What is an Aerodrome Reference Point (ARP)?

Definition

The Aerodrome Reference Point (ARP), also known as the Airport Reference Point in the United States, is the officially designated geographic location of an aerodrome. It is defined by precise latitude and longitude coordinates, representing the airport’s location for all aeronautical, regulatory, and charting purposes.

• ICAO: The ARP is the designated geographical position of an aerodrome, typically near the geometric center of the airfield.
• EASA: Adopts the ICAO definition, the ARP is referenced for aerodrome design, certification, and official documentation.
• FAA: Defines the ARP (Airport Reference Point) as the approximate geometric center of all usable runway surfaces, calculated as a weighted average of runway end coordinates.
• Publication: The ARP is published in the Aeronautical Information Publication (AIP) of each State.

References:

• ICAO Annex 14, Vol 1, 2.2.1
• EASA CS-ADR-DSN
• FAA AC 150/5300-18B
• Wikipedia: Airport Reference Point

Regulatory Framework

International (ICAO):

• The ARP must be established for every certified aerodrome and reported in degrees, minutes, and seconds, referenced to the WGS-84 geodetic datum.
• The ARP location should remain constant unless a significant reconfiguration occurs.

European Union (EASA):

• The ARP is included in the aerodrome certificate and AIP.
• Its accuracy and placement are subject to regulatory oversight.

United States (FAA):

• The ARP is calculated using a weighted average of all runway end coordinates, with runway lengths as weights.
• The ARP is published in the FAA’s databases and updated when significant changes to the runway layout occur.

References:

• WGS-84 Implementation Manual
• FAA AC 150/5300-13

Technical Description and Requirements

Purpose and Use

• Official Aerodrome Identification: The ARP is the central reference for all aeronautical charts, regulatory, and data systems.
• Regulatory Documentation: Required for certification, planning, and infrastructure management.
• Navigation and ATC: Used in defining navigation aids, airspace structure, and ATC procedures.
• Publication: Mandatory in AIP, NOTAMs, and flight planning databases.

References:

• SKYbrary: ARP

Placement and Determination

ICAO/EASA Practice:

• Placed near the geometric center of the aerodrome and typically remains fixed unless a major reconfiguration occurs.
• Determined via geodetic survey using WGS-84 or equivalent, with coordinates expressed to the nearest arc-second.
• Published in the national AIP and validated during audits and major works.

FAA Practice:

• Calculated as the weighted average of all runway end coordinates, using runway lengths as weights.
• Recomputed when runway configurations are significantly changed.

Reference:

• NOAA ARP Computation Tool

Reporting Standards

Data Quality and Maintenance

• Accuracy: ARP coordinates must meet strict geodetic accuracy standards.
• Integrity: Changes must be formally documented and reported.
• Validation: Regularly verified during major works and certification reviews.

Application in Airport Planning and Operations

Aerodrome Design and Certification

• The ARP is the reference point for all airport infrastructure distances and bearings.
• It underpins the design of Obstacle Limitation Surfaces (OLS), approach surfaces, and safety areas.

Reference:

• ICAO OLS Manual

Aeronautical Information Management

• The ARP is a required field in every certified airport’s AIP.
• Used in digital data sets for flight management systems and EFBs.

Air Traffic Control and Navigation

• Used to define airspace classes, control zones, reporting points, and as a datum for many navigation aids.

Emergency Response and Coordination

• The ARP is the key reference for search and rescue (SAR) and emergency resource dispatch.

Reference:

• CAA Emergency Planning

Regional Variations

Examples and Use Cases

Example 1: ICAO Standard Aerodrome

• Aerodrome: Example International Airport
• Runway Configuration: Two intersecting runways
• ARP Location: At the intersection of the bisectors of each runway, near the geometric center of movement.
• AIP Reporting: 53°21'45"N 006°16'12"W

Example 2: FAA Methodology

• Aerodrome: Major U.S. Regional Airport
• Runway Configuration: Three parallel and one intersecting runway
• ARP Calculation: Weighted average of all runway ends, considering each length.
• FAA Reporting: 33°56'36"N 118°24'29"W

Use Cases:

• Aerodrome certification and regulatory filings
• Charting and navigation databases
• Flight planning and dispatch
• FMS and GPS airport identification
• Airspace and ATC sector design
• Emergency response coordination

Related Concepts and Cross-References

• Aeronautical Information Publication (AIP)
• Runway Reference Point (RRP)
• Obstacle Limitation Surfaces (OLS)
• Aerodrome Elevation
• Airport Reference Code (ARC)

References

• ICAO Annex 14 – Aerodromes
• FAA Pilot/Controller Glossary
• EASA CS-ADR-DSN
• Wikipedia: Airport Reference Point
• SKYbrary: ARP
• WGS-84 Implementation Manual
• NOAA ARP Computation Tool
• ICAO OLS Manual
• CAA Emergency Planning

Summary Table: ARP Key Points

Further Reading

• ICAO Annex 14 – Aerodromes
• FAA Aeronautical Information Manual (AIM)
• EASA CS-ADR-DSN
• Wikipedia: Airport Reference Point
• SKYbrary: ARP

See Also

• Aerodrome Elevation
• Runway Reference Point (RRP)
• Aeronautical Information Publication (AIP)
• Aerodrome Certification
• Obstacle Limitation Surfaces (OLS)
• Air Traffic Control (ATC) Vocabulary

Note:
The ARP is a foundational element in airport planning, design, operation, and regulation. Its correct establishment, rigorous maintenance, and precise reporting ensure consistency, safety, and interoperability across international aviation systems. For technical details, computation tools, and real-world examples, consult official ICAO, FAA, and EASA documentation.