Flight Controls Flashcards
- Name the flight control Laws
Normal law, alternate law, direct law, unusual attitude law mechanical backup
- What is the purpose of mechanical backup
To be able to control the aircraft in the event of the temporary loss of the flight control computers
- What is the purpose of unusual attitude law?
To recover from an abnormal attitude.
Conditions:
Bank angle > +/- 125 degrees
Pitch +50 to -30 degrees
Speed 440kts /0.91 70-90kts>
Display “use man pitch trim” in direct law
Pitch Altn law
Roll DCT law
Yaw Mechanical
Aircraft then remains in alternate law
- In normal law, explain bank angle protections
0-33 degrees the aircraft will be autotrimmed and remain at set angle within 33 degrees. 33-67 degrees the max bank angle, if sidestick released, aircraft will roll back towards 33 degrees to give spiral stability.
- What is the maximum bank angle when α protection is in force
45 degrees- no FDs beyond 45 degs, return at 40 degs
- What’s the maximum bank angle when high speed protection is in force
40 degrees- due to load factor, if sidestick returned to neutral, the bank angle will return to zero
- When in α prot what happens when you release the sidestick
The speed will settle above the alpha protection band.
- What is the max pitch available in clean config and config full
-15 (no FDs beyond -13 but return -10) to +30 degs (clean to conf 3)
-15 (no FDs beyond -13 but return -10) to +25 degs, no FDs beyond+20 (conf full)
Max pitch will reduce by 5 degs during alpha protection (+25 and +20 respectively)
- What is the max g load in clean and other configs
Clean- +2.5 -1.0
Other - +2.0 -0.0
- Can you explain α prot, α Floor and αMax
αprot- alpha protection, extra layer of protection before alpha max. Side stick goes from g load to alpha. Continue pulling back to αmax can maintain safe envelope during evasive manouvres
αfloor- autothrust protection that commands TOGA to assist with performance and aid recovery
αmax- maintains a protection above the aerodynamic stall of the aircraft
- Once out of the αfloor condition, what thrust mode would you expect to see and how would you recover
TOGA LOCK- locked in TOGA, released by disconnecting A/T returning to clb gate and re-engaging the autothrust.
- What is Vls and it’s relation to the stall speed
VLS- lowest selectable speed
Represented by the top of an amber strip along the airspeed scale.
Computed by FAC corresponds to 1.13vs at takeoff or following touch and go
- becomes 1.23vs after retraction of one step of flaps
-becomes 1.28vs when in clean config
If in CONF 0 VLS were 1.23vs instead of 1.28vs the alpha protection strip would hit the VLS strip on the PFD
- Can high speed protection be overridden
Yes- by pitching forward in case of a TCAS RA
The structural speed will not be exceeded by reducing side stick input to 0
- Draw the speed tape in alternate law and in normal law
- When might you see “use man pitch trim” and when might you see “Man Pitch trim only”
Direct law - use man pitch trim
Mechanical backup - man pitch trim only
- What is α Lock and when might you see it?
Inhibits slats retraction at high angles of attack and low speeds ie if you try to move flap lever too early.
- In alternate law explain high and low speed stability
Vmo/mmo- still have the overspeed warning and ECAM. Aircraft will try to pitch up but can be overridden. When pitching down you can overspeed and overstress the aircraft.
VLS
VSW- 5-10kts above the stall speed, aircraft will try to pitch down but you can stall the aircraft if overridden.
- What protections do we have in direct law?
There are no protections. PFD “use man pitch trim”
- What control surfaces have a mechanical link to the flight deck
Rudder
Stabiliser trim
- What is the purpose of aileron droop and how do you know if your aircraft is fitted with it?
Droop- a function of when the flaps are extended. Droop- 5-10 degs to give the wing form extra lift.
- In pitch, how long does it take to transition from ground to flight mode
In pitch there is a blend of 5 seconds. In roll its instantaneous
- What is ground mode?
When flight controls have a direct side stick/rudder pedals to control surface relationship allowing full deflection.
No autotrim.
During take off >70kts max elevator deflection reduces from full 30 down to 20 degrees.
- What is flare mode?
Induces to allow the pilot to flare in a conventional way by pitching down by -2 degrees over 8 seconds at 30ft forcing the pilot to counter this through flare.
At 50ft the aircraft memorises the pitch attitude and freezes the trim.
- What computer controls the characteristic speeds displayed on the PFD?
The FACs (flight augmentation computers)