FCC-908

[Ephemeral 11]

In the LSAS section of the PMDG MD-11 SYSTEMS manual it says:Above 20,000 feet, LSAS provides pitch rate damping (PRD) when force is applied to the control column. This damping is gradually reduced to zero, between 20,000 feet and 15,000 feet.But as of the FCC-908 software update that the PMDG MD-11 is modeled upon, the pitch rate damping logic has been changed:The MD-11 FCC-908 software upgrade will activate the PRD control loop below 15,000-feet pressure altitudes at a reduced gain. Whereas the -907 PRD feature was inactive at low altitudes, the -908 PRD will remain active at 30 percent strength from approximately 17,500 feet down to takeoff/landing field elevation.Which PRD logic is currently modeled on the PMDG MD-11?

[downscc 1,327]

I know this is not a direct anwer Sam, but I noticed you can select either -920 or -912 software in the equip and performance options.

[Ephemeral 11]

I know this is not a direct anwer Sam, but I noticed you can select either -920 or -912 software in the equip and performance options.

That is the FMC software load. I am talking about the Flight Control Computer (FCC) 908 software changes that augments the LSAS system to provide Pitch Attitude Protection, Positive Nose Lowering, and modified Pitch Rate Damping logic.Might a developer be able to drop in here and answer?

[Aristoteles 471]

Lord, that is a what I call hardcore simmer question, good luck with the answer...It may prove useful to know it anyway.

[SierraDelta 1,337]

I would have thought that the answer is in the manual part you quoted????

....But as of the FCC-908 software update that the PMDG MD-11 is modeled upon, the pitch rate damping logic has been changed:The MD-11 FCC-908 software upgrade will activate the PRD control loop below 15,000-feet pressure altitudes at a reduced gain. Whereas the -907 PRD feature was inactive at low altitudes, the -908 PRD will remain active at 30 percent strength from approximately 17,500 feet down to takeoff/landing field elevation.

Then again, I've been wrong before :(

[Ephemeral 11]

I would have thought that the answer is in the manual part you quoted????Then again, I've been wrong before :(

Haha. Well I expect that Pitch Rate Damping per the 908 software upgrade is currently modeled on the PMDG MD-11. I remember a thread long ago where PMDG said that they were modeling FCC-908 as all MD-11 aircraft and simulators they can use to test and validate are updated with -908. The curious part is why the PMDG edited SYSTEMS manual outlines the PRD logic from the previous FCC-907 update. Likely it is a simple mistake caused by old source material, but I thought I'd bring it to PMDG's attention. Also IF the PMDG MD-11 is modeled per the PRD logic from FCC-907 for a particular reason, it would be interesting to know.