aircraft, Bombardier, C, Certification, Chief, CS100, CS300, Engineering, Flight, ground, Pilot, Progress, Series, Shimmy, Simulator, Stability, test, Vehicle, Vibration
Robert “Rob” Dewar, Vice President and General Manager, C-Series, Bombardier Commercial Program, gave a brief insight into the certification program of the C-Series, one month after it’s first flight on the 16th of September, 2013.
The C-Series is poised to usher in a new era for Bombardier, while posing as a market threat for popular Airbus and Boeing single aisle aircraft.
There have been a total of 3 test flights till date.
The landing gear and certification tests have been completed for the shimmy. Shimmy is an unstable lateral (yaw) vibration, typically in the range of 10 to 30Hz, which can lead to structural damage and/or collapse of the landing gear. Landing gear as seen on aircraft such as the Airbus A320 family, Boeing 737NG family and the C-Series, among others, are twin wheeled cantilevered, and such landing gears may experience shimmy stability problems at low speeds, and must be tested to validate the design of the landing gear against shimmy.
The ground vibration test of the aircraft is in progress. This testing is part of the plane’s certification program. Selected parts of the aircraft are excited with an external oscillatory force. By observing the aircraft’s response to these vibrations, engineers can model the aircraft’s transfer functions and determine the airplane’s in-flight stability.
These tests results will be compiled and will determine when the airplane takes to the skies for the fourth time, when the test flight envelope will be further opened up. The last three flights have witnessed the C-Series reaching an altitude of 25,000ft, landing gear extension and retraction cycles, tests of both high lift devices: the slats and flaps, and other in-flight manoeuvres.
The aircraft’s performance an handling closely matches the predicted flight model in the simulator. Bombardier is using a Engineering Flight Simulator (ESIM),built by CAE, from the last one year to test actual flight systems and system controllers when integrated in the aircraft, such as the slat-flap computer, fly-by-wire computer, landing gear computer, APU-simulator, brake computers, the PW1500G Engine FADECs (Full Authority Digital Engine Computer), and so forth. Using this ESIM, the flight test program can rely a lot on the simulator to do a lot of the system and integration tests while also preparing flight test crew for various flight test exercises. This builds the confidence of the crew in the aircraft, while also helping complete real flight test exercises with higher success rates and lower risks. System testing has entered the certification testing phase.
Bombardier find the structural test results, in the certification phase, very pleasing. Testing on the cabin management system as well as the environmental control system are in progress.
The CS100 Flight Test Vehicles (FTV) 2, 3, 4, and 5, as well as the first production aircraft are in very advanced stages of final assembly at Mirabel. The larger CS-300’s first major fuselage section is being transported, expected to arrive at the presently non-optimised-for-the-C-Series Mirabel facility.
Which is why the construction of a new 667,000 sq-ft plant, located close to its current facilities in the vicinity of the airport in Mirabel, Quebec, entirely dedicated to the assembly of the CSeries family of aircraft, is progressing well.
According to Charles “Chuck” Ellis, Chief Flight Test Pilot C-Series, emphasising on the need for so many flight test vehicles, “We say it’s (certification program) a one year program but within that one year we’ll probably be doing 5 years of work. We can take one year and 5 airplanes, or 5 airplanes and one year”
Now that the ESIM’s flight and system model has been verified, it will making the certification easier and faster by offering a lot of flexibility and bandwidth in the C-Series certification program, as it is almost like having a 6th airplane in the fleet.