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the approach identifier field for the VOR/DME Runway 34 approach at Eugene Mahlon Sweet Airport (KEUG) in Eugene, Oregon, as “V34,” different avionics platforms may display the identifier in any way the manufacturer deems appropriate. For example, a GPS produced by one manufacturer might display the approach as “VOR 34,” whereas another might refer to the approach as “VOR/DME 34,” and an FMS produced by another manufacturer may refer to it as “VOR34.” [Figure 6-29] 

These differences can cause visual inconsistencies between chart and GPS displays, as well as confusion with approach clearances and other ATC instructions for pilots unfamiliar with specific manufacturer’s naming conventions. The manufacturer determines the capabilities and limitations of an RNAV system based on the decisions that it makes regarding that system’s processing of the airborne navigation database. 

## Users Role 

Like paper charts, airborne navigation databases are subject to revision. According to 14 CFR Part 91, § 91.503, the end user (operator) is ultimately responsible for ensuring that data meets the quality requirements for its intended application. Updating data in an aeronautical database is considered to be maintenance and all Part 91 operators may update databases in accordance with 14 CFR Part 91, § 43.3(g). Parts 121, 125, and 135 operators must update databases in accordance with their approved maintenance program. For Part 135 helicopter operators, this includes maintenance by the pilot in accordance with 

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14 CFR Part 43, § 43.3(h). 

Pilots using the databases are ultimately responsible for ensuring that the database they are operating with is current. This includes checking Notices to Airmen (NOTAM)­ type information concerning errors that may be supplied by the avionics manufacturer or the database supplier. The database user is responsible for learning how the specific navigation equipment handles the navigation database. The manufacturer’s documentation is the pilot’s best source of information regarding the capabilities and limitations of a specific database. [Figure 6-30] 

## Operational Limitations of Airborne Navigation Databases 

Understanding the capabilities and limitations of the navigation systems installed in an aircraft is one of the pilot’s biggest concerns for IFR flight. Considering the vast number of RNAV systems and pilot interfaces available today, it is critical that pilots and flight crews be familiar with the manufacturer’s operating manual for each RNAV system they operate and achieve and retain proficiency operating those systems in the IFR environment. 

Most professional and general aviation pilots are familiar with the possible human factors issues related to flightdeck automation. It is particularly important to consider those issues when using airborne navigation databases. Although modern avionics can provide precise guidance throughout all phases of flight, including complex departures and arrivals, not all systems have the same capabilities. 

RNAV equipment installed in some aircraft is limited to direct route point-to-point navigation. Therefore, it is very important for pilots to familiarize themselves with the capabilities of their systems through review of the manufacturer documentation. Most modern RNAV systems are contained within an integrated avionics system that receives input from several different navigation and aircraft system sensors. These integrated systems provide so much information that pilots may sometimes fail to recognize errors in navigation caused by database discrepancies or misuse. Pilots must constantly ensure that the data they enter into their avionics is accurate and current. Once the transition to RNAV is made during a flight, pilots and flight crews must always be capable and ready to revert to conventional means of navigation if problems arise. 

## Closed Indefinitely Airports 

Some U.S. airports have been closed for up to several years, with little or no chance that they will ever reopen; yet their “indefinite” closure status – as opposed to permanent or UFN closure, or abandonment – causes them to continue 

