737 RSEP Program

[SR71]

Not wishing to hijack the Vmcg/Vmva (http://www.pprune.org/forums/showthread.php?t=260467) thread, I've started another one....
In post 36 (http://www.pprune.org/forums/showpost.php?p=3093714&postcount=36) CaptSandL mentions
Non-RSEP a/c you are correct; full rudder pressure will return with a 45% N1 difference at any altitude.
Quote from Vol 2:
“A rudder pressure reducer is connected to the A system hydraulic line upstream of the main rudder PCU. Hydraulic pressure to the rudder is reduced when the airplane climbs above 1000 feet AGL. Hydraulic pressure returns to normal when the airplane descends through 700 feet AGL, or if B hydraulic system depressurizes, or whenever the N1 difference between the left and right engines exceeds 45%.”
However for RSEP a/c the only factor is airspeed:
“At speeds above approximately 135 kts, both hydraulic system A and B pressure are each reduced within the main PCU by approximately 25% each. This function limits full rudder authority in flight after takeoff and before landing.”

Now my manuals and this figure (http://www.b737.org.uk/rsep.gif) suggest that RPR's and RPL's are still fitted in RSEP modified aircraft?
My manual diagram agrees with the figure above.
However, this figure (http://www.b737.org.uk/yaw_cont_schm_new.gif) fails to include them.
I'm very confused!
:{
Can anyone clarify?

[CaptainSandL]

They are the “Control Valves” in your second figure, otherwise known as “Load Limiters”. I believe that they are not called RPR/RPL in post-RSEP aircraft because the activation criteria are different (135kts not RA/N1/Hyd pressure).

Your first figure is an amalgam of systems; it is meant to be read in the context of the text with it.

Anyway, enough from me. I look forward to other responses if I have mis-understood the rudder system in all its many forms!

S&L

[alexban]

the schematic I have after RSEP modification it's a bit different from the second figure you have. There are no control valves in mine,both of the classic and the NG.
The RSEP it's new system,with an added stby rudder PCU (and Stby yaw damper on the NG ) .
On before RSEP system's there was no stby rudder pcu,the stby system had acces to the same pcu as main hyd systems.
After RSEP modification , when the FFM trips , the stby hyd sys will become active automatically, and it will power the rudder through the Standby rudder PCU.
With automatic operation you will have stby power for the rudder and thrust reversers , and lights STBY RUD ON,Master caution and Flight controls will be illuminated.

[JammedStab]

So when the 737-200 was manufactured, was there no reduction in a system hydraulic pressure based on altitude but always 3,000 lbs pressure to the PCU?