Jun 21 2012 By Jenny Coombes
THAT roaring noise that woke you up from your slumber last night was a plane from RAF Northolt carrying out an essential safety check.
The air base in Ruislip carried out a 'precision approach radar check' on one of its planes at about 2am.
It involved repeated approaches to the runways, which could be heard by residents across the borough.
The tests are essential for calibrating radar in planes.
Squadron Leader Richard Willis said the checks have to be done when Heathrow Airport is closed because they involve several approaches to the runway, which is why they take place at night.
They take place about half a dozen times a year and the council, resident associations and other comunity groups are warned in advance, he added.