The upper of the two panels is the FCES Panel. We're into avionics now, which is not my field of depth. ALL of my comments apply to L-1011s other than the -500.
Each Flight Control system has two independent "channels" of monitored operation. A single fault will cause automatic shutdown of that channel. However, there are some faults in a single channel that would shut down both channels.
All of the switchights on the panel are normally latched in. The white OFF light illuminates only when the switchlight is unlatched - switchlight position. With the switchlight latched in, the OFF light is extinguished and the amber FAIL light is "armed". When the system monitor has detected a fault, the appropriate FAIL light will illuminate and the faulty channel is automatically deactivated. When a single channel has failed, the other channel provides normal system operation (a dual channel system).
For Yaw SAS (Stability Augmentation System), when both channels have failed, some features are unavailable - such as autopilot turn coordination, runway alignment and rollout guidance.
For Stall Warning, with a single failure, the other channel can still provide Stick Shaker operation.
For Pitch Trim, with a single failure, trim will be at a slower rate. When both channels have failed, only mechanical trim is available.
For DLC/Auto Spoilers (Direct Lift Control), when both channels have failed, only manual operation of spoilers is available.
For ATS (Auto Throttle System), with a single failure, the other channel can still provide ATS.
For Mach Trim, with a single failure the other channel will provide normal Mach trim.
The TEST switch provides the means to be able to test both Stall Warning channels on the ground.
The lower of the two panels is the PFCS Panel. It is part avionic, part mechanical.
The unlatched/latched operation of the Pitch and Roll switchlights is the same a described for the switchlights for the FCES Panel. Both systems have "jam" switches that will illuminate the appropriate FAIL light(s)
For the guarded RUDDER switchlight, the white OFF light illuminates when the switchlight is unlatched. It is normally latched in. Unlatching the switchlight will shut down the rudder servo entirely and allow the rudder to be in the "faired" position. The rudder uses three hydraulic systems - A, B, C. Rudder (and other flight controls) position can be monitored on the Surface Position Indicator, which is located on the Center instrument panel. The SPI does NOT show position of the elevator or all of the spoilers.
The stabilizer uses all four hydraulic systems. The legends in the switchlights are similar to what we've discussed for the FCES panel - but there are important differences. The switchlights are normally latched in. When they are unlatched, the INOP light illuminates (switchlight position), and the PUSH light is not armed.
To explain this properly, you need a good understanding of the operation of the stabilizer control system. To simplify it, the stabilizer system is operated by movement of the control column, which gives inputs via two feel/trim assemblies to two dual servos, which drive four hydraulic actuators which are attached to the forward end of the stabilizer. This is also linked via an "aft disconnect coupler" which can sense a jam in the control path. The jam will result in the illumination of the A and B, or C and D (stabilizer) PUSH lights A pilot will then unlatch the respective switchlights, the coupler will open, isolating the jam, allowing input from only one pilot (the "unjammed" side), and will illuminate the amber AFT COUPLER OPEN light on the PFCS panel. At the same time the amber PULL PITCH DISConnect light will illuminate, advising the captain to pull up on the Pitch Disconnect handle, which is located near his right knee by the stabilizer trim wheel (on the center console). When the handle has been pulled up and rotated 90° counter-clockwise, the pitch disconnect will have occurred (the pitch disconnect mechanism is located under the Flight Station floor) and the amber PITCH DISC light in the handle will illuminate. After the problem has been cleared, the reconnect can be made by rotating the handle 90° clockwise and allowing the handle to re-stow. The two control columns, which had been separated, must be moved to allow the dog-tooth clutch to re-syncronie.
Thee are NO controls or indications for the elevator. It moves as a function of stabilizer movement. (There is an ELEVATOR light on the FE's annunciator panel, which illuminates if there is a problem in its operation.)
There are four switchlights for the four ailerons. In total, all four hydraulic systems are used, but only two or three per aileron. The switchlights have white OFF legends, which illuminate when the switchlight is unlatched. It is normal for the switchlight to be latched in. The "cross-hatch" legend will illuminate when a jam is detected. It is a "cross hatch" to advise the crew of the problem, but they may or may not choose to unlatch the respective switchlights, depending on the flight situdation at the time. The amber PULL ROLL DISC light illuminates whenever a jam is detected in the system, and advises the crew to do a mechanical disconnect. The co-pilot will pull up on the Roll Disconnect handle, which is located by his left knee by the stabilizer trim wheel (center console). When the handle has been pulled up and rotated 90° clock-wise, the roll disconnect will have occurred and the ROLL DISC light will illuminate. The roll disconnect mechanism also is located under the floor of the flight station. Aileron control is normally through the captain's control path, due to a lost motion devise in the co-pilot's path. However, this lost motion devise is modified when the two halves have been disconnected from each other.
Inboard aileron position is normally shown on the SPI. To see outboard aileron position, press and hold the OUTBD AIL -PUSH- switch. You cannot see the position of all ailerons at the same time.
Here it gets even more confusing. I'll talk a bit about Spoilers.
Note the labeling for the Spoiler switchlights; they vary. The spoiler control system operates through a DLC (Direct Lift Control) servo and two spoiler mixers. However, the #1 spoilers are independent of the mixers. Therefore, the switchlight for the #1 spoiler (both sides) is labeled L&R 1, and does not have a PUSH light - only an OFF light, which indicates switchlight position - and the #1 spoilers are the only spoilers not used for "roll augmentation". Spoilers 2 and 3 (left and right sides) are controlled via the "right mixer". Spoiler #4 (both sides) are controlled from the "left mixer". Spoilers #5 and 6 (both sides) are controlled from either the left mixer or flap input - depending whether flaps are retracted or not.
So if there is problem in the right mixer, the PUSH lights will illuminate in the L&R 2 and L&R 3 switchlights If the problem is in the "left mixer", the PUSH light for theL&R 4 and perhaps L5&6 and R5&6
spoilers will illuminate. There are two outboard spoiler selectors, which select an input from either the mixer or flaps. The L5&6 or R5&6 PUSH light will illuminate if the respective outboard spoiler selector has a problem.
Thee are four modes of operation for the spoilers - 1) Air Speedbrakes, operated by pilot input, using the Speedbrake lever, 2) Roll Augmentation to assist the ailerons, 3) Direct Lift Control, used during approach for landing, and 4) Automatic Ground Spoilers (AGS) , which occurs after landing, or during a rejected takeoff; this system "dumps" lift after the L-1011 lans.
I could spend hours more on this. I'm going way too deep. Flight Controls is one of the most complex systems on the L-1011. You need to know a lot about the system to be able to understand it. I probably have only scratched the surface of the explanation. It is difficult to explain the panel indications without know a bit about system operation - especially with the PFCS panel.
Don
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