Citation
SERVICE BULLETIN
SB750-55-10
ACCOMPLISHMENT INSTRUCTIONS
1.
Prepare the airplane for maintenance.
A.
Make sure that all switches are in the OFF/NORM position.
B.
Disconnect electrical power from the airplane.
(1)
Disconnect the airplane batteries.
(2)
Disconnect external electrical power.
C.
Attach maintenance warning tags to the batteries and external power receptacle that have
"DO NOT
CONNECT ELECTRICAL POWER - MAINTENANCE IN PROGRESS"
written on them.
2.
Remove access panels 343RL and 343TR. (Refer to the Cessna Model 750 Maintenance Manual,
Chapter 6, Access Plates and Panels Identification - Description and Operation.)
3.
(Refer to Figure 1, Detail A.) Remove the HSTA ECM.
•
4214-0021-5
•
4214-0021-6
•
4214-0021-7
•
4214-0021-8
•
4214-0021-9
•
4214-0021-11
NOTE:
This modification can be done with out removing the horizontal stabilizer trim actuator.
A.
(Refer to Figure 1, Detail A.) Remove and keep the eight MS27039-080 Screws that attach the
two 6731037-X Panels to the HSTA.
B.
(Refer to Figure 1, Detail A.) Remove the four screws that attach the debris cover to the ECM.
(1)
Discard the two forward MS21295-22 Screws and keep the two aft screws for installation later.
C.
Remove the quick release pins that attach the ECM to the base plate.
D.
Remove the ECM from the airplane and return to Cessna.
E.
Remove the six screws, washers and nuts that attach the old base plate to the HSTA and discard.
F.
Return the old base plate to Cessna.
4.
Install the 6738022-7 HSTA Controller Assemblies and the 6738021-9 HSTA Filter Assembly.
A.
(Refer to Figure 1, Detail B.) Attach the 6738023-3 HSTA Base Bracket Assembly to the 9914509
Actuator with six MS24694-S50 Screws, six MS15795-846 Washers, and six NAS1291C3M Nuts.
B.
(Refer to Figure 1, Detail B.) Attach the 6738023-4 HSTA Cover Bracket Assembly to the 6738021-9
HSTA Filter Assembly with two AN3-21A Bolts.
C.
(Refer to Figure 1, Detail B.) Attach the 6738021-9 HSTA Filter Assembly to the 6738023-3 HSTA
Base Bracket Assembly with two AN3-21A Bolts.
D.
(Refer to Figure 1, Detail B.) Attach the debris cover to HSTA cover bracket assembly with two
MS21295-22 Screws.
E.
Install the four NAS1523C3B Packings on the four MS27039-1-16 Screws.
F.
Make sure that the O-ring is present on both sides of the 6738021-9 HSTA Filter Assembly.
G.
Install the four MS27039-1-16 Screws with the NAS1523C3B Packings into the two center holes of
the two 6738022-7 HSTA Controller Assemblies as shown below.
SB750-55-10
Revision 4 - April 7, 2016
Page 3