B735 Stby Rud On light...help

[sudden Winds]

Hi folks, does anyone know why the "uncommanded rudder/yaw or roll" non normal checklist mentions the standby rudder on light and asks to check whether the light is installed and operative but does not mention to check whether it illuminated or extinguished?

What does that light exactly indicate? we don't have it in most our 735s.

Thank you.

[Boeingmann]

The STBY RUD ON light is fitted in the STANDBY HYD column just below the LOW PRESSURE light in the STANDBY HYD column of the FLT CONTROL panel.

When the STBY RUD ON light is illuminated the standby rudder PCU is pressurised. It will come on automatically when system A or B is lost or when the FLT CONTROL switch is manually turned on.

[sudden Winds]

ok, but why does the checklist direct the flt crew to proceed different based on the light being installed or not, no matter whether it's illuminated or extinguished?

Thanks for your help so far.

[Flight Detent]

The Uncommanded Rudder/Yaw or Roll checklist is used for those airplanes that do not have the automatic force fight detection system installed, and with that the STBY RUD ON light.
In that case, the checklist directs the pilots to manipulate the hydraulic system with the flight control switches, turn the yaw damper off, etc.
The airplanes with the STBY RUD ON light operational, have the automatic function of the standby hydraulic system available, so the checklist they would use will be the one called Jammed or Restricted Flight Controls, which involves only the overpowering of the control effected.
Each of these checklists refer to the other with respect to which one to use.

Symplistic, but hey, that's all I have!!

Cheers, FD

[alexban]

If the STBY RUD ON light is installed and operational ,then the RSEP system is installed and operational in your aircraft.You will also notice that the 'uncommanded rudder' NNP has also disapeared from your QRH.

[sudden Winds]

Thanks a lot for your reply...this makes me very happy...
THANKS !!!!!!!!!!!!!!!!!!

[BOAC]

.and, as usual, Chris Brady (http://www.b737.org.uk/theruddersystem.htm) comes up trumps!

[CaptainSandL]

Thanks BOAC. That page (http://www.b737.org.uk/theruddersystem.htm) now updated with more info & new schematic, should answer most questions.
S&L