Question: What type of aircraft can be used in congested or isolated areas and is used at Langley Regional Airport?

full_context: Document 1: Mil Mi-17: The Mil Mi-17 (NATO reporting name: Hip) is a Russian helicopter in production at two factories in Kazan and Ulan-Ude. It is known as the Mi-8M series in Russian service. It is a medium twin-turbine transport helicopter. There are also armed gunship versions.
Document 2: Canadian Museum of Flight: The Canadian Museum of Flight (formally the Canadian Museum of Flight Association since 1998) is an aviation museum at the Langley Regional Airport in Langley, British Columbia, Canada. The museum has over 25 civilian and military jets, piston driven engine aircraft, gliders, and helicopters on display, six of which have been restored to flying condition. Other displays include an aviation art gallery and aviation artefacts.
Document 3: Bell UH-1 Iroquois: The Bell UH-1 Iroquois (nicknamed "Huey") is a utility military helicopter powered by a single turboshaft engine, with two-blade main and tail rotors. The first member of the prolific Huey family, it was developed by Bell Helicopter to meet a United States Army's 1952 requirement for a medical evacuation and utility helicopter, and first flew in 1956. The UH-1 was the first turbine-powered helicopter to enter production in 1960 for the United States military, and more than 16,000 have been built since.
Document 4: Langley Regional Airport: Langley Regional Airport (IATA: YLY, ICAO: CYNJ) is located in Langley Township, British Columbia, Canada. The airport serves mostly general aviation, and also provided scheduled passenger service to the Victoria Airport Water Aerodrome via Harbour Air Seaplanes before service was ended on May 20, 2011. Helicopter operations are a major part of Langley Airport's traffic; the airport has 3 helipads.
Document 5: Vought-Sikorsky VS-300: The Vought-Sikorsky VS-300 (or S-46) was a single-engine helicopter designed by Igor Sikorsky. It had a single three-blade rotor originally powered by a 75 horsepower (56 kW) engine. The first "free" flight of the VS-300 was on 13 May 1940. The VS-300 was the first successful single lifting rotor helicopter in the United States and the first successful helicopter to use a single vertical-plane tail rotor configuration for antitorque. With floats attached, it became the first practical amphibious helicopter.
Document 6: Pitt Meadows Airport: Pitt Meadows Airport (ICAO: CYPK) is a Canadian general aviation airport located in the southwest of corner of Pitt Meadows, British Columbia. In 2016, it was the 17th busiest airport in Canada with 109,188 aircraft movements and is the 4th busiest airport in the Lower Mainland.
Document 7: Harbin Z-20: The Harbin Z-20 or Zhi-20 is a medium lift helicopter produced in the Northeast of China. Its first flight was on 23 December 2013. The helicopter has a maximum takeoff weight in the range of 10 tons, can drop troops at locations of up to 3,000 ft altitude, and could operate from the Chinese aircraft carrier Liaoning. It is thought to be comparable to the US made Sikorsky UH-60 Black Hawk helicopter, the civilian Sikorsky S-70C-2 variant of which has been used by the People's Liberation Army since 1984. Some sources suggest that the Z-20 is a copy of the Black Hawk and link the design to the Black Hawk that was abandoned by US special forces in Pakistan during the operation to kill Osama bin Laden on 1 May 2011. The sources say that Pakistan allowed Chinese officials to examine the Black Hawk wreckage. However, Aviation Week also points out that although some aspects of the design do appear similar, such as the tail wheel arrangement, there are also marked differences. For example, the Chinese Z-20 has a five blade rotor compared with the Black Hawks' four blades.
Document 8: Vancouver International Airport: Vancouver International Airport (IATA: YVR, ICAO: CYVR) is located on Sea Island in Richmond, British Columbia, Canada, about 12 km from Downtown Vancouver. It is the second busiest airport in Canada by aircraft movements (306,799) and passengers (22.3 million), behind Toronto Pearson International Airport. It has non-stop flights daily to Asia, Europe, Oceania, the United States, Mexico and other airports within Canada. The airport has won several notable international best airport awards; it won the Skytrax Best North American Airport award in 2007 and 2010 through 2017. The airport also made the list of top 10 airports in the world for the first time in 2012, rated at 9th (2012), 8th (2013), and 9th (2014) overall. It is the only North American airport included in the top 10 for 2013 and 2014. YVR also retains the distinction of Best Canadian Airport in the regional results. It is a hub for Air Canada and WestJet. It is also an operating base for Air Transat. Vancouver International Airport is one of eight Canadian airports that have US Border Preclearance facilities. It is also one of the few major international airports to have a terminal for scheduled floatplanes.
Document 9: Iqaluit Airport: Iqaluit Airport (IATA: YFB, ICAO: CYFB) serves Iqaluit, Nunavut, Canada and is located adjacent to the town. It is operated by the government of Nunavut. It hosts scheduled passenger service from Ottawa, Montreal, Rankin Inlet and Kuujjuaq on carriers such as First Air and Canadian North, and from smaller communities throughout eastern Nunavut. It is also used as a forward operating base by the CF-18 Hornet. In 2011, the terminal handled more than 120,000 passengers.
Document 10: West Kootenay Regional Airport: The West Kootenay Regional Airport, (Castlegar Airport) (IATA: YCG, ICAO: CYCG) is a small regional airport located 2 NM south southeast of Castlegar, British Columbia, Canada. It is owned and operated by the City of Castlegar, and has a 15317 sqft passenger terminal. Due to the mountainous terrain impinging on both runway approaches, there is no possibility of a straight-in approach. The airport is therefore certified for day operations only, and the glideslope on approach is set to a steep 5.0° rather than the standard 3.0°. The instrument approaches to Castlegar are considered among the most challenging of any in use at a commercial airport in North America. As of 2011, the Dash-8s serving the airport required minimums of 3400 foot cloud ceilings and three miles visibility (Air Canada Jazz adds 100 feet and one mile to these minimums).
Document 11: Langley Regional Airport: Langley Regional Airport (IATA: YLY, ICAO: CYNJ) is located in Langley Township, British Columbia, Canada. The airport serves mostly general aviation, and also provided scheduled passenger service to the Victoria Airport Water Aerodrome via Harbour Air Seaplanes before service was ended on May 20, 2011. Helicopter operations are a major part of Langley Airport's traffic; the airport has 3 helipads.
Document 12: List of surviving Sikorsky CH-54s: The Sikorsky CH-54 Tarhe is a twin-engine heavy-lift helicopter designed by Sikorsky Aircraft for the United States Army. The civil version is the Sikorsky S-64 Skycrane. The Army purchased 105 CH-54s before its discontinuation. The S-64 Aircrane is still in production. There are currently numerous complete and partial airframes in existence for this aircraft. Some CH-54's and some S-64's (both E and F models) are owned, and have been remanufactured, by Erickson Air-Crane Inc."
Document 13: Tiltrotor: A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called "proprotors") mounted on rotating engine pods or nacelles usually at the ends of a fixed wing or an engine mounted in the fuselage with drive shafts transferring power to rotor assemblies mounted on the wingtips. It combines the vertical lift capability of a helicopter with the speed and range of a conventional fixed-wing aircraft. For vertical flight, the rotors are angled so the plane of rotation is horizontal, lifting the way a helicopter rotor does. As the aircraft gains speed, the rotors are progressively tilted forward, with the plane of rotation eventually becoming vertical. In this mode the wing provides the lift, and the rotor provides thrust as a propeller. Since the rotors can be configured to be more efficient for propulsion (e.g. with root-tip twist) and it avoids a helicopter's issues of retreating blade stall, the tiltrotor can achieve higher speeds than helicopters.
Document 14: Sikorsky R-4: The Sikorsky R-4 was a two-seat helicopter designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter used by the United States Army Air Forces, the United States Navy, the United States Coast Guard and the United Kingdom's Royal Air Force and Royal Navy. In U.S. Navy and U.S. Coast Guard service, the helicopter was known as the Sikorsky HNS-1. In British service, it was known as the Hoverfly.
Document 15: Helicopter: A helicopter is a type of rotorcraft in which lift and thrust are supplied by rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward, and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of VTOL (vertical takeoff and landing) aircraft cannot perform.
ground_truth: Helicopter