History of PBN (Performance-Based Navigation)

History of PBN

• RNP concept was introduced in the 1990s, defining navigation performance accuracy necessary for operation within a defined airspace.
• However, the RNP concept was insufficient, lacking specification of the relationship between RNAV and RNP, and the need for an RNAV system.

Insufficiencies of RNP

• Focused on oceanic and remote area applications, with no specific guidelines for continental en-route, terminal, and approach applications.
• Led to the proliferation of national standards, a wide variety of functional requirements, and different navigation sensors, resulting in a lack of global harmonization.

Consequences of RNP Insufficiencies

• Operators had to qualify multiple times to operate in 'RNP' airspace, where the RNP 'value' was the same, resulting in increased costs.
• Confusion in the stakeholder community, with uncertainty about what RNP meant.

PBN Definition

• PBN stands for "Performance-Based Navigation", redefining the aircraft's required navigation capability from sensor-based to performance-based.
• Navigation procedures as an alternative to point-to-point navigation techniques using ground-based stations only.
• Combination of RNAV + RNP, incorporating a 3D aspect to navigation (continuous and engine idle descent).

ICAO's PBN Standardization

• RNAV with no alert to pilot, and RNP with alert to pilot.
• Route width and route centerline are defined.

PBN Manual

• Volume I: Concept and Implementation Guidance.
• Volume II: Implementing RNAV and RNP.
• 4th edition released in 2014, introducing new operations.

RNP Concept

• RNP concept is based on navigation performance by reference to MASPS (DO-236/ED-75).
• RNP requirements include accuracy, integrity, and continuity.
• Accuracy: Aircraft must remain within accuracy limit 95% of flight time (maximum TSE with 95% probability ≤ 1xRNP).
• Integrity: Probability of transgressing the containment limit set at 2 x RNP without alert must be less than a specified value.