TB
1-1520-237-20-167
b.
For manpower/downtime and funding impacts. See paragraph 12.
c.
The purpose of this TB is to add a clearance notch in station 635 lower frame for the tail wheel strut.
End Items to be inspected. UH-60A series helicopters serial number 77-22714 through 89-26172.
5.
UH-60L series helicopters serial number 89-26179 through 90-26277.
6.
Assembly to be Modified.
NSN
Part Number
Nomenclature
70211-05009-041
1560-01-253-0358
Frame Assembly
Parts to be Inspected. N/A.
7.
Inspection Procedures. Inspect helicopter lower frame at station 635 figure 1 for notched with an angle
8.
riveted across bottom of frame web, if repair is complete, TB does not apply, continue to paragraph 9, and
annotate log book.
9.
after a one time inspection of station 635 lower frame or modifying the lower frame assembly as follows:
a.
Remove tail landing gear per TM 1-1520-237-23, Chapter 3.
b. Cut or route a 1.00 inch X 0.40 inch deep notch with 0.160 inch radius in station 635 lower web
(70211-05009-101) centered on buttline 0 (Figure 1).
c.
Trime frame assembly flange as follows:
(1) Measure outboard 2.00 inches on each side of buttline 0
(2) Measure back from front of flange 0.380 inch.
(3) Remove material from front of flange.
d. Treat new exposed surfaces with Chemical Coating for Aluminum (MIL-C-81706, Class 1A) and
Expoxy Primer (MIL-P-23377).
e. Temporarily clamp angle (70211-05009-110) on front of station 635 frame assembly centered on
buttline 0, or 3.46 inches from tooling hole, approximately 0.40 inch below top of frame flange.
f. Transfer-drill seven No, 40 (0.098-inch diameter) holes from angle through frame assembly and
open to final size No. 21 (0.159-inch diameter).
g.
Remove angle (70211-05009-110) from station 635 frame assemblyi and deburr drilled parts.
h.
Attach angle to station 635 with seven MS20470AD5 rivets.
Install tail landing gear per TM 1-1520-237-23, Chapter 3.
i.
10. Supply/Parts and Disposition.
a. Parts Required
NOMENCLATURE CAGE
PART NUMBER
NSN
QUANTITY
70211-05009-110 1
Angle
78286
MS20470AD5
Rivet
7
96906
b. Requisitioning Instructions. Requisition replacement parts through normal supply channels using
normal supply procedures. All requisitions shall use project code "CST" per this TB.
c.
Bulk and Consumable Materials. N/A.
2
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