by:  AAT-320                                                       
                 AIRCRAFT - PROCEDURES AND COVERT SIGNALS                      
      1.  PURPOSE.  This order prescribes the signals which may be used        
      by pilots experiencing certain types of unlawful interference            
      (i.e., hijack/bomb [threat] aboard) to make their situation known        
      to air traffic control (ATC) and outlines the required                   
      dissemination of these signals to pilots who may have a need for         
      the information.                                                         
      2.  DISTRIBUTION.  This order is distributed to Branch level and         
      above in Washington Air Traffic, Flight Operations, and Civil            
      Aviation Security; to Branch level and above in Regional Air             
      Traffic, Flight Standards, and Air Transportation Security               
      Divisions; to all supervisors in the regional Communications             
      Control Center; to all Air Traffic Field Offices, General                
      Aviation, Air Carrier, and Flight Standards District Offices,            
      Aeronautical Quality Assurance Field Offices, and Flight                 
      Standards International Field Offices; and Air Transportation            
      Security Field Offices.                                                  
      3.  CANCELLATION.  Order 7110.49C, Unlawful Interference -               
      Hijack/Bomb (Threat) Aboard Aircraft - Procedures and Covert             
      Signals, is canceled.                                                    
      4.  EFFECTIVE DATE.  This order is effective May 1, 1980.                
      5.  GENERAL.  The material contained herein, while not considered        
      national security information requiring classification, shall be         
      handled as privileged information and shall be disseminated to           
      operators and ATC specialists on a strict "need-to-know" basis.          
      LOCAL REPRODUCTION IS NOT AUTHORIZED.  The procedures were               
      developed for covert application solely within U.S. airspace.            
      Designated representatives of the Department of Justice and              
      airlines have been made familiar with the procedures and pilot           
      signals herein.  Inquiries regarding information contained herein        
      from the above sources, as well as those official requests from          
      International Civil Aviation Organization contracting states,            
      should be referred to the Director, Air Traffic Service, AAT-1.          
      6.  PROCEDURES.                                                          
          a.  When possible, the pilot of an aircraft experiencing             
      unlawful interference (i.e., hijack/bomb [threat] aboard) should         
      transmit a description of the predicament and any requests for           
      assistance to air traffic control in the clear.  Air traffic             
      controllers shall respond to all requests, comply if possible,           
      and notify the proper authorities.  Circumstances may prevent            
      radio transmissions in the clear and will necessitate use of             
      covert signaling either by voice or by transponder when radar            
      service is available.  NOTE:  There are areas where radar service        
      is not available and radio is the only communication method.  In         
      these areas, ATC will advise when radar service is terminated.           
      The following actions include messages transmitted in the clear          
      and transmitted covertly either by voice or by transponder               
              (1)  SITUATION.  Am being hijacked/subjected to unlawful         
                   (a)  PILOT MESSAGE (Overt):  Same as 6(1) above.            
                   1  When an in-the-clear radio transmission of               
      unlawful interference is received, controllers shall assign Code         
      7500 to the aircraft (this does not preclude a subsequent change         
      to Code 7700 by the pilot, if necessary).                                
                   2  When a radio transmission is received indicating         
      the possibility of unlawful interference without accompanying            
      Mode 3/A, Code 7500 transmission, controllers shall assign Code          
      7500 to the aircraft.  Should the pilot question such assignment,        
      or otherwise indicate that a clear condition exists, the                 
      controller can then determine the specific nature of the                 
      situation and be in a better position to make subsequent                 
      judgments regarding the need for notification, clearance and             
      other actions.  Should the pilot acknowledge assignment of Code          
      7500 without further communication, or fail to acknowledge or            
      communicate further, the controller shall assume that the flight         
      is being subjected to unlawful interference and act accordingly.         
                   3  Following initiation of a hijacking, the pilot           
      may communicate or respond to routine controller transmissions by        
      using the word "TRIP" following the aircraft designator (Trans           
      World TRIP 419 or United TRIP 517).  This indicates the pilot is         
      unable to communicate in the clear (the hijacker is probably in          
      the cockpit).  In such cases, the controller should respond using        
      "TRIP" in the flight designator as in the example above.  During         
      an incident, the Civil Aviation Security Command Center in FAA           
      Headquarters may request that the controller use the "TRIP"              
      designator in routine communication with the aircraft as a query         
      to the pilot whether clear communication is possible.  Should            
      this action result in a response from the pilot that                     
      communication in the clear is possible, the Command Center may           
      request the controller to pass information to the pilot or               
      solicit information from the pilot.  Should the controller               
      transmission using "TRIP" result in a pilot response also using          
      the "TRIP" designator, the controller should limit transmissions         
      to the aircraft to essential air traffic control functions and           
      should not communicate with the aircraft about the incident in           
      progress (reference paragraph 6(1)(a)4 below).                           
                   4  When a controller knows or believes that an              
      aircraft is being subjected to unlawful interference, no                 
      reference shall be made in ATC air-ground communications to the          
      nature of the emergency unless it has first been referred to in          
      communications from the aircraft involved or unless the pilot is         
      transmitting in the clear and it is certain that such reference          
      will not aggravate the situation.                                        
                   (b)  PILOT SIGNAL (COVERT):  Set transponder to Mode        
      3/A, Code 7500.  When unable to change the transponder setting or        
      when not under radar service, transmit a radio message which             
      includes the phrase "(aircraft call sign) transponder seven five         
      zero zero."                                                              
                   1  Controllers shall acknowledge receipt of beacon          
      Code 7500 by transmitting "(aircraft call sign) (name of                 
      facility) verify squawking 7500."  An affirmative reply from the         
      pilot indicates confirmation and proper authorities shall be             
      notified by the receiving facility.                                      
                   2  Should the pilot believe it unwise to use the            
      phrase "(aircraft call sign) transponder seven five zero zero,"          
      he may use the "TRIP" designator described in paragraph 6(1)(a)          
      above.  In such cases, the controller should follow the                  
      procedures outlined in paragraph 6(1)(a)3.                               
                   3  Controllers shall honor clearance requests               
      insofar as possible.                                                     
              (2)  SITUATION IN THE AIR:  Situation grave; imminent            
      danger is anticipated; require immediate assistance.                     
                   (a)  PILOT MESSAGE (Overt):  Same as above.                 
                        Same as 6(1)(a)1 thru 2 except Code 7700 should        
      be assigned.                                                             
                   (b)  PILOT SIGNAL (Covert):  After using Code 7500,         
      change the transponder to Code 7700.  When unable to change the          
      transponder setting or when not under radar service, transmit            
      "(aircraft call sign) transponder seven seven zero zero."                
                   1  Before changing from Code 7500 to Code 7700,             
      pilots should remain on 7500 for at least 3 minutes or until a           
      confirmation of Code 7500 has been received from the controller,         
      whichever is sooner.  Controllers shall acknowledge receipt of           
      Code 7700 by transmitting "(aircraft call sign) (name of                 
      facility) now reading you on transponder seven seven zero zero."         
                   2  Same as 6(1)(b)2 above.                                  
                   3  Aircraft switching from Code 7500 to Code 7700           
      that are not in radio contact with the ground will be considered         
      by ATC to have an in-flight emergency (in addition to condition          
      of unlawful interference) and the appropriate emergency                  
      procedures shall be followed.  In these cases, notification of           
      concerned authorities shall include information that the aircraft        
      displayed the unlawful interference (i.e., hijack/bomb [threat]          
      aboard) code as well as the emergency code.                              
              (3)  SITUATION ON THE GROUND:  Situation grave; want             
      armed intervention and aircraft immobilized.                             
                   (a)  PILOT MESSAGE (Overt).  Same as 6(3) above.            
                   (b)  PILOT SIGNAL (Covert):  Leave full flaps down          
      after landing or lower full flaps while on the ground.                   
              (4)  SITUATION ON THE GROUND:  Leave alone - do not              
                   (a)  PILOT MESSAGE (Overt).  Same as 6(4) above.            
                   (b)  PILOT SIGNAL (Covert):  Retract flaps after            
                        NOTE:  Pilots who retract flaps after squawking        
      Code 7700 should return to Code 7500 and remain on Code 7500 for         
      the next leg of the hijacked flight unless the situation changes         
      again.  The pilot may transmit "(aircraft call sign) back on             
      seven five zero zero" to emphasize the fact that intervention is         
      no longer desired.                                                       
          b.  Air Carrier District Offices and Flight Standards                
      District Offices shall ensure that Part 121 air carrier and              
      commercial operator pilots are trained and knowledgeable about           
      unlawful interference (i.e., hijack/bomb [threat] aboard)                
      procedures and covert signals.  General Aviation District Offices        
      and Air Transportation Security Field Offices will be responsible        
      for disseminating this information to general aviation and air           
      taxi pilots.  Flight Standards field offices having                      
      responsibility for Part 129 foreign air carriers will ensure that        
      this information is disseminated to those operators.                     
      /s/ Langhorne Bond                                                       
      FOR OFFICIAL USE ONLY - Public Availability to be determined             
      under 5 U.S.C. 552.