Autoflight (22) Flashcards
What does SCAS Mean and what do they do?
- Stability and Control Augmentation System
- Provide AFCS input into the servo actuator
Where are the trim actuators mounted?
Under the floor of the cockpit (copilot position)
What controls both MR and TR SCAS?
The FCC
What components make up the AFCS?
- FCC
- 3x MRA SCASS
- 1xTRA SCASS
- 4x Trim actuators
- APCP (Autopilot Control Panel)
What authority can the MRA (Main Rotor) SCAS provide?
+/- 10%
What authority does the TRA SCAS provide?
+/- 20%
Are the SCAS actuators self centring?
YES
The AFCS consists of the following controls:
- Collective and Cyclic Grips
- Pilot and copilot pedals
- APCP
- EDCU
- DCP
Can FD SEL be given to the other side?
NO
What happens when you disengage the APs
- Chime
- ATT Appears on AFCS Bar
- [1(2) AP OFF]
What happens when you press WLVL button on the cyclic?
6deg Pitch Up
Zero Roll
What does the fifth switch do on the cyclic beeper trim?
Engages HOVer hold
What does the collective beep trim fifth position (push down) do?
Disengages the collective AFCS Upper Modes
What component directs the trim actuators to move?
The FCC
How are the trim positions fed back to the FCC?
A resolver
What drives the Trim physically?
28 Vdc brushless motor
When is the Trim Actuator deactivated?
- Hands on/feet on mode
- WOW made
- When de clutched through EDCU
How many channels are in the FCC?
2
Channel 1 - AP1
Channel 2 - AP2
What are the basic modes of the AFCS?
(3)
ATT
SAS
WLVL
What are the basic Functions of the AFCS?
(6)
- Control Augmentation
- Auto Trim
- Turn coordination
- Collective Decoupling
- Collective Safety Function
- Automatic Variable Speed Rotor
What are the BASIC upper modes of the AFCS?
(8)
HDG
ISA
ALT
ALTA
RHT
VS
HOV
GSPD
What are the Nav and Approach Modes of the AFCS?
(11)
(3NAV/ 8 APP)
NAV
VNAV
VOR
LOC
VAPP
NLOC
NAPP
DCL
NDCL
GA
NGA
How do you start a BIT on the AFCS AutoPilot Control Panel (ACP)
Pressing the two rotary knobs simultaneously
(only the panel is checked, not the AP)
What does the white mode status indicate on the Autopilot Control Panel
Armed
You press a rotary knob on the AP Control Panel - how does it indicate a successful engagement?
Green ring around the knob
How does an AFCS annunciation indicate a mode failure?
Amber dashes
How does an AFCS annunciation indicate a degraded mode?
Flashing amber box
What do amber chevrons either side of an AFCS Annunciation mean?
Excessive deviation
How do you view the status of the Force Trim?
Via EDCU
What happens to all other engaged modes when WLVL is pressed?
They are disengaged
How do you disengage the WLVL function?
Press ATT then selecting another mode
During WLVL activation, what happens when both new pitch and roll datum’s are achieved?
ALT mode is engaged
What is the purpose of Collective Decoupling (C-DCPL)?
To remove the automatic cross-coupling of controls
What speed can IAS be engaged?
> 45kts
When can ALTA be engaged?
> 40kts
200ft
What ROC does the G/A default to?
+1000fpm
What ROD does the ALTA default to?
-750fpm
When will ALTA not engage ALT upon level off?
When <200ft
Will go to RHT
Which Upper modes drop out below 35Kts?
(9)
IAS
HDG
NAV
VS
APP
GA
ALTA
DCL
NDCL
When does “ALTITUDE ALTITUDE” annunciate with RHT engaged?
Discrepancy exists between current height and datum reference of 1/8 height +7ft
At what heights can you engage RHT mode?
30 - 2500ft
What are the engagement limits for HOV mode?
- Airspeed up to 75kts
- RHT 20 - 2500ft
- Longitudinal ground speed les that 60kts
What are the GA engagement criteria?
> 40kts
What is the automatic Mode engagement sequence of GA?
- GA displayed on Coll & Picth
- HDG mode engaged
- Climb set to achieve 1000fpm ROC
- Aircraft pitched to 75kts
- At 75kts (Vy), 1000fpm and >200ft VS & IAS capture
What are the engagement criteria for the NAV mode?
> 40kts
How can you change the NAV primary source?
NAV Bezel key on the PFD
When is ALVL engaged and what height does it take you down to?
<200ft
down to 70ft then RHT and IAS engage
What does NLOC stand for and why is it different to LOC?
Autonomous Localizer
Used FMS, not a ground station
What does the DCL mode do and what mode can it be used on?
ILS only
200ft @ 75kts
What are the default NDCL parameters?
Initial (3nm) @ 120kts
Final (0.5nm) @ 90kts
When will NDCL disengage?
- Pressing DCL
- Pressing GA/TU
- Loss of FMS capture condition
- Loss of FMS Valid
- <40kts
- NAPP mode not armed or engaged on collective axis
What happens to NDCL when the MAP is reached?
Disengaged
How is the AFCS Preflight test initiated and how long does it take?
On the AFCS Control Panel
2 minutes
What does [TEST ABORTED HYDRAULIC PRESSURE LOW] mean?
Insufficient hydraulic pressure from electric hyd pump to perform AFCS test
What happens if the CBIT fails in the AFCS?
[1(2) AP FAIL]
What generates [1(2) AP HOT]?
> 90°C >10s
What does the PWR LIM AFCS non-CAS message mean?
Collective Safety Function engaged
(generates an aural tone - single chime)
What is the Max ROD on an Approach?
900fpm
