COBHAM S-TEC Twenty Owner's manual

3rd Ed. Feb 15, 07 i
S–TEC
List of Effective Pages * Asterisk indicates pages changed, added, or deleted by
currentrevision.
Record of Revisions Retain this record in front of handbook. Upon receipt of a
revision, insert changes and complete table below.
Revision Number Revision Date Insertion Date/Initials
1
st Ed. Feb 01, 00
2
nd Ed. Jun 24, 02
3
rd Ed. Feb 15, 07

ii 3rd Ed. Feb 15, 07
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Page Intentionally Blank

3rd Ed. Feb 15, 07 iii
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Table of Contents
Sec. Pg.
1Overview...........................................................................................................1–1
1.1 Document Organization....................................................................1–3
1.2 Purpose..............................................................................................1–3
1.3 General Control Theory....................................................................1–3
1.4 Modes of Operation...........................................................................1–4
1.4.1 Roll Axis Control.................................................................1–4
1.4.2 Pitch Axis Control...............................................................1–4
1.5 Block Diagrams..................................................................................1–4
2Pre-FlightProcedures...................................................................................2–1
2.1 Power-Up Test....................................................................................2–3
2.1.1 System Twenty.....................................................................2–3
2.1.2 System Thirty.......................................................................2–7
2.1.3 System Thirty ALT...............................................................2–13
2.2 Pre-Flight Test....................................................................................2–17
2.2.1 System Twenty.....................................................................2–17
2.2.2 System Thirty.......................................................................2–25
2.2.3 System Thirty ALT...............................................................2–35
3In-FlightProcedures......................................................................................3–1
3.1 Normal Operating Procedures........................................................3–3
3.1.1 Stabilizer (ST) Mode, System Twenty / Thirty...................3–3
3.1.2 Heading (HD) Mode, System Twenty / Thirty...................3–4
3.1.3 Low Track (LO TRK) Mode, System Twenty / Thirty........3–5

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3.1.4 High Track (HI TRK) Mode, System Twenty / Thirty........3–6
3.1.4.1 LOC Course Tracking........................................3–6
3.1.4.2 GPS Course Tracking........................................3–6
3.1.4.3 VOR Course Tracking........................................3–6
3.1.5 Altitude Hold (ALT HOLD) Mode, System Thirty / ThirtyALT.....3–7
3.1.5.1 System Thirty........................................................3–7
3.1.5.2 System Thirty ALT................................................3–8
3.1.6 Manual Elevator Trim Prompts, System Thirty / ThirtyALT.....3–8
3.1.6.1 System Thirty........................................................3–8
3.1.6.2 System Thirty ALT................................................3–8
3.2 Approach Procedures.......................................................................3–11
3.2.1 Straight-In LOC Approach.................................................3–11
3.2.1.1 Heading System DG..........................................3–11
3.2.1.2 Heading System HSI.........................................3–11
3.2.2 Straight-In VOR Approach.................................................3–11
3.2.2.1 Heading System DG..........................................3–11
3.2.2.2 Heading System HSI.........................................3–11
3.2.3 LOC Approach with Procedure Turn..............................3–16
3.2.3.1 Heading System DG..........................................3–16
3.2.3.2 Heading System HSI.........................................3–16
3.2.4 VOR Approach with Procedure Turn..............................3–19
3.2.4.1 Heading System DG..........................................3–19
3.2.4.2 Heading System HSI.........................................3–19

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3.3 Yaw Damper Operation....................................................................3–22
3.3.1 AUTO Mode..........................................................................3–22
3.3.2 ON Mode..............................................................................3–22
3.3.3 Yaw Damper Trim..............................................................3–22
3.4 Autopilot Disconnect ........................................................................3–23
3.4.1 System Twenty / Thirty.......................................................3–23
3.4.2 System Thirty ALT...............................................................3–23
4OperatingParameters..................................................................................4–1
4.1 Roll Axis Limits..................................................................................4–3
4.2 Pitch Axis Limits.................................................................................4–3
5Glossary...........................................................................................................5–1

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List of Figures
Fig. Pg.
1–1 SystemTwenty Block Diagram....................................................................1–5
1–2 System Thirty Block Diagram......................................................................1–6
1–3 System Thirty ALT Block Diagram...............................................................1–7
1–4 Yaw Damper Block Diagram.......................................................................1–8
2–1 AP Display, Lamps Illuminated at Power-Up (System Twenty)...............2–4
2–2 AP Display, All Lamps Extinguished (System Twenty).............................2–4
2–3 AP Display, RDY for Operation....................................................................2–5
2–4 AP Display, Turn Coordinator Failure (System Twenty)...........................2–5
2–5 AP Display, Low Voltage Flag (System Twenty).........................................2–6
2–6 AP Display, Lamps Illuminated at Power-Up (System Thirty).................2–8
2–7 AP Display, TRIM UP Lamp Extinguished (System Thirty).......................2–8
2–8 AP Display, ALT Lamp Only Illuminated (System Thirty)...........................2–9
2–9 AP Display, All Lamps Extinguished (System Thirty)................................2–9
2–10 AP Display, RDY for Operation (System Thirty).......................................2–10
2–11 AP Display, Turn Coordinator Failure (System Thirty)............................2–10
2–12 AP Display, Low Voltage Flag (System Thirty).........................................2–11
2–13 ALT HOLD ON/OFF Switch Display, Lamps Illuminated at Power-Up (System Thirty ALT)....2–14
2–14 ALT HOLD ON/OFF Switch Display, UP Lamp Extinguished (System Thirty ALT)...............2–14
2–15 ALT HOLD ON/OFF Switch Display, DN Lamp Extinguished (System Thirty ALT)..............2–15
2–16 ALT HOLD ON/OFF Switch Display, ALT ON Lamp Extinguished (System Thirty ALT).........2–15
2–17 AP Display, ST Mode Engaged (System Twenty)....................................2–19
2–18 AP Display, HD Mode Engaged (System Twenty)...................................2–19
2–19 AP Display, LO TRK Mode Engaged (System Twenty)...........................2–21

3rd Ed. Feb 15, 07 vii
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2–20 AP Display, HI TRK Mode Engaged (System Twenty)...........................2–21
2–21 AP Display, ST Mode Engaged (System Thirty).......................................2–27
2–22 AP Display, HD Mode Engaged (System Thirty)......................................2–27
2–23 AP Display, LO TRK Mode Engaged (System Thirty)..............................2–29
2–24 AP Display, LO TRK Mode Engaged (System Thirty)..............................2–29
2–25 AP Display, HI TRK and ALT HOLD Modes Engaged (System Thirty)........2–31
2–26 AP Display, HI TRK and ALT HOLD ModeS Engaged, TRIM UP Required (System Thirty).....2–32
2–27 AP Display, HI TRK and ALT HOLD ModeS Engaged, TRIM DN Required (System Thirty).....2–32
2–28 ALT HOLD ON/OFF Switch Display, ALT HOLD Mode Engaged (System Thirty ALT).......2–36
2–29 ALT HOLD ON/OFF Switch Display, ALT HOLD Mode Engaged, TRIM UP Required (System Thirty ALT).....2–36
2–30 ALT HOLD ON/OFF Switch Display, ALT HOLD Mode Engaged, TRIM DN Required (System Thirty ALT).....2–36
3–1 AP Display, ST Mode Engaged....................................................................3–3
3–2 AP Display, HD Mode Engaged...................................................................3–4
3–3 AP Display, LO TRK Mode Engaged...........................................................3–5
3–4 AP Display, HITRK Mode Engaged............................................................3–6
3–5 AP Display, ST and ALT HOLD Modes Engaged (System Thirty)............3–7
3–6 ALT HOLD ON/OFF Switch Display, ALT HOLD Mode Engaged (System Thirty ALT)............3–8
3–7 AP Display, Manual Trim Prompts (System Thirty)...................................3–9
3–8 AP Display, Manual Trim Prompts (System Thirty ALT)..........................3–10
3–9 Straight-In LOCApproach (DG)..................................................................3–12
3–10 Straight-In LOC Approach (HSI)..................................................................3–13
3–11 Straight-In VOR Approach (DG)..................................................................3–14
3–12 Straight-In VOR Approach (HSI)..................................................................3–15
3–13 LOC Approach with Procedure Turn (DG)................................................3–17

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3–14 LOC Approach with Procedure Turn (HSI)...............................................3–18
3–15 VOR Approach with Procedure Turn (DG)................................................3–20
3–16 VOR Approach with Procedure Turn (HSI)...............................................3–21
3–17 Yaw Damper Master Switch........................................................................3–22
3–18 Yaw Damper Trim Knob..............................................................................3–22
List of Tables
Table Pg.
2–1 Power-Up Test, System Twenty...................................................................2–3
2–2 Power-Up Test, System Thirty.....................................................................2–7
2–3 Power-Up Test, System Thirty ALT.............................................................2–13
2–4 Pre-Flight Test, System Twenty...................................................................2–17
2–5 Pre-Flight Test, System Thirty.....................................................................2–25
2–6 Pre-Flight Test, System Thirty ALT.............................................................2–35

3rd Ed. Feb 15, 07 1-1
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SECTION 1
OVERVIEW