AoC number


Primary domain


Secondary domain



Larger GPS, digital terrain elevation data, and ground obstacle databases will be incorporated into future FMS and airport moving map displays. Current systems integrate data from Jeppesen, Lufthansa, and the EAG into a singular database, the ARINC 424. This database provides information on environmental hazards and aviation procedures that may be required over the course of the flight.
The integrity of the computerized navigation and performance systems rests on the quality of the FMC/FMGS databases. 85,000 changes, on average, are made to the database every 28 days, requiring constant updating of systems in order to stay current. As the volume of data coming into the databases intensifies, updates will become more frequent and more extensive (see AoC_078). Furthermore, due to current systems coordinating information from multiple agencies, inconsistencies will occasionally arise, which could lead to serious errors during the course of a flight.
The capacity of in-flight databases is also an issue. Although the amount of data processed by the three major providers is increasing, the size of individual FMC databases is not, and companies will often resort to deleting data from the master ARINC 424 database in order to fit it into their avionic systems. Advances in data compression and miniaturization of technology could correct this issue (see AoC_041).

Potential hazard

  1. Reduced ability to cross-check information
  2. Failure of process to upload current databases during pre-flight
    (Current regulations require a check of the 28-day FMS revision S/W by the database provider as part of the LOA [Letter of Acceptance], with the exception of RNP AR. AMC 20-26 then requires the operator to perform such a check for RNP AR procedures.)
    Potential for entering incorrect data through the FMC/FMGS
  3. Cyber attack

Corroborating sources and comments

NextGen Avionics Roadmap, Version 2.0, Joint Planning and Development Office, September 30, 2011,

Database management: the heart of integrated avionics, Roth, M.A.; Ruberg, S.A.; Eldridge, B.L.; Air Force Inst. of Technol., Wright-Patterson AFB, OH (Boeing report on flight management systems.) (A pilot explains the mechanics of FMS. Essentially, it allows you to find an optimal route and coordinate it with the autopilot. Sometimes, pilots will reprogram in the middle to account for weather or environmental hazards. The ACARS, meanwhile, accompanies it, and transmits data from the cockpit to the outside.) (Avionics data FAQs from Jeppesen. Note in particular that every 28 days, there are an estimated 85,000 changes to their Nav database. Updates should occur close to the end of the 28-day cycle in order to be effective.) (Rockwell Collins’ electric database system. Note in particular that it’s coordinating updates and alerts from Jeppesen and Lufthansa, and contains not only coordinates and information but also a variety of basic aviation procedures.) (Paper written in 2012 regarding the capacity of in-flight databases. The necessary capacity was projected to grow anywhere from 3% to 8% annually for the foreseeable future, but current systems are capped at lower rates.)

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