Joined: 11 Dec 2005
|Posted: Fri Aug 15, 2014 10:13 pm Post subject: RNP and RNAV Operations
| Understanding RNP and RNAV Operations
This document clarifies the current Required Navigation Performance (RNP) and Area Navigation (RNAV) requirements in the United States, Europe, and other parts of the world. It also discusses how Universal Avionics’ Flight Management System (FMS) product line supports approved RNP operations.
Operators may use this information to assist in making future equipment acquisitions and aircraft modification choices necessary to allow them to fly into RNP airspaces or fly RNAV Instrument Approach Procedures (IAP). Failure to address RNP will, as time progresses, force non-RNP approved aircraft into undesirable lower altitudes (greatly increasing fuel burn), or severely limit the capability of a non-RNP aircraft to fly into a desired airport in instrument weather conditions.
The Federal Aviation Administration’s (FAA) plan to modernize the National Airspace System (NAS) is through the Next Generation Air Transportation System (NextGen). The goals of NextGen are to increase NAS capacity and efficiency while simultaneously improving safety, reducing environmental impacts, and improving user access to the NAS. It is expected to be implemented through new Performance-Based Navigation (PBN) routes and procedures. This requires avionics that support RNP/ RNAV capability.
In addition, the FAA has taken the initial steps toward removing ground based navaids and the supporting IAPs based upon
those navaids. RNAV approach capability may become the mandatory method of flying into numerous airports that only support instrument approaches that are RNP/RNAV based. RNP/RNAV capable systems can also form the basis of a compliant Automatic Dependent Surveillance-Broadcast (ADS-B) Out system.
RNP with AR (Authorization Required)
The Performance Based Navigation concept allows to optimize the instrument procedure design with the aircraft navigation performance. This concept is used en route, to reduce aircraft separation, and in terminal area to optimize arrival and departure procedures. The utmost development of Performance Based Navigation for approach, missed approach and departure is known under different names.
FAA initially referred to RNP SAAAR Operations, SAAAR standing for Special Aircraft and Aircrew Authorization Required.
ICAO now refers to RNP Operations with Authorization Required (RNP AR). Compared to standard RNAV approach procedures, the RNP AR approach procedures are characterized by:
• RNP values ≤ 0.3 NM and/or
• Curved flight path before and after the Final Approach Fix (FAF) or Final Approach Point.
• Protections areas laterally limited to 2xRNP value without any additional buffer.
These approach procedures are always designed to be flown with baro-VNAV capability. RNP AR operations may include missed approach procedures and instrument departures with reduced RNP (<1NM).
The RNP AR operations are accessible to aircraft and operators complying with specific airworthiness and operational requirements. This brochure aims at providing Airbus customers with the background information necessary to launch an RNP AR project.