in Guernsey.
That is one conclusion of a report from Economic Development examining air and sea route investment objectives.
However, it warned that upgrading Guernsey Airport systems would require additional land and potentially require a runway extension.
The Assembly is set to discuss the report as well as decide whether to give ahead for the States to provide a guarantee to Aurigny to buy three new ATRs equipped with the ClearVision system.
The taxpayer-owned airline has previously said that it is anticipated that the system can cut disruption caused by fog by up to 50% with the new planes replacing its current ATRs.
Under a section titled Low visibility landing capability, the ED report said: ‘Delays due to fog can be reduced or even eliminated with investment in the appropriate landing systems. However, enabling landing in very low visibility is not easy to achieve.
Airport-based systems would require additional land and safeguarding areas around the airport which would only become possible with certain runway extension options.’
It also said: ‘Aircraft based systems (such as the ClearView system used on the next generation ATR 72 600s) provide a solution for certain aircraft types, but these do not present a universal solution for all operators using Guernsey airport.
‘Airfield-based systems therefore represent the best opportunity to extend low visibility landing to the greatest number of operators.’
Airports have different categories of instrument landing systems. These are the basis of the decision height at which the captain has to decide whether to land or go around as well as the minimum visibility in which they are allowed to commence an approach.
Guernsey Airport has a Category 1 ILS, which allows the pilot to make a decision at around 200ft above ground. It is ‘a basic system which is the easiest to install, maintain and work with,’ according to a section on Guernsey Airport’s website dealing with poor weather.
The same section also said: ‘Category 2 and 3 ILS equipment affords greater accuracy, attracts greater protection and engineering requirements and therefore offers lower decision heights and lower approach minimum visibility.’
Most commercial aircraft types currently operating into Guernsey airport are equipped to Cat2 capability, according to Colin Le Ray, general manager, ports.
However, geographical constraints – specifically the valley at the eastern end of the runway – meant Cat2 could only be used for aircraft landing from the west in an easterly direction. These account for approximately 50% of all landings in an average weather year.
A ‘sizeable area’ outside of the airport boundary, including roads and buildings, would need to be cleared to achieve Cat2 status for westerly approaches.
‘The costs associated with this property work, alongside the relatively minimal gain in additional operating hours, is highly unlikely to make a sound business case in terms of the investment,’ added Mr Le Ray.
‘Whilst Cat3 also brings similar challenges, there would be few, if any, commercial aircraft currently capable of operating to Cat3 in regular use at Guernsey.
‘The ClearVision technology, once approved for use, is not constrained in the same manner, and provides near-Cat2 capability for approaches in both directions and without the need for work on the ground.
‘We have not undertaken any review of the estimates provided by Aurigny for additional operating hours that could be achieved, but we are aware that disruption due to fog is highly variable year-on-year; and is generally becoming an increasing challenge for that airline and the others.’
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