How is the stabilizer trim controlled and powered?
Controlled: stab trim switches on the control wheel and alternate stab trim switches on the control stand, with normal and alternate electrical channels to two trim control modules, to hyd system 2 and 3 powered trim actuators.
Which provides increased range of stabilizer travel, normal or alternate stab trim switch?
Alternate.
What does >STAB GREENBAND EICAS advisory message mean?
Nose gear pressure switch disagrees with FMC calculated stab green band. ( the green band is selected by the Modularized Avionics and Warning Electronics Assembley)
When automatic cutout occures with the stab trim cutout switch in AUTO?
Cuts out the related hyd system in case of unscheduled stab trim is detected.
What happens if one trim actuator fails?
The flight crew commanded trim reduces to half the normal scheduled rate.
What happens when using the alternate stab trim switches with any APs engaged?
It will override AP trim and will not cause disengagement.
What features stab trim has to improve handling characteristics? 8/400
And what inhibits it?
400: speed stability trim at lower airspeed (Speed Trim System (STS)
Purpose: Provides positive speed stability, especially at low gross weight, aft center of gravity, and high thrust (e.g., takeoff, climb, go-around).
Operation: When the autopilot is disengaged, the flight control computers detect speed deviations from a set target. If the plane accelerates, it trims nose-up; if it slows down, it trims nose-down.
Functionality: It operates behind the scenes, typically by moving the stabilizer at half the speed of the electric trim, helping to maintain V2 + 20. ), mach stability trim at higher. (Counteracts Mach Tuck, an aerodynamic phenomenon where the center of pressure moves aft at high speeds, causing a strong nose-down pitching moment.)
8: stability trim at lower and higher speeds.
Inhibits: activating the stab trim switch or engaging AP
Which elevator is controlled by the control column?
Mechanical transfer of input to hyd actuator (left: hyd sys 1 ( when ram air turbine deploys, and sys3 pressure is greater than 1, then it’s 3) and 2, right 3 and 4) on the INBOARD elevator control surface, and its position controls input for the related outboard elev actuator (left powered by hyd sys 1, right 4)
Where are shearouts (elnyíródó betét) in the flight control system?
- Between inboard and outboard elevators
- Each side of the mechanism, which connects the control wheels (for aileron movement)
- between upper and lower rudder (if jam occures downstream of the ratio changer) 8. a secondary linkage allows full control of both rudder surfaces in case the primary disconnects.
OM-B V1 NN Proc Sys Spec: override function: 400 control wheel, 8 control wheel and rudder pedals
Which hyd sys powers the elevator feel and centering mechanism?
Hyd sys 2 and 3. The force increases with speed. If both system fails, mechanical springs provide feel force, which is no longer a function of airspeed.
8: What does the elevator feel shift function do?
It provides increased feel force as the airplane approaches stall if the flaps are not up.
8: What does the Pitch Augmentation Control System do?
(It does not move the control column)
Nose-down elevator
1. High aoa sensed by the redundant vane
2. Counteract spoiler induced pitch up in case of maneuver load alleviation (csökkentés)
3. Tail strike protection
Nose up
1. When flaps are 5, 10 or 20
2. Prior to and during landing flare
400 What does the aileron lockout system do?
It locks the outboard aileron in the neutral position above 238 kts.
Which spoilers function as flight spoilers (assists ailerons)?
400: All, except inboard. (total of 2 inboard, 4 outboard on each wing)
8: all
How do the ailerons operate if one control wheel jams?
The other wheel can move independently, because there is an override mechanism between the two. In this case
400: only app. half of the spoilers assist the ailerons on the free wheel side
8: roll control via the both outboard ailerons and spoilers plus the inboard aileron of the free wheel.
How does aileron trim operate?
A feel and trim mechanism reposition the neutral point. It will not disengage AP.
8 How are the ailerons controlled and powered?
Inboard: mechanically controlled, outboard electonically, both hidraulically powered. (12,13,24,43)
8 When are the outboard ailerons commanded to the neutral position?
Above app. 258 kts/.53M
8 How can the ailerons be deflected? (When not in turn.)
Inboard: down F10 and more, in this case upward deflection is limited
Otboard: down for improve takeoff performance and reduce noise when F10 or 20. It is removed, when aoa is beyond stick shaker
How do the rudders operate? Chain of operation.
Rudder input - mechanical transfer- 1 feel and trim (8 centering also) mechanism - 2 ratio changers - upper and lower hydraulic actuator
What happens if a rudder ratio changer fails?
The ratio will not change with airspeed. Result: excessive rudder deflection (high speed), not enough rudder (low speed). Reduced xw capability for manual and autoland.
What do yaw dumpers do?
Use rudder surfaces to improve lateral and directional stability (prevent dutch roll) and provide turn coordination. Powered by hyd sys 2 and 3. IRS is needed for the operation.
8 Why is the lower rudder double hinged with a mechanically slaves rubber tab (which has different thermal characteristic)?
To increase rudder authority, with increased rudder trim adjustments.
- What happens if you push the Rudder Trim Center switch a second time?
Cancel rudder trim centering.
