Helicopters are often used for services that are of benefit to communities, such as fire fighting, crime prevention, search and rescue, construction and media coverage. Helicopter operations require flexibility, as they can be required to fly over residential areas that are rarely flown over by other aircraft. The noise helicopters generate can therefore be particularly noticeable to people who are not accustomed to aircraft noise on a regular basis.
Several airports and airfields have established Fly Neighbourly Agreements (FNAs) between aircraft operators and airports or local councils. These agreements help reduce the impact of aircraft noise on local communities. FNAs are voluntary agreements and are not legally enforceable.
FNAs for helicopter operators will normally include advice on how to avoid noise sensitive areas by following unpopulated routes (for example, waterways) or areas with high ambient noise levels such as highways. They usually advise that above residential areas, if possible, operators should:
- maintain a hover/circling altitude of at least 2000 ft (610 m),
- reduce speed
- observe low noise speed/descent settings
- avoid sharp manoeuvres
- vary routes
- use high take-off/descent profiles.
At most airports or helipads, standard departure and arrival procedures ensure that, if possible, twin engine helicopters should not fly over residential areas below 1500ft, however, normal flight is permitted down to 1000ft over residential areas. Lower levels will be flown during landing and take-off.
Occasionally, helicopters need to fly at lower levels. This could be, for example, for law enforcement, search and rescue, surveying or construction purposes. If a helicopter operator needs to fly below 500 ft for private operations or aerial work operations, authorisation is required from the Civil Aviation Safety Authority. In addition, helicopters that are being used in response to an emergency are permitted to operate outside normal procedures, should the circumstances demand.
If a helicopter pilot needs to cross a ‘controlled’ zone around an airport, it may be necessary for air traffic control to hold the helicopter in one place until it is safe. This could be why some helicopters appear to hover over a location when there is no obvious reason to do so.
Airservices has produced a factsheet on helicopter operations.