CERTIFYING AUTOLAND SYSTEMS

摘要

Bombardier is equipping the C Series aircraft with an Autoland system. No other Bombardier aircraft has an Autoland system. This system will enable C Series aircraft to land in low visibility conditions, thus maximizing the number of flights conducted by carriers and minimizing the number of missed connections for passengers. Carriers may enable CAT II, CAT IIIA, or CAT IIIB options on a C Series aircraft. AC 120-28D provides guidance for obtaining approval for a new Autoland system. A major part of certification is to prove that the Autoland system will meet certain 10~(-6) landing criteria. Since it is obviously impracticable to conduct a million landings during a flight test program, the AC allows designers to use simulation results to prove adherence to the landing criteria. Even still, it is time prohibitive to run one million simulated landings, so extrapolation techniques must be carefully used. A Monte Carlo approach is used to simulate a variety of initial conditions, winds, and sensor errors. Once the simulation results show compliance with the AC criteria, flight tests must be conducted to validate the simulation. During the C Series Autoland certification effort, an iterative approach is being used. Initial simulation results were promising but did not fully meet all the landing criteria. Flight tests were conducted in relatively benign environmental conditions to gather data so that adjustments could be made to the simulator. Further design changes were then made to the autoland system and more simulations were performed before resuming flight testing. Per the AC, simulation and flight testing must be conducted in a variety of conditions, which include head/cross winds, irregular terrain, sloped runways, seawalls, and high elevation runways. In total, 100 flight test landings should be conducted for proper validation of the simulator results (as recommended in the AC). The team investigated different methods of validating the simulations results before finally deciding to use a reconstruction technique. This brief will provide an overview of simulation techniques, methods of evaluating simulations results, flight test execution, post-flight analysis, and simulator validation.