Give one example of how this layer of security would work successfully

You will select one of TSA’s 20 layers of security or one of the five layers of security for General Aviation. In your opinion, how effective is it? Give one example of how this layer of security would work successfully. Give one example of how this layer of security would not work.
My topic #20 passenger, I will need 2 paragraph
1) Intelligence-
2) Customs and border protection
3) Joint Terrorism Task Force
4) No Fly list and Passenger Pre Screening
5) Crew Vetting
6) VIPR -Visible Intermodal Prevention and Response
7) Canines
8) Behavior Detection Officers
9) Travel Document Checker
10) Checkpoint/Transportation Security Officers
11) Checked baggage
12) Transportation security inspectors
13) Random Employee Screening
14) Bomb Appraisal Officers
15) Federal Air marshal Service
16) Federal Flight Deck officers
17) Trained Flight Crew
18) Law Enforcement Officers
19) Hardened Cockpit Door
20) Passengers- It is the last line of defense in the system; Passengers are required to undergo a number of screening processes once they have entered into the security checkpoint. These processes include X ray, metal detector, trace explosive detector and maybe even a pat down search if he/she appears to be suspicious by the officers.