AIM 8/15/19  TBL 5 − 3 − 17 Free Text Downlink Message Elements (TXTD) TBL 5 − 3 − 18 System Management Uplink Message Elements (SYSU) TBL 5 − 3 − 19 System Management Downlink Message Elements (SYSD) CPDLC Message Sets Operational Definition in PANS − ATM (Doc 4444) FANS 1/A ATN B1 Response Message  Element  Identifier Message Element Intended Use Format for  Message Ele- ment Display DM68  (free text) Note 1.  −  Urgency or Distress Alr (M) Note 2.  −  Selecting any of the emergency message elements will result in this message ele- ment being enabled for the flight crew to include in the emergency message at their discretion. N/A Y TXTD − 1 ( free text )  Note  −  M alert  attribute. CPDLC Message Sets Operational Definition in PANS − ATM (Doc 4444) FANS 1/A ATN B1 Response Message  Element  Identifier Message Element Intended Use Format for  Message Ele- ment Display UM159 ERROR  (error information) UM159 ERROR (error informa- tion) N SYSU − 1 System − generated notification of an error. ERROR  (error in- formation) UM160 NEXT DATA AUTHORITY  (ICAO facility designation) Note  −  The facility des- ignation is required. UM160 NEXT DATA AUTHOR- ITY  (facility) Note  −  Facility parameter can specify a facility designation or no facility. N SYSU − 2 System − generated notification of the next data authority or the cancellation thereof. NEXT DATA AUTHORITY (facility designa- tion [O]) CPDLC Message Sets Operational Definition in PANS − ATM (Doc 4444) FANS 1/A ATN B1 Response Message  Element  Identifier Message Element Intended Use Format for  Message Ele- ment Display DM62 ERROR  (error information) DM62 ERROR (error informa- tion) N SYSD − 1 System − generated notification of an error. SYSD − 1 En Route Procedures 5 − 3 − 11