Aircraft Performance

Dear “ship 741”

This is exactly I wanted to know. I gained a lot. Thank you so much.

Rgds/GSK

Based upon the very slim information you have provided, I would guess that you are confusing several issues.

I believe the terms “legacy” and “pegasus” WRT to navigational databases refer to the Flight Management Computer (FMC), 2 of which, with other components, normally comprise the Flight Management System (FMS) on modern airliners. The Flight Management System is a computerized system which contains, among other things, navigational databases and aircraft performance data. Prior to flight, the crew loads the route into the system and after takeoff they connect the FMS to the automatic pilot. On Boeing aircraft, the autopilot is engaged in LNAV (lateral navigation) and VNAV (vertical navigation). Airbus calls the vertical navigation function “profile.” The system also has a time component, as in being programmed to be over a fix at a specific time. The system can be re-programmed or amended in flight.

This is a very, very rudimentary description. More basics: The “legacy” systems were the original systems installed in the early 80’s that basically have a processor with similar capacity to an IBM 8086 with very limited memory. The “pegasus” system is a progressive upgrade of the FMS, with much improved processor speed, memory, and integration of GPS. Older aircraft are being upgraded in steps in order to comply with future ATC requirements of very precise navigation, commonly referred to as “nextgen” (for next generation) in the U.S.

The nav database is simply the list of pre-stored fixes in the box that are available for use. More memory (ie., Pegasus) = More fixes = more system capability.

Furthermore, focusing on Airbus or Boeing, is, I believe, a non sequiter. The subcontractor to both that is the leader in the field is Honeywell. Also, the topic of engines, per se, is related only tangentially to the topic of FMC’s/FMS’s. The system just needs to know what engines are installed and what performance they provide.

As stated, this is very rudimentary. My suggestion to use a search engine and look for “pegasus fmc” “honeywell fmc.” Also, go to the Honeywell website and search “pegasus fms.” Other useful searches: “RNAV” “RNP” “RNAV RNP.”

I hope this has been helpful. I almost answered your tankering post, but didn’t because it seems you want everyone here to do your research for you. Most people, including me, like to help, but you need to do your part. My suggestion is to take a little more upon yourself and google aggressively.

I maybe able to help you with the Legacy, but only if I know what you want to know.

Never heard of it. Can you expand a little?