Greetings, I wonted to insert additional 8 bit to the equipment field. I tried several attempts without success. I have got the following error: ******************************* flight_msg_.a ****************************** 1758: Departure_Time at 52 range 8 .. 71; - -sam A -------^ A:error: Appendix F: component must be aligned on a 4 byte boundary 1759: Cruising_Level at 60 range 8 .. 167; - -sam A -------^ A:error: Appendix F: component must be aligned on a 4 byte boundary 1760: Route at 80 range 8 .. 14423; - -sam A -------^ A:error: Appendix F: component must be aligned on a 2 byte boundary The original record representation is in file named flight.org.txt The modified one, which produced the above error, is in the file named flight.new.txt Your help is highly appreciated! Best regards, sam original record representation as follow: ---------------------------------------------------------------------------- for Flight_Plan_Msgs use record at mod 4; FLID at 0 range 0 .. 143; Flight_Rule at 16 range 16 .. 23; Flight_Type at 16 range 24 .. 31; Number_Of_AC at 20 range 0 .. 7; Type_Of_Aircraft at 20 range 8 .. 39; Equipment at 24 range 8 .. 175; Surveillance_Equipment at 44 range 16 .. 31; Departure_Point at 48 range 0 .. 31; Departure_Time at 52 range 0 .. 63; Cruising_Level at 60 range 0 .. 159; Route at 80 range 0 .. 14415; Destination at 1880 range 16 .. 47; Elapsed_Time at 1888 range 0 .. 63; Other at 1896 range 0 .. 4895; Allocate_Next_SSR_Code at 2508 range 0 .. 7; Insert_Preferred_Route at 2508 range 8 .. 15; Wake_Turbulence at 2508 range 16 .. 23; Cruising_Speed at 2512 range 0 .. 127; SSR_Code at 2528 range 0 .. 15; SSR_Mode at 2528 range 16 .. 23; Alternate_1 at 2528 range 24 .. 55; Alternate_2 at 2532 range 24 .. 55; Arrival_Runway at 2540 range 0 .. 47; Departure_Runway at 2544 range 16 .. 63; Address_List at 2552 range 0 .. 1311; Valid at 2716 range 0 .. 71; end record; Flight_Plan_Msgs_Size : Constant := 21824; -- rep_clause for Flight_Plan_Msgs'Size use Flight_Plan_Msgs_Size; ---------------------------------------------------------------------------- modified record representation as follow: ---------------------------------------------------------------------------- ------- for Flight_Plan_Msgs use record at mod 4; FLID at 0 range 0 .. 143; Flight_Rule at 16 range 16 .. 23; Flight_Type at 16 range 24 .. 31; Number_Of_AC at 20 range 0 .. 7; Type_Of_Aircraft at 20 range 8 .. 39; Equipment at 24 range 8 .. 183; --sam Surveillance_Equipment at 44 range 24 .. 39; --sam Departure_Point at 48 range 8 .. 39; --sam Departure_Time at 52 range 8 .. 71; --sam Cruising_Level at 60 range 8 .. 167; --sam Route at 80 range 8 .. 14423; --sam Destination at 1880 range 24 .. 55; --sam Elapsed_Time at 1888 range 0 .. 63; Other at 1896 range 0 .. 4895; Allocate_Next_SSR_Code at 2508 range 0 .. 7; Insert_Preferred_Route at 2508 range 8 .. 15; Wake_Turbulence at 2508 range 16 .. 23; Cruising_Speed at 2512 range 0 .. 127; SSR_Code at 2528 range 0 .. 15; SSR_Mode at 2528 range 16 .. 23; Alternate_1 at 2528 range 24 .. 55; Alternate_2 at 2532 range 24 .. 55; Arrival_Runway at 2540 range 0 .. 47; Departure_Runway at 2544 range 16 .. 63; Address_List at 2552 range 0 .. 1311; Valid at 2716 range 0 .. 71; end record; Flight_Plan_Msgs_Size : Constant := 21824; -- rep_clause for Flight_Plan_Msgs'Size use Flight_Plan_Msgs_Size; --------------------------------------------------------------------