Safety & Training
Standards & Regulations
Heliports by Design: Ensuring a Safe Landing
February 20, 2008 By Blair Watson
Each year, there are thousands of helicopter flights in Canada that
begin and end at a heliport designed in accordance with Transport
Canada standards. There are 296 heliports in this country; the lowest
is located at Vancouver Harbour at an elevation of 2 ft., while the
highest is a fire base in Shunda, Alta., 4,700 ft. above sea level.
|The Victoria, BC (Camel Point), heliport. (Photo by Dan Barnes)|
Each year, there are thousands of helicopter flights in Canada that begin and end at a heliport designed in accordance with Transport Canada standards. There are 296 heliports in this country; the lowest is located at Vancouver Harbour at an elevation of 2 ft., while the highest is a fire base in Shunda, Alta., 4,700 ft. above sea level.
Fifty percent of Canadian heliports are located at health care facilities (127 hospitals and 21 health care centres). The most northerly is at the Yellowknife Regional Hospital, while 3,058 km to the southeast the Chatham General Public Hospital also receives patients at its
heliport. A number of hospitals in Canada have rooftop helipads, the design of which involves compliance with not only the Transport Canada standard for heliports – Standard 325 – but also provincial engineering requirements since health care facilities are the responsibility of the provinces (and territories).
Standard 325 “outlines the minimum technical specifications for the physical characteristics, obstacle limitation surfaces, and technical services at a heliport necessary for the purposes of complying with Part III of the Canadian Aviation Regulations (CARs).” The standard also provides “a means to assess the operational use of a facility,” “reflects recognized international safety parameters,” and “provides the technical specifications to be used when building a new heliport or modifying an existing heliport where the objective is for the heliport to be certified by the Minister of Transport.”
Several articles would be required to cover all the elements of Standard 325, which is online at the Transport Canada Civil Aviation Web site. The purpose of this article is to provide an overview of heliport design. Suffice to say that the 15 divisions of Standard 325 have been written to ensure that heliports are designed to ensure safe helicopter operations. Subjects covered in detail in the divisions include heliport general certification requirements, physical characteristics, obstacle limitation surfaces, air navigation and obstacle visual aids, lights, markers, equipment and installations, and emergency and other services. Certain minimum helicopter dimensions were assumed in developing Standard 325: An overall length of 11m, a rotor diameter of 9m, a skid length or wheelbase of 2m, and a gross weight of 1,200kg.
There are several terms used in Standard 325, most of which have the same meaning as in the Aeronautics Act and CARs. Although too many to be listed in this article, two key acronyms include FATO (Final Approach and Takeoff Area – “a defined area over which the final phase of a helicopter approach manoeuvre to hover or to land is completed and from which the take-off manoeuvre is commenced”) and TLOF (Touchdown and Lift-Off area – “[a] load-bearing area on which a helicopter may touch down or lift off”). The Transport Canada Web site also contains a glossary and list of acronyms related to heliport design and operations.
Heliports are classified by the obstacle environment within which the heliport is located and the availability of emergency landing areas, which dictate the performance requirements of the helicopters using the facility. For example, medevac helicopters that use rooftop helipads at hospitals in built-up areas must be multi-engine and powerful enough to climb away on a single engine following a powerplant failure after lift-off. When determining an appropriate site for a heliport, the availability of approach and departure paths leading to/from the facility are a major safety consideration. It is not always possible to safely conduct unrestricted operations at every heliport.
Heliports are divided into two categories: instrument and non-instrument, the latter being comprised of three classifications: H1, H2 and H3. Only multi-engine helicopters are permitted to use H1 heliports because there is no place to conduct an emergency landing within 625m of the FATO after lift-off. H2 heliports have an emergency place to land within 625m of the takeoff surface and are located within an obstacle environment “where the height of the obstacles are infringing the first section slope of the approach and takeoff surface” (Transport Canada defines the dimensions and slopes of obstacle limitation surfaces for non-instrument FATOs in an online table). The H3 classification essentially applies to all other non-instrument heliports.
LANDING PAD DESIGN
AT HAMILTON GENERAL
Another important consideration in designing heliports is load-bearing strength, which in this case is a measure of the ability of a surface to withstand the weight of a stationary or slowly moving helicopter at its gross weight. Helipads, taxiways and parking areas are engineered to support aircraft up to a certain mass. For example, the TLOF of an elevated surface (e.g., an above-ground helipad at a ski resort) or rooftop heliport “shall be capable of supporting static and dynamic loads imposed by the largest helicopter for which the heliport is certified.” Also, “the design static load shall be equal to the helicopter’s maximum certificated takeoff weight applied through the total contact area of the wheels or skids” and “the dynamic loads shall be at least 150 per cent of the maximum certificated takeoff weight transmitted through the main wheels or through the contact areas of a skid-equipped helicopter.”
Maximum helicopter length is another critical aspect of the design of heliports where the operator intends to receive Transport Canada certification. For example, no helicopter using a heliport is to be longer than two-thirds the width or diameter of the FATO. If the FATO is on an elevated helipad or rooftop heliport, the length of the helicopter is not to exceed the width or diameter of the TLOF contained within the FATO. There are other factors that dictate
maximum helicopter length for certified heliports.
The design of heliports also includes protection and safety areas. A protection area is approximately three times the overall length of the largest helicopter using the heliport, and is measured from the tip of the rotor blades. The safety area provides an obstacle-free area for helicopters accidentally diverging from the FATO, the installation of visual and non-visual aids, and drainage and run-off from the FATO.
Rejected takeoff areas, helicopter clearways, taxiways, and helicopter parking positions are other aspects of heliport design, but they do not necessarily apply to every facility. For example, many Canadian heliports do not have a taxiway, and a portion do not have helicopter parking positions (i.e., the pilot shuts down the helicopter after landing on the TLOF area). There are unique Transport Canada requirements for surface-level, elevated/rooftop, located-at-aerodrome, and H1 heliports.
In terms of visual aids at heliports, Standard 325 states that “a heliport shall be equipped with at least one wind direction indicator” and defines where it is to be located. There are also requirements pertaining to the “H” painted in the centre of the TLOF (e.g., at hospitals); helipad perimeter, taxiway, and parking position markings; and other visual aids to pilots.
Designing heliports requires singular knowledge and a unique set of skills; there are design consultants, such as Pryde Schropp McComb in Ottawa, with the relevant expertise. For more information about heliport design, contact a consulting firm, visit the Aerodromes and Air Navigation Branch of Transport Canada, or visit the Transport Canada Civil Aviation Web site.