Citation
SERVICE BULLETIN
SB750-55-10
B.
Do the secondary trim, split trim switch functional test.
(1)
Make sure circuit breaker SEC STAB TRIM CONT on the left circuit breaker panel is engaged.
(2)
Find the secondary trim ON-OFF control switch (SC017) on the upper left portion of the center
pedestal.
(a)
Pull the switch guard up.
(b)
Place the switch to the ON position.
(3)
Move the left half of the secondary split trim switch for NOSE UP and then NOSE DOWN
momentarily, make sure the horizontal stabilizer does not move.
(4)
Move the right half of the secondary split trim switch for NOSE UP and then NOSE DOWN
momentarily, make sure the horizontal stabilizer does not move.
(5)
Move the left and right halves of the secondary split trim switch together for NOSE UP and
then NOSE DOWN and make sure the stabilizer trim follows the trim command.
(6)
Position secondary ON-OFF control switch to OFF.
(a)
Close cover guard.
C.
Do the primary channel A travel verification.
NOTE:
Channel A or B is selectable from the pilot’s display unit (PFD). Press the left arrow key, then
press the FGC SRC key. Observe on the FGC controller that the annunciator displays A.
(1)
Select primary trim channel A.
(2)
Run the trim system to full leading edge down position.
(a)
Make sure the EICAS indicated position is 12 degrees, +0.6 or -0.6 degrees.
(b)
Make sure the EICAS position indication is not amber.
(3)
Run the trim system to full leading edge up position
(a)
Make sure the EICAS indicated position is 1.2 degrees, +0.3 or -0.3 degrees.
(b)
Make sure the EICAS position indication is not amber.
D.
Do the primary channel B travel verification.
NOTE:
Channel A or B is selectable from the pilot’s display unit (PFD). Press the left arrow key, then
press the FGC SRC key. Observe on the FGC controller that the annunciator displays B.
(1)
Select primary trim channel B.
(2)
Run the trim system to full leading edge down position.
(a)
Make sure the EICAS indicated position is 12 degrees, +0.6 or -0.6 degrees.
(b)
Make sure the EICAS position indication is not amber.
(3)
Run the trim system to full leading edge up position.
(a)
Make sure the EICAS indicated position is 1.2 degrees, +0.3 or -0.3 degrees.
(b)
Make sure the EICAS position indication is not amber.
E.
Do the secondary channel travel verification.
(1)
Make sure the circuit breaker SEC STAB TRIM CONT on the left circuit breaker panel is
engaged.
(2)
Locate the secondary trim control switch (SC017) on the upper left portion of the center
pedestal. Pull the switch guard up and place the switch to the ON position.
SB750-55-10
Revision 4 - April 7, 2016
Page 7
