AUTOPILOT.

Question 1

How is the autopilot system powered?

Answer 1

The system receives power from the DC 2 PRI bus ( through the MER FAN 2A, MER FAN 1B, AP 1, and AP 2 circuit breakers,) and

DC 2 ESS bus ( through the AFCS TRIM CYCLIC, CLTV, and YAW circuit breakers)

The system also receives power from the DC 1 PRI bus ( through the MER FAN 1A and AP 1 circuit breakers), and

DC 1 ESS bus ( through the MER FAN 2B and AP 2 circuit breakers.)

Question 2

How many computers make up the FCM?

Answer 2

Each FCM consists of two independent computers running the same software.

These two processors compare their calculated results to detect any processing or computation error.

Question 3

What does the upper and lower sections of the FMA display?

Answer 3

The upper section displays the currently active mode in green text. The lower section indicates an armed mode in white.

A green box bordering the active mode will flash for approximately 5 seconds each time a mode change is performed on an axis. This serves to highlight the mode change to the pilot.

A degraded condition of the flight director on a single axis will be indicated by an amber box outlining the affected axis. The box will initially flash and then remain steady as long as the degraded condition is present.

Question 4

Which of these trims will cause the Autopilot operating in ATT mode to revert to SAS mode?

Cyclic trim?
Yaw trim?

Answer 4

Autopilot operation in the ATT mode will automatically revert to SAS mode if the cyclic stick trim switch is turned off.

ATT mode is still available with yaw trim actuator turned off.

Question 5

How many Series SAS actuators are used by the Autopilots?

Answer 5

Six series SAS actuators are utilized, one actuator per control axis (pitch, roll, yaw) for each autopilot.

Each autopilot controls a single SAS actuator per axis.

Question 6

What is the control authority limit of the SAS actuator?

Answer 6

The SAS actuators provide limited authority fast rate AFCS inputs to the flight controls, which do not result in stick movement.

They are limited to a control authority of ±5% each.

During normal dual autopilot operation, the two SAS actuators in each axis combine for a total of ±10% high rate autopilot control authority.

Question 7

How many parallel trim Actuators are used by the Autopilot?

Answer 7

Three electro mechanical (pitch, roll, and collective) and one hydro mechanical (yaw) parallel trim actuators are mounted on the aircraft upper deck, prior to the control mixer.

The trim actuators provide full authority slow rate AFCS inputs to the flight controls. These inputs result in cockpit flight control movement.

Question 8

What are the sensors used by the Autopilot ?

Answer 8

The AFCS uses inputs from the

Air Data Computers (ADC),

Attitude Heading Reference Systems (AHRS),

VHF navigation radios,

Radar Altimeter(s) (RALT),

Flight Management Systems (FMS),

Integrated Electronic Standby Instrument (IESI), and

Electronic Engine Controls (EECs)

for the computation of both basic autopilot and flight director modes.

Question 9

What conditions will make the Autopilot Preflight built in test (PFBIT) to be locked out?

Answer 9

The PFBIT test will be locked out and inhibited if

1. Either of the autopilots has been engaged,
2. The aircraft is or has been in flight, or
3. If collective has been raised above 10%.

If any of these conditions has occurred since the last autopilot power-up, a reset of both autopilots (via AP1 and AP2 buttons) is necessary to allow PFBIT activation.

Question 10

How long should the autopilot test normally take for a successful completion?

Answer 10

The test sequence requires approximately 3 minutes for successful completion.

Question 11

How is the SAS mode selected with ATT mode on?

Answer 11

If the autopilot ATT mode is active, SAS mode is engaged by pressing and deselecting the ATT mode button.

This eliminates the possibility of a malfunctioning SAS button disengaging both ATT and SAS modes.

Question 12

Why is it necessary to keep feet on the pedals when taxiing with ATT mode engaged?

Answer 12

When taxiing on ground with ATT mode engaged,
the pilot’s feet should remain on the pedal
switches or an autopilot mistrim caution message may result.

Question 13

When will the Autopilot utilize yaw inputs to maintain trimmed aircraft heading?

Answer 13

The autopilot will utilize yaw inputs to maintain the trimmed aircraft heading;

At all times below 60 kts, or

When the aircraft roll attitude is less than 4° and the pilot’s feet are off the pedal switches,

Question 14

What is the function of the auto trim?

Answer 14

The auto trim function ensures that all SAS actuators are nominally located near their centered position for optimum authority.

The function eliminates any steady SAS actuator displacement by automatically displacing the corresponding trim actuator to allow the SAS actuator to return to center.

Because the trim actuator will move the cockpit controls, the pilot will feel the associated cockpit control move during this centering operation.

Question 15

When is the auto trim function inhibited?

Answer 15

The auto trim function is inhibited when

1. The detent switches in the pitch, roll, and collective trim servos detect the controls are moved from their center detent (pilot flying against trim), or
2. The trim release switch is depressed.
3. The auto trim function is also not available while operating the aircraft in SAS mode.

Question 16

At what PLI values will the AFCS POWER LIMITING caution illuminate?

Answer 16

When coupled to the collective axis, the AFCS system will automatically limit upward collective movement to 97% PLI in order to prevent N R droop.

In the event PLI exceeds 97% while the collective is coupled, the AFCS will lower the collective until 97% is achieved.

While the high power limiting is active the AFCS performance is degraded and AFCS POWER LIMITING caution will illuminate.

V400 Similarly, the AFCS system will automatically limit downward collective movement to 3% PLI in order to limit the likelihood of the helicopter entering an autorotation.

In the event PLI decreases below 3% while the collective is coupled, the AFCS will raise the collective until 3% is achieved.

While the low power limiting is active the AFCS performance is degraded and the AFCS LOW POWER LIMIT caution will illuminate. This limiting will occur during dual engine, single engine, and engine training operations.◄

Question 17

How does the aircraft alert the pilot to automatic FD mode changes?

Answer 17

When an automatic transition occurs the crew will be alerted by:
1. A 3 beep audio advisory signal.

2. A flashing box on the FMA on the axis that has been affected. The box will flash for 5 seconds.
3. Changes on the Autopilot Control Panel (APCP) engagement indicator LEDs indicating the new mode(s) engaged.

Question 18

When will the HDG mode use yaw inputs for small heading adjustments ?

Answer 18

When above 60 kts and less than 4° bank angle, the HDG mode will use yaw inputs only to perform small heading adjustments (~4°).

Question 19

What could cause the HDG mode to disengage?

Answer 19

The HDG mode will disengage if:

1. The HDG button on the APCP is pressed.
2. Airspeed drops below V303 55 KIAS ◄ V400 50 KIAS ◄. Basic heading hold will then be performed by the yaw axis as part of the ATT mode.
3. Another flight director mode is engaged on the roll.
4. Heading information to AFCS is not valid.
5. The APCP STBY or the cyclic FD STBY button is pressed.

Question 20

At what airspeed value will the FD automatically decouple ?

Answer 20

50KTS?

Question 21

What is the default vertical speed that will be used when ALTPRE is selected?

Answer 21

Upon engagement the aircraft will climb or descend at a default vertical speed of 500 fpm.

Question 22

What is the maximum vertical speed that can be selected?

Answer 22

Vertical speed is pilot adjustable up to ± 1500 fpm.

Question 23

Durung descent, below what height will the ALTP mode not engage?

Answer 23

ALTP will not engage below 200 feet AGL when aircraft is in descent.

Question 24

What is the maximum height to engage RADALT mode?

Answer 24

2000ft.

Question 25

What ground speeds, longitudinally and laterally, can be commanded while using the VHLD mode?

Answer 25

The mode is capable of maintaining the helicopter at any combination of ground speeds:-

-20 kts to +55 kts longitudinally and
± 10 kts laterally.

Question 26

What does the VHLD hold mode use to maintain ground referenced velocities?

Answer 26

AHRS accelerometer data is used along with GPS position data to maintain the ground referenced velocities.

Question 27

Below what IAS is the VHLD mode available?

Answer 27

The VHLD mode is available below 60 KIAS airspeed.

Groundspeed must not exceed 55 kts forward, 20 kts rearward, or 10 kts laterally.

Question 28

When using the VHLD mode, at what speed will the reference velocities change when an input is made?

Answer 28

The reference velocity will change at 3.5 kts/sec.

Question 29

What happens when the Go Around ( GA) mode is selected?

Answer 29

GA mode will cause the AFCS capture

1. a 750 fpm climb on the collective axis,
2. 75 KIAS on the pitch axis, and
3. maintain the aircraft heading on the roll axis.

Question 30

What can the GA mode be used for?

Answer 30

It may be used to terminate an instrument approach procedure, during an instrument departure or

to recover from an unusual attitude.

Question 31

What happens when the DPT mode is selected?

Answer 31

The DPT mode will accelerate the aircraft to 70 kts and enter a climb. The target climb rate will be the greater of 200 fpm, or the climb rate at the time of engagement, with a maximum of 750 ft/min.

Below 60 KIAS, the mode will acquire and hold a null lateral ground speed, and the FMA roll indication will be DPT.

Above 60kts, the DPT will maintain current heading, and HDG will be shown on the FMA roll box.

Question 32

At what point will the DPT mode change to GA mode?

Answer 32

The DPT mode will accelerate and climb until the targets of 70 kts and 200 ft AGL RALT are achieved. Once these targets are reached, DPT will automatically disengage and GA mode will be engaged.

Question 33

What happens when the DCEL mode is selected?

Answer 33

When the DCEL mode is selected, the flight director will provide a smooth deceleration from any approach speed to 70 KIAS at approximately 200 feet AGL.

The GS and DCEL modes require that the IAS mode be engaged.