Blog

Back to Blog

Blueprint for 2030: Understanding the Annex 14 Amendment 18 Transition

AOIWEB LTD · 14 March 2026

Share

The aviation industry is currently navigating a radical change following the adoption of Amendment 18 to ICAO Annex 14, Volume I. This update represents a complete shift from a prescriptive safeguarding system established in the 1950s to a modern, performance-based framework. By aligning aerodrome design with modern aircraft technology and actual flight trajectories, the new standards aim to enhance safety while improving aerodrome accessibility.

The Performance-Based Revolution: ADG

The most fundamental shift in the new Annex 14 is the introduction of the Aeroplane Design Group (ADG). For the purposes of obstacle management, the ADG replaces the traditional Aerodrome Reference Code number, which was based on aeroplane reference field length.

The ADG categorizes aircraft using two performance-based criteria: indicated airspeed at threshold (Vat​) and wingspan. This change ensures that the volume of protected airspace around an airport is directly consistent with the airborne behavior and performance of the aircraft it serves.

The Twofold Concept: OFS vs. OES

Amendment 18 disestablishes several legacy surfaces, such as the Conical and Outer Horizontal surfaces, replacing them with a more flexible twofold system.

  • Obstacle Free Surfaces (OFS): These are "strictly limited" volumes of airspace near the runway. They protect the visual phase of approach and take-off where aircraft cannot easily adapt to new obstacles.

  • Obstacle Evaluation Surfaces (OES): These act as "trigger" surfaces. If an object penetrates an OES, it is not automatically prohibited; instead, it triggers an aeronautical study to evaluate the impact on the safety and regularity of flight operations.

This new approach allows States to better balance aviation safety with local land-use needs by releasing areas not required for flight operations for development.

Implementing these surfaces in practice requires tools that can draw them correctly and evaluate penetrations. AOI Web Pro supports the full Annex 14 Amendment 18 surface set -- you can model OFS and OES, run penetration evaluations, and support aeronautical studies as the new standards take effect.

Key Technical Redesigns

Beyond the conceptual shift, Amendment 18 introduces critical geometric and operational updates:

  • The 60 m Datum: To improve accessibility for Category III operations, the height limit for the Obstacle Free Zone (OFZ), specifically the inner transitional and balked landing surfaces, has been increased from 45 m to 60 m above the highest threshold.

  • Disconnected Transitional Surfaces: In a "radical change," the transitional surface is now disconnected from the runway strip boundary. Its lower edge is now defined by a line parallel to the runway centre line, making the protected volume independent of the physical grading of the strip.

  • Enhanced Ground Safety: The amendment introduces Runway Distance Remaining Signs (RDRS) to provide pilots with distance-to-go information and help prevent runway excursions. It also reduces required strip widths for Code 3 non-instrument runways from 75 m to 55 m to correct previous geometric discrepancies.

Critical Implementation Deadlines

The implementation of Amendment 18 follows a tiered schedule to allow the industry time to adapt:

  • 27 November 2025: General aerodrome design, visual aids, and apron management service provisions become applicable.

  • 26 November 2026: New standards for the safety oversight of ground handling become applicable.

  • 21 November 2030: The full OLS rewrite and the new ADG system become applicable.

By 2030, aerodromes worldwide will have transitioned to this new blueprint, ensuring that airport safeguarding is as technologically advanced as the aircraft it supports.

How AOI Web Pro Helps You Transition

Navigating the transition from legacy prescriptive rules to a complex, performance-based environment can be challenging. Our app, AOI Web Pro, is designed specifically to assist aerodrome operators and authorities in this journey:

  • Automated ADG Classification: Instantly determine your runway's new Aeroplane Design Group (I through V) based on Vat​ and wingspan data, ensuring your safeguarding starts with the correct regulatory foundation.

  • 3D Visualization of Complex Geometries: Manually calculating the new disconnected transitional surfaces or the 60 m height datums is prone to error. AOI Web Pro visualizes these complex 3D OFS and OES layers, including the multi-height horizontal surfaces required for mixed-aircraft operations.

  • Gap Analysis for 2030 Compliance: Don't wait until the 2030 deadline. Use our platform to run a comparative gap analysis between your current legacy OLS and the future OFS/OES requirements today, identifying potential future non-compliances or development opportunities.

  • Data-Driven Aeronautical Studies: When an Obstacle Evaluation Surface (OES) is penetrated, AOI Web Pro provides the precise geographical coordinates and elevation data necessary to assess the impact on flight operations, forming the digital backbone for the mandatory aeronautical studies required to determine the acceptability of an obstacle

    .