What is ICAO Flight Plan Item 18 and How Does Navigation Data Delays or Rejections?

When filing an ICAO flight plan, Item 18 might seem like just another field—but it’s actually one of the most important parts of the entire form. This is where operators can include all the extra information that doesn’t neatly fit into the standard boxes. Think of it as the “notes” section, but with real operational significance. Its proper use ensures that air traffic controllers and flight service units are fully informed, which can enhance safety, improve coordination, and make sure the flight gets the support it needs.

What is ICAO Flight Plan Item 18?

ICAO Flight Plan Item 18, labeled as “Other Information,” is a field in the ICAO flight plan form used to include additional details that are not covered in the standard items of the form. It allows operators to specify important supplementary information such as emergency equipment carried, search and rescue details, navigation or communication capabilities (e.g., “NAV/RNP10”), surveillance details (e.g., “SUR/ADS-B“), and special handling requests (e.g., “RMK/Medical Flight”). This item uses specific indicators and abbreviations defined by ICAO to ensure clarity and standardization across international air traffic services.

Structure and Contents of Item 18

Item 18 is titled “Other Information” and is composed of multiple subfields, each introduced by a standardized prefix. These include airport names, flight details, equipment, and special status. Key subfields are:

 

• DEP/ – Name of departure airport (or bearing/distance from a fix if no ICAO code). Example: DEP/SMALL AIRPORT.
• DEST/ – Name of destination airport (or navigational reference if no code). Example: DEST/BIG AIRPORT.
• TYP/ – Aircraft type(s), used when no ICAO code is entered in Item 9 (type unknown). E.g. TYP/2 DE HAVILLAND HERON.
• REG/ – Aircraft registration (if different from Item 7 callsign). Example: REG/4XDKM.
• ALTN/ – ICAO code or name of alternate aerodrome(s). Example: ALTN/MEDIUM AIRPORT. In Item 16, “ZZZZ” can be entered for alternate(s), with the actual name in Item 18.
• TALT/ – Takeoff alternate aerodrome (new in 2012 format) if required.
• DLE/ – Delay enroute. Specifies a fix or waypoint and a duration (minutes) for a planned hold or delay, e.g. DLE/XYZ0015 for a 15-min delay over VOR XYZ.
• COM/ – Extra communications capabilities. Free text (up to 50 chars) for additional radios or data links, e.g. COM/UHF ONLY.
• NAV/ – Extra navigation equipment or capabilities. This free-text field (up to 50 chars) can list additional units or approvals (e.g. “INS”, “SBAS”, “UHF/DF”), or overflow for PBN codes beyond 8 entries. For example, NAV/INS indicates an inertial system onboard.
• EET/ – Estimated Enroute Time to significant points or FIR boundaries. Lists waypoints with time since departure, e.g. EET/ABC0120 XYZ0200 (ABC at +1:20, XYZ at +2:00). This is required only if ATC demands it.
• STS/ – Special status or reason for handling by ATC. Examples include medical flights (STS/HOSP), single-engine inoperative (STS/ONE ENG INOP), or hazardous cargo (STS/HAZMAT). A new code “ALTRV” denotes an altitude reservation, and others like “FFR” (fire-fighting) were introduced in 2012.
• OPR/ – Operator name, if not obvious from call sign in Item 7. Example: OPR/BIG COMPANY
• DOF/ – Date of Flight in YYMMDD format (only if filing earlier than 24 hours before ETD, up to 120 hours in advance).
• PER/ – ICAO performance category (A–E for fixed-wing, H for helicopters) as per Doc 8168. Example: PER/A for Category A aircraft.
• ORGN/ – Originator’s contact information (e.g. dispatcher email) if required.
• RMK/ – Free-text remarks (unlimited length). Operators or pilots can include any plain-language notes useful to ATS (e.g. RMK/TRAINING ILS APPROACH).

 

Finally, PBN/ and CODE/ are the new additions related to navigation:

• PBN/ – Specifies Performance-Based Navigation authorizations (RNAV/RNP specifications). Each approved navigation specification (from ICAO Doc 8168 lists, e.g. RNAV 5, RNP 1, RNP AR APCH) is coded here, such as PBN/C2D2 (RNAV 10, RNAV 2) or PBN/A1B1 for older codes. If a letter “R” appears in Item 10A (equipment field), indicating PBN approval, then corresponding entries must appear in PBN/.
• CODE/ – Aircraft address (Mode A/C transponder code in hex, if required by authority).

 

Each prefix is followed by data (letters, digits,/or names) as prescribed by Doc 4444. Item 18 is written in all-caps, with one entry per prefix (some may be repeated, e.g. multiple ALTN/). Importantly, these entries ensure that ATC and ATS systems have all relevant flight details. For instance, listing a takeoff alternate (TALT/) or departure time (DOF/) in Item 18 may be regulatory requirements in some jurisdictions.

Item 18 in Business Aviation Operations

Business aviation frequently relies on Item 18 to convey nuances of a charter or corporate flight. For example, if a large-cabin jet (e.g. Gulfstream G650) departs an unlisted private strip, the dispatcher enters DEP/ with coordinates. If the call sign is generic (e.g. corporate flight number) but the registration matters for CAR/EASA release, the REG/ element provides clarity. High-end business jets often hold multiple PBN/RNP approvals and extra FMS capabilities; these must be carefully encoded under PBN/ and NAV/. For instance, a Dassault Falcon 8X might have Satellite Based Augmentation System (SBAS)-enabled GPS (EGNOS) and an inertial system: the dispatcher could file PBN/A1B2 and NAV/SBAS INS to fully declare the equipment.

 

Business operators must also be mindful of special items: e.g. TALT/ (takeoff alternate) is often mandatory for IFR dispatch on twin-engine jets departing remote airports. DOF/ is used when filing days in advance (common for repositioning flights). ORGN/ can supply the dispatch office contact in case ATC needs clarifications. When Item 18 is incomplete or inconsistent, business jets can face tangible impacts: an incorrect PBN/ or missing RMK/ may lead to an ATC clearance that the crew is not qualified for, or even an automatic rejection by flight plan processing systems.

 

Item 18 entries flow from Doc 4444 (PANS-ATM) procedures; for example, ICAO explicitly notes that failure to include required PBN details after marking Item 10A with ‘R’ will cause a flight plan rejection. Likewise, if an alternate airport is specified as “ZZZZ” in Item 16, the ALTN/ name must appear in Item 18. In practice, professional flight operations personnel ensure all relevant codes (PBN, NAV, STS, etc.) are present to avoid back-and-forth with ATC or FMS loading errors.

PBN/RNAV Requirements and Item 18

Performance-Based Navigation (PBN) is central to modern flight planning. Business jets typically carry RNAV-1/2 and RNP-approach approvals, so the ICAO flight plan must reflect this. Under Amendment 1 to PANS‑ATM (2012), the meaning of the Item 10A code ‘R’ became “PBN approved,” and the specific RNAV/RNP codes must be “amplified” in Item 18. In other words, if a flight plan includes an ‘R’ suffix in Item 10A, the dispatcher must provide a PBN/ entry in Item 18 listing each navigation specification (e.g. RNAV 5 (code B2), RNAV 1 (B1), or RNP APCH (T1, A1), etc.). All navigation sensors (GPS, INS, etc.) that support those PBN specs must also appear in Item 10A. 

 

For example, a Gulfstream G650 with standard RNAV 5 and RNP 1 authorizations (plus WAAS/LPV) might file:

 

• Item 10A: /R-SDFG1Z (where R=approved PBN, S=RVSM, D=GNSS, F=GPS, G=GLONASS, 1=GBAS, Z=other)
• Item 18: PBN/B1C2 D2L1 NAV/SBAS

 

Here “B1”=RNAV 5, “C2”=RNP 1, “D2”=Advanced RNP AR approach, “L1”=Lateral deviation 0.1 (example codes), with SBAS added in NAV/. Such detail tells ATC exactly what routes and approaches the aircraft can fly. If these items are inconsistent (e.g. R in Item 10A but no PBN/ line), modern ATS processing will reject the flight plan. Operators are therefore required to tie their actual onboard capabilities (including database currency and approvals) to the codes in Item 18.

Regulatory Context: ICAO and Data Integrity

ICAO standards underpin these practices. Annex 15 requires that any significant aeronautical data change be propagated through the Aeronautical Information Regulation and Control (AIRAC) cycle, with Aeronautical Information Service (AIS) ensuring data reaches users at least 28 days before it is effective. If data is not ready, AIS must issue precautions (e.g. “NIL” by 28 days prior) to warn operators. For example, when a new fix is not in the published AIP cycle, a “Trigger NOTAM” alerts pilots and flight planners.

Doc 4444 (PANS-ATM)

Specifies the Flight Plan format (including Item 18) and encourages uniform filing. It explicitly links Item 10 (equipment codes) to Item 18: e.g., under PANS-ATM, filing ‘R’ in 10A without the proper PBN/ entries is noncompliant and causes rejection. PANS-ATM also details standard prefixes (DEP, ALTN, EET, etc.) used in Item 18.

Doc 8168 (PANS-OPS)

For aircraft operations reinforces data currency: before flying any RNAV or RNP procedure, the crew must verify that all required navaids and database content are correct. Crucially, it states that a procedure must not be flown if the navigation database lacks it. In effect, outdated or missing data translate to “no-go” for an RNAV approach.

 

On the operator side, authorities require a data chain and database LOA (Letter of Authorization) for RNAV/RNP usage. In business aviation, failing to meet these integrity requirements (for example, by installing a chart that conflicts with the FMS data) can violate airworthiness or operations rules.

Case Study: Business Jet at Dubai Al Maktoum Airport (OMDW), UAE – Falcon 8X (Jet)

Dubai’s Al Maktoum International Airport is equipped for RNAV and RNP operations. A Dassault Falcon 8X inbound from Europe may plan an RNP AR approach to runway 31L. The flight plan item 18 must include, for example, PBN/A1B2 (RNAV 5, RNAV 2) and equipment NAV/GPS if using GPS-based RNP. If a new waypoint (e.g. ALICE, a SMAP) was added but not yet in the Airbus/FMS navdata, the FPL might be flagged. Annex 15-compliance means the UAE AIS should publish any critical fix by AIRAC, but if late, ATC would have to issue a NOTAM (which the crew reads via DMAN (departure manager) or briefing).

 

The result: the Falcon’s dispatch may reserve extra fuel to hold if vectors replace the RNAV arrival, and file an alternate like DXB with ALTN/DUBAI INTL. In extreme cases, without current nav data, an 8X cannot legally fly RNP AR (per PANS-OPS) and must revert to simpler procedures. Mastering fuel efficiency in such scenarios becomes critical—not just for cost control but also for maintaining compliance and operational flexibility when routing uncertainties arise.

 

In conclusion, understanding and correctly completing ICAO Flight Plan Item 18 is vital for safe, efficient business aviation operations. From accurately filing PBN and NAV capabilities to managing delays in navigation data, Item 18 ensures compliance, clarity, and effective communication with ATC. At Just Aviation, we prioritize precision in maximizing business jet flight planning to minimize disruptions and support seamless operations—because every detail matters when delivering exceptional aviation service worldwide.