Template:Aircraft Phases with Forced Landing

Aircraft Phases with Forced Landing
Consider to simulate a flight journey for a four-engine aircraft. The configuration of the aircraft changes at different time. During taxing phase, the navigation system and only 1-out-of-4 engines and all three landing gears are need. During take-off phase, four engines, navigation system and three landing gears are need. During cursing phase, navigation system and 3-out-of-4 engines are required. During landing phase, navigation system, 2-out-of-4 engines and three landing gears are required. After finishing a journey with these four phases, the aircraft would goes into a maintenance phase for maintenance. However, except these four phases, there is a special phase named forced landing phase. This phase is used for modeling the case when there is a failure occurred during take-off, cruising or landing phase, the aircraft would be forced to land. If the forced landing successes, the aircraft would goes into maintenance phase for maintenance. However, if the forced landing fails, the aircraft crashed and the simulation ends.

Purposes
The purposes of this example are to illustrate how to create a nonlinear system with F/S links in phase simulation.

RBDs for Phase and settings
The RBDs for Taxing phase and Take-Off phase are as followings:

The RBDs for other three phases are as followings:

The Phase diagram is as followings:

The reliability of navigation system follows Weibull distribution with Beta=1.5 and Eta=30 hours. The reliability of engines follows Weibull distribution with Beta =1.5 and Eta=20 hours. The reliability of landing gears follow Weibull distribution with Beta=1.5 and Eta=15 hours.

In maintenance phase, all blocks has CM with duration=3 hours. And the CM is performed upon item failure. All blocks also are subjected to PM with duration =0.5 hours and the PM is performed when the maintenance phase starts. Both CM and PM restore the blocks to as good as new.

Blocks Up/Down plot

 * 1) At time 5.506, in Phase 3: Cruising phase, Engine 2 fails. However, this failure doesn't bring system down because in Cruising phase, only 3-out-of-4 engines are required.
 * 2) At time 6.41, in Phase 3: Cruising phase, Engine 1 fails too. This failure brings system down and the system goes into Forced Landing phase immediately.
 * 3) At time 7.91, Forced Landing phase (Phase 5) is done. There is not failure happened in this phase, which means the forced landing is successful. And the system goes into Maintenance phase (Phase 6). And all blocks except Engine 1 and Engine 2 get PM in maintenance phase.
 * 4) At time 10.91, Engine 1 and Engine 2 are done with their CM and system goes back to the Phase 1: Taxing phase.
 * 5) At time 20.721, in Phase 3: Cruising phase, Engine 1 fails again. Of course, this failure doesn't bring system down.
 * 6) At time 23.25, in Phase 3: Cruising phase, Engine 3 fails and this failure bring system down. System goes into Phase 5: Forced Landing phase. After the Forced Landing phase, the system goes into maintenance phase.
 * 7) At time 33.706, in Phase 3: Cruising phase, Engine 1 fails again. This failure doesn't bring system down.
 * 8) At time 34.25, system goes into Phase 4: Landing phase.
 * 9) At time 34.576, in Phase 4: Landing phase, Landing Gear 3 fails and this failure bring system down. Thus system goes into Phase 5: Forced Landing phase immediately.
 * 10) At time 45.953, in Phase 4: Landing phase, Navigation system fails. This failure brings system down and system goes into Phase 5: Forced Landing phase immediately. In Phase 5: Force Landing phase, Navigation system is in series with other blocks, the failure of navigation system brings system down in Phase 5: Forced Landing phase. Thus there is a system failure in Phase 5: Forced Landing phase which means the forced landing fails and system goes into STOP node. Simulation stops.


 * [[Image:Aircraft phase Up Down plot.png|thumb|center|600px]]