Well, messing with manual additions in the FMS can have unintended consequences (as you illustrated)
A. Following the release of OPSB 0166-17 Rev 4 in December 2017, Rockwell Collins has continued to discuss this issue with the FAA. These discussions have resulted in the release of the following publications. The FAA performed a review of these documents and provided feedback on their content before release.
- OPSB 0166-17 (523-0824828) : THE FMS MAY TURN IN THE WRONG DIRECTION AFTER SEQUENCING A “CLIMB TO” ALTITUDE THAT WAS MANUALLY EDITED OR TEMPERATURE COMPENSATED
- Revision 5 has been released to clarify the Limitations for the aircraft, and the error conditions.
- Service Information Letter FMC-XX00-18-1 (523-0825523) : INSTRUCTIONS FOR AIRCRAFT FLIGHT MANUAL LIMITATIONS FOR ALTITUDE EDITS ON SPECIFIC PRO LINE 4 AND PRO LINE 21 FLIGHT MANAGEMENT SYSTEMS.
- This document provides the list of applicable FMS part numbers which are affected by the issue and the FAA approved wording for the AFM Limitation.
- Service Information Letter CSU-XX00-18-1 (523-0825521) : INSTRUCTIONS FOR DISABLING OF AUTOMATIC TEMPERATURE COMPENSATION OPTION IN PRO LINE 4 AND PRO LINE 21 SYSTEMS.
- This document provides a reference for those aircraft type which have previously enabled the Temperature Compensation option (in those which have the affected FMS part number)