Frequently Asked Questions

Flight Management System


Why is the Performance Database missing from my Flight Management System (FMS) after receiving it back from repair?

It is important to note that the Performance Database is critical, and use of an incorrect Performance Database in an aircraft could result in improper speed references being displayed to the crew. The FMS Navigation Computer Unit (NCU) RAM is cleared as part of the repair process. Since repair personnel cannot know with certainty that the unit will be installed in the same aircraft, they cannot install a Performance Database. The aircraft operator should maintain a copy of the applicable Performance Database with the aircraft records or loose equipment.