I am writing in reply to the letter 'Querying the necessity of low-flying helicopters' (South China Morning Post, February 22) from P.A. Crush of Sha Tin.
The environmental noise impact of helicopters is a worldwide concern and is under continual review by the Government Flying Service as part of our normal procedures.
Where possible, steps are taken to minimise the effect by either avoiding genuine sensitive areas such as the Mai Po marshes, and monasteries, or transiting at a higher altitude if this is practical.
The size of Hong Kong and its expansive populous areas make it unavoidable to fly over - or operate in - some built-up zones.
Some areas are affected more than others if they are on regular flight paths or designated entry/exit points within the Hong Kong flying zone.
Sha Tin happens to be one of the well-used areas as it is centrally located.
The area has a busy aircraft entry/exit point at Lion Rock - called North Pass in air traffic control language - for access to Kai Tak, and in the reverse for aircraft proceeding to the north in Hong Kong's airspace.
