Wednesday, February 19, 2014

FANS-1 ACARS and Satcom must pass Airplane Equipment Interoperability Test (AEIT) (1995)

Boeing sold production and retrofit commitments to install and certify FANS-1 functionality without regard to specific ACARS and SATCOM part numbers.  All existing ACARS, and many SATCOM systems, do not support the Airplane Equipment Interoperability Test (AEIT) requirements.

Until their ACARS and SATCOM are approved, customers who purchased the FANS-1 changes will not be able to activate the air traffic services (ATS) function, which is not what they are expecting.


FANS-1 includes a data link function to support airline operational control (AOC) and air traffic services (ATS). The ATS data link function includes Automatic Dependent Surveillance (ADS) and two-way data link (TWDL).  The AOC data link was first developed in the 757/767 product improvement package (PIP), whereas the ATS data link was a feature first developed in the 747-400 FANS-1 FMCS.  When the FANS-1 changes were sold to customers, the contingency was to install an ACARS management unit that was compliant to AEEC 724B and would meet the interoperability requirements of the Air Traffic Services System Requirements and Objectives (ATS SR&O), document D240U123.  As additional estimating information, it was assumed that other than the first one, all subsequent ACARS part numbers would be demonstrated for certification to connect to the FMC using a lab test.  It was also noted that SATCOM would need to be installed to achieve optimum benefit for the ATS data link function.

It was the original assertion that simply complying with the AEEC specifications, such as 618, would provide an adequate basis to support certification of the ATS data link function.  However, as the program was implemented and tested, significant concern was raised by the FAA over ACARS performance.  Also, both ACARS and SATCOM needed to support a new set of EICAS messages (advisory, memo and status).  Finally, it was determined that the use of a high gain SATCOM antenna introduced the potential for the SATCOM system to not support any data link traffic unless a low gain antenna was installed, or alternate means to utilize the high gain antenna were implemented.  As a result of the FAA requirements to ensure acceptable data link performance, the AEIT was developed.

The AEIT was originally envisioned to be small number of tests used to determine the suitability of the ACARS and SATCOM for use with ATS data link.  It was originally thought that most ACARS in existence could pass the AEIT.  However, to optimize data link performance enough to gain acceptance by the FAA, a number of new test conditions were created which resulted in a set of requirements that no existing ACARS could meet.  Fortunately, the latest SATCOM systems from Collins and Honeywell can be used to satisfy these requirements.  Collins has now produced three ACARS parts which are deemed acceptable, Allied has a part in test at this time, and Teledyne has been appraised of the requirements of the AEIT (D6-36412 rev A).

As a result of the use of the AEIT in gaining FAR part 25 certification of the FANS-1 ATS data link function, the FAA has effectively disqualified all existing ACARS.  Boeing has taken the following steps to respond to this situation:

1)  Boeing will issue, per originally committed schedule, both production and retrofit configurations to all existing FANS-1 customers with the ATS data link function disabled.

2)  For those customers with existing FANS-1 commitments (production and retrofit), Boeing will test the airline's ACARS and SATCOM systems for compliance to the AEIT.  If the airlines ACARS and SATCOM system pass the AEIT, Boeing will issue a service bulletin activating the ATS data link function on that customer's airplanes.  Boeing will support a single AEIT approval effort for each existing FANS-1 customer.  The customer must submit their ACARS and SATCOM for testing.  The part numbers must not be the same of any existing ACARS and SATCOM which are determined to be non-AEIT compliant.  The ACARS and SATCOM part numbers may not necessarily match the originally delivered production configuration, and should reflect the configuration the customer intends to utilize in service.  The ATS activation service bulletin will call out the specific ACARS and SATCOM part numbers and is not transferable to other ACARS and SATCOM part numbers.

3)  Existing FANS-1 production configurations that include an existing ACARS part number will be presumed to be non-AEIT compliant, and the ATS data link function will be disabled.  Production activation of the ATS data link function will require installation, by separate change request, of a new ACARS part number (and SATCOM if applicable) that is tested to comply with the AEIT.

4)  Boeing will support, via a technical services contract, additional AEIT approvals, if requested, if the customer chooses to change the ACARS or SATCOM system from that which was originally approved.  Alternatively, the customer may choose to gain certification of follow on part number changes through direct negotiation with their appropriate civil aviation authority, presumably with support from their equipment supplier.  Boeing will supply the AEIT document, D6-36412 rev A, as requested to support the customer's independent efforts.

5)  Boeing will provide the capability for AOC data link functionality in the FANS-1 service bulletins.  The airline must install a compatible ACARS to activate this functionality.  Production FANS-1 configurations will be tested by Boeing to ensure a functioning interface.  In any case, it is Boeing's expectation that all customer's existing ACARS will support the AOC data link function.

6)  New FANS-1 customer commitments in production will be sold in multiple, functionally segregated parts.  AOC data link functionality will be assumed if an ACARS is already installed (Boeing will test this function).  If the customer chooses to install a new ACARS and/or SATCOM in production, the customer will need to select a companion change to activate the ATS data link function (presuming the configuration is AEIT compliant).  It is assumed that all new ACARS and SATCOM systems will be AEIT compliant.  If the customer does not select an ACARS and/or SATCOM that are AEIT compliant in the production configuration, the customer may select, via separate change, retrofit activation of the ATS data link function.

7)  New FANS-1 retrofit commitments will be sold in multiple, functionally segregated parts.  The capability to support AOC data link functionality will be assumed; the customer will need to install a compatible ACARS to activate this function.  The customer may select a companion change to activate ATS data link, in which case the customer will be required to submit their ACARS and SATCOM systems for AEIT approval.  Note, the customer may submit any ACARS and SATCOM for testing and are in no way obligated to stay with the ACARS and/or SATCOM originally delivered in production.

8)  In all cases, Boeing activation of the ATS data link will entail specific ACARS and SATCOM part number dependencies.  All AEIT approvals will require Boeing testing of the ACARS and SATCOM systems.