Aviation accidents are tragic events that sometimes leave important clues about risks to flight safety. Following two such accidents, investigations and studies revealed new ice cloud threats – supercooled large droplets and ice crystal/mixed phase ice. As a result, in 2015, North American and European aviation regulators introduced new requirements for aircraft to be certified to these atmospheric conditions.

In response to the new regulations, the National Research Council of Canada (NRC) has upgraded its Altitude Icing Wind Tunnel, one of the few wind tunnels in the world that can simulate and test aircraft surfaces, components and probes in icing conditions at altitude.

"The expansion of our wind tunnel capabilities allows us to collaborate with aerospace manufacturers who must meet new and evolving regulations to prove the airworthiness of their products," says Jerzy Komorowski, General Manager, Aerospace at the NRC. "This new capability will enhance aviation safety and ensure safer air travel."

Able to simulate altitudes up to 40,000 feet and temperatures down to -40 °C, the Altitude Icing Wind Tunnel can test sections and scaled down versions of aircraft, as well as engine components and engine probes that alert pilots to particular icing conditions. The new ice crystal generating system allows the wind tunnel to produce high intensity levels of ice crystals and mixed phase conditions (ice crystals and water drops combined) similar to those experienced when flying through convective storms at high altitude. Additional updates to the tunnel spray system allow for supercooled large droplets in the form of freezing drizzle (drops less than 0.5 mm diameter) and freezing rain (drops greater than 0.5 mm diameter).

As aircraft manufacturers race to certify to the new regulations, the Altitude Icing Wind Tunnel presents competitive advantages: it is more cost-effective than flight testing and allows for consistent and repeatable testing conditions.