Aerodrome Reference Point (ARP) – Comprehensive Glossary

Definition and Core Concept

Aerodrome Reference Point (ARP), sometimes called the Airport Reference Point, is the precisely defined set of geodetic coordinates (latitude and longitude) that officially represents the location of an airport or aerodrome. According to ICAO Annex 14 , the ARP is established near the geometric center of all usable runway surfaces and typically remains fixed for data continuity, serving as the single point of reference for all regulatory, planning, and operational purposes related to the airport.

• The ARP is not a physical marker but a published point in geodetic coordinates (WGS-84).
• It is crucial for navigation, airspace design, airport planning, regulatory filings, and safety management.
• Its position is included in national and international Aeronautical Information Publications (AIP) and airport layout documentation.

Regulatory Framework

International Standards (ICAO)

The International Civil Aviation Organization (ICAO ), under Annex 14, mandates:

• Every aerodrome must have an ARP, ideally near its geometric center.
• Coordinates must be referenced to WGS-84 and published for international use.
• The ARP should remain unchanged unless operational necessity demands relocation.

ICAO’s Procedures for Air Navigation Services – Aeronautical Information Management (PANS-AIM) further detail ARP data handling, publication, and exchange protocols.

United States Standards (FAA)

The Federal Aviation Administration (FAA ) provides detailed guidance:

• FAA Advisory Circular 150/5300-13B: Defines ARP as the weighted average of runway end coordinates.
• FAA Orders 5010.4A and 8260.3D: Establish ARP usage in instrument procedure design and database management.
• FAA ARP SOP 9.2: Outlines ARP data collection, calculation, and publication procedures.

The ARP is central to the FAA’s data systems, including the NASR (National Airspace System Resources) and OE/AAA (Obstruction Evaluation/Airport Airspace Analysis) databases.

Calculation and Data Management

ICAO Guidance

• The ARP should be as close as possible to the geometric center of the aerodrome’s operational runways.
• Once set, the ARP should remain fixed to ensure stability in navigation and regulatory databases.
• Coordinates are referenced to the WGS-84 standard.

FAA Methodology

• The ARP is computed as a weighted average of all usable runway end coordinates, weighted by runway length.
• Coordinates are checked via aeronautical surveys and confirmed against airport layout plans.
• The ARP is updated in the NASR and OE/AAA databases and published in AIP and other official documents.

Example Calculation (FAA):

1. Identify all operational runway ends.
2. Collect latitude and longitude (WGS-84) for each.
3. Weight by runway length:

   ARP_lat = [Sum of (RunwayEnd_lat × RunwayLength)] / [Total Runway Length]
   ARP_lon = [Sum of (RunwayEnd_lon × RunwayLength)] / [Total Runway Length]
   

4. Publish and maintain data continuity unless significant changes require recalculation.

ARP Data Elements and Associated Fields

Applications and Uses

Airport Planning and Design

• The ARP is the reference for the Airport Layout Plan (ALP), guiding phased development, zoning, and infrastructure alignment.
• Used for land use compatibility studies and site selection.

Airspace and Obstruction Evaluation

• The ARP is the datum for obstruction evaluation under FAA Part 77 and for defining protected airspace surfaces.
• Used in the OE/AAA process to assess the impact of proposed construction near airports.

Navigation and Charting

• ARP coordinates are published in AIPs and navigation databases.
• The ARP is the center for calculating airport-to-airport distances, Minimum Sector Altitude (MSA), circling approaches, and remote altimeter settings.

Airport Safety and Management

• The ARP is a required data element in Safety Management Systems (SMS) and Safety Risk Management (SRM).
• Used in Construction Safety Phasing Plans (CSPP) to coordinate safe operations during construction.

Regulatory Compliance and Grants

• Required for Airport Improvement Program (AIP) grant applications and project oversight.
• Key field in airport certification (FAA Part 139).

Examples of ARP Usage

• Instrument Approach Design: The ARP is the fixed point for MSA areas during instrument approach procedure design.
• Airspace Analysis: Used to assess whether proposed structures penetrate protected surfaces.
• Airport Data Publication: ARP is included in all major databases and official publications.
• Layout Planning: Referenced for siting infrastructure and planning expansions.

Methodological and Regulatory Differences

Data Integrity, Quality Assurance, and Maintenance

• Ensures airspace protection, navigation safety, and regulatory compliance.
• The ARP must remain consistent across all databases and publications.
• Changes require coordination, documentation, and, if needed, aeronautical surveys.

Glossary of Related Terms

Airport Layout Plan (ALP):
A graphical representation of an airport’s current and planned facilities, using the ARP as the central reference.

Obstruction Evaluation/Airport Airspace Analysis (OE/AAA):
FAA program for assessing the impact of new structures using the ARP as the datum.

Safety Management System (SMS):
Organizational framework for managing safety, reliant on accurate ARP data.

Safety Risk Management (SRM):
Systematic process within SMS for hazard and risk analysis, often referencing the ARP.

Construction Safety Phasing Plan (CSPP):
Plan for sequencing airport construction, referencing the ARP for temporary changes and safety zones.

Airport Improvement Program (AIP):
FAA grant program for airport development, requiring up-to-date ARP data.

References and Further Reading

• ICAO Annex 14, Aerodromes (PDF)
• FAA Advisory Circular 150/5300-13B
• FAA Order 5010.4A
• Airport reference point – Wikipedia
• International Civil Aviation Organization (ICAO) – Wikipedia
• Federal Aviation Administration (FAA) – Wikipedia
• Minimum Sector Altitude (MSA) – SKYbrary