Year 2000 Readiness Disclosure

Heightened attention to the potential effects of the change exists in both the media and among the traveling public, as commercial airplanes rely on computers for many functions. Boeing has surveyed its commercial airplane fleet and identified some nuisance flight deck effects that could occur for a few airborne systems. Upgrade programs are now in place to replace the affected systems and ensure operators uninterrupted service both during and after the date change.

Many computer systems use only two digits to define the year, such as "98" for "1998." When the year changes from 1999 to 2000 (and beyond), applications, operating systems, microcode, databases, processes, monitoring equipment, and so on may have logic or arithmetic problems. The year "00" may appear in sequence before "99," for example, or software may consider "00" to be invalid. To ensure uninterrupted service for operators, a Boeing team assessed the effect of the Year 2000 (Y2K) on airborne systems for all Boeing airplane models currently in production, out of production, and in development. The assessment showed that a very small number of airborne systems on Boeing airplanes and some immediate support equipment will be affected by the Y2K date rollover.

The search for potential Y2K effects was restricted to systems with embedded software that use a date, which made it possible to exclude systems and components that do not contain embedded software. However, even a simple system such as a clock or a communications radio control panel often uses software, potentially making it susceptible to Y2K effects. The approach Boeing used for airborne systems included supplier evaluation and reporting results and providing upgrade paths for affected systems. This approach was aligned with the company's goal to prepare computers for the Y2K rollover a year early, by December 31, 1998.

Supplier Evaluations
Suppliers of equipment with embedded software were asked to respond to a set of questions in specific areas (see table 1). All responses were entered into a relational database to assist with sorting, generating reports, and compiling other status information.

Results of Supplier Evaluations and Upgrade Paths
Boeing separated its airplane systems into 12 functional areas of responsibility (see table 2) for the purposes of the Y2K assessment. The results of the assessment addressed the following as potentially affected by the date rollover:

  • Airborne systems with date effectivity checks.
    - Flight management system (FMS) with either the Honeywell or Smiths flight management computer (FMC).
    - Inertial navigation system (INS).
  • Ground-based software tool (GBST).
  • Onboard maintenance system (OMS).
  • Buyer-furnished equipment (BFE).

The survey revealed that the only airborne systems checking date are those containing an embedded navigation database (NDB). (See "Regulatory Requirements for Current Navigation Data") Though recording and maintenance systems use dates, they do not perform any processing based on those dates or use the month/day format only and so are not susceptible to Y2K problems. The affected systems include the FMS and INS.

To allow maintenance crews and flight crews to verify the currency of the NDB prior to dispatch, an identification (IDENT) or aircraft status (A/C STATUS) page is provided on the flight crew entry and display device or control display unit (CDU) of the FMS. The IDENT or A/C STATUS page contains information about the current and previous cycle of the NDB, notably the month and year of effectivity. The ACTIVE navigation database can only be changed while the airplane is on the ground. On most FMSs the year of effectivity is indicated by two digits as /YY (/98 indicates the year 1998, for example). However, on a few systems, this field overflows for the year 2000 and beyond and is displayed as 111 or /100, with an additional zero wrapped to the next line of the display, rather than /YY. The alphanumeric database identifier in the NAV DATA field (which contains the year) is presented correctly and provides 100 percent assurance that the correct database was loaded.

Some FMSs offer an alert message to indicate an out-of-date NDB (NAV DATA OUT OF DATE). This message is triggered when the NDB effectivity does not match the clock date input when selected or at power-up or flight completion on the ground. On a few systems, this message will be triggered erroneously, even if the NDB is current. Because such an erroneous message can delay dispatch or distract the flight crew, Boeing considers it a nuisance for flight operations.

Figure 1 shows representative IDENT pages for the second-to-last and last 28-day NDB cycles of 1999. The latter depicts the /YY overflow and erroneous NAV DATA OUT OF DATE scratchpad message.

Boeing considers these Y2K issues significant because they generate flight deck effects that are inconsistent with the company's "quiet, dark" flight deck philosophy. However, no flight critical effects exist, and safety of flight is not compromised. In addition, dispatch is still possible, and full and normal functionality of the FMS is available. These flight deck effects do not occur in the FMSs of the latest Boeing models, namely the 777-200/ -300, 737-600/-700/-800, MD-11, and models under development (717, 737-900, 757-300, 767-400, and MD-10).

The FMSs affected are those with one of two flight management computers: Honeywell (for both Boeing- and Douglas- designed airplanes) and Smiths.

The Honeywell FMC versions in the 747-400 issue an erroneous NAV DATA OUT OF DATE message, and some also have the IDENT page/YY overflow. A new software version, Load 14, which incorporates fixes to remove these effects is available. (See "Communicating About the Year 2000" for further information on service bulletins and other communication with operators.) Operators should note that Load 12 and subsequent versions require S242T102-552 hardware.

The 757 and 767 models with early 100K disk or early 200K systems exhibit the IDENT page anomaly, which was rectified in the latest 200K versions. Operators should note that due to parts obsolescence, Honeywell will not support 100K disk-based FMCs beyond December 31, 1999. The 1 Megaword PIP FMC versions on the 757 and 767 issue the erroneous NAV DATA OUT OF DATE message; an upgrade is planned to fix this anomaly. Early clocks installed on the 757 and 767 do not have date output capability. If the date is not available, the NAV DATA OUT OF DATE is not displayed. Operators of 757s and 767s may also choose to upgrade to the recently certified Future Air Navigation System (FANS) FMC (Pegasus), which is Y2K-ready and available. Service bulletins for the 757 and 767 FANS retrofit will be issued upon operator request.

Douglas-designed models have Honeywell FMSs similar to those in Boeing-designed models. All MD-80s and MD-90s (except MD-90s with the Pegasus FMS) use a two-digit display of database year on the IDENT page, which will overflow to /100, with an additional zero wrapped to the next line of the display. The MD-11 has no Y2K effects. The Pegasus FMS under development for MD-11 has no Y2K effects and will be the basis for the FMS under development for the 717 and MD-10 (DC-10 upgrade).

For the Smiths FMC, in software Update 7 (U7) and beyond, the NAV DATA OUT OF DATE message will be erroneously generated during the NDB cycle that begins in December 1999 and ends in January 2000. This transient flight deck effect has been rectified in Update U7.5/8.5 for 4 MCU systems in the 737-300/-400/-500 and in Update U10 for 4 MCU systems in the 737-600/-700/-800.

Table 3 summarizes all Y2K effects for various FMCs. Table 4 lists applicable service bulletins and service letters to upgrade Y2K-affected FMCs. These service bulletins and service letters address new FMC versions with operational enhancements and software fixes in addition to Y2K fixes.

NDB effectivity checks are also performed on certain INSs installed on some out-of-production models (727, 737-200, 747-100/-200/-300/ -SP, and DC-10). The Y2K effects for these systems are significant, since crews will be unable to complete preflight procedures for the INS, thus precluding dispatch. The affected INSs are certain versions of Litton LTN-72RL and LTN-92, and Litton has issued a service information letter, GENERAL SIL-07 dated January 27, 1998, to address these anomalies. Some of these systems have been retrofitted to post-production airplanes through a supplemental type certificate (STC). Operators should contact the holder of the STC for additional information.

Some DC-10 airplanes were fitted with the AINS-70 area navigation system, and the ground support software for this system is susceptible to Y2K problems. Rockwell-Collins has already informed AINS-70 operators that it will not support the system after 1999.

An important Boeing-supplied support system is GBST, hosted on Sun Microsystems SPARC2 and SPARC5 workstations. GBST is used to generate 777 airplane information management system (AIMS) airline modifiable information (AMI) files for tailoring AIMS functionality and for ensuring FMS functionality in the FANS upgrade (Pegasus FMC) on the 757 and 767. The UNIX operating system for these workstations is affected by the Y2K change. The specific Y2K-supported versions are SunOS 4.1.3_u1 Version B and SunOS 4.1.4, both currently available from Sun Microsystems. AMIs are also used on the Boeing 717, MD-10, MD-90 (Pegasus), and MD-11 (Pegasus). The AMIs are generated by Honeywell, using the GBST hosted on Sun Microsystems workstations.

The central maintenance computing (CMC) system on the 747-400 and the CMC function on the 777 are components of the ARINC 624-defined OMS. Maintenance messages are time- and date-stamped. These systems are not affected, however, because the maintenance messages are stored in chronological sequence and because no calculations are performed on the stored time and date stamps. This also applies to the centralized fault display system and onboard maintenance terminal on the 717 and MD-11.

BUYER-FURNISHED EQUIPMENT (BFE). BFE includes systems purchased directly by operators from suppliers and certified by Boeing installation on operators' airplanes. Boeing will communicate to operators any information it obtains on BFE systems.

POST-DELIVERY MODIFICATIONS TO BOEING AIRPLANES. Numerous after-market modifications to Boeing airplanes are available and may be purchased from various modification agencies and airlines. These modifications, usually alterations made through the STC process, are not normally reviewed or approved by Boeing. Modifications designed by parties other than Boeing that are performed on Boeing airplanes after delivery may affect the applicability of Boeing engineering, maintenance data, and spare parts. Operators should contact the holder of each STC for additional information regarding Y2K. Boeing will communicate to operators any Y2K information it obtains on systems installed by STC.

As part of its preparations for the date rollover to Y2K, Boeing conducted an assessment of the airborne systems on its commercial airplane fleet. Though all computing systems in use throughout the world are susceptible to problems because of incompatibility between existing and future date functions, the Boeing assessment showed that only a few of the airborne systems on its airplanes use the date function. As a result, most are immune to potential problems with the date rollover. In addition, no safety-of-flight issues related to Y2K for airborne systems exist for an airplane in flight.

Certain airborne systems on some Boeing models (727, 737, 757, 767, 747, and DC-10) will have erroneous flight deck effects following rollover to Y2K. Although most of these systems will continue to function as designed, Boeing recommends that operators upgrade such affected systems. For the MD-80 and MD-90, no upgrade is considered necessary, but if a change is implemented for other reasons, it will include a Y2K upgrade and will be made available to those operators who request it.

For More Information
Operators with questions about the effects of the Y2K date rollover on airborne systems in Boeing airplanes should contact their Boeing Customers organization representative.

Forward-Looking Information Is Subject to Risk and Uncertainty
Certain statements on this site and related sites contain "forward-looking" information that involves risk and uncertainty, including discussions of plans for addressing the Year 2000 challenge, timetables for accomplishing such plans, and the costs of implementing such plans. Actual future results and trends may differ materially depending on a variety of factors, including the Company's successful execution of internal performance plans including technical solutions to the Year 2000 problem, and performance issues with suppliers, subcontractors and customers. Additional information regarding these factors is contained in Form 10-Q for third-quarter 1999 and the Company's Annual Report on Form 10-K for the year ended 1998.

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