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During implementation of the superseded Service Bulletin 340–27–105 it was found that the trunnion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
Service Bulletin

19 July 2013 340–27–115

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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.
Service Bulletin

19 July 2013 340–27–115

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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

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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.
Service Bulletin

19 July 2013 340–27–115

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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
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19 July 2013 340–27–115

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(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

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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

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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 column

trunnion 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.
Service Bulletin

19 July 2013 340–27–115

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FWD

STOP

SCREW

TURNBUCKLES

PUSH ROD

SHOULDER

CONTROL

COLUMN

TRUNNION

CONTROL

CAPSTAN CABLES PUSH ROD

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

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A31443

123 4 5 6

7

8

10

9

Controll Column Trunnion – Corrective Action

FIG. 2