FLUG REVUE April 2006: A380 cold weather trials in Canada

April 2006

A380 ON ICE

By Sebastian Steinke

There was very nearly a problem with the low-temperature tests in North Canada: what initially were the coldest temperatures, at minus 15 degrees Celsius, would have been almost too hot for the Airbus engineers. This year, the winter season in Iqaluit, formerly Frobisher Bay, on Baffin Island was unusually mild. But the 55-person test team needed the full frost programme with extreme winter temperatures of at least minus 25 degrees for their five-day “cold soak tests” with the deliberately chilled F-WWDD on the ground. So there was much relief in mid-February when finally, just in time, the daytime temperature sank to minus 29 degrees with increased frost.

A380

Even though most jets are routinely subjected to very low temperatures at cruise altitude, extreme cold on the ground can pose special challenges for an aircraft. Thus, according to Advisory Circular 500-006 issued by the Canadian aviation authorities, at extremely low temperatures the hydraulic fluid can harden, threatening leaks on the landing gear and the hydraulic actuators. Again, landing gear legs can lose their springy characteristics and pneumatically operated systems can fail due to freezing condensate in the lines. Metal parts, especially ones made from different metal alloys, can contract in the cold, making the control surfaces difficult to move or even causing control surfaces to seize up, maintenance hatches can jam, to name but a few of the possible undesirable side-effects. The trim actuators and sensors, for example, those used to measure the angle of attack, can fail. For this reason, with every new passenger aircraft it is necessary to gain practical experience at extremely low temperatures so that this can then flow into the official operating and maintenance instructions for this aircraft type. The official Canadian requirements specify a minimum temperature of minus 35 degrees Celsius for low-temperature tests and that the test aircraft should be exposed to this temperature for at least 10 hours. The A380 was parked overnight and actually spent twelve hours in the ice.

It is at least permitted to cover the engines and air inlets with protective covers beforehand and to remove the batteries for storage in the warm. After a detailed external inspection, the pressures and filling levels in the hydraulic systems, landing gear legs, tyres and batteries are measured. Another item on the low-temperature test agenda is to refuel the aircraft. On the other hand, because the A380's flight control system is electronic, it is no longer necessary to check the tension of the pull cables under low temperatures.

After being parked for the prescribed time, the system pressures are measured again, the batteries are reinstalled and all the doors and hatches inspected. It is now a question of switching on all the systems, including in reserve mode, before the engines are started up. All nonconformities are noted and the aircraft is henceforth fit for cold weather operations under the conditions tested. Having completed the above programme, MSN004's return flight to Toulouse on 11 February was then used for polar navigation tests.

The airport of the municipality of Iqaluit (IATA code: YFB / ICAO code: CYFB), the regional capital of the Canadian Inuit province of Nunavut, is the ideal test location due to its very low temperatures, a 2,621 metre long runway with 24-hour operations, combined with extensive ramp area and lack of airspace restrictions. The airbase, which until 1963 was operated by the US Air Force and today is home to the Canadian CF-18s besides being the regional airport, has previously been used for measurement programmes by Airbus with the A340-600 (in February 2003) and by Boeing, Raytheon and Eurocopter. Alternative locations for Airbus low-temperature tests have been Yakutsk in Siberia (A340-300 and A310) and Lulea in Sweden (A300).

According to Claude Lelaie, Senior Vice President Flight Division at Airbus and chief test pilot, MSN001 and MSN004, both with heavy test equipment, are currently flying twice a day. “They fly six days a week on top of the special test programmes. We are satisfied with their performance on the tests up to now. We are making headway with the certification procedures.” The three flying A380's to date have so far completed 900 hours in the air over a total of 250 flights. By the time that this issue of FLUG REVUE is published, MSN004 should have flown with Singapore Airlines stickers on it to south-east Asia in order to take part in the daily flight programme of the Asian Aerospace air show in Singapore starting on 21 February. There it will be able to acclimatise to hotter temperatures before flying to Africa in the summer for hot weather tests at 40 degrees Celsius.

From FLUG REVUE 4/2006

Last updated 10 March 2006

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