DAFCS Flashcards
Define DAFCS
Digital advanced flight control system
How do you momentarily disengage altitude hold when changing altitude?
Thrust brake switch
When flying in known or forecast moderate or above turbulence, what are the three concerns/restrictions the pilot should be aware of?
LCT’s must be in manual, operating thrust break, do not use barometric altitude hold
Will the cyclic move when the DAFCS trim switch is moved laterally?
No
Which actuator makes the control input for positive stick gradient, pitch attitude, and airspeed hold purposes?
DASH- differential airspeed hold
Will the LCTs function with the DAFCS switch in the off position?
Yes
What is the name of the DAFCS component which the #1 FCC controls to provide the altitude hold feature?
Thrust CCDA (Collective Cockpit Control Driver Actuator)
Which DAFCS computer controls the radar and inertial altitude hold feature?
FCC #1
At what ground speed does TRC capture?
<9 KGS
What two features of DAFCS disengages when the centering device release which is pressed?
Bank angle hold, heading hold
What are the three control laws (regimes)?
Flight regime, low speed regime, ground regime
What is the maximum aircraft bank angle with altitude hold engaged?
45° Roll
30° pitch
What must be monitored to prevent transmission damage when changing Airspeed or heading with altitude hold engaged?
TQ, thrust control inputs
Which fight control computer (FCC) controls the pitch CCDA?
2 FCC
If you have a hard over with both DAFCS on how will you know when you have the good system selected on and the malfunctioning system off?
Erroneous inputs to flight controls will continue until The healthy system is selected
How will the aircraft react if the AFCS is turned off at one air speed and back on at a different airspeed?
Pitch transients
Possible DASH 1/2 failure as it reprograms/adjusts
What visual indication will you see when the DASH actuators are re-centering when DFCS is first turned on?
DASH1 and/or DASH2 FAIL caution
Define CPT
Control position transducer
Define LVDT
Linear variable differential transducer
What portion of the ILCA’s are controlled by the DAFCS flight control computers?
Extensible links portion
How accurate is the DAFCS heading hold feature?
+/-3 degrees
When the landing gear WOW/proximity switches are activated, the DAFCS input into the pitch ILCA is reduced by what percent? How does this help the pilot control the acft
-50%
-During two-wheel taxi, this helps prevent the porpoising of the aircraft
What 3 DAFCS features are provided by the DASH actuator?
Airspeed hold above 40 kts, pitch attitude hold below 40 knots, positive cyclic stick gradient
Which flight control computer (FCC) controls the thrust CCDA?
1FCC
At what groundspeed does the position hold feature become active or captured?
Below 1KGS
Is go around a DAFCS feature or a feature of the flight director?
Flight Director
When can radar altitude hold be used in forward flight?
Over water or known flat ground
Does the cyclic have to be centered for the cyclic to be in detent?
No
At what airspeeds (accelerating and decelerating) is the low speed regime active?
Aircraft has not Accelerated past 45 KCAS
-or-
Aircraft decelerates below 35 KCAS
Above what airspeed can LEVEL (Roll Wings Level Mode) be activated?
45 knots
Under what 2 conditions will ALT-RAD automatically switch to ALTINRT?
The aircraft climbs above 8000’ AGL or the radar altimeter fails for more than 2 seconds
Held presses of the UP/DOWN sw on the Thrust Control Grip commands an altitude change rate of what?
200 ft/min (3.33 ft/sec)
ALT-INRT may allow the aircraft to drift above or below the reference altitude at a rate of _______ /min or ______ /min when GPS aiding is off without any corresponding annunciation.
5 ft per minute
-or-
15 feet per minute
How does DAFCS provide torque limiting for DAFCS altitude hold and vertical axis coupled modes to prevent overtorque, exceeding engine limitations and to prevent rotor droop?
-maintains dual engine torque below 96%
-maintains the higher of the two engines below 10 minute limit (899 • Celsius)
-keeps dual engine torque above 14% to prevent spray clutch disengagement
torque limiting will not lower the thrust of radar altitude is less than 100’ AGL
DESCENT mode will descend the aircraft at approximately ___ degrees and rates of descent no more than approximately _____ fpm until termination at a hover flight condition at a minimum height of ___ feet AGL.
9 degrees
600 fpm
20 feet AGL
At gross weights above 42,400lbs with BALT mode engaged, bank angles greater than ___degrees results in large uncommanded pitch attitude and airspeed deviations.
22 degrees
At night or in IMC flight, this may cause the pilot to become spatially disoriented
When groundspeed is less than ____ knots and the hover hold mode is activated, the current ground track, speed, radar altitude, and track angle will be maintained.
40 knots ground
DECEL/PSN Hold can be armed at any speed but will be activated only below _____ knots ground speed and remain active up to ____knots ground speed.
65 knots ground
70 knots ground
With the aircraft at a hover and Velocity (VEL) captured, what will occur if the DAFCS Trim Switch is beeped forward 3 times?
Acft will move at 3kgs
Flight Control Computers (FCC)
What sensors supply information to the Flight Control Computers
EGIs (Embedded Global Positioning/Inertial Navigation System, Pitot Static system and ADC’s, Radar Atimeter, WOW switches and Power Steering Control Box, Control Position Transducers
What conditions must be met for VEL HOLD mode to operate
-it’s armed
-acft airborne
-below 35 KGS
-CDR button not pressed
-DASH is in normal rate mode
What airspeed does Forward Flight Velocity Mode (roll wings level mode) activate
above 40 KGS
What airspeed does Descent mode activate
below 65 KGS
What component does DAFCS work with to maintain pitch attitude hold below 40 KCAS
DASH
Name features provided by DAFCS
-Attitude Hold
-velocity
-PSN Hold
-Decel
-Descent Mode
-Bank Angle Hold
-heading Hold
-attitude command/altitude hold ACAH
-Automatic LCT Operation
What is the status of the Heading Hold Feature when the Swivel Lock Switch is not in the Locked position
the FCC’s disengage Heading Hold
How do the flight control computers know to place the LCT actuators to the GRD position when in AUTO
Both weight on wheels/proximity switches must be engaged
When accelerating from a hover, what is the max airspeed which can be flown to remain within the Low Speed Regime
45 knos A/S
-Turns off when accelerating beyond 45 KGS
-Turns on when decelerating below 35 KGS
At what GS decelerating does the VEL feature become active/captured
35 KGS
Name the features of DAFCS that disengage when the CDR switch is depressed
VEL, PSN HOLD, DECEL, Descent Mode, Bank Angle Hold, Heading Hold, Attitude Command/Attitude Hold (ACAH)
What must be monitored to prevent transmission damage when changing A/S or hdg with attitude hold engaged
Monitor TQ
What groundspeed does the Low Speed Regime become active when decelerating
35 knts
What visual indication will you see when the DASH actuators are re-centering when DAFCS is first turned on
Possible DASH 1/2 failure as it reprograms/adjusts
Is “Go Around” a DAFCS feature or a Flight Director feature
Flight Director Feature
should you allow the cyclic to move when the DAFCS trim switch is moved forward or aft
yes
what are 2 groundspeed-based “velocity stabilized” pilot-selectable modes
Velocity Hold mode and Decel/PSN Hold mode
What action shold the pilot take to select Radar Altitude Hold
-in DAFCS mode select Radar Alt Hold by selecting ALT twice on TCL
-In FD, the pilot must select the MFD key to RALT on FD control layer
Holding the AFCS Trim Sw produces a fixed translational rate of ____ fps (3 knots) in the direction of actuation. Bank angle hold will not reengage until the roll rate is less than ___ °/second
5 fps
1.5°/sec
Roll Wings Level Mode (LEVEL) can be selected when the aircraft is traveling greater than ___ knots forward groundspeed
45 KGS
Altitude hold will level-off and capture a new reference when the vertical velocity is less than ___ fpm
25 fpm
the RETRIM REQUEST Advisory is active when either the roll or yaw ILCA is using more than 40/50% of its avail authority for trim. The pilot should re-trim the controls with the ___ switch to allow the actuators to re-center
CD REL
Will the cyclic move when the DAFCS trim switch is moved laterally
No
With VEL captured (hovering), what happens to the status of VEL when either WOW sw engages
it is disabled
What should be done if the LCT actuators fail to position to GND during taxi, water, or slope operations
Select MANUAL on the LCT panel and adjust them manually
Do not manually extend the LCT actuators beyond the GND position on the cyclic trim indicators at airspeeds below _____ KCAS
60 KCAS
One way you can change the aircraft bank angle without moving the cyclic
lateral movement of the DAFCS trim sw
With the aircraft at a hover and VEL captured, what will occur if the DAFCS Trim Switch is beeped forward 3 times
Acft will move at 3 KGS
