Originally Posted by fireflybob
Talkdown, do you have a reference for that?
It would appear that I do not have it immediately to hand. I thought it was from a GASIL but that appears not to be the case. I saved that little gem as a discussion point for when I was a Thames Radar Examiner. If I find the reference I will let you know.
This is a quotation from GASIL 2006/2:
Flight over congested areas
Listening to conversations among groups of pilots, we have been reminded that some may not be fully conversant with the application of the Rules of the Air regarding flight over congested areas. While the Rules themselves are clear, the interpretation of the phrase “congested area” is perhaps not.
As defined in Article 155 of the Air Navigation Order 2005, the “congested area” in relation to a city, town or settlement, means any area which is substantially used for residential, industrial, commercial or recreational purposes. While most of that may be obvious, it is often forgotten that an area within the boundaries of any such city, town or settlement which is used for recreational purposes forms part of the congested area. The pilot of any aircraft (except helicopters which have their own rules) must be able to alight clear of the whole congested area in the event of failure of a power unit. What might appear from above to be a possible suitable emergency landing field in the middle of a town will almost certainly be substantially used for recreational purposes, as will stretches of water such as the Lea valley to the North of London City Airport. We would also remind everyone that air traffic controllers do not know whether an aircraft is capable of alighting clear of the congested area in the event of the failure of a power unit, and may offer a pilot a routing which he cannot legally accept. It is the commander’s responsibility to ensure that he remains legal and safe at all times, so if an air traffic clearance would contravene the Rules of the Air, the pilot should inform the controller that he is unable to accept it and request an alternative clearance.
From GASIL 2002/3:
Single-engined aircraft have been seen flying over the built up area of greater London, in the area of the London City Control Zone. While the map shows areas which appear to have no major buildings (for example along the valley of the river Lee, to the west of the aerodrome), this is still regarded by the courts as being a ‘congested area of a town, city or settlement’ for the purposes of Rule 5 of the Rules of the Air Regulations 1996. Pilots have been prosecuted and penalised for flying over that area at a height below that which would allow the aircraft to alight clear of the area and without danger to persons or property on the surface, in the event of a failure of a power unit, as required by Rule 5(1)(a)(i).
An air traffic controller may give a pilot clearance to fly on a special VFR flight through a control zone. Such a clearance entitles a pilot to disregard Rule 5(1)(a)(ii) (so that he may fly below 1500 feet where so instructed by ATC) but not Rule 5(1)(a)(i) (the alight clear requirement). It remains the pilot’s responsibility to be able to comply at all times with Rule 5(1)(a)(i) regardless of whether or not he has been issued with a special VFR clearance.
From
Directorate of Airspace Policy - Report of the London CTR Review Group, Para 2.15.3.6 :
The River Thames is part of the 'congested area' of London