**[Twin Otter SOP Run-up checks Page 1 11/13/2023]{.underline}**

**[RUN-UP CHECKS (AMPLIFIED)]{.underline}**

# PARKING BRAKE SET

The PIC will check and verify that the parking brake is set.

**PROP FEATHER CHECKED**

The PIC will pull the propeller levers to the feather position, verify
that the props feather and stabilize at approximately 23% on the Np
gauge, then select the prop levers to full forward.

**PROP RESET LIGHTS** **CHECKED**

During the prop feather check (above), note that the PROP RESET light on
the Caution Light Panel comes on as the prop lever is pulled back from
the full forward position, and that the light goes out when the prop
levers are repositioned to the full forward position.

**BETA RANGE LIGHTS** **CHECKED**

Retard the power levers from flight idle towards reverse until the left
and right Beta Range Lights come on. Return the power levers to the
flight idle position and check that the Beta range lights are off.

**BETA BACKUP** **TEST**

1.  Power levers set at flight idle

2.  Prop levers set at max rpm

3.  Retard the left power lever into the reverse range, until the beta
    range light comes on.

4.  Lift and hold the BETA RANGE TEST Switch. Check that the BETA
    BACKUP/DISARMED light and the beta range light come on and go out
    for two complete cycles while the beta backup system functions.

5.  Release the BETA RANGE TEST Switch.

6.  Return the power levers to flight idle.

7.  Retard the right power lever into the reverse range, until the beta
    range light comes on.

8.  Lift and hold the BETA RANGE TEST Switch. Check that the BETA
    BACKUP/DISARMED light and the beta range light come on and go out
    for two cycles while the beta backup system functions.

9.  Release the BETA RANGE TEST Switch and return the power levers to
    flight idle.

**PROP OVERSPEED** **TEST**

1.  With the power levers at flight idle, check that the oil pressures
    are above 40 psi and oil temperatures are above 10 degrees C.

2.  Set the prop levers at max rpm.

3.  Lift and hold the PROP GOV TEST Switch.

4.  Advance both power levers slowly and check that both propellers
    govern at approximately 70% Np.

5.  Return the power levers to flight idle.

6.  Release the PROP GOV TEST Switch.

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**AUTOFEATHER** **ON/TEST**

1.  With the power levers at flight idle, check that the oil pressures
    are above 40 psi and oil temperatures are above 10 degrees C

2.  Prop levers set at Max rpm.

3.  Select the Autofeather system on, and check that the autofeather
    SELECT light illuminates.

4.  Advance both power levers to approximately 25 lbs torque.

5.  Lift and hold the AUTO FEATH TEST Switch, and check that the amber
    ARM light illuminates.

6.  Select the left power lever to flight idle, and check that the left
    propeller feathers approximately 2 seconds later. Check that the
    autofeather ARM light goes out.

7.  Select the right power lever to flight idle, and check that the
    right propeller does not feather. The left propeller will begin to
    come out of feather when both power levers are at flight idle. Wait
    until the propeller has unfeathered.

8.  Advance both power levers to approximately 25 lbs torque, and check
    that the amber ARM light illuminates.

9.  Retard the right power lever to flight idle, and check that the
    right propeller feathers approximately 2 seconds later. Check that
    the autofeather ARM light goes out.

10. Select the left power lever to flight idle, and check that the left
    propeller does not feather. The right propeller will begin to come
    out of feather when both power levers are at flight idle.

11. Release the AUTO FEATH TEST Switch.

12. Advance the left power lever to 88% Ng, and check that the amber ARM
    light [is not]{.underline} illuminated.

13. Advance the right power lever to 88% Ng, and check that the amber
    ARM light [is]{.underline} illuminated.

14. Retard the left power lever below 88% Ng, and check that the amber
    ARM light goes out.

15. Retard the right power lever below 88% Ng.

16. Set the Autofeather Switch as required.

# POWER LEVER MICROSWITCH CHECK CHECKED

1.  Set the power levers to idle.

2.  Press and hold the PWR LEV TEST button, and check that the green
    light in the button illuminates.

3.  Release the PWR LEV TEST button.

4.  

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**ANTI-ICE/DE-ICE** **CHECKED**

If there is any chance that you may encounter icing conditions, it is
good practice to check the operation of the Anti-ice and De-ice systems.

1.  Set the power levers to idle Ng + 15%. Select the BLEED AIR Switches
    on, and check that the PNUEMATIC LOW PRESS caution light goes out.

2.  Select the Manual/Auto Switch for the Deicer Boots to Manual. Toggle
    each boot switch (Inner Wing/Outer Wing, and Left Stab/Right Stab
    and have a ground crew member visually check inflation of each boot.
    Note that the appropriate STAB DEICE PRESS blue light illuminates
    when the stabilizer boots are inflated.

3.  Advance the power levers to 80% Ng, select the Intake Deflector
    Switch to Extend for 3 to 5 seconds, and check that the EXT shows on
    the "Doll's Eye" Indicators. Momentarily select Retract on the
    Intake Deflector Switch to retract the deflectors. Retard the power
    levers to flight idle, and select the BLEED AIR switches ON or OFF,
    as appropriate.

4.  Select both generators off. Switch on, then off in turn the VALVE
    HTR switch, the WINDSHIELD HEAT switch, and the PROP DEICE switch,
    checking for amperage

> Draw on the battery.

5\. Select the Generators to ON.

**AUTOPILOT** **CHECKED**

1.  Check that the attitude indicator is erect, the heading indicator is
    slaved, and that no warning flags are in view.

2.  Select ENG on the ENG/DIS switch, and check that the ENG annunciator
    light comes on.

3.  Turn the Autopilot Annunciator Dimmer Switch fully clockwise and
    check that all annunciator lights come on. Adjust light level as
    required.

4.  Apply a force to the controls, one axis at a time. The autopilot
    should not disengage until the force is sufficient to cause clutch
    slippage.

5.  Pitch Control Knob......DOWN. The control yoke should move forward,
    the TRIM DN light should flash, and the TRIM IN MOTION light should
    come on.

6.  Pitch Control Knob......UP. The control yoke should move rearward,
    the TRIM UP light should flash, and the TRIM IN MOTION light should
    come on.

7.  Roll Control Knob......LEFT, THEN RIGHT. Check that the control
    wheel moves left, then right.

8.  Control Yoke......PULL BACK AND HOLD. After a few seconds, the TRIM
    DN light should flash, and the TRIM IN MOTION light should come on.

9.  AFCS DISC Button......PRESS. Check that the DIS light comes on, the
    autopilot does disengage, and that the controls may be moved freely.

10. Set the heading bug to the present aircraft heading, engage the
    autopilot, and press the HDG button. Move the heading bug 10 degrees
    right and then 10 degrees left of the present heading. Check that
    the control wheel moves left and right, and that the flight director
    command bars command the appropriate left or right bank.

11. Tune the number 1 navigation radio to a local VOR. Adjust the course
    arrow to center the track bar and obtain a "TO" indication. Press
    the NAV button on the autopilot. Adjust the course arrow left, then
    right 10 degrees. Check that the control wheel moves left and right,
    and that the flight director command bars command the appropriate
    left or right bank.

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12. Press the APPR button. Adjust the course arrow left, then right 10
    degrees. Check that the control wheel moves left and right, and that
    the flight director command bars command the appropriate left or
    right bank.

13. Tune the number 1 navigation radio to any unused localizer
    frequency. Engage the autopilot and then press the G/A button. Check
    that the autopilot disengages and that the flight director bars move
    to a wings level, pitch up attitude.

14. Engage the autopilot. Press the CWS button. Check that the control
    wheel can be freely moved in all directions. Release the CWS button.
    Check that the autopilot re-engages and holds the control wheel in
    the position selected.

15. Engage the autopilot. Engage the yaw damper. Check that the YAW DAMP
    light illuminates. Press the AFCS DISC button. Check that the
    autopilot disengages, the yaw damper disengages and the YAW DAMP
    light goes out, and that the flight controls have full and free
    movement in all six directions.