Template:Aircraft Phases with Forced Landing

Aircraft Phases with Forced Landing

Consider simulating a flight mission for a four-engine aircraft. The configuration of the aircraft changes at different time. During the taxiing phase, the navigation system, one out of the four engines and all three landing gears are needed. During the take-off phase, all four engines, the navigation system and all three landing gears are needed. During the cruising phase, the navigation system and three of the four engines are required. During the landing phase, the navigation system, two of the four engines and all three landing gears are required. After finishing a journey with these four phases, the aircraft goes into a maintenance phase for maintenance. However, in addition to the four operational phases discussed, there is a special operational phase called the forced landing phase. This phase is used for modeling the case when there is a failure during take-off, cruising or landing phase, forcing the aircraft to land. If the forced landing succeeds, the aircraft goes into the maintenance phase. However, if the forced landing fails, the aircraft crashes 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.

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