June 1, 2015
A cost-saving way to achieve required navigation performance authorization required (RNP AR) database validation was detailed during a recent free NBAA webinar, offering operators an avenue for overcoming what has been a significant hurdle to overall RNP AR certification.
Jeppesen, which sponsored the webinar, along with Garmin, invested two years in the alternative method of compliance (AMOC), which takes the place of a linear process that requires operators (or approved third parties) to validate an average of 350 parameters per RNP AR approach against its government source data. This AMOC is available to all avionics OEMs, noted webinar presenter Andrew Riedel, Jeppesen’s manager of corporate technical standards.
Jeppesen formats the government data (which ranges from the FAA’s online files to paper printouts from some foreign governments) into an ARINC 424 file. Then Jeppesen validates the data in two stages, as approved by its FAA Type 1 letter of authorization (LOA). Garmin packs the ARINC 424 file into a binary navigation database employing another two-step data validation process approved by its Type 2 LOA, said presenter Clay Barber, principal engineer for Garmin’s aviation products.
Every RNP AR approach must be validated before use because each of them is created using an obstacle evaluation area tighter than other instrument approaches, explained Barber. The final validation of the AMOC is a cyclic redundancy check that verifies the entire database against the packed navigation database with every activation of the avionics.
A survey conducted during the webinar revealed that 15 percent of participants are now RNP AR certified, and that the majority were interested in the capability and were considering it for their next aircraft.
Required redundant capabilities limits RNP certification to integrated avionics, said Barber, and he said Garmin’s G3000 and G5000 systems will be RNP AR certified. Retrofit systems depend on a demonstrated market and airframe partner. While this AMOC lowers a significant hurdle, overall RNP certification is an involved, yearlong process said presenter Rick Buergel of NetJets Aviation.