of the primary surface, and from the approach surfaces, at a slope of 2-to-1 for a distance of , measured horizontally from the centerline of the primary and approach surfaces. Approach paths can either be straight or curved to accommodate obstructions and avoidance areas. See also Helicopter deck List of countries by number of heliports List of helicopter airlines List of heliports in Turkey List of heliports in Canada List of heliports in Singapore List of heliports in Washington, D.C. References Footnotes General sources de Voogt, A.J. 2007. Helidrome Architecture. Rotterdam: 010 Publishers. ICAO Annex 14 Aerodrome Standards, Aerodrome Design and Operations ICAO 1995. Heliport Manual. Montreal, Canada: ICAO Publications. Frost, John B. 1996. British helipads. Chester, UK: Appledore Publications. External links UK CAA, CAP 437 Standards for Offshore Helicopter Landing Areas (September 2018) UK CAA, CAP 1264 Standards for Helicopter Landing Areas at Hospitals (First amendment edition, August 2019) National Fire Protection Association (NFPA) 418 Standards for Heliports, 2016. International Fire Code International Building Code National EMS Pilots Association Hospital Helipad Safety Federal Aviation Administration (FAA) Advisory Circular AC 150/5390-2C - Heliport Design.. Unified Facilities Criteria (UFC) Airfield and Heliport Planning, UFC 3-260-0,1Nov 2008 National Interagency Fire Center PMS 510, Interagency Helicopter Operations Guide, Chapter 8 Helicopter Landing Areas, Feb 2013. Helitecnica Light Heliports Point Lighting Corporation Helipad/Helideck Lighting - Wind Cones - Obstruction Lighting Helicopters Airports by type