PARC Chairman Laments Slow Progress of RNP Approach Approvals

Dave Nakamura, the chairman of the FAA's Performance-Based Operations Aviation Rulemaking Committee (PARC), told the FAA's recent New Technologies Workshop that the number of RNP (required navigation performance) SAAAR (special aircrew and aircraft authorization required) operations and criteria aren't meeting expectations.

Mr. Nakamura, who is also a technical fellow at Boeing Commercial Airlines dealing with CNS (communications, navigation and surveillance) regulations, said the communication and approval processes need improvement, and there needs to be agreement on critical priorities and schedules in order to get better results.  There needs to be better guidance material and a single set of regulatory criteria to integrate new performance-based navigation technology, and greater participation in the process; "More resources are needed to do the work," he said.

After rhetorically asking "what is the measure of success," regarding performance-based navigation, Mr. Nakamura proposed the following criteria:

• A scheduled implementation that meets and even exceeds expectations.
• Simpler operational qualification processes and approvals.
• Easy transferability from "special" to SAAAR procedures.
• Global interoperability to improve universal utility of equipment.
• Benefits that motivate operators, as well as airports and air traffic control providers, to invest in advanced capabilities.

Regarding the number of RNP procedures developed and approved so far, Mr. Nakamura suggested there aren't enough.  While we can expect eventually that there will be fleet-wide approvals for all RNP certified aircraft and systems, so far they have been limited to only SAAAR and a few others, he noted.  Regional carrier and private aircraft users want basic RNP but are still waiting for necessary criteria and approval processes, which is causing discouragement for some.  Meanwhile, airlines are seeking to leverage the certified RNP capabilities of their fleets, and other users of fixed-wing aircraft and rotorcraft are waiting in line.

As for global operability, Mr. Nakamura noted that the U.S., Europe, Canada, Japan, have been developing an ICAO PBN (performance-based navigation) manual in coordination with industry and the International Federation of Air Line Pilots' Associations.  The manual is expected to be released sometime this summer, and should clarify RNAV and RNP concepts and provide consistency in approval guidance and criteria.  It also should address GPS interference and augmentation issues, Nakamura said.

The validation of benefits is still somewhat mixed and problematic, Nakamura said.  While operators are seeing savings in time and fuel from the RNAV capabilities of existing FMS (flight management system) equipment for standard departures and arrival routes (SIDs and STARs), as well as efficiencies and accessibility improvements from RNP SAAAR, there are questions about the validity of some benefits assumed for LPV (localizer performance with vertical guidance) and LPV200 (200 foot decision height) approaches.  Some EVS (enhanced vision system) users have not been able to validate all of their anticipated benefits either, Mr. Nakamura interjected.

To help this situation, Mr. Nakamura called for a simpler operational qualification and approval process.  He noted that while some B-737NGs (next generation), A320s, and Q400s have been qualified for RNP, significant levels of post-certification airworthiness analysis and data are still required.  The qualification of other models, such as B-757/767s, B-777s, A330/340s, are still underway, he said.

There are a number of obstacles preventing a streamlining of these approvals, Mr. Nakamura suggested, such as current criteria which present potential complications which seemingly preclude the use of their electronic maps to display required lateral deviation.  And these problems are complicated even further by the wide range of aircraft that must be considered - military, regional jets, rotorcraft, and more.

There are other frustrations as well, he said. The entire application process is expensive and subject to delays, and any equipment software change invalidates the existing approval.

Nakamura addressed the need to make it easier for users to transfer their own special procedures to public SAAARs.  He acknowledged that a few U.S. domestic operators have been creating their own RNP approach procedures via FAA Advisory Circular 120-29A, but said few operators have such approvals so far.  One complicating issue is the need to reapply under AC90-101, to make these procedures non-special, and no relief from this requirement has been granted. "Some specials must remain specials," Nakamura asserted.  02-01-2007.

Click here to become a registered Flt Tech Online subscriber and receive headlines delivered to your e-mail each week

Click here to go back to the headlines