Airbus has doubled its active A350 test-flight fleet, after conducting the maiden flights of its third and fourth prototypes within the space of a few hours.
The cabin-equipped MSN2 departed Toulouse on 26 February with MSN4, which bears a hybrid livery for launch customer Qatar Airways, following later the same day.
MSN4 is carrying light instruments and will be used for low-weight envelope certification and noise measurement. MSN2 will perform cabin function tests and early long flights.
Airbus says the first two instrumented airframes, MSN1 and MSN3, have accumulated close to 1,100h, accounting for some 45% of the overall certification programme.
One more test aircraft, MSN5, is due to join the A350 fleet around May. This aircraft will also be fitted with a cabin.