InFO 12006: Flight Identification (FLT ID) Entry Errors During Flight Management System (FMS) Initialization or Transponder Input Causing Air Traffic Control (ATC) Surveillance Anomalies

Distributed by: AFS-200 OPR: AFS-406

InFOInformation for Operators

U.S. Department InFO 12006

of Transportation DATE: 3/12/12

Federal Aviation

Administration Flight Standards Service

Washington, DC http://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/info An InFO contains valuable information for operators that should help them meet certain administrative, regulatory, or operational requirements with relatively low urgency or impact on safety.

Subject: Flight Identification (FLT ID) Entry Errors During Flight Management System (FMS) Initialization or Transponder Input Causing Air Traffic Control (ATC) Surveillance Anomalies

Purpose: This InFO provides background information on the function of FLT IDs transmitted by Mode S transponders within ATC systems and discusses reports of some operators transmitting incorrect FLT IDs. Also provided are causal factors associated with the reports and guidance to aid operators in addressing these factors.

Background: ATC systems worldwide are becoming more reliant upon information transmitted by Mode S transponders to manage air traffic. An aircraft’s FLT ID (call sign) is one piece of information transmitted by Mode S transponders. ATC systems use transmitted FLT IDs to uniquely identify each aircraft within a given airspace and correlate them to a filed flight plan for the provision of surveillance and separation services.

A FLT ID is comprised of a maximum of seven alphanumeric characters (for example, N235RA, AAL3342, BONGO33) and corresponds to the Aircraft Identification entered in Block 7 of the International Civil Aviation Organization (ICAO)/Domestic Instrument Flight Rules (IFR) flight plan form (FAA Form 7233-4) filed for the flight. A FLT ID is typically entered by the flightcrew during preflight through either an FMS interface (Control Display Unit/CDU) or transponder control panel. For ATC systems to function correctly, flightcrews must ensure the FLT ID entry matches exactly the aircraft identification indicated in Block 7 of the associated ICAO flight plan.

Discussion: The FAA has received reports from EUROCONTROL, Airservices Australia, and NAV CANADA of some U.S. registered aircraft transmitting a FLT ID which does not correlate to the aircraft identification indicated on the filed flight plan. In such instances, ATC requests the flightcrew to correct the erroneous FLT ID, or in instances where corrections can not be made, assign a discrete transponder code to the aircraft. The result of which creates unnecessary distractions and increased workloads for both the flightcrew and ATC.

Provided below are common factors associated with the erroneous FLT ID transmissions and guidance to aid operators in correcting them.

1. Initial FLT ID input error. The FLT ID input into the transponder interface (FMS/Transponder Control Panel) did not correlate to the aircraft identification annotated on the ICAO flight plan.

Distributed by: AFS-200 OPR: AFS-406

Flightcrews need to ensure the FLT ID entered into the transponder interface (FMS/Transponder Control Panel) matches exactly the aircraft identification in Block 7 of the filed ICAO flight plan (FAA Form 7233-4). Any deviation between these entries will result in ATC system errors.

Some avionics installations prevent entry or modification of a FLT ID while airborne. Flightcrews should be aware of and report any such limitation when responding to ATC requests to correct an erroneous FLT ID.

3. Flightcrew unaware of procedures to modify FLT ID. In some reports flightcrews indicated they were unaware of procedures to modify the FLT ID while airborne. Training and procedures should be provided that enable flightcrews to comply with ATC requests to correct an erroneous FLT ID.

4. Difficulty understanding ATC phraseology during requests to correct an erroneous FLT ID. Reports indicate that some flightcrews experienced difficulty understanding the ATC phraseology used during requests to correct an erroneous FLT ID.

Flightcrews are advised that ATC may use “Mode S Code” phraseology when referring to and requesting FLT ID corrections. In such instances, flightcrews should confirm the intent of the request (Mode S Code = FLT ID) with ATC before modifying their FLT ID.

Recommended Action: Directors of Operation, chief pilots, fractional ownership program managers, training managers, and individual operators should review their training and equipment operating procedures to ensure the content of this InFO is adequately addressed. For more detailed information refer to the following: www.eurocontrol.int/msa; JAA Temporary Guidance Leaflet 13; ICAO Doc 4444 section 6 subparagraph 4.5.3.4; and, ICAO Doc 8585.

Contact: Questions or comments regarding this InFO should be directed to Pat Zelechoski or James Marks, FAA Flight Technologies and Procedures Division (AFS-406) at (202) 385-4586.