PBN (Performance Based Navigation)

What is PBN?

Performance Based Navigation (PBN) is a navigation concept that shifts the focus from traditional, sensor-specific navigation (like VOR or NDB) to a system where the required performance—such as accuracy, integrity, and continuity—defines how aircraft navigate. PBN allows routes, approaches, and departures to be designed as points in space, independent of ground-based navigation aids.

Components of PBN

PBN consists of three key components:

• Navaid Infrastructure: The network of ground or space-based navigation aids (e.g., VOR, DME, GNSS) that support position determination. Note that NDBs are not part of PBN-supported infrastructure.
• Navigation Specification: The set of standards that define the required navigation performance for RNAV (Area Navigation) or RNP (Required Navigation Performance) systems. These specifications detail the necessary accuracy, integrity, and continuity, and may include crew procedures and equipment requirements.
• Navigation Application: The practical use of a navigation specification and its supporting infrastructure within a defined airspace or for a specific procedure.

Linear vs. Angular Guidance

• En-route, Oceanic/Remote, and Terminal Phases: PBN is limited to operations with linear lateral performance requirements and time constraints. This means the navigation accuracy is defined as a fixed value (e.g., RNAV 5, RNP 4) measured in nautical miles.
• Approach Phase: PBN accommodates both linear and angular laterally guided operations. Linear guidance uses fixed-width corridors, while angular guidance (such as ILS or GLS) provides narrowing guidance as the aircraft approaches the runway.

PBN vs. RNAV

While all RNP systems are a subset of RNAV, RNP specifications require on-board performance monitoring and alerting, whereas RNAV specifications do not. Both are essential for optimizing airspace, but only RNP guarantees the system will alert the crew if performance drops below the required standard.

Operational Awareness

Flight crews and controllers must understand the capabilities of their RNAV or RNP systems to ensure compliance with the navigation requirements of the airspace they are operating in. This is critical for both safety and regulatory compliance.