TB 1--1520--240--20--146
c.
Estimated Cost Impact to the Field.
NOMENCLATURE PART NO. / NSN
QUANTITY
COST EACH
TOTAL $
TIE BAR
114R155-1/
6
75.15
,050.90
ASSEMBLY
TIE BAR PIN
114R2168-3/
6
33.34
200.04
TIE BAR PIN
114R2168-4/
6
63.05
378.30
TOTAL COST PER AIRCRAFT = ,692.24
d. TB/MWOs to be Applied Prior to or Concurrently with this Inspection. N/A.
e. Publications Which Require Change as a result of this Inspection -- The following publications shall
be changed to reflect this Technical Bulletin. A copy of this Technical Bulletin shall be inserted in the appropri-
ate TM as authority to implement the change until the printed change is received.
(1) TM 55-1520-240-23, Aviation Unit and Aviation Intermediate Maintenance Manual, CH-47D
Helicopter, Task 5-23.1.1 --
(a) Change paragraph 2.G. to read as follows -- "Inspect washers for deformation (dishing)
and cracks. A dished washer will have a gap between it and the adjacent plate. The maximum separation
between the washer and the adjacent plate is 0.015 inch. No cracks allowed."
(b) Change title of Task 5-23.1.1 to read as follows -- "1200 Hour Tie Bar and Pin Assemblies
Inspection".
(2) TM 55-1520-240-23, Aviation Unit and Aviation Intermediate Maintenance Manual, CH-47D
Helicopter, Task 5-23.2 -- Add the following to the "Initial Setup" section to read as follows: "Equipment Condi-
tion: tie bar inspected in accordance with Task 5-23.1.2".
(3) TM 1-1520-252-23, Aviation Unit and Aviation Intermediate Maintenance Manual, MH-47E
Helicopter, Task 5-31 --
(a) Change paragraph 2.F. to read as follows -- "Inspect washers for deformation (dishing)
and cracks. A dished washer will have a gap between it and the adjacent plate. The maximum separation
between the washer and the adjacent plate is 0.015 inch. No cracks allowed."
(b) Change title of Task 5-31 to read as follows -- "1200 Hour Tie Bar and Pin Assemblies
Inspection".
(4) TM 1-1520-252-23, Aviation Unit and Aviation Intermediate Maintenance Manual, MH-47E
Helicopter, Task 5-32 -- Add the following to the "Initial Setup" section under 'Equipment Condition' to read
as follows: "Tie bar inspected in accordance with Task 5-31.1"
(5) TM 55-1520-240-23, Task 5-23.1.2 (CH-47D) and TM 1-1520-252-23, Task 5-31.1 (MH-47E)
-- Insert a new task, title should read: "Inspect Tie Bar Assembly", procedures to read as follow --
1 Visually inspect tie bar plates for cracks using 10X magnification. No cracks allowed.
2 Inspect the four tie bar slots using a borescope with a rigid right angle probe. Insert the
borescope probe in each slot and examine the plates for cracks along the full depth and
span of the slot. Recommend the probe not exceed 0.110 inch diameter. If a suitable
borescope and probe are not available, visually inspect each slot using a light source.
NOTE
Cracks will appear perpendicular to the plate surfaces and should not be
confused with horizontal scratches or tool marks.
6