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Monday 21 January 2019
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Aviation operating without a WAM system

The Namibian Directorate of Civil Aviation (DCA) says the withdrawal of the ERA Wide Area Multilateration(WAM) system from both the Hosea Kutako International Airport (HKIA) and Eros Airport in Windhoek was made in accordance with international standards and does not pose any threat to the country’s aviation sector.
Documents seen by this publication indicate that WAM system was removed from the TopSKy ATC display on 1 March 2017 and will not be available for use by air traffic controllers until further notice.
“Following a number of WAM target loss occurences that have been experienced for the past couple of months, consultations between all stakeholders took place and it was decided and agreed that the ERA WAM System be immediately removed from operation due to safety concerns, because ERA explicitly stated that the system is not working as designed,” reads a memo dated 1 March 2017 signed by the acting air traffic controller of Namibia Civil Aviation Authority.
Responding to questions sent to him by this paper, DCA Deputy Director Tobias Günzel maintained that the withdrawal of the ERA WAM does not pose a “security” threat to aviation in the country.
“With respect to Namibia’s civil aviation operations the withdrawal of the ERA WAM for safety considerations does not pose a security threat to Namibia. All relevant notifications of the withdrawal of the one ERA WAM system was made in accordance with international standard procedures,” responded Günzel.
Günzel said the WAM system is the newest surveillance technology available for air traffic control and was quickly developing and adapting to various circumstances associated with each location and installation.
Furthermore, reason which prompted NCAA to remove the aviation surveillance technology is because it was not “working as designed”.
“The switching off of one of Namibia’s ERA WAM Systems was a result of information being received that the system was not operating as designed and this initiated a safety concern,” he said.
When asked whether there were contingencies in place to cater for surveillance for Namibian aviation during the absence of the malfunctioning ERA WAM, Günzel said: “A number of years ago, after extensive consideration of surveillance requirements for Namibia, Secondary Surveillance Radar (SSR) was a tool provided to air traffic control for surveillance purposes.”
“This SSR, which in itself has full redundancy, was positioned at Hosea Kutako Airport to ensure coverage of the airspace above Namibia’s primary international airport (Hosea Kutako International Airport) and above Namibia’s busiest airport (Eros Airport),” he explained.
According Günzel, Namibia Civil Aviation Authority (NCAA) SSR coverage extends to over 200 nautical miles which equivalent to about 370 kilometers (km) from HKIA.
Moreover, there are currently tow ERA WAM systems available to air traffic control surveillance operations in Namibia according to Günzel.
One of the ERA WAM systems provides additional redundancy to both HKIA and Eros Airport.
Similarly, the surveillance extends coverage to lower areas surrounding abovementioned airports while the second WAM covers airspace high level airspace above areas further that have lower air traffic densities.
Additionally, Günzel said the procedural air traffic control services are in line with International Civil Aviation Organization (ICAO) standards.
“Our air traffic controllers are trained and licensed to provide procedural air traffic control services in controlled airspace that are not covered by WAM,”
“And procedural air traffic control services are the ICAO prescribed contingency with respect to surveillance services failures,” concluded Günzel.




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