What is the Aerodrome Reference Point (ARP)?

The ARP is the officially designated latitude and longitude coordinate that represents the geographic center of an aerodrome. It is used for regulatory, operational, and charting purposes, and is required by ICAO, EASA, and FAA regulations.

How is the ARP determined?

According to ICAO and EASA, the ARP is placed as close as practicable to the geometric center of the aerodrome’s movement area. The FAA calculates it as the weighted average of all runway end coordinates, considering runway lengths and configurations. The coordinates are measured using geodetic surveys and referenced to the WGS-84 standard.

Where is the ARP published?

The ARP is published in the Aeronautical Information Publication (AIP) of each State, as well as in digital aeronautical databases, airport certificates, and official charts.

When must the ARP be updated?

The ARP is updated whenever there is a major reconfiguration of the airport, such as the addition, removal, or realignment of runways. Any change must be formally reported and published according to regulatory requirements.

Why is the ARP important for airport operations?

The ARP is a fundamental reference for navigation, airport design, regulatory compliance, certification, airspace management, emergency response, and publication in aeronautical charts and digital systems.

Aerodrome Reference Point (ARP)

The Aerodrome Reference Point (ARP) is the officially designated geographic location of an aerodrome, defined by precise latitude and longitude coordinates. It is fundamental in airport planning, regulation, navigation, and certification, as specified by ICAO, EASA, and FAA standards.

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:

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:

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

Attribute	Requirement
Datum	WGS-84
Units	Latitude/Longitude (degrees, minutes, seconds)
Precision	Nearest arc-second
Documentation	AIP, Aerodrome Certificate, Regulatory filings
Publication	AIP, digital databases, aeronautical charts
Update Trigger	Major configuration change (e.g., runway addition)

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.

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

Jurisdiction	Term Used	Definition/Methodology	Reporting Requirement
ICAO	Aerodrome Reference Point	Near geometric centre of aerodrome; fixed unless major change.	Latitude/longitude in degrees/min/sec
EASA	Aerodrome Reference Point	As per ICAO; referenced for certification, design, and regulatory compliance.	As above; included in AIP
FAA (USA)	Airport Reference Point	Approximate geometric center of all usable runway surfaces, computed as weighted average of runway end coords.	Latitude/longitude; published in FAA data
Others	Country-specific variants	Local adaptations may exist, but generally aligned with ICAO/EASA/FAA standards.	Included in national AIP or equivalent

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

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

References

Summary Table: ARP Key Points

Attribute	ICAO/EASA Standard	FAA (U.S.) Practice
Definition	Designated geographic location of aerodrome	Approximate geometric center of all runway surfaces
Coordinates	Latitude/Longitude (deg, min, sec, WGS-84)	Latitude/Longitude (deg, min, sec, WGS-84)
Calculation	Near geometric centre of aerodrome	Weighted average of runway end coordinates
Use	Charts, AIP, design, regulatory docs	FAA data, AIP, charts, planning, regulatory docs
Change Process	Only if major reconfiguration occurs	When runways change significantly

Frequently Asked Questions

: The ARP is the officially designated latitude and longitude coordinate that represents the geographic center of an aerodrome. It is used for regulatory, operational, and charting purposes, and is required by ICAO, EASA, and FAA regulations.
: According to ICAO and EASA, the ARP is placed as close as practicable to the geometric center of the aerodrome’s movement area. The FAA calculates it as the weighted average of all runway end coordinates, considering runway lengths and configurations. The coordinates are measured using geodetic surveys and referenced to the WGS-84 standard.
: The ARP is published in the Aeronautical Information Publication (AIP) of each State, as well as in digital aeronautical databases, airport certificates, and official charts.
: The ARP is updated whenever there is a major reconfiguration of the airport, such as the addition, removal, or realignment of runways. Any change must be formally reported and published according to regulatory requirements.
: The ARP is a fundamental reference for navigation, airport design, regulatory compliance, certification, airspace management, emergency response, and publication in aeronautical charts and digital systems.

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