Due to the pandemic and restrictions in Canada, the Chinese COMAC decided to postpone a new phase of testing the C919 in extreme cold.
Now the tests will be carried out in the autumn of this year in the northern hemisphere, that is, between September and December 2021. According to the International Test Pilots School (ITPS), which will manage the tests, the postponement was carried out by the restrictions implemented by Canada to the entry of foreigners into the country.
In this way, and due to the proximity of spring, COMAC directors need to wait for the formation of ice in the Great Lakes region, in southern Ontario, which takes place between October and November.
COMAC has previously conducted some tests in northern China, in the Mongolian region, in extreme cold. However, it is not yet clear whether COMAC needs these tests to complete the certification of the C919, something expected to occur in 2021.
COMAC also expects to deliver the first C919 to a customer in 2021, a deadline that is becoming increasingly tight for the Chinese state-owned company.
The C919 testing and certification program has come a long way after the initial design phases, where the C919 needed to receive numerous design upgrades and improvements. The Chinese plane has already completed many important tests, such as operation in high temperatures and in the freezing winter of the Mongolian Desert.
It is possible that Comac has chosen to repeat this type of test with another prototype of the C919 in Canada, to double-check this certification process in a cold western climate, already targeting a possible sale of the plane to companies outside China. Certification in other countries can also be streamlined with this Comac test out of China.
for what reason perform tests in severe cold?
With a very low temperature, some parts of the plane may break or crack, due to the characteristic of expansion different from the materials used in aircraft. The engineers deg the plane already expect this behavior, and currently few planes suffer from this problem during testing.
But in the same way, the tests are focused on ing the level of efficiency of the lubricants, aircraft heating systems and functioning of the moving parts, which may suffer from the formation of ice in their actuation systems.
In conditions of extreme cold, as in Siberia, an airplane can also suffer problems in its rubbers and plastics, which do not the low temperature and become brittle, causing problems during the use of the airplane.
Another interesting test, quoted by AirlinesRatings, is to turn on the engines after 24 hours of the aircraft not being used, and check how a cold start is performed, both for the engines and for the APU.
Additionally, the crew checks how it is to land and take off on “frozen” runways, as well as check the use of engine reversers in the snow, and also some emergency procedures, such as an Aborted Takeoff (RTO, in English), performed by the pilots when they encounter some failure in the plane, and the speed is below V1.
Tests are carried out by all aircraft manufacturers to ensure that the aircraft can operate in all extreme weather conditions.
