TB 1-1520-238-20-120
NOTE
Frequent repositioning of the mast support wrench is required to prevent
interference and damage.
2. Use appropriate mast support wrench (7--263110003 = 15/16 or 7--263110003--601
= 13/16) and breaker bar to remove the bolt, and recessed washer from the deck. If bolt binds in hole,
loosen struts at mast base to aid in alignment of holes.
3. Remove the self--locking barrel nut and nut retainer from the FS 176 bulkhead.
(b) Remove aft barrel nut, and if necessary the bolt, IAW TM 1--120--238--23 or the IETM and
as follows --
1. Use appropriate mast support wrench (7--263110002 = 15/16 or 7--263110002--601
= 13/16) and breaker bar, loosen bolt and unthread from barrel nut. If bolt binds in hole, loosen struts
at mast base to aid in alignment of holes.
NOTE
If the threads of the bolt are not damaged, do not remove the bolt from the deck.
2. Raise bolt clear of barrel nut. Remove the self--locking barrel nut and nut retainer from
the FS 230 bulkhead.
3. If the bolt is damaged and must be removed, remove hardware attaching struts to
mast support base IAW TM 1--1520--238--23 or the IETM so that struts can be removed to allow bolt
to clear nacelle frame upon removal.
4. Perform a visual inspection/identification of all 4 barrel nuts/bolts.
NOTE
QA all bolts and nuts for serviceability prior to reinstallation.
a. Inspect the nut with a 10 power magnifier for elongation, thread damage,
corrosion, and/or cracks.
NOTE
If the run--on torque is less than 50 inch pounds, the nut may be reused and
the recurring torque inspection will be performed IAW para 8C until the nut
can be replaced.
b. Visually inspect bolt for damage.
c.
If no damage to the nut or bolt is noted, proceed to para 8B(5).
d. If any damage to the nut or bolt is noted --
1. Contact the Tech POC in para 16A immediately for disposition instructions.
2. Check frame support holes for cracks and damamge IAW TM 1--1520--238--23,
and for corrosion IAW TM 1--1520--238--23 paragraph 1.49, or the IETM (Aircraft General
Maintenance -- Aircraft General Repair -- Corrosion).
3. Check strut base for damage IAW TM 1--1520--238--23, paragraph 2.89.5, or
the IETM.
4. Install a new barrel nut and bolt IAW para 9A.
5. If the barrel nut can be identified as HS5813--12 series and the bolt is
HS4243V12H34/62 or HS4243--12H34/62, the inspection is complete for this nut/bolt and can be
reinstalled IAW para 9. No recurring torque check is required. Continue the inspection until all four nuts
and bolts are completed.
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