TB 1-1520-240-20-96
four (4) shallow flat bottom holes that are filled with white paint. The holes are equally spaced 90 degrees
apart around the body assembly. Also, "Rev D" is marked on the body assembly. The designs prior to revision
D do not have four (4) shallow flat bottom holes filled with white paint on the body assembly, or the "REV D"
marking.
5.
End Items to be inspected. All CH-47D, MH-47D, and MH-47E aircraft.
6.
Assembly Components to be Inspected.
NATIONAL STOCK NUMBER
PART NUMBER
NOMENCLATURE
N/A
145H1201-5 (AE-A620-14)
Module Assembly, Power Control
N/A
145H1201-6 (AE-A620-15)
Module Assembly, Power Control
7.
Parts to be Inspected.
NATIONAL STOCK NUMBER
PART NUMBER
NOMENCLATURE
4C3074
Check Valve
Inspection Procedures.
8.
a.
Prepare aircraft for safe ground maintenance.
b. Locate the No. 1 power control module assembly (refer to TM 55-1520-240-23P-2, Figure 206, Item
26 or TM 1-1520-252-23P-2, Figure 7-7, Item 28) and No. 2 power control module assembly (refer to
TM 55-1520-240-23P-2, Figure 215, Index 19 or TM 1-1520-252-23P-2, Figure 7-16, Item 19).
c. If necessary, remove the Crissair, Inc. P/N 4C3074 check valves from power control module assem-
blies from the ports marked "FLT CONT PUMP, only (refer TM 55-1520-240-23-6, Task 7-54.1 or TM
1-1520-252-23-7, Task 7-66).
NOTE
Only the Crissair, Inc. P/N 4C3074 check valve installed in the port marked "FLT CONT
PUMP" of the power control module assemblies cited in paragraph 6 above need to be
replaced. The other two valves in the assemblies are "on condition" replacement items.
NOTE
The Crissair, Inc. P/N 4C3074 check valves installed in the following components do not
need to be replaced as they are "on condition" replacement items:
NOMENCLATURE
PART NUMBER
MODULE HOUSING ASSEMBLY
145HS551-4 (AE-A620-33D1A)
MODULE HOUSING ASSEMBLY
145HS601-4 (AE-A620-23D1A)
d. Visually inspect the P/N 4C3074 check valve for four (4) shallow flat bottom holes filled with white
paint. The holes are equally spaced 90 degrees apart around the valve base. Also, the marking "REV D" is
marked on the body assembly.
e. If there are four (4) holes filled with white paint and/or "REV D" is marked on the valve base, the valve
is the improved revision D one-piece design and the inspection is complete. Reinstall the check valve (refer
to TM 55-1520-240-23-6, Task 7-54.2 or TM 1-1520-252-23-7, Task 7-67) and record and report compliance
f. If the valve is not the improved revision D one-piece design as described above, proceed to para-
3