The Mayor's Ambient Noise Strategy - Greater London Authority

126 Mayor of London
The Mayor’s Ambient Noise Strategy
Figure 17 Map of Heathrow standard instrument departure routes 17
source: Department for Transport - Noise Exposure Contours for Heathrow Airport 2002 8
4C.17 Noise and track keeping systems (see glossary) are used to monitor the
adherence of aircraft to designated departure routes. Feedback from
monitoring enables pilots to improve their performance. For 2003, 2004
and 2005, the airport operator has a target of 95% of departures on
track. 18 Noise Preferential Routes used on take off towards the west (the
predominant mode of operation) were designed, within constraints related
to aircraft handling and navigation, to require flights to pass between the
more densely built up areas. This is not possible for Noise Preferential
Routes used when aircraft, for reasons of wind direction and strength, take
off to the east, over built up areas. An alternative system for dispersal of
aircraft departures on easterly operations at Heathrow could reduce the
burden on the most-affected, but this would require detailed study.
4C.18 Most complaints about noise associated with Heathrow now concern
aircraft coming in to land. At Heathrow aircraft continue to need to
approach at a standard 3 degree glideslope. London City Airport, with
specific obstacle clearance requirements, is exceptional in being limited to
use by aircraft which can approach more steeply. Steeper approach
reduces the area affected, but would be demanding for some aircraft
types (some would require special certification), and steeper approach
procedures are only permitted under international procedure design
criteria (PANS-OPS) for the purpose of obstacle clearance. Aircraft are
required to join the glide path (see glossary) at or above 2,500 feet in
daytime, and 3,000 feet at night. When aircraft are approaching towards