From the Introduction:
While most helicopters can land on any reasonably flat and hard surface most pilots still prefer the clearly marked landing areas called helicopter landing pad or for short helipad. Add that many companies prefer quick air taxi services for their top executives to slow and traffic jam prone ground bound transportation and you get helipads situated on rooftops, just like this one.
As a matter of fact, the reinforced concrete roof of this office building can accommodate much more than a conventional helipad. This one is built large and sturdy enough to suit the needs of larger tilt rotor aircraft making it actually more of a small airport than just a landing pad.
The rooftop is flat and without obstacles for the larger craft except for the single concrete structure and its heavy steel doors leading into a room containing access to basic necessities for operating aircraft from the top of this building, the flight control room and the VIP lounge situated on the floor below.
The top of the concrete structure carries a single warning beacon while the landing pad itself is surrounded by slightly stronger signal lamps to help pilots land their craft in fog, at night or similar conditions with poor vision. While the actual landing pad is paved with a thin coat of tarmac and marked with reflective paint as a helipad the whole roof is heavily reinforced to avoid disaster should a pilot slightly miss the mark. Iron ladders allow access to the top of the rooftop access and the concrete moat surrounding the landingpad.