Boeing Bulletins

FMC-15 : FMC VFR Approach Anomaly

27 May 2004

Effectivity

Please refer to source document.

Reason

This bulletin provides information informing flight crews of temporary recommended procedures for FMC generated VFR approaches.

Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM), the AFM shall supersede. The Boeing Company regards the information or procedures described herein as having a direct or indirect bearing on the safe operation of this model airplane.

Background Information

On a recent customer revenue flight, an anomaly was discovered when a VFR approach was selected. Further evaluation concluded that the anomaly affects airplanes with software version PS4052970-952. The anomaly does not pertain to other FMC software versions.

When operating an FMC with software version PS4052970-952 and an FMC generated VFR approach is selected on the Arrivals page by line selecting the "VFR APPR" prompt, the resulting course from the VFR final approach fix to the runway threshold may be computed in error. The erroneous course is displayed on the legs page and the HSI. The T/D may also be displaced. If engaged, LNAV will fly the displayed erroneous course.

Operating Instructions

Do not perform FMC generated VFR approaches using the VFR APPR line select key when using this software number. A valid VFR approach with accurate course information can be created by manually inserting the desired runway extension on the RWY EXT line.

When operating FMCs with other software numbers, VFR approaches may still be selected, if available.

Administrative Information (Extract)

This Operations Manual Bulletin will be canceled after Boeing is notified that all affected airplanes in the operators fleet have been modified.