Fix Records  ARINC 424  Simple Route Records  6-4  National Airlines installed the Collins ANS-70 and AINS­ 70 RNAV systems in their DC-10 fleet, which marked the  first commercial use of avionics that required navigation  databases. A short time later, Delta Air Lines implemented  the use of an ARMA Corporation RNAV system that also  used a navigation database. Although the type of data  stored in the two systems was basically identical, the  designers created the databases to solve the individual  problems of each system, which meant that they were not  interchangeable. As the implementation of RNAV systems  expanded, a world standard for airborne navigation  databases was needed.  The data included in an airborne navigation database is  organized into ARINC 424 records. These records are strings  of characters that make up complex descriptions of each  navigation entity. ARINC records can be sorted into four  general groups: fix records, simple route records, complex  route records, and miscellaneous records. Although it is not  important for pilots to have in-depth knowledge of all the  fields contained in the ARINC 424 records, pilots should be  aware of the types of records contained in the navigation  database and their general content.  In 1973, Aeronautical Radio, Inc. (ARINC) sponsored the  formation of a committee to standardize aeronautical  databases. In 1975, the committee published the first  standard, ARINC Specification 424, which has remained the  worldwide accepted format for transmission of navigation  databases.  Database records that describe specific locations on the  face of the earth can be considered fix records. Navigational  aids (NAVAIDs), waypoints, intersections, and airports are  all examples of this type of record. These records can be  used directly by avionics systems and can be included as  parts of more complex records like airways or approaches.  ARINC 424 is the air transport industry’s recommended  standard for the preparation and transmission of data for  the assembly of airborne system navigation databases. The  data is intended for merging with the aircraft navigation  system software to provide a source of navigation  reference. Each subsequent version of ARINC 424  Specification provides additional capability for navigation  systems to utilize. Merging of ARINC 424 data with each  manufacturer’s system software is unique and ARINC 424  leg types provide vertical guidance and ground track for  a specific flight procedure. These leg types must provide  repeatable flight tracks for the procedure design. The  navigation database leg type is the path and terminator  concept.  ARINC 424 Specification describes 23 leg types by their path  and terminator. The path describes how the aircraft gets to  the terminator by flying direct (a heading, a track, a course,  etc.). The terminator is the event or condition that causes  the navigation computer system to switch to the next leg (a  fix, an altitude, an intercept, etc.). When a flight procedure  instructs the pilot to fly runway heading to 2000 feet then  direct to a fix, this is the path and terminator concept. The  path is the heading and the terminator is 2000 feet. The  next leg is then automatically sequenced. A series of leg  types are coded into a navigation database to make a flight  procedure. The navigation database allows an FMS or GPS  navigator to create a continuous display of navigational  data, thus enabling an aircraft to be flown along a specific  route. Vertical navigation can also be coded.  Another concept pilots should understand relates to how  aircraft make turns over navigation fixes. Fixes can be  designated as fly-over or fly-by, depending on how they  are used in a specific route. [Figure 6-4] Under certain  circumstances, a navigation fix is designated as fly-over.  This simply means that the aircraft must actually pass  directly over the fix before initiating a turn to a new course.  Conversely, a fix may be designated fly-by, allowing an  aircraft’s navigation system to use its turn anticipation  feature, which ensures that the proper radius of turn is  commanded to avoid overshooting the new course. Some  RNAV systems are not programmed to fully use this feature.  It is important to remember a fix can be coded as fly-over  and fly-by in the same procedure, depending on how the  fix is used (i.e., holding at an initial approach fix). RNAV or  GPS stand-alone IAPs are flown using data pertaining to  the particular IAP obtained from an onboard database  to include the sequence of all waypoints used for the  approach and missed approach, except that step down  waypoints may not be included in some TSO-C129 receiver  databases. Included in the database, in most receivers, is  coding that informs the navigation system of which WPs  are fly-over or fly-by. The navigation system may provide  guidance appropriately to include leading the turn prior  to a fly-by waypoint; or causing over flight of a fly-over  waypoint. Where the navigation system does not provide  such guidance, the pilot must accomplish the turn lead or  waypoint over flight manually. Chart symbology for the fly ­ by waypoint provides pilot awareness of expected actions.  Route records are those that describe a flightpath  instead of a fixed position. Simple route records contain 