Advisory 

Circular 

Subject: REPORTING OF THREATS IN Date: 9/11/06 AC No: 90-103 

ACCORDANCE WITH THE COMMON Initiated by: AIR-0 

STRATEGY 

1. PURPOSE. This advisory circular (AC) provides information to the aviation community, 

particularly to aircrews operating within the National Airspace System (NAS), regarding 

methods to manage and report instances of passenger interference with crewmembers. The 

Aviation and Transportation Security Act (ATSA), Public Law 107-7 1, created the 

Transportation Security Administration (TSA) and tasked the Administrator of TSA to work with 

the Administrator of the Federal Aviation Administration on security actions that may affect 

safety and aircraft operations. The ATSA created a new Title 49, United States Code (USC), 

Chapter 449, Section 4491 8, Crew training, requiring new, detailed guidance for crew training. 

As a result of this provision, a new Common Strategy was developed and implemented. 

a. Common Strategy identifies four distinct threat levels that help crewmembers identify 

their responsibilities and appropriate response: 

Level 1 : Disruptive behavior - suspicious or threatening 

Level 2: Physically abusive behavior 

Level 3: Life-threatening behavior 

Level 4: Attempted or actual breach of the flight deck 

b. While it is not possible to write procedures and guidance for every conceivable situation, 

Common Strategy provides a standardized approach developed with involvement of TSA, FAA, 

air carriers, and crewmembers. The U.S. aviation community, air traffic, security, law 

enforcement, and military agencies use their core concepts for response to security events, 

including hijackings. 

2. DISCUSSION. The modus operandi of terrorist organizations is to make coordinated, 

simultaneous attacks designed to confuse and overwhelm defenses. Events perceived by 

aircrews, as isolated to one aircraft, may be part of a broader scheme or the precursor to an 

elaborate attack. Therefore, the rapid exchange of information is paramount to ensure the 

security and integrity of the NAS. 
3. AUTHORITY. The FAA has the authority to regulate the safe and efficient use of 

navigable airspace (Title 49, USC, Chapter 401, Section 40103, Sovereignty and use of 

airspace). The FAA also has the authority to protect the flight of aircraft in air commerce 

(Title 49, USC, Chapter 447, Section 44701, General requirements, subparagraph (a)(5). 

The FAA has the authority to update aircrew training guidance to reflect new or different 

security threats, to require air carriers to revise their programs accordingly, and to provide 

additional training to their flight and cabin crews (Title 49, USC, Chapter 449, Section 4491 8, 

Crew training, subparagraph (e)(2). Title 14, Code of Federal Regulations (CFR), Part 91, 

Section 91.1 1, Prohibition on interference with crewmembers; Title 14, CFR, Part 121, 

Section 12 1.3 17, Passenger information requirements, smoking prohibitions, and additional 

seatbelt requirements; Title 14, CFR, Part 12 1, Section 121 -575, Alcoholic beverages; and, 

Title 14, CFR, Part 135, Section 135.127, Passenger information requirements and smoking 

prohibitions. 

4. EFFECTIVE DATE. This AC is effective September 14, 2006. 

5. FAA NOTIFICATIONS AND REPORTING. 

a. All FAA air traffic control (ATC) facilities will immediately report interference with 

flightcrews through the Domestic Events Network (DEN). The DEN supports sharing real-time, 

security-related information affecting the NAS air traffic operations among FAA, TSA, and other 

governmental stakeholders, including law enforcement agencies. 

b. The ATC report will include the coordinated universal time (UTC), operator, 

flight number, aircraft type, nearest major city, altitude, transponder code, level of disturbance, 

and any other information needed to support the action. 

6. AIRCREW REPORTING PROCEDURES. All aircrews are requested to immediately 

report incidents of interference with flightcrews to the appropriate ATC controlling facility. 

Reports should include level of interference, UTC, whether priority handling is being requested, 

if the crew is requesting to divert due to the incident, a confirmation the flight deck is secure, and 

any other information deemed necessary for ATC, law enforcement, and other governmental 

action taken to safeguard the safety of aviation operations in the IVAS. 

7. AIRCREW INFORMATION RESOURCES. The FAA recommends that aircraft 

operators, particularly aircrews, check regularly for updates regarding the NAS security in the 

appropriate Notice to Airmen. Additional information may be available at the following 

Web sites: 

8. APPENDIX. 

- Common Strategy - The Four Distinct Threat Levels 
9. RELATED DOCUMENTS. 

a. Common Strategy, Detailed Guidance dated January 3,2005. 

b. FAA Notice 71 10.422, Aircraft Hijack and Suspicious In-flight Activities - Response and 

Notification Procedures. 

10. PAPERWORK REDUCTION ACT STATEMENT. Through the use of this AC, the 

FAA intends to maintain an increased level of security in the NAS. 

Michael A. Cirillo 

Vice President, System Operations Services 

Air Traffic Organization 
AC NO: 90-103 

Appendix 1 

APPENDIX 1. COMMON STRATEGY - THE FOUR DISTINCT THREAT LEVELS 

LEVEL 1 THREAT 

Definition: Disruptive behavior - suspicious or threatening. 

Examples: Irrational behavior that creates the potential for physical conflict, nonviolent 

threatening behavior, verbal harassment, inebriation, and, threats (both verbal and 

written) - does not include battery or possible medical conditions. 

LEVEL 2 THREAT 

Definition: Physically abusive behavior. 

Examples: Pushing, kicking, hitting, grabbing, tripping, or inappropriate touching. 

LEVEL 3 THREAT 

Definition: Life-threatening behavior 

Examples: Weapon displayedlused, credible terrorist threats, credible bomb threats, or actual 

use of bombs, sabotage of aircraft systems, credible threats of hijacking, and 

deadly hand-to-hand techniques such as choking or eye gouging. 

LEVEL 4 THREAT 

Definition: Attempted or actual breach of the flight deck. 

Examples: Mentally disturbed individuals, goal-oriented hijackers, and suicidal hijackers.