### Service Bulletin

19 July 2013 

# 340–27–115

Page 1 of 10 

### ATA CHAPTER: 27 FLIGHT CONTROLS – STALL WARNING/IDENTIFICATION SYSTEM – INSPECTION OF THE STICK PUSHER RIGGING Mod No. –

1. PLANNING INFORMATION

A. EFFECTIVITY (1) Aircraft: Aircraft Mfg. Serial No’s SAAB 340B – 160 thru – 459. NOTE : This Service Bulletin supersedes Service Bulletins 340–27–105 and 340–27–114. (2) Spares: Not affected.

B. REASON At delivery of the SAAB 340B (A/C 160–459), the stick pusher max elevator position was set to 7.5 ° trailing edge down. This had not been correctly referenced in the AMM that states an elevator position of 4 ° trailing edge down for all aircraft. In the situation that a SAAB 340B aircraft has been re–rigged in accordance with current AMM procedure, there is a possibility that the deflection of the elevator will be less than intended affecting aircraft handling at stall at the outer part of the envelope at maximum flap setting and aft CG configuration. During implementation of the superseded Service Bulletin 340–27–105 it was found that the trunnion installed at the lower part of the control column was incorrectly installed on some aircraft. The trunnion must be correctly installed in order to ensure a proper inspection of the stick pusher rigging. Inspection and, if necessary, adjustment in accordance with this Service Bulletin will make sure that the stick pusher max elevator position is correct.

C. DESCRIPTION This Service Bulletin gives instructions for: FOR A/C POST SB 340–27–105 – Inspection of the control column trunnion for correct installation – If necessary, correct the installation of the control column trunnion and inspection of the stick pusher rigging and adjustment of the stick pusher rigging (if necessary). FOR A/C PRE SB 340–27–105 – Inspection of the control column trunnion for correct installation – If necessary, correct the installation of the control column trunnion – Inspection of the stick pusher rigging – Adjustment of the stick pusher rigging (if necessary). FOR A/C ALL AFFECTED

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19 July 2013 

# 340–27–115

Page 2 of 10 D. COMPLIANCE Mandatory. Saab recommends this Service Bulletin to be performed within 24 months from release of this Service Bulletin. This Service Bulletin is under EASA consideration for an Airworthiness Directive. The final compliance terms will be set by the EASA Airworthiness Directive (AD) when issued.

E. APPROVAL The technical content of this Service Bulletin is approved under the authority of DOA nr. EASA.21J.066.

F. MANPOWER Estimated time to complete this Service Bulletin is: FOR A/C PRE SB 340–27–105 3 persons required. Total manhours: 12 Elapsed time (hours): 4 FOR A/C POST SB 340–27–105 1 persons required. Total manhours: 2 Elapsed time (hours): 2 FOR A/C ALL AFFECTED NOTE : The estimated time is for completion of inspection only, possible adjustment of the stick pusher rigging is not included. Labour cost at operators expense.

G. MATERIAL – COST AND AVAILABILITY Refer to para 3. Material Information.

H. TOOLING (1) Inspection: (a) Contour board, elevator, TOV 915892. Alternative: 7293540–501 or TOV2–4650217. (b) Platform (for access to the horizontal stabilizer and the elevator). (c) Protractor, four bar, TOV 915894 or TOV 915424 Alternative: Digital clinometer with an accuracy of ± 0.2 °

. (d) Sign, warning, ”DO NOT OPERATE THE FLIGHT CONTROLS”. (e) Tensiometer, Cable, TDO3–4650231 (Pacific Scientific No. T5–2002–104–00) or as alternative; Pacific Scientific No. T5–2002–101–00, calibrated for cable type 7x7, 3/32 inch. (2) Adjustment (If necessary): (a) Cable tensiometer.

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19 July 2013 

# 340–27–115

Page 3 of 10 I. WEIGHT AND BALANCE None.

J. ELECTRICAL LOAD DATA Not affected.

K. REFERENCES Aircraft Maintenance Manual (AMM) 06–30–00–00 27–00–00–05 27–31–00–02

L. OTHER PUBLICATIONS AFFECTED Aircraft Maintenance Manual (AMM) 27–35–20–04

2. ACCOMPLISHMENT INSTRUCTIONS FOR A/C PRE SB 340–27–105

A. JOB SET–UP (1) Before you start the SB, make sure: – The documentation is available – The special tools are available – The parts and local supply items listed in the Service Bulletin are available. (2) In the flight compartment, put up the warning sign ”DO NOT OPERATE THE FLIGHT CONTROLS”. (3) On the RH circuit breaker panel 10VU, open, tag and safety the circuit breaker:

LABEL POS C/B STICK PUSHER L–4 36 WH (4) Remove the access door 115AL, Ref. AMM 06–30–00–00. (5) Put the access platform in position.

B. INSPECTION REF. FIG. 1 (1) Inspect the control column trunnion (the trunnion) for correct installation (a) Measure and make sure that the trunnion is correctly installed and that the dimension 0.78 in (20.0 mm) in view A is correct. – If the trunnion is correctly installed, continue with step (2) – If the trunnion is not correctly installed, change the position of the trunnion, ref. step (1)(b): (b) Change the position of the trunnion REF. FIG. 2 1 Remove and discard the cotter pin (1). Remove the nut (2), the washer (3) and the bolt (10) that attach the pushrod (5) to the fork of the quadrant wheel (4).

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19 July 2013 

# 340–27–115

Page 4 of 10 2 Remove and discard the cotter pin (8). Remove the lock pin (7) together with the washer (6). 3 Move the pushrod (5) forward, until you can rotate the trunnion (9). Rotate the trunnion 180 ° and push the pushrod (5) into the trunnion (9) again. 4 On the trunnion (9), make sure that the dimension 0.78 in (20.0 mm) is correct, ref. view A in figure 1. 5 Hold the pushrod (5) in correct position and install the the bolt (10), the washer (3) and the nut (2). Torque the nut (3) to between 110–180 lbf.in (12.4 – 20.3 Nm). Install a new cotter pin (1). 6 Install the lock pin (7) together with the washer (6). Safety the lock pin (7) with a new cotter pin (8).
7 Continue with step (2). (2) Engage the gust lock. (3) Turn the capstan clockwise until it is against its mechanical stop. With the capstan in this position, check and make sure that: (a) the upper control cable leaves the quadrant not less than 0.078 in ( ± 2.0 mm) of the black arrowhead indicator. If necessary, remove the clips from the turnbuckles and adjust the control cable length. (b) the cable tension is within 50 ± 5 lb (22.7 ± 2.3 Kg). If necessary, adjust the cable tension and safety the turnbuckles with new clips or lockwire, Ref. AMM 27–00–00–05. (4) Disengage the gust lock. (5) Verify the elevator deflection (a) Install the elevator contour board and the four bar protractor (or the digital clinometer) on the horizontal stabilizer and the elevator. (b) Move the elevator to neutral position (0 ° ) and reset the four bar protractor. (c) Engage the gust lock. (d) With the capstan against its mechanical stop, hold the control column and carefully disengage the gust lock. (e) Carefully move the control column until there is no clearance between the pushrod shoulder and the control column trunnion. Hold the control column in this position and make sure the elevator position is 7.5 ° ± 1.0 ° down. – If the elevator position is within limit, no further action required, continue with Para 2.C. (Job Close–Up). – If the elevator position is not within limit, do the steps that follow: 1 Do the rigging of the elevator controls, Ref. AMM 27–31–00–02. 2 Verify correct elevator deflection again, refer to steps 2.B.(5)(a) thru (e). – If the elevator position is within limit, no further action is required, continue with Para 2.C. (Job Close–Up). – If the elevator position is not within limit, do the steps that follow:
a Pull the control column fully aft until it touches its stop. Hold the control column in this position. b Measure and make sure that the clearance between the pushrod shoulder and the control column trunnion is 0.06 ± 0.02 in (1.5 ± 0.5 mm).

c If necessary, cut and remove the lockwire from the stop screw and adjust until correct clearance is achieved.

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19 July 2013 

# 340–27–115

Page 5 of 10 d Safety the stop screw with lockwire.

e Verify the the upper control cable leaves the quadrant within specified limit and that the cable tension is correct, refer to step 2.B.(3). f Verify correct elevator deflection again, refer to steps 2.B.(5)(a) thru (e). – If the elevator position is within limit, continue with step (6). – If the elevator position is not within limit, contact Saab for corrective action. Saab AB Business Area Support and Services Air Division Technical Support E–mail: Saab340.techsupport@saabgroup.com Fax: +46 (0) 13 18 48 74 (6) Move the control column slowly to fully aft and forward position. At the same time make sure there is a clearance between all components and no binding. (7) If, during the inspection, any value is found outside specified limit, make a record of the value and corrective action. Send the details to Saab, refer to E–mail and/or Fax details above.

C. JOB CLOSE–UP (1) Remove all the tools and equipment from the work area. Make sure the work area is clean. (2) Install the access door 115AL, Ref. AMM 06–30–00–00. (3) On the RH circuit breaker panel 10VU, remove the tag and close the circuit breaker:

LABEL POS C/B STICK PUSHER L–4 36 WH (4) Remove the warning sign ”DO NOT OPERATE THE FLIGHT CONTROLS” from the flight compartment. FOR A/C POST SB 340–27–105

D. JOB SET–UP (1) Before you start the SB, make sure: – The documentation is available – The special tools are available – The parts and local supply items listed in the Service Bulletin are available. (2) In the flight compartment, put up the warning sign ”DO NOT OPERATE THE FLIGHT CONTROLS”. (3) On the RH circuit breaker panel 10VU, open, tag and safety the circuit breaker:

LABEL POS C/B STICK PUSHER L–4 36 WH (4) Remove the access door 115AL, Ref. AMM 06–30–00–00.

E. INSPECTION REF. FIG. 1 (1) Inspect the control column trunnion (the trunnion) for correct installation

### Service Bulletin

19 July 2013 

# 340–27–115

Page 6 of 10 (a) Measure and make sure that the trunnion is correctly installed and that the dimension 0.78 in (20.0 mm) in view A is correct. – If the trunnion is correctly installed, continue with Para F. Job Close–Up. – If the trunnion is not correctly installed, change the position of the trunnion, ref. step (1)(b): (b) Change the position of the trunnion REF. FIG. 2 1 Remove and discard the cotter pin (1). Remove the nut (2), the washer (3) and the bolt (10) that attach the pushrod (5) to the fork of the quadrant wheel (4). 2 Remove and discard the cotter pin (8). Remove the lock pin (7) together with the washer (6). 3 Move the pushrod (5) forward, until you can rotate the trunnion (9). Rotate the trunnion 180 ° and push the pushrod (5) into the trunnion (9) again. 4 On the trunnion (9), make sure that the dimension 0.78 in (20.0 mm) is correct, ref. view A in figure 1. 5 Hold the pushrod (5) in correct position and install the the bolt (10), the washer (3) and the nut (2). Torque the nut (3) to between 110–180 lbf.in (12.4 – 20.3 Nm). Install a new cotter pin (1). 6 Install the lock pin (7) together with the washer (6). Safety the lock pin (7) with a new cotter pin (8).
7 Continue with step (2). (2) Engage the gust lock. (3) Put the access platform in position. (4) Turn the capstan clockwise until it is against its mechanical stop. With the capstan in this position, check and make sure that: (a) the upper control cable leaves the quadrant not less than 0.078 in ( ± 2.0 mm) of the black arrowhead indicator. If necessary, remove the clips from the turnbuckles and adjust the control cable length. (b) the cable tension is within 50 ± 5 lb (22.7 ± 2.3 Kg). If necessary, adjust the cable tension and safety the turnbuckles with new clips or lockwire, Ref. AMM 27–00–00–05. (5) Disengage the gust lock. (6) Verify the elevator deflection (a) Install the elevator contour board and the four bar protractor (or the digital clinometer) on the horizontal stabilizer and the elevator. (b) Move the elevator to neutral position (0 ° ) and reset the four bar protractor. (c) Engage the gust lock. (d) With the capstan against its mechanical stop, hold the control column and carefully disengage the gust lock. (e) Carefully move the control column until there is no clearance between the pushrod shoulder and the control column trunnion. Hold the control column in this position and make sure the elevator position is 7.5 ° ± 1.0 ° down. – If the elevator position is within limit, no further action required, continue with Para 2.F. (Job Close–Up). – If the elevator position is not within limit, do the steps that follow: 1 Do the rigging of the elevator controls, Ref. AMM 27–31–00–02.

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19 July 2013 

# 340–27–115

Page 7 of 10 2 Verify correct elevator deflection again, refer to steps 2.E.(6)(a) thru (e). – If the elevator position is within limit, no further action is required, continue with Para 2.F. (Job Close–Up). – If the elevator position is not within limit, do the steps that follow:
a Pull the control column fully aft until it touches its stop. Hold the control column in this position. b Measure and make sure that the clearance between the pushrod shoulder and the control column trunnion is 0.06 ± 0.02 in (1.5 ± 0.5 mm).

c If necessary, cut and remove the lockwire from the stop screw and adjust until correct clearance is achieved. d Safety the stop screw with lockwire.

e Verify the the upper control cable leaves the quadrant within specified limit and that the cable tension is correct, refer to step 2.E.(4). f Verify correct elevator deflection again, refer to steps 2.E.(6)(a) thru (e). – If the elevator position is within limit, continue with step (7). – If the elevator position is not within limit, contact Saab for corrective action. Saab AB Business Area Support and Services Air Division Technical Support E–mail: Saab340.techsupport@saabgroup.com Fax: +46 (0) 13 18 48 74 (7) Move the control column slowly to fully aft and forward position. At the same time make sure there is a clearance between all components and no binding. (8) If, during the inspection, any value is found outside specified limit, make a record of the value and corrective action. Send the details to Saab, refer to E–mail and/or Fax details above.

F. JOB CLOSE–UP (1) Remove all the tools and equipment from the work area. Make sure the work area is clean. (2) Install the access door 115AL, Ref. AMM 06–30–00–00. (3) On the RH circuit breaker panel 10VU, remove the tag and close the circuit breaker:

LABEL POS C/B STICK PUSHER L–4 36 WH (4) Remove the warning sign ”DO NOT OPERATE THE FLIGHT CONTROLS” from the flight compartment.

### Service Bulletin

19 July 2013 

# 340–27–115

Page 8 of 10 FOR A/C ALL AFFECTED

3. MATERIAL INFORMATION

A. Parts required for Inspection/adjustment:

Item Part Number Qty Nomenclature Designation Remarks – MS21256–1 Alt. MS20995C32 4

A/R Safety clip

Lockwire –

– For adjustment

CRES, 0.032 in(0.81 mm) diameter. 1, 8 – FIG. 2 MS24665–155 2 Cotter pin – If rotation of the control columntrunnion is necessary.

B. Local supply (for adjustment)

Item Part Number Qty Nomenclature Designation Remarks – MS20995C32 A/R Lockwire – CRES, 0.032 in(0.81 mm) diameter.
NOTE : Equivalent materials can be used for listed items, Ref. SRM 51–33–00.

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19 July 2013 

# 340–27–115

Page 9 of 10 FWD STOP SCREW

TURNBUCKLES PUSH ROD SHOULDER

CONTROL COLUMN TRUNNION CONTROL CABLES PUSH ROD CAPSTAN

SERVO ACTUATOR

STA 145.10 STA 181.10 A CONTROL COLUMN



### VIEW A 0.78 in (20.0 mm)

REF TRUNNION

A31442 Stick Pusher Mechanism – Inspection FIG. 1

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19 July 2013 

# 340–27–115

Page 10 of 10 A31443 123 4 5 6 7

8

10 9

Controll Column Trunnion – Corrective Action FIG. 2