The Checkerboard Approach "(also spelled as Chequerboard approach)" initially begins to the south-west of the airport, heading 270 at a minimum altitude of 6000 ft. At this beginning stage of the approach, the aircraft should be passing above Cheung Chau - a small island just off Lantau Island. After that, the aircraft was required to proceed up to "Point Golf", which was on the south side of Lantau Island and directly south of the current Chek Lap Kok Airport. Approaching aircraft then had to make a right-hand U-turn in order to intercept the localiser for the Runway 13 IGS, which generally happened above the current Chek Lap Kok Airport site. The IGS was, in essence, a heavily modified ILS system designed uniquely for Kai Tak Airport, otherwise functioning identical to a normal ILS. At roughly ~2500 ft, the autopilot was disconnected, and the rest of the approach was flown manually. The aircraft then descended below 1000 ft and shortly afterwards reached Kowloon Tsai Park and its small hill. Upon reaching the small hill above Kowloon Tsai Park, which was painted with a large "aviation orange" and white checkerboard (), used as a visual reference point on the final approach (in addition to the middle marker on the Instrument Guidance System), the pilot needed to make a 47° visual right turn to line up with the runway and complete the final leg. The aircraft would be just from touchdown, at a height of less than when the turn was made. Typically the plane would enter the final right turn at a height of about and exit it at a height of to line up with the runway. That demanding manoeuvre became known in the aviation community as the "Hong Kong Turn" or the "Checkerboard Turn". For many airline passengers on planes approaching and landing on Runway 13 at Kai Tak Airport, it became referred to as the "Kai Tak Heart Attack", because they were often frightened to be turning at such a close proximity to the ground, which, at less than 150 ft, or 45 metres, was generally less than even the Boeing 767's wingspan, which is considered a medium-size airliner. The turn was so low that passengers could see television sets running in people's residences near the airport.