Helicopter pilots warn of threat posed by tall buildings "It's a bit too early to draw conclusions from this accident about this or that tall building," he said. What is inevitable is that we'll want to review all our policies, we'll want to look at the way we illuminate tall buildings, the way cranes are illuminated, to make sure nothing went wrong in this case and make sure nothing goes wrong in the future. Other tall buildings, albeit not on the scale of St George Tower, are planned for the area. Restrictions have already been put in place in other parts of the world. In Australia new guidelines by the country's aviation authorities will restrict the height of future buildings business district amid fears the skyscrapers could reflect radar signals. In Britain airspace in the vicinity of airports is protected under a process known as Safeguarding. It is designed to prevent developments which could interfere with navigational aids both on the aircraft and airports themselves. In 2006 the Civil Aviation Authority placed a 1000 feet limit on buildings in London, amid fears anything taller that it would infringe airspace over the capital, although an exemption was granted for The Shard - which is 1016 feet tall - after a safety case was made. Four years later the CAA updated guidance on warning lights on tall buildings, taking into account the spiralling number of skyscrapers being erected in the heart of London. According to the CAA, there were lights on both the tower and the crane. However the Air Accident Investigation Branch will seek confirmation both were working at the time. Under CAA rules the lights are supposed to remain on from dusk to dawn. But unlike cars, there is no obligation for these lights to be working during fog. They were introduced to enhance the visibility of tall buildings for aircraft and helicopter pilots operating at night. Some buildings and structures, including St George Tower and the crane. are subject to a Notice to Airmen - or NOTAM - warning pilots of their presence. Normally a pilot will study a list of Notams in the vicinity ahead of planning a flight. Strict rules are in place governing the path aircraft and helicopters can take flying over London. Single engined aircraft, including helicopters, must stick to designated "helilanes" which follow the river.