By Kenneth I. Swartz | April 20, 2017 Estimated reading time 5 minutes, 54 seconds.
Touch down at Billy Bishop Toronto City Airport today in a private or commercial aircraft and you can’t help but notice a large new shimmering steel-clad building on the airfield’s southern boundary.
From a distance, it’s hard to know what the space-age structure is used for, but all was revealed on April 18 when Marc Garneau, Canada’s Minister of Transport, flew in from Ottawa for a ribbon-cutting ceremony to officially open the downtown airport’s new $9 million ground run-up enclosure (GRE).
The three-sided, open-roof GRE facility was specifically designed to dampen the community noise impact of engine run-ups, a procedure that is performed after aircraft engines or propellers undergo maintenance.
The GRE–only the second of its kind in Canada–weighs 200 tonnes, and measures 63 metres wide and 66 metres deep. It was specifically designed so a Bombardier Q400 can taxi into the GRE under its own power, turn around and be tested without requiring the use of an aircraft tug.
“Aircraft noise is a complicated issue faced by airports and communities, one that must be managed while ensuring that aviation safety remains paramount,” said Garneau. “This project at Billy Bishop Airport is a great example of the federal government working closely with the municipal government and the airport authority to achieve this balance while making a positive difference to the neighbourhood.”
“Operating an airport that is part of a thriving, mixed-use urban waterfront requires the right balance to ensure that operations keep pace with the surrounding community and that measures are in place to mitigate the impacts associated with running a successful airport,” said Geoffrey Wilson, CEO of PortsToronto, which owns and operates Billy Bishop Airport.
The GRE was designed and constructed as part of the airport’s three-year airfield rehabilitation program that has already seen the resurfacing and addition of lighting on Runway 06-24 used by general aviation, and the recent decommission of Runway 15-33, which was only used three per cent of the time and will facilitate new hangars and offices on the northwest part of the island airport.
Billy Bishop GRE
PortsToronto engaged the same facility design-builder, Blast Deflectors, Inc. (BDI) that constructed a GRE at Vancouver International Airport. BDI focuses exclusively on aircraft run-up noise and has built 30 such GRE facilities worldwide.
Don Bergin, president of BDI, told Skies the new GRE was oriented at 250 degrees to provide the best aerodynamic and acoustic results.
Wind conditions will be suitable about 85 per cent of the time for run-ups in the enclosure.
“Turboprop engines need to be tested in smooth, turbulent free air to run efficiently at high power settings while stationary,” said Bergin. “This is not a problem when an aircraft is in an open field, but can be challenging when an aircraft is put in an enclosure with high acoustic walls.”
BDI’s solution to creating an aerodynamically stable enclosure is a design with a sloped entry to improve air flow during quartering head wind conditions; acoustically treated vented side walls to provide adequate turbulent free-air during side wind conditions; a roll top edge on the walls to eliminate turbulence in cross wind conditions; and an independent curved/slotted jet blast deflector at the rear of the facility that directs exhaust out of the GRE to avoid gas recirculation.
The acoustic performance is determined by the height of the facility, the type of aircraft and the power settings.
The Billy Bishop airport enclosure has a 14-metre-high wall on the north side, and the east and south walls are 11 metres high, which will protect all residential areas to the north and east.
Inside the structural framing (the skeleton) there are 1,726 noise blotter acoustic panels weighing 45 kilograms each that have a good noise reduction coefficient and are made from non-hydroscopic materials to ensure a long and maintenance-free life.
The outside cladding of the wall was applied for aesthetic reasons to improve its visual profile.
BDI also built the engine testing enclosure surrounding GE’s jet engine ice test facility at Winnipeg Airport.
This noise barrier is more of a PR exercise than a noise reducer. First, the GRE is oriented so that engine blasts are aimed at the city, instead of turning the GRE around so the noise would blast south-west, out over the water. Then the engine noise is deflected upward into the wind, which carries the noise farther than before, and the GRE walls are mostly hollow, allowing the noise to pass through the enclosure. In other words, it looks good, but it doesn’t reduce the noise much, if at all. I live near this airport, and it sounds as noisy now as it ever did in our neighbourhood.