Two Instrument Landing Systems switched off at OR Tambo

Posted by Kirsten on 12 August 2020

The South African Civil Aviation Authority (SACAA) is clarifying reports that aviation activities in the country will halt due to the airports Instrument Landing Systems (ILS) calibration status expiring at some airports.

In a notice posted to aviation forum Avcom, there were reports that two runway systems used at OR Tambo would be shut off because their calibration dates have expired.

Two Instrument Landing Systems switched off at OR Tambo

An Instrument Landing System (ILS) is a ground-based navigational instrument system.

‘Instrument Landing System JS 03R/21L will be switched off today because it has reached its calibrations expiry date, 25 days extension, and 180 days exemption today,’ reads the notice.

‘Instrument Landing System JS 03L/21R also reaches its 90 days exemption period today; we have applied for the extra 90 days exemption, however the CAA has not yet signed; if not signed by 16:00 today (Monday 10 August) we will have to switch off these ILS’ as well.’

An Instrument Landing System (ILS) is a ground-based navigational instrument system that provides guidance to an aircraft when approaching or landing on a runway when the pilot cannot see the runway due to bad weather.

This must be calibrated regularly to ensure it remains accurate and safe for use. The SACAA is responsible for calibrating ILSs.

In a statement on August 11, the SACAA confirmed that two ILSs at OR Tambo International have been switched off as the exemption period has lapsed. This airport will neither be downgraded or closed as reported.

‘In addition, King Shaka International Airport has been downgraded to a lower instrument meteorological usage level as a result of two ILS’s being switched-off. Other airports affected are Kruger Mpumalanga International Airport and George Airport whose exemptions have also expired.

These are the only ones that have been switched off. The rest, even though they are also nearing expiry during the month of August, and later on in the year, are still operational.’

Calibration must take place to bring these expired ILSs back to service.

When an ILS expires or it is not functioning, the affected airport must be downgraded to a lower instrument usage level and its status must be published to notify pilots and assist them in planning a safe flight before they depart.

SACAA points out that the ILS is one of a few landing and take-off techniques, so its absence does not prevent pilots from flying or landing. They also explain that the notices have been misunderstood.

‘Assertions that suggests that all ILS’s at all South African airports are switched-off and not functioning are misguided. Regulations prescribe that ILS certificates are valid for 150 days with an automatic tolerance of 30 days without the requirement for an extension application.

‘Thereafter, an airport operator can apply for a 25 day extension in accordance with applicable civil aviation regulations. After the expiry of the 25 days extension, if the calibration of the ILS has not taken place, the operator can apply for an exemption, which can be granted for up to 180 days, provided that the system has a history of being stable during previous calibration intervals and that certain additional maintenance and monitoring measures are in place. This is a perfectly acceptable practice and is in line with global standards and practices.’

Image: Unsplash

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