Special Correspondent

CHENNAI: The Monopulse Secondary Surveillance Radar (MSSR) at the Chennai airport was shut down for sometime on Sunday for maintenance work. It was shut down from 8 a.m., airport sources said.

Arrival and departure of several flights were delayed and an aircraft was diverted to another airport.

Airports Authority of India (AAI) officials said that following the shut down, the Air Traffic Control tower reverted to degraded mode of operation.

Under this procedure, specified routes are provided for certain sector, which will take longer distance than the normal route.

Moreover, pilots are not conversant with this method, as they are totally accustomed to radar navigation.

With the absence of radar, departures were staggered during the day. A senior AAI officer said that they informed the airline operators nearly ten days ago about the proposed maintenance shut down.

With the information available in advance, the airline operators would have prepared themselves, the officer said.

Around 6 p.m., the primary radar, which is part of MSSR, was restored, airport sources added.

The MSSR was restored around 10.30 p.m.