Dynon Avionics SkyView HDX Instruction Manual

SkyView
Autopilot Servo Installation & Maintenance Manual
Piper PA-34 Seneca Series
PA-34-200T Seneca II
PA-34-220T Seneca III
PA-34-220T Seneca IV
PA-34-220T Seneca V
Except for serial numbers 34-7570001 through 34-8170092,
when equipped with pneumatic de-ice boots.
103741-000
Rev A
8/6/2020
Copyright © 2020 by Dynon Avionics, Inc.
Dynon grants third parties’ permission to print this document

Contact Information
Dynon Avionics, Inc.
19825 141st Place NE
Woodinville, WA 98072
Phone: [phone]
Business Operations: 8:00 AM - 5:00 PM (Pacific Time) Monday - Friday
Technical Support Operations: 7:30 AM - 4:00 PM (Pacific Time) Monday - Friday
Email Sales: [e-mail]
Email Support: [email protected]
Web: www.dynoncertified.com
Copyright
©2020 Dynon Avionics, Inc. All rights reserved. No part of this manual may be reproduced, copied, transmitted, disseminated or stored in any
storage medium, for any purpose without the express written permission of Dynon Avionics. Dynon Avionics hereby grants permission to
download a single copy of this manual and of any revision to this manual onto a hard drive or other electronic storage medium to be viewed for
personal use, provided that such electronic or printed copy of this manual or revision must contain the complete text of this copyright notice and
provided further that any unauthorized commercial distribution of this manual or any revision hereto is strictly prohibited.
Information in this document is subject to change without notice. Dynon Avionics reserves the right to change or improve its products and to
make changes in the content without obligation to notify any person or organization of such changes. Visit the Dynon Avionics website
(www.dynonavionics.com) for current updates and supplemental information concerning the use and operation of this and other Dynon Avionics
products.

HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Page | i
Revision History
REV
DATE
APPROVED
DESCRIPTION OF CHANGE
A
8/6/2020
ECO 330214
Initial Document Release

Page | ii
HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Table of Contents
1Introduction..................................................................................................4
1.1 Product Delivery and Warranty..................................................................................... 4
1.2 Product Registration..................................................................................................... 4
1.3 Using this Manual......................................................................................................... 4
1.4 Manual Iconography..................................................................................................... 5
1.5 Referenced Documents................................................................................................ 5
1.6 Mechanical Drawings ................................................................................................... 5
1.7 Installation Record........................................................................................................ 5
2Installation Compliance ..............................................................................6
2.1 Pre-installation Information........................................................................................... 6
3Control Cable Verification ..........................................................................7
4Materials .......................................................................................................8
5Servo Bracketry Installation and Bridle Cable Preparation..................10
5.1 Roll Servo Bracketry Installation................................................................................. 10
5.2 Roll Servo Bridle Cable Preparation........................................................................... 14
5.3 Pitch Servo Bracketry Installation............................................................................... 16
5.4 Pitch Servo Bridle Cable Preparation......................................................................... 21
6Servo Electrical Wiring .............................................................................23
7Servo Maintenance....................................................................................24
7.1 Roll Servo Removal and Installation........................................................................... 24
7.2 Pitch Servo Removal and Installation......................................................................... 28
7.3 Servo Calibration Procedure....................................................................................... 31
7.4 Servo Test Procedure................................................................................................. 32
7.5 Servo Capstan Removal and Re-installation.............................................................. 32
7.6 Cable Guard Adjustment ............................................................................................ 33
7.7 Servo Shear Screw Replacement............................................................................... 33
8Figures........................................................................................................34
8.1 Servo Locations and Access ...................................................................................... 34
8.2 Roll Servo Parts, Assemblies, and Installation ........................................................... 35
8.3 Pitch Servo Parts, Assemblies, and Installation.......................................................... 47

HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Page | iii
8.4 Servo Capstan and Cable Guard Installation.............................................................. 57

Page | 4
HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
1 Introduction
This document provides instructions for installing and maintaining the SkyView HDX Autopilot
servos in the Piper PA-34 Seneca series of airplanes.
Autopilot servo installation in any airplane with modifications to areas where the servos will be
installed is not addressed in this document. See Section 2: Installation Compliance for more
information.
1.1 Product Delivery and Warranty
Upon delivery, visually inspect all SkyView Autopilot components, brackets, fasteners, cable
harnesses, and accessories for damage that may have occurred during shipping. If damage has
occurred, contact Dynon at https://www.dynonavionics.com/warranty-returns.php.
Disassembled or modified components may not be eligible for repair under warranty.
Additionally, once a component has been disassembled, it is not considered airworthy and must
be serviced at the factory. SkyView components do not contain any field-serviceable parts like
fuses, so there is no reason to disassemble any component.
1.2 Product Registration
Register SkyView components at https://www.dynonavionics.com/product-registration.php.
Product registration verifies ownership, expedites warranty claims, and allows Dynon Avionics
to send notification when product Service Bulletins and Technical Advisories are published. This
site also allows owners and installers to register to receive news and product announcements
from Dynon. Dynon will not share contact information with third-parties or send announcements
without explicit consent.
1.3 Using this Manual
To reduce paper, Dynon Avionics does not provide a printed version of this manual. However,
Dynon grants permission to third parties to print this manual, as necessary. The most recent
PDF version is available for download at www.dynon.aero/stcdocs. This manual is updated
periodically. It is important to use the most recent version when installing SkyView components.
Dynon suggests keeping a PDF version of the manual on a smartphone, tablet, or laptop
computer while installing SkyView components. Using the manual electronically allows quick
navigation of the document, figures to be viewed in color, and keyword searches.

HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Page | 5
1.4 Manual Iconography
This manual uses the following iconography:
Alerts reader to critical guidance that if not followed could result in an unsafe
condition.
Alerts reader to FAA regulatory information.
Alerts reader to important installation and/or maintenance information.
Alerts reader to helpful tips or suggestions.
1.5 Referenced Documents
The following Dynon Avionics documents are referenced in this manual:
•103261-000 SkyView HDX System Installation Manual
•103947-000 SkyView HDX Wiring Diagram - Twin Engine
•103777-000 SkyView HDX System Equipment Installation Record
•103000-000 Dynon Servo Shear Screw Replacement Kit Instructions
1.6 Mechanical Drawings
All mechanical drawings included in this manual are for reference purposes only. They should
not be scaled or copied and used as templates or patterns.
1.7 Installation Record
The mechanic or facility performing the installation should record where each SkyView Autopilot
component has been installed in the airplane. This documentation should be entered into
airplane’s permanent record. Dynon provides a document template to record this information.
Download the SkyView HDX Equipment Installation Record document at
www.dynon.aero/stcdocs.

Page | 6
HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
2 Installation Compliance
Airplanes on the AML meet a minimum required configuration for applicability of the STC.
However, some airplanes may have been modified, and consequently, it may be difficult to use
the information in this manual to completely substantiate the installation in compliance with the
STC. It is the installer's responsibility to make the final determination of applicability for each
individual airplane.
Prior to completing the installation, and before returning the airplane to service, the installer must
complete and submit a completed Form FAA 337 - Major Repair & Alteration (Airframe,
Powerplant, Propeller, or Appliance) to the appropriate FAA Flight Standards District Office. The
form must include the following:
•Description of the SkyView Autopilot installation.
•Description of how the SkyViewAutopilot interfaces with existing equipment and systems.
•Appropriately approved or acceptable data that demonstrates compliance.
Refer to AC 43.9-1E - Instructions for Completion of FAA Form 337 for additional information.
2.1 Pre-installation Information
Read and understand the following before proceeding with installation activities.
Always install avionics equipment in compliance with regulatory requirements
found in FAR Part 23 - Airworthiness Standards: Normal Category Airplanes,
Subpart G -Flightcrew Interface And Other Information.
Always install avionics equipment in accordance with the guidance and approved
engineering methods outlined the following FAA documents:
•FAR 23.1311-1C - Installation of Electronic Display in Part 23 Airplanes
•AC 43.13-1B Acceptable Methods, Techniques, and Practices - Aircraft
Inspection
•AC 43.13-2B Acceptable Methods, Techniques, and Practices - Aircraft
Alterations
The certified mechanic who will authorize the airplane's return to service should
agree with the installation plan (i.e., methods, component locations, wiring harness
routing, etc.) before installation activities begin. This will help avoid potential
rework should any part of the installation be found non-compliant.

HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Page | 7
3 Control Cable Verification
The SkyView HDX Autopilot system for the Piper PA-34 Seneca series of airplanes is designed
to attach to the airplane's original 1/8" diameter control cables. It is important for installers to
verify the diameter of the control cables before starting installation activities. The diameter of
control cables should be measured in the vicinity where the autopilot servos will be installed (see
Figure 1).
To gain access to this area, installers will need to remove the second row seats, carpeting, and
the floor in accordance with the Piper PA-34 Seneca Service Manual. The servos will be located
beneath the cabin floor between the main spar and the rear spar carry-through structures. The
roll servo will be on the left-hand side of the cabin (see Figure 1); the pitch servo will be located
on the right-hand side of the cabin (see Figure 1).
Control Cable Specification:
The airplane's control cables must meet the requirements for 1/8" wire rope as specified by
MIL-DTL-83420.
NOMINAL DIAMETER
MINIMUM DIAMETER
DIAMETER TOLERANCE
1/8"
0.125"
+0.014"
If the airplane's original control cables are outside this specification, contact
Dynon Technical Support for a resolution.
Out-of-specification control cables can cause cable clamps to slip under load,
causing the bridle cable to loosen and come off the capstan.

Page | 8
HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
4 Materials
The materials identified in Table 1 are required to install the roll servo into a Piper PA-34 series
airplane. ITEM numbers refer to call-out numbers in the figures in Section 8.2: Roll Servo Parts,
Assemblies, and Installation.
Table 1:Roll Servo Installation Materials
ITEM
DYNON P/N
DESCRIPTION
QTY
1
503406-000
ROLL SERVO ASSEMBLY (SV42C)
1
2
503560-000
ROLL SERVO CAPSTAN ACCESSORY KIT, 1/8" CONTROL CABLE
1
2-1
AN365-10 LOCK NUT #10-32
6
2-2
AN970 FLAT WASHER FLAT #10
6
2-3
AN3H-6A HEX BOLT #10-32 X 3/4", DRILLED HEAD
6
2-4
BRIDLE CABLE CLAMP 1/8"
4
2-5
BRIDLE CABLE
1
2-6
ST2-2 STOP SWAGE, 1/16" CABLE
2
3
503719-000
SENECA ROLL SERVO BASE BRACKET
1
4
503720-000
SENECA ROLL SERVO MOUNT BRACKET
1
5
503721-000
SENECA ROLL SERVO BRACE
1
6
503991-000
SENECA ROLL SERVO BRACKET HARDWARE KIT
1
6-1
AN3H-4A HEX BOLT #10-32, DRILLED HEAD
8
6-2
AN970 FLAT WASHER #10
8
6-3
AN525-10R10 WASHER-HEAD SCREW #10-32
1
6-4
MS1047-03 ANCHOR NUT #10-32, STEEL, FULL-SIZE, 2-LUG
2
6-5
MS20426AD-3-4 SOLID FLUSH MOUNT RIVET 3/32" D, 1/4" L
4
6-6
MS20427AD-4-5 SOLID UNIVERSAL HEAD RIVET 1/8" D, 5/16" L
8
6-7
MS20427AD-4-6 SOLID UNIVERSAL HEAD RIVET 1/8" D, 3/8" L
8
Items without Dynon part numbers are parts packaged in a kit.

HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Page | 9
The materials identified in Table 2 are required to install the pitch servo intoa Piper PA-34 series
aircraft. ITEM numbers refer to call-out numbers in the figures in Section 8.3: Pitch Servo Parts,
Assemblies, and Installation.
Table 2:Pitch Servo Installation Materials
ITEM
DYNON P/N
DESCRIPTION
QTY
7
503933-000
PITCH SERVO ASSEMBLY (SV42C-068)
1
8
503560-000
PITCH SERVO CAPSTAN ACCESSORY KIT, 1/8" CONTROL CABLE
1
8-1
AN365-10 LOCK NUT #10-32
6
8-2
AN970 FLAT WASHER #10
6
8-3
AN3H-6A HEX BOLT #10-32 X 3/4", DRILLED HEAD
6
8-4
BRIDLE CABLE CLAMP 1/8"
4
8-5
BRIDLE CABLE
1
8-6
ST2-2 STOP SWAGE, 1/16" CABLE
2
9
503718-000
SENECA PITCH SERVO MOUNT BRACKET
1
10
503722-000
SENECA PITCH SERVO BASE BRACKET
1
11
503735-000
SENECA PITCH SERVO GUSSET
1
12
503992-000
SENECA PITCH SERVO BRACKET HARDWARE KIT
1
12-1
AN3-4A HEX BOLT #10-32, DRILLED HEAD
4
12-2
AN970 FLAT WASHER #10
4
12-3
AN365-832A LOCK NUT #8-32
1
12-4
AN525-832R8 PHILLIPS WASHER-HEAD SCREW #8-32 X 1/2", CADMIUM
1
12-5
AN960-8 WASHER FLAT STL #8
1
12-6
MS20427AD-4-5 SOLID UNIVERSAL HEAD RIVET 1/8" D, 5/16" L
30
12-7
MS20427AD-4-6 SOLID UNIVERSAL HEAD RIVET 1/8" D, 3/8" L
8
Items without Dynon part numbers are parts packaged in a kit.

Page | 10
HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
5 Servo Bracketry Installation and Bridle Cable Preparation
This section provides instructions for installing the roll and pitch servo bracketry, and then
fabricating the bridle cable assemblies that attach to the aileron and elevator control cables. The
instructions apply to all Seneca model airplanes except for serial numbers 34-7570001 through
34-8170092, when equipped with pneumatic de-ice boots. These instructions assume that the
areas affected by these installations are unmodified from the factory-delivered configuration.
Refer to Section 6: Servo Electrical Wiring for servo wiring information.
Refer to Section 7: Servo Maintenance to remove or install a roll servo after the bracket
installation is complete.
5.1 Roll Servo Bracketry Installation
The roll servo base bracket and brace mount directly to the airplane (see Figure 13 for complete
installation example). The mount bracket has the roll servo fastened to it, and it is fastened to
the base bracket. The roll servo brace is fastened to base bracket and the airplane's crossover
cable guide assembly. The roll servo is connected to the aileron control cables by a bridle cable.
Make sure all flight control cables are rigged and tensioned in accordance with the
manufacturer’s servicing manual.
Failure to do so may result in poor Autopilot system performance.
5.1.1 Location and Access
The roll servo is located beneath the cabin floor between the main spar and the rear spar carry-
through structures on the left-hand side of the cabin as indicated in Figure 1.
Access requires removing the second-row seats, carpeting, and the floor in accordance with the
Piper PA-34 Seneca Service Manual.
5.1.2 Temporary Roll Servo Base Bracket Installation
This section provides instructions for temporarily installing the mount bracket, base bracket, and
brace (see Figure 2). For the mount and base brackets, different instructions are provided for
airplanes with (see Section 5.1.2.1) and without (see Section 5.1.2.2) factory-installed autopilot
servos. Follow the appropriate instructions for the airplane. Instructions are the same for all
airplanes for the brace installation (see Section 5.1.2.3).

HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Page | 11
5.1.2.1 Mount and Base Bracket Installation (With Factory-installed Autopilot)
Complete the following steps to temporarily install the roll servo mount bracket and base bracket
in an airplane equipped with a factory autopilot roll servo that is installed in the same general
position.
To temporarily install the mount and base brackets:
1. Remove left and right air supply ducts in accordance with the Piper PA-34 Seneca Service
Manual.
2. Remove existing roll servo and its bridle cables.
3. Remove fasteners that secure existing roll servo brackets, and then remove roll servo
brackets. The new servo brackets and brace utilize some existing holes through fuselage
skin/structure.
4. If needed, remove rivets from crossover cable guide assembly (see Figure 3).
5. Temporarily secure roll servo to mount bracket (see Figure 4).
6. Temporarily secure mount bracket to base bracket (see Figure 5).
7. Locate bracket assembly into position so capstan is centered below and correctly aligned
with aileron crossover cable (see Figure 6).
8. From outside airplane, with an assistant holding bracket assembly in place, mark 12 holes
on base bracket flanges using holes in fuselage skin/structure as a guide.
9. Remove bracket assembly and inspect markings, making sure a minimum edge margin of
0.187" from center of hole is maintained for all fastener locations. If edge margin is not
adequate, repeat Step #7, adjusting bracket assembly location until adequateedge margin
is maintained and capstan is aligned with aileron crossover cable.
10. When satisfied edge margin requirement has been met, replace bracket assembly in
position and align marks.
11. From outside airplane, with an assistant holding bracket assembly in place, match drill
(#30) holes through base bracket flanges using holes in fuselage skin/structure as a guide;
install temporary fasteners as you go (see Figure 7 and Figure 8).
12. If needed, use rivets to fill unused holes in fuselage skin/structure.

Page | 12
HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
5.1.2.2 Mount and Base Bracket Installation (Without Factory-installed Autopilot)
Complete the following steps to temporarily install the roll servo mount bracket and base bracket
in an airplane not equipped with a factory autopilot pitch servo.
To temporarily install the mount and base brackets:
1. Remove rivets on crossover cable guide assembly (see Figure 3).
2. Temporarily secure roll servo to mount bracket (see Figure 4).
3. Temporarily secure mount bracket to base bracket (see Figure 5).
4. Remove existing fasteners through fuselage skin/structure where base bracket flange is
parallel to structure (see Figure 8).
5. Locate bracket assembly into position so capstan is centered below and correctly aligned
with aileron crossover cable (see Figure 6).
6. From outside ofairplane, with an assistantholding bracket assembly in place, mark 4 holes
on base bracket flange using holes in fuselage skin/structure as a guide.
7. Remove bracket assembly and inspect markings, making sure a minimum edge margin of
0.187" from center of hole is maintained for all fastener locations. If edge margin is not
adequate, repeat Step #5, adjusting bracket assembly location until adequate edge margin
is maintained and capstan is aligned with aileron crossover cable.
8. When satisfied edge margin requirement has been met, replace bracket assembly in
position and align marks.
9. From outside airplane, with an assistant holding bracket assembly in place, match drill
(#30) holes through base bracket flange using holes in fuselage skin/structure as a guide;
install temporary fasteners as you go (see Figure 7 and Figure 8).
10. Remove temporary fasteners and base bracket from airplane.
11. Locate and mark positions for remaining rivet holes on base bracket flanges (see Figure
8). Make sure a minimum edge margin of 0.187" from center of rivet hole is maintained.
12. Drill pilot-size holes in base bracket flanges in positions marked in Step 11.
13. Temporarily secure base bracket to fuselage skin/structure using holes drilled in Step #9.
14. From inside airplane, with an assistant holding bracket assembly in place, drill (#30) holes
through base bracket flanges and fuselage skin using pilot holes as guides; install
temporary fasteners as you go (see Figure 7 and Figure 8).

HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Page | 13
5.1.2.3 Brace Installation (All Airplanes)
Using Figure 9 as reference, complete the following steps to temporarily install the roll servo
brace.
To temporarily install the roll servo brace:
1. Place brace into position, and then secure brace to mount bracket.
2. Using crossover cable guide assembly as a guide, mark hole locations on brace.
3. Remove brace and inspect markings, making sure a 0.187" edge margin exists for fastener
locations.
4. When satisfied edge margin requirement is met, place brace into position and align marks.
5. Using crossover cable guide assembly as a guide, match drill (#30) 1 hole in brace; install
a temporary fastener.
6. Using crossover cable guide assembly as a guide, match drill (#30) remaining holes in
brace; install temporary fasteners as you go.
7. Using mount bracket as a guide, mark 2 hole locations on brace.
8. Remove brace and inspect markings to ensure a 0.290" edge margin exists for fastener
locations.
9. When satisfied edge margin requirement is met, place brace into position and align marks.
10. Using pilot holes in mount bracket as guides, drill (#10) holes in brace.
11. Install provided anchor nuts with flush-mount rivets centered on holes made in Step #10
on bottom side of brace, as shown in Figure 9.
5.1.3 Permanent Roll Servo Bracketry Installation
This section provides instructions for permanently installing the roll servo base bracket and
brace. The roll servo and mount bracket are a removable assembly.
To permanently install base bracket and gusset:
1. Disassemble and remove all temporarily secured brackets.
2. Deburr all holes in bracketry and fuselage skin/structure.
3. Reassemble installation with temporary fasteners in every other hole.
4. In open holes, permanently fasten bracketry with provided rivets and other hardware. Use
correct hardware for application, as identified in Table 1.
5. Remove temporarily fasteners from every other hole.
6. In remaining open holes, permanently fasten bracketry with provided rivets and other
hardware. Use correct hardware for application, as identified in Table 1.

Page | 14
HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
5.2 Roll Servo Bridle Cable Preparation
This section provides instructions for preparing the roll servo bridle cable assembly for final
installation. Performing these tasks after installing the roll servo bracketry, and before
permanently installing the roll servo, simplifies the overall installation.
The instructions in this section assume the roll servo is still temporarily installed in
airplane per procedures in Section 5.1.
5.2.1 Temporary Bridle Cable Attachment to Servo Capstan
Reference Figure 12 and Figure 24 when performing the following procedure.
To temporarily attach roll servo bridle cable to the servo capstan:
1. Remove capstan from servo. (See Section 7.5: Servo Capstan Removal and Re-
installation for instructions.)
2. Insert capstan engagement swage of bridle cable into engagement hole of capstan.
3. Starting from swage engagement hole, wrap bridle cable in each direction around capstan,
as shown in Figure 12.
4. Temporarily secure cable to capstan.
Temporarily securing bridle cable to the capstan with tape or a rubber band
prevents the cable from unraveling when handling.
5.2.2 Temporary Servo Capstan Attachment to Servo Shaft
Reference Figure 12 and Figure 24 when performing the following procedure.
To temporarily attach roll servo capstan/cable assembly to the servo shaft:
1. Place capstan/cable assembly onto servo shaft. Orient capstan as shown in Figure 13.
Make sure bridle cable does not make excessive contact with cable guard.
The position of cable guard may need to be adjusted.
The bridle cable will prematurely wear if bridle cable and cable guard make
excessive contact (i.e., the angle of the control cable is deflected when in a
neutral position).
2. If bridle cable makes excessive contact with cable guard, remove guard and re-install in
new position. (See Section 7.6: Cable Guard Adjustment for instructions.)
3. Secure capstan/cable assembly onto servo shaft. (See Section 7.5: Servo Capstan
Removal and Re-installation for instructions.)

HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Page | 15
5.2.3 Temporary Bridle Cable Connection to Aileron Cable
Reference Figure 11 and Figure 12 when performing the following procedure.
To temporarily connect bridle cable ends to the airplane's aileron crossover cable:
1. Secure ailerons in neutral position.
2. Connect inboard and outboard cable ends to airplane's aileron crossover cable. Loosely
secure to permit cable slippage.
3. Position inboard and outboard clamps so that:
•Capstan swage engagement hole is on opposite side of capstan from control cable,
as shown in Figure 12.
•Cable clamps are located at the dimensions shown in Figure 11.
•Cable clamps are positioned to best avoid contacting any structures.
4. Mark bridle cable at clamp edges oriented away from (opposite of) capstan.
5. Loosen cable clamps.
6. Remove capstan/cable assembly from servo shaft. (See Section 7.5: Servo Capstan
Removal and Re-installation for instructions.)
5.2.4 Fabricate Roll Servo Bridle Cable
To fabricate the roll servo bridle cable:
1. Slide a stop swage onto an end of cable.
2. Position stop swage so it is aligned with mark on cable, and so stop swage is on opposite
side of mark from capstan engagement swage.
3. Use a swage compression tool to squeeze stop swage permanently onto cable.
4. Trim cable end flush with outside end of stop swage.
5. Repeat steps 1 through 5 for opposite cable end.

Page | 16
HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
5.3 Pitch Servo Bracketry Installation
The pitch servo mount bracket, base bracket, and gusset mount directly to the airplane (see
Figure 23 for complete installation example). The mount bracket positions the base bracket and
becomes fastened to the base bracket. The pitch servo gusset is fastened to base bracket and
the airplane's existing structure. The mount bracket will initially be temporarily installed to locate
the base bracket in the airplane. The pitch servo fastens directly to the mount bracket after the
bracket is permanently installed. The pitch servo connects to the elevator control cables bybridle
cables and bridle cable clamps.
Make sure all flight control cables are rigged and tensioned in accordance with the
manufacturer’s servicing manual.
Failure to do so may result in poor Autopilot system performance.
5.3.1 Location and Access
The pitch servo is located beneath the cabin floor between the main spar and the rear spar carry
through structure on the right-hand side of the cabin as shown in Figure 1.
Access requires removing the second-row seats, carpeting, and the floor in accordance with the
Piper PA-34 Seneca Service Manual.
5.3.2 Temporary Pitch Servo Bracketry Installation
This section provides instructions for temporarily installing the mount bracket, base bracket, and
gusset (see Figure 14). For the mount and base brackets, different instructions are provided for
airplanes with (see Section 5.3.2.1) and without (see Section 5.3.2.2) factory-installed autopilot
servos. Follow the appropriate instructions for the airplane. Instructions are the same for all
airplanes for the gusset installation (see Section 5.3.2.3).
5.3.2.1 Mount and Base Bracket Installation (With Factory installed Autopilot)
Complete the following steps to temporarily install the pitch servo mount bracket and base
bracket in an airplane equipped with a factory autopilot pitch servo that is installed in the same
general position.
To temporarily install the mount and base brackets:
1. Remove left and right air supply ducts in accordance with the Piper PA-34 Seneca Service
Manual.
2. Remove existing pitch servo and its bridle cables.
3. Remove fasteners that secure existing pitch servo brackets, and then remove pitch servo
brackets. The new servo bracketsand gussetutilize some existing mounting holes through
fuselage skin/structure.
4. If needed, remove rivets on crossover cable guide assembly (see Figure 15).
5. Temporarily secure pitch servo to mount bracket (see Figure 16).

HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
Page | 17
6. Temporarily secure mount bracket to crossover cable guide assembly so that:
•Servo capstan is centered above right-side outboard elevator control cable, as shown
in Figure 20.
•Servo capstan is aligned with right outboard elevator control cable so that the bridle
cables will feed onto grooves in the capstan.
•Crossover cable guide assembly holes will maintain a minimum of 0.187" edge margin
on mount bracket.
7. Using crossover cable guide assembly as a guide, match drill (#30) 1 hole through mount
bracket; install a temporary fastener.
8. Using crossover cable guide assembly as a guide, match drill (#30) remaining holes
through mount bracket; install temporary fasteners as you go.
9. On base bracket horizontal flange, measure, and mark rivet hole centerline. Make sure a
minimum edge margin of 0.187" from center of rivet hole is maintained.
10. Temporarily secure base bracket to inboard side of mount bracket so that:
•Base bracket maintains a clearance of ~0.01" to avoid contact with the rear spar and
forward spar.
•A minimum edge margin of 0.187" from center of rivet hole is maintained.
11. From outside of airplane, with an assistant holding base bracket in place, match drill (#30)
holes through base bracket horizontal flange using existing holes in fuselage skin as a
guide; install temporary fasteners as you go (see Figure 17).
12. With base bracket temporarily attached to fuselage skin and secured to mount bracket,
drill (#30) holes through base bracket vertical flange usingmount bracket asa guide; install
temporary fasteners as you go (see Figure 18).
13. If needed, use rivets to fill unused holes in fuselage skin/structure.

Page | 18
HDX Autopilot Servo Installation & Maintenance Manual - Piper PA-34 Seneca Series, Rev A
5.3.2.2 Mount and Base Bracket Installation (Without Factory-installed Autopilot)
Complete the following steps to install the pitch servo mount bracket and base bracket in an
airplane not equipped with a factory autopilot pitch servo.
To temporarily install the mount and base brackets:
1. Remove rivets on crossover cable guide assembly (see Figure 15).
2. Temporarily secure pitch servo to mount bracket (see Figure 16).
3. Locate and mark positions for rivet holes on base bracket horizontal flange. Ensure
positions for rivet holes have an adequate edge margin of 0.187".
4. Drill 23 pilot-size holes through base bracket horizontal flange.
5. Temporarily secure mount bracket to crossover cable guide assembly so that:
•Servo capstan is centered above right-side outboard elevator control cable.
•Servo capstan is aligned with right outboard elevator control cable so that the bridle
cables will feed onto grooves in the capstan.
•Crossover cable guide assembly holes will maintain a minimum of 0.187" edge margin
from center of hole on mount bracket.
6. Using crossover cable guide assembly as a guide, match drill (#30) 1 hole through mount
bracket; install a temporary fastener.
7. Using crossover cable guide assembly as a guide, match drill (#30) remaining holes
through mount bracket; install temporary fasteners as you go.
8. Temporarily secure base bracket to inboard side of mount bracket so that the following
criteria is met:
•Base bracket maintains a clearance of ~0.01" to avoid contact with rear spar and
forward spar.
•Align assembly laterally so that servo capstan maintains alignment with right outboard
elevator control cable, and so that bridle cables will feed onto grooves in capstan.
9. While holding base bracket in place, drill (#30) holes through fuselage skin using base
bracket horizontal flange as a guide; install temporarily fasteners as you go (see Figure
17).
10. With base bracket temporarily attached to fuselage skin and secured to mount bracket,
drill (#30) holes through base bracket vertical flange using mount bracket asa guide; install
temporary fasteners as you go (see Figure 18).