Autopilot

Altimatic III Autopilot

Altimatic III Autopilot is a three axis autopilot which is linked to the HSI. The Display consists of:

1 A rotating Radio Coupler Selector knob (white at far left)

NOTE - when rotating this knob - that it is extremely easy inadvertently to knock the fwd. Right Engine Magneto Switch to the Off Position with the knuckle of he left hand. For Obvious reasons ALWAYS check the Magneto Switch after altering the position of this knob.

2 A row of Mode Selector Rocker Switches "Roll" "Hdg" "Alt" and "Pitch"

3 A Left and Right Roll knob

4 A Trim Needle Indicator in window

5 A White Pitch Trim Adjustment rotating disc with central detente position (just visible)

MODE SELECTOR OPERATION

When engaged (and some or all may be engaged) the Mode Switches have the following effects:

ROLL To engage ROLL mode, Select HDG on the Radio Coupler, then centre the ROLL knob. Then push ROLL rocker switch to ON (ie (Top section in). To turn the aircraft, simply rotate the ROLL knob and the aircraft will effect a roll. Limit angles of bank to 30 degrees. This action merely replicates the action of rotating the yoke on the control column.

HDG To engage Heading (HDG) Mode, (which can only be engaged when ROLL mode rocker switch is set to ON), again Select HDG on the Radio Coupler, then set HSI Hdg Bug to desired heading. Then engage HDG Mode by pressing the HDG rocker switch. The aircraft will then make roll adjustments of up to 20 degrees bank angle to maintain that heading. A change in the Hdg Bug setting will be followed by the Autopilot

PITCH To engage Pitch Mode. First engage ROLL mode by pressing ROLL rocker switch. Then Centre the pitch trim indicator needle using the white pitch command disc. Finally engage PITCH rocker switch. The pitch of the aircraft can then be adjusted up or down by rotating the pitch disc in the direction shown, (which mirrors the pitch trim wheel found on the floor in the PA28 and other aircraft - ie forward = down, back = up). Pitch mode replicates the action of (a) using the manual trim in the ceiling (b) using the electric trim switch on the control column.

ALT (hold) Once you have reached the desired altitude, engaging Altitude Hold mode (by pressing the ALT rocker switch, which again can only be pressed when PITCH switch has been pressed) will keep the aircraft at that altitude. Proper operation requires that you trim the aircraft in Pitch by using the procedure referred to above (ie PITCH Mode). If you don't trim first, engaging Alt Hold Mode will result in the aircraft executing a fugoid path through the air, making large adjustments for errors in trim. NOTE Before disengaging Alt Hold Mode, ensure that the pitch command disc is centered.

RADIO COUPLER OPERATION USING THE HSI DISPLAY

The White Selector Switch can be set to one of five options (from the left) NAV, OMNI, HDG, LOC (Norm), LOC (Rev). Operation of the Radio Coupler is as follows:

1 VOR Navigation - to intercept and track a VOR Radial

Select on NAV 1 and Identify the VOR transmitter.
Select the desired course on the HSI by rotating the Course Knob on the HSI
Select OMNI on the radio Coupler
Select HDG mode on Autopilot (ie press ROLL and HDG rocker switches) to engage coupler. The aircraft will turn to give a 45 degree intercept of the radial., the cut will diminish as the offset diminishes.

NAV mode may be engaged to provide a reduced VOR sensitivity for tracking weak or noisy VOR signals. It should only be engaged when the aircraft is well established on course.

2 ILS - LOC (Front Course) - To intercept and track inbound to localiser

Select on NAV1 and Identify the Localiser Transmitter
Select the desired course on the HSI by rotating the Course Knob on the HSI
Select LOC(Norm) on Coupler to intercept and track inbound on the localiser
Engage Hdg Mode (ie press ROLL and HDG rocker switches) to engage Coupler

3 ILS (Back Course)

Select on NAV1 and Identify the Localiser Transmitter
Select the inbound front localiser course on the HSI by rotating the Course Knob on the HSI
Select LOC(Rev) on Coupler to intercept and track inbound on the localiser OR (more likely scenario on a go-around)
Select LOC(Norm) on Coupler to intercept and track outbound from the localiser.
Engage Hdg Mode (ie press ROLL and HDG rocker switches) to engage Coupler

4 COUPLED APPROACH OPERATIONS

After arrival at the VOR, track outbound to the procedure turn area as described under VOR Navigation above, slowing to 104 - 122 Kts IAS
Use HDG mode and PITCH and/or ALT HOLD modes as appropriate during the procedure turn.
At FAF inbound disengage ALT HOLD mode and return to PITCH mode for control of descent and lower gear
At MDA Select ALT HOLD mode again and add power for level flight. Monitor Altimeters to assure accurate altitude holding
Go- around. For Missed approach select desired Pitch attitude with pitch command disc and disengage ALT HOLD mode.
Upon Pitch Up attitude initiation, immediately add (full) power for climb, monitoring Altimeters and Rate of Climb
When Climb established (as normal) retract flaps and gear
Adjust attitude for desired airspeed. Bug new hdg
Select HDG Mode for turn from initial VOR/LOC approach course

5 ILS - FRONT COURSE APPROACH WITH GLIDESLOPE CAPTURE

Track inbound to LOM as described in VOR Navigation above and in ALT HOLD mode
Inbound to LOM reduce speed to 104-122 kts IAS
Automatic Glideslope Capture will occur at Glide Slope Intercept if

(a) Coupler is in LOC(Norm) Mode

(b) ALT HOLD mode is engaged (all Rockers are "ON")

(d) Localiser frequency is selected (and Identified) on NAV1

At Glide Slope Intercept immediately lower landing gear and reduce power to maintain 104 kts IAS
Glide Slope Capture is indicated by the lighting of the Green Glideslope Annunciator light located beside the Door Ajar Light and by a slight pitch down of the aircraft
Monitor Localiser and Glide Slope raw data throughout the approach on the HSI. Adjust Power to as necessary to maintain correct final approach speed. Power changes should be small and smoothly applied to ensure proper tracking. DO NOT CHANGE AIRCRAFT CONFIGURATION during approach while autopilot is engaged
Go- around. For Missed approach select desired Pitch attitude with pitch command disc and disengage ALT HOLD mode.
Upon Pitch Up attitude initiation, immediately add (full) power for climb, monitoring Altimeters and Rate of Climb
When Climb established (as normal) retract flaps and gear
Adjust attitude for desired airspeed. Bug new hdg
Select HDG Mode for turn from initial VOR/LOC approach course

NOTE - Glide Slope Coupler will not automatically decouple from Glide Slope. Decoupling may be accomplished by

(a) Disengaging Altitude Hold Mode
(b) Switching Radio Coupler to HDG Mode
(c) Disengaging Autopilot

YOU MAY ONLY ATTEMPT COUPLED APPROACHES AND GLIDESLOPE CAPTURE WHEN A SAFETY PILOT IS PRESENT OR WHEN YOU HAVE BEEN CHECKED OUT ON AUTOPILOT OPERATIONS