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Flashcards in Flight controls Deck (12):

What's an ACE? How many do we have?

• Actuator Control Electronics: Unit that connects the control column electronically to the respective control surface, providing direct analog control of the surface.

4 ACEs
1. P-ACE primary
2. SF-ACE slat/flap
3. H-ACE horizontal
4. S-ACE spoiler


What's a FCM? How many do we have?

• Flight Control Module: Software based assistance connected to the P-ACE providing digital inputs and is required for normal-mode operation of flight control system. Provides high-level functions

• 4 FCMs : broken into 2


What high-level functions are provided by the FCM?

1. Control laws scheduling with airspeed
2. Auto-thrust compensation w/elevator
3. AoA limiting
4. Rudder airspeed gain
5. Yaw damper and turn coordination
6. Rudder authority
7. Roll spoiler scheduling w/ speed and speed brake deployment
8. Configuration change compensation with high speed due to speed brake actuation.


What is Direct mode?

• Removes the FCM (high level functions) from the control loop and control limits default to the value set by the hardware in the P-ACE.


What systems provides data to the flight control system?

1. Smart probes and Air Data Application modules (ADA): provide air data for airspeed argumentation commands

2. IRS: provides attitude and accelerations to the FCMs for AoA function computation

3. PSEM: provides WoW and ground spoiler position data

4. BCM Brake Control Module: provides wheel speed signals for ground spoiler deployment

5. FADEC: provides thrust lever angle to FCM for thrust level compensation and AFCS provides autopilot commands

6. EICAS: data shared to display warnings. cautions, advisory, and system status.


How long do the Fly By Wire backup batteries last?

- 15 min
- No dedicated message to indicate failure
- charged by DC ESS 3


What is a PCU? How many?

• Power Control Unit: receives FCM compensated data from the P-ACE and directly actuates the control surface

1. Hyd Sys 1: left outboard
2. Hyd Sys 2: left and right inboard
3. Hyd Sys 3: right outboard


What is the Stabilizer Trim priority logic?

1. Backup
2. CA
3. FO
4. FCM (auto-trim) commands


Any flight control concerns during an electrical emergency?

1. Trim works at half speed (manual or Auto)
2. Horizontal stabilizer moves at a low rate


When will the ground spoiler surfaces deploy?

1. WoW
2. Wheel speed 45kt / Airspeed >60kts
3. TLA below 26º


What is a FLT CTRL BIT EXPIRED message?

PBIT time expired: Test must be Re-run.


What are the 2 PBIT tests? How are they powered? How long do they take? What will interrupt them?

1. Electric:
- AC power established
- takes 3 min
- loss of AC power, Pressurizing any Hyd pump, press any FCM button

2. Hydraulic:
- All hydraulic systems powered
- takes 1 min
- movement of flight controls