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Frequently Asked Questions

General Questions

Q: Will flights that enter Canadian airspace be required to file an FPL with each/all Canadian Flight Information Regions (FIR)?
A: (Response by NavCanada) Yes. Canada requires the FPL to be filed with all Canadian FIRs along the route of flight in accordance with ICAO.

Q: Will DUATS handle ICAO flight planning?
A: Yes. See How to file your flight plan (domestic or international).

Q: Are Point-to-Point (PTP), RNAV and "T" routes auto assigned when filing an ICAO FPL?
A: Yes. Put relevant information in Item 18 after "RMK/" or "NAV/", as applicable.

Q: Do we continue to follow current procedures for PTP, RNAV and the CDR Playbook?
A: Yes. There are no changes to current procedures; please continue to follow them.

Q: Do we file an ICAO FPL from Alaska to destination within the conterminous U.S.?
A: Yes. An ICAO FPL is required when crossing international boundaries.

Q: Should the ICAO FPL be addressed to each U.S. Flight Information Region (FIR)/ARTCC?
A: Domestic-only ICAO FPLs and international flights which remain in North America (i.e., destination Canada or Mexico) should only be addressed to the departure US FIR/ARTCC. International ICAO FPLs should be addressed to the departure US FIR/ARTCC only, domestically, and to each FIR IAW Doc 4444 instructions.

Q: Why is FAA diverging from ICAO standards?
A: FAA will accept ICAO FPLs filed IAW Document 4444 in compliance with ICAO standards. Our software will also accommodate some NAS FP-only conventions for domestic-only ICAO FPLs, such as block altitudes and message assurance responses to a third party; these will be documented in the Flight Plan Guidance section of the website. Please refer to International (ICAO) Flight Plan Filing.

NOTE: Filers are cautioned these conventions should be filed in a domestic-only ICAO FPL, as such FPLs may be rejected by the flight plan systems of other ANSPs.

Q: What about proposed changes to the ICAO FPL which replace "NAV/" with "PBN/"?
A: Once ICAO guidance is final, FAA will work toward implementation of FPL changes and timeframes.

Q: Is there a list of critical DME facilities?
A: The RNAV/RNP office does not maintain a master list of critical DME facilities to be cross-referenced with procedures. The critical DMEs are published on the individual charts as "xxx DME required". Per Advisory Circular (AC) 90-100A paragraphs 6b and c, we validate the infrastructure, provide the information on required facilities and NOTAM as appropriate. It is the operator's responsibility to monitor the requirements/availability of infrastructure supporting procedures for each location to which aircraft are dispatched.

Q: Is ETMS able to process early intent filing in the new format?
A: Yes. ETMS is able to process early intent messages.

Q: What is the difference between "preferred routes" and "preferential routes"?
A: "Preferential routes" are RNAV and/or conventional departure and arrival routes that may be automatically assigned by Host/ERAM. These routes are assigned based on equipment and other data filed in the ICAO FPL. Preferred routes" are routes described in Airport/Facility Directories (AFD) intended to guide route planning and better provide for efficient departure, en route and arrival air traffic service. These routes can be filed/assigned to filers of either a NAS FP or an ICAO FPL.

Q: Do filing requirements change for automatic assignment of Preferential Departure Arrival Routes (PDAR) and Preferred Arrival Routes (PAR)?
A: No. ERAM will process consistent with current Host procedures. NAS FPs will only qualify for conventional routes, while FPLs will qualify for either conventional or RNAV routes.

NAS Flight Plans

Q: Can we still file a NAS FP.
A: Yes. Users can file NAS FP for domestic flights only, but you will be assigned conventional routing. Users who choose to file a NAS FP will not be eligible for assignment of RNAV SIDs or STARs or ADS-B services.

Q: What NAS equipment suffixes cannot be derived from equipment filed in an ICAO FPL?
A: NAS equipment suffixes /E, /J, /F, /K, /I, /C and /Y cannot currently be accurately derived from equipment qualifiers filed in an ICAO FPL. FAA is exploring options to compensate for these differences between NAS and ICAO equipment qualifiers.

Item 3 (Message type, number & reference data)

Q: Can filers include the proposed departure time in an ICAO Modification (CHG) message?
A: No. In accordance with ICAO Doc. 4444, FAA's En Route Automation System (ERAS) does not accept a CHG message which includes a proposed departure time; the CHG would be rejected. Please refer to the Interface Reference Guide (PDF) for guidance.

Q: How do filers ensure a reply is sent to the responding terminal as currently done with a domestic Flight Plan (FP)?
A: ERAS will use the 3-letter facility address in Item 3b of the FPL for acknowledgements, if present; otherwise, the acknowledgement will be sent to the originator's AFTN address. In either case, the address must be adapted as a "responding" station in ERAS to receive acknowledgements. If your system is not currently receiving acknowledgements, contact us to register your address as a responding station. Please refer to the Interface Reference Guide (PDF) for guidance and examples.

Q: Will an FPL be automatically rejected or is that a manual function?
A: ERAS automatically rejects an improperly formatted FPL. The Rejection (REJ) message usually includes information which identifies the error. The filer should correct the error and reenter the FPL. Occasionally, messages rejected for reasons other than format errors are sent to ARTCC Flight Data personnel and result in a phone call (manual rejection). Please refer to the Interface Reference Guide (PDF) for guidance and examples.

Q: Should filers continue to follow current procedures for advanced flight plan filing (e.g., 30 minutes prior to proposed departure time)? How will FAA handle "DLA" and "ACK" inside this parameter?
A: Yes. Flight plan filing parameters have not changed. Flight plan revisions submitted less than 30 minutes prior to proposed departure time will normally be rejected. Filers should contact the ARTCC Flight Data Unit for changes less than 30 minutes prior to the proposed departure time.

Item 7 (Aircraft Identification & SSR Mode & Code)

Q: Can we file call signs beginning with a number?
A: Users should file the FPL IAW ICAO Doc 4444. If the FPL is rejected, contact the ARTCC Flight Data Unit to which the FPL was sent so they can ensure acceptance in ERAS.

Item 8 (Flight rules & type of flight)

Q: Is it required that filers include ICAO Items 8a/b in a domestic FPL?
A: For domestic flights, Item 8a (Flight Rules) is required, but Item 8b (Type of Flight) is optional.

Item 9 (Number/type of aircraft & wake turbulence category)

Q: Can filers continue to use the National Airspace System (NAS) aircraft designator? What about type designator "ZZZZ"?
A: Where ICAO and FAA differ, comply with the ICAO FPL filing instructions in Doc 4444. Users should file the appropriate Type of Aircraft specified in ICAO Document 8643; aircraft Type Designators (e.g., B747-200 is indicated as "B742"); if no designator has been assigned or it is not known, insert ZZZZ in Item 9 and specify the type of aircraft in Item 18 following "TYP/". Refer to How to prepare your international flight plan form.

Q: Will FAA resolve the differences between ICAO documents and FAA handbooks regarding the Wake Turbulence Category (WTC) for Heavy (H) and Medium (M); in particular, what about differing WTC for the B757-200 series aircraft?
A: Where ICAO and FAA differ, comply with the ICAO FPL filing instructions in Doc 4444 and FAA will handle the difference procedurally. For example, the ICAO WTC for all B757s is M, while the FAA certified WTC for some B757-200s is H. In Item 9, filers should indicate WTC as M for all B757s. Please refer How to prepare your international flight plan form.

Q: Have the A388 and B748 been designated as a 'Super Heavy' (/J) wake turbulence category, or should we continue filing them as 'Heavy' (H/)?
A: The Airbus 380-800 (A388) is still classified in the Heavy Wake Turbulence Category (WTC), indicator (/H). The FAA is aware of discussions about the "Super" WTC, but the official ICAO publication (Doc 8643, Aircraft Type Designators) has not been amended to reflect this change. ICAO guidance has indicated that the "/J" will be used to describe this new WTC, which presently applies only to the Airbus 380-800. There is speculation that it may also include aircraft such as the Boeing 747-8 in the future.

Please continue to refer to ICAO Document 8643 for any updates of WTC descriptions and appropriate aircraft type designators.

Item 10 (Equipment)

Q: If I ‘R’ is filed in ICAO Field 10a, am I also required to enter PBN/ data in Field 18?
A: Yes... The ‘R’ in Field 10a indicates that PBN/ data are filed in PBN/

Q: Should the qualifiers filed in Field 10b be listed in a particular order?
A: Our software will accept Field 10b entries in any order. We suggest that you file these in the order shown in Amendment 1, since some ANSPs might require it.

Item 13 (Departure aerodrome & Time)

Q: How do I revise my departure time (EOBT) past mid-night?
A: If the original FPL did NOT contain a DOF/ (recommended) you may simply revise the time using the DLA message. If the original FPL contained a DOF/ you should use the CHG message to revise both the EOBT and the DOF/ in a single message.

Q: Currently, if an FP is filed and there is no activity with respect to the flight two (2) hours after the proposed departure time ("P time"), the FP will drop out of the system. Is that also the case for an ICAO FPL?
A: Yes. The FP or FPL will drop out in accordance with an adaptable parameter based on the "P" time; at most facilities this is nominally set to 2 hours. It works the same for FPs and FPLs, and will not change with ERAM implementation.

NOTE: If an Expect Departure Clearance Time (EDCT) is applied to a flight, the later of the EDCT and the "P" time will apply (i.e., if the "P" time is 1200 and EDCT is 1330, the FPL/FP will drop at 1530 if not activated, not at 1400).

Q: Should we file a 3-letter or 4-letter location identifier (LOCID) (e.g., W66)? Currently each center has a unique identifier table. Will they all be configured the same with the 4-letter LOCID?
A: Users should file the ICAO 4-letter LOCID in Item 13. U.S. 3-letter LOCIDs can be converted by prepending a K, e.g., IAD is KIAD. Center information is being standardized to include both the 3- and 4-letter LOCIDs, as we will be accepting both ICAO FPLs and NAS Flight Plans (FP). If no four-letter LOCID is assigned or it is not known, insert ZZZZ in Item 13 and provide the NAS identifier of the departure airport in Item 18 following DEP/, e.g., DEP/W66. Please refer to International (ICAO) Flight Plan Filing.

Item 15 (Route)

Q: Filing latitude/longitude (lat/long) coordinates is different for a domestic FP and an ICAO FPL; the domestic FP requires a slash ("/") between the lat and the long. Will ERAM implementation resolve the discrepancy?
A: No. Lat/long is filed differently in an ICAO FPL and a domestic FP. You cannot use the / in an ICAO FPL. ERAS will accept ICAO format lat/long in an FPL message and NAS format lat/long in an FP message. Please refer to Domestic Flight Plan Filing (Domestic Cases) / International (ICAO) Flight Plan Filing.

Q: Will users be able to file "T-routes" using the ICAO FPL and using DUATS (e.g., Caribbean)?
A: Yes. Continue to file "T-route" information in ICAO Item 15 (Route) as you do in a NAS FP. DUATS will accept the routing as well.

Item 16 (Destination, EET & Alternate Aerodromes)


Item 18 (Other Information)

Q: Following the ICAO 2012 implementation, do I still need to file NAV/RNV data in Field 18?
A: Yes... The FAA will continue using NAV/RNV data to determine eligibility for RNAV arrivals and departures, until some future date.

Q: Am I required to file a DOF/ in Field 18?
A: DOF/ is only required if the FPL is filed more than 24 hours prior to departure. En route FAA systems do not accept FPLs more than 24 hours in the future (as little as 23 at some facilities). We recommend that operators not file the DOF/ unless required.

Q: Am I required to file Field 18 indicators in a specific order?
A: International guidance requires that these indicators be filed in the specified order. FAA systems, however, will not enforce this requirement. Other air navigation service providers may.

Q: My aircraft meets the requirements for PBN/A1B2B3B4B5C1D1O1T1T2S1S2, how can I file these capabilities without exceeding the maximum 8 entries allowed in the PBN/ field?
A: You may file PBN/A1B1C1D1O1T1S2 because…

  • PBN/B1 includes B2B3B4B5, but not B6
  • PBN/S2 includes S1 capabilities
  • PBN/T1 includes T2 capabilities

Q: Is the callsign LIFGUARD still valid, or should I change to MEDEVAC?
A: The callsign LIFEGUARD has been replaced with MEDEVAC in radio and telephone communications. The RMK/LIFEGUARD has been replaced with STS/MEDEVAC in ICAO Field 18. Operators may continue filing callsigns beginning with ‘LN’ (e.g. LN1234A) for flights that will remain within U.S. Domestic airspace.

Q: Will including domestic EET/ data cause an FPL to be rejected?
A: No. ERAS does not require EET/ data in an ICAO FPL for the route portion in U.S. domestic airspace. The FPL will not be rejected; however, ERAS will not process EET/ data if filed. Please refer to How to prepare your international flight plan form.

Q: Will ERAS accept an "EET/" in Item 18 with no associated data included?
A: ERAS will reject an ICAO FPL which has EET/ with no trailing data string in Item 18. If your filing system automatically inserts EET/, please contact us to discuss mitigating this issue by inserting a trailing data string which will work for your system, e.g., EET/NONE. ERAS will not process the data string you enter; however, we will test the suggested data string to ensure your FPLs are accepted. Please refer to How to prepare your international flight plan form.

Q: If the flight goes into Canadian airspace should "EET/" data be included?
A: Yes. EET/ data should normally be included for any international portions of the route of flight.

Q: Is there any scenario where a user would insert "NAV/D1E99A1" in Item 18 as an RNAV value?
A: Any operator capable of RNAV 1 can file E2 or E1 (we recommend E2), but it would not be an error to file E99 and the FPL would be accepted. Please note that we request you file your maximum RNAV capability in Item 18. Filing E99 would make the flight ineligible for any portions of an RNAV Standard Instrument Departure (SID) or Standard Terminal Arrival Route (STAR) which extend into the en route environment. Please refer to How to prepare your international flight plan form.

Q: In order to be assigned RNAV PTP, do you file RNVE99 or RNVE2?
A: It can be appropriate to file either value. You can qualify for PTP using AC 90-45A (RNVE99) or AC 90-100A (RNVE2) IAW; see Domestic Flight Plan Filing. Please file your maximum RNAV capability in Item 18.

Q: Will the system accept RNAV arrival data only? Do you have to file values for all RNAV flight segments (i.e., D1, E2 or E99, A1) in every FPL?
A: ERAS will accept an A value without a D or E value. You can file values for any combination of flight segments – one, two or all three. Omit Item 18 RNAV value information for any segment for which RNAV preferential route application is not desired. Please refer to How to prepare your international flight plan form.

Q: We have seen examples of both E1 and E2 in the NAV/RNV string of an FPL; can E1 be filed and will it be shown as E1?
A: Yes. E1 can be filed, although we are recommending filers use E2. If E1 is filed, ERAS will assign any E2 or E99 routes. Please refer to How to prepare your international flight plan form.

Q: What is meant when you say RNAV preferential routes will be "automatically assigned by Host/ ERAM"?
A: When an FPL/FP is filed through AFTN/NADIN, ERAS checks FPL/FP fields for information on equipage, requested route, requested procedures, etc. It uses that information to determine whether to assign conventional routes/procedures or RNAV preferential routes (RNAV SID/STAR/PTP). When an ICAO FPL is filed, ERAS will: check Item 10, Equipment, to determine whether the aircraft is equipped for and requesting RNAV routes; and if "no" – apply an appropriate conventional route/procedure. If "yes" – check Item 18, Other Information, for an acceptable data string following "NAV/" to determine if the flight/crew is capable and desirous of an RNAV SID/STAR/PTP; and if "no" – apply a conventional route/procedure. If "yes" – automatically apply appropriate RNAV SID/STAR/PTP to the FPL and present it to the controller. In each case, the appropriate route/procedure assigned may be the route requested; however, in cases where the route requested is not active or is otherwise not appropriate ERAS will automatically assign a different one.

Q: Does ICAO FPL Item 18 have a character limitation? Air Navigation Service Providers (ANSP) have varying requirements. A: ICAO Doc 4444 does not limit the number of characters in Item 18; Host/ERAM will handle FPLs with any/all ANSP-required data. FAA is aware the Eurocontrol/CFMU flight plan system will reject an FPL with:

  • Information in Optional fields b/c of Item 3; and/or
  • More than 20 characters in Item 18 after "NAV/", a problem for those needing to file RNAV/RNP information for multiple ANSPs.

Q: Does use of ICAO Item 18 solve the current "pass-back" problem wherein RNAV-equipped aircraft are taken off an RNAV route by a subsequent Air Route Traffic Control Center (ARTCC) because the equipment suffix presented to the controller does not indicate RNAV capability?
A: The problem described is related to a component of the NAS Host system, and will occur less frequently at facilities which have completed the transition to ERAM. In the interim, it may lessen the problem you described but it may not completely solve it.

Q: What process do we use to modify Item 18?
A: Filers should use an ICAO CHG message. Please refer to How to prepare your international flight plan form.

Q: Can "RMK/" be filed anywhere in Item 18 of an ICAO FPL?
A: Yes. ERAS will accept RMK/ information anywhere in Item 18. For standardization, our preference is the RMK/ information be placed last in Item 18. Please refer to How to prepare your international flight plan form.

Q: Will FAA guidance change regarding information currently filed in the Remarks section of a NAS FP?
A: No. Filers should continue to follow the conventions currently requested by placing the information after "RMK/" in Item 18 of the ICAO FPL (e.g., "RMK/HAR," "RMK/PTP").

Item 19 (Supplementary Information)

Q: Host rejects Item 19 data if filed in the ICAO FPL. Will ERAM do the same?
A: There is no requirement in ICAO Doc. 4444 to include Item 19 in an FPL. We understand various filing conventions have evolved which may loosely conform to ICAO guidance, but Host/ERAM does not accept an FPL with an appended Item 19. Additionally, other interfaced automation systems (e.g., Mexico's Eurocat X) have compatibility problems accepting Item 19 data in cross border messaging. Please refer FAA Flight Planning Information.

Last updated: Wednesday, August 26, 2020