Systems - Flight Controls Flashcards
How many Primary Flight Computers are there?
3
With the switch in the AUTO position, what flight control mode should be active?
Normal or the next per system logic
How can the flight control mode be confirmed?
FLT synoptic page and EICAS MSG
What are the three flight control modes?
- Normal
- Secondary
- Direct
What envelope protections exist in the normal mode?
- Overspeed
- Stall
- Bank
Is envelope protection available in the Secondary or Direct modes?
No
Is TAC available in Secondary or Direct modes?
No
Define Envelope Protection.
-A/T spool up for stall and elevator trim feel
-Overspeed elevator trim feel
-Bank yoke feel and force to return inside 30 degrees
The 777 provides visual, aural and tactile cues during envelope exceedances. What happens during an overbank?
- “Bank angle, Bank angle” aural warning
- yoke feel in opposing direction
- amber pointer
What are the principal differences between the Normal and Secondary or Direct modes?
GENERAL
* Normal all functions operate normally
* Secondary no envelope protections, no TAC, no A/P, no gust suppression, no auto speedbrakes, no tailstrike protection, yaw dampening degraded or lost, no wheel rudder crosstie.
* Direct all functions lost flight controls respond directly
PITCH
* Normal pitch elevator feel is variable based on trim speed
* Secondary and direct pitch compensation is lost and trim directly moves the elevator, flaps out=less feel force, flaps up=greater feel force
ROLL
* Normal spoiler 5 and 10 are locked out at high speed, 4 and 11 are mechanical
* Secondary and Direct spoilers 5 and 10 are ALWAYS locked out
YAW
* Normal Rudder ratio auto controls rudder movements based on speed
* Secondary and Direct rudder ratio is based on flap position Flaps up= less response, Flaps down= greater response
What would an illuminated DISC light indicate?
PFC has been disconnected manually or automatically and the system is in direct mode
How is stall protection achieved?
Elevator feel force is greater in the nose up direction, autothrottles spool up to maintain min maneuvering speed based on trim reference
How is overspeed protection achieved?
Elevator feel force is greater in the Nose down direction.
When does the wheel to rudder cross-tie operate?
In flight between 70 and 210 knots
What flight control mechanical backup capability exists?
Spoiler panes 4 and 11 cable linked to yoke, along with ALTN trim levers cable linked to stab trim control module
Which unit receives the pilot control orders directly?
ACES
How many modes of flap operation are there?
- Primary
- Secondary
- Alternate
In the primary mode, when will flap trailing edge load relief work with excessive speed?
Flap positions 15-30
What are the differences between the three flap modes?
Primary
* Hydraulically driven with normal sequencing via Flap lever to FSEU’s
* Flap load relief positions 15-30, Autoslat armed 1-20, assym and uncommanded motion protections
Secondary
* Electrivally driven with altered sequencing also via Flap lever to FSEU’s
* Expanded indication on EICAS, normally slats extend to full range at all flap selections unless speed is >256kts, then slats extend to mid range, <256kts flaps extend to full (slat degraded load relief), assym and uncommanded motion protections
Alternate
* must be manually selected and is Electrically driven via ALTN flap selector switch
* Expanded indication on EICAS, slats and flaps extend simultaneously limited to slat mid range and flap 20 degrees. No reliefs are awarded.
Upon establishing AC electrical power at the gate, you move the flap lever to position 20, will the flaps move?
Why?
No.
Flaps would have to move in secondary mode, however secondary mode is inhibited with groundspeed below 40kts, Center Hyd pressure low and external power avail and one engine below 50% N1
What is Trim Reference Speed?
A calculated speed at which the aircraft would eventually stabilize without control inputs.
When is bank angle protection active?
In normal flight control mode bank greater than 35 degrees
In what modes are Gust suppression and TAC available?
Normal only
What surface moves when you select flaps 1?
Slats only
When will slats extend to full position?
Beyond flaps 20
Which flap positions have flap load relief?
In normal mode 15-30
Ailerons and flaperons droop at what flap setting?
- Ailerons droop 5-20 to augment takeoff performance
- Flaperons droop through all settings
Explain in basic terms how the fly by wire system works.
Inputs to ACEs to PFCs back to ACESs to PCUs
Is there a way we can manually select the secondary mode?
No happens automatically
When the PFC switch is in auto and there are no other malfunctions, what flight control mode are we in?
Normal
Can we manually select the direct mode?
Yes disconnect the PFCs
How does the airplane fly in secondary or direct mode?
Like a 767 sort of
Can you engage the autopilot in either the secondary or direct mode?
No
There are two sets of computers in the flight control system. What are they?
ACEs and PFCs
If a failure should occur, would you rather it be ACEs or PFCs?
PFCs
If all four ACEs are lost, what control do you have?
ALTN pitch trim and spoiler panels 4 and 11
Will use of the ALT TRIM switch disconnect the A/P?
No
How can you tell that you are in the flap secondary mode?
EICAS expanded flap displays and FLAPS PRIMARY FAIL EICAS MSG
What other means do you have to confirm the malfunction?
Synoptic page
What does an EICAS message FLAPS DRIVE indicate?
When the FLAP DRIVE mechanism has failed
What will happen if you add power and begin your takeoff roll with STAB not in green band?
Takeoff Config Warning
How many ways can the stabilizer be trimmed in the 777?
Primary via yoke switch, ALTN trim switches
