TB 1--1520--240--20--141
11. Special Tools and Fixtures Required. As required.
12. Application.
a. Category of Maintenance. AVUM. Aircraft downtime will be charged to AVUM maintenance.
b. Estimated Time Required-
(1) Time to complete the records inspection -- Total of 0.5 man-hours using 1 person.
(2) Time to complete inspection of the tie bar assembly --
(a) Total of 124 man-hours using 8 persons.
(b) Total of 20.0 hours downtime for one end item. Down time includes time required mainte-
nance test flight.
(3) Time for Tachometer Rework --
(a) Total of 1 man-hours using 1 person.
(b) Total of 1 hour downtime for one end item.
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
1615-00-740-6480
TIE BAR PIN
114R2168-3/
6
33.34
200.04
1615-00-740-6477
TIE BAR PIN
114R2168-4/
6
63.05
378.30
1615-01-115-3619
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 55-1520-240-10, Operator's Manual for Army CH-47D Helicopter -- Change maximum
transient rotor speed limit to 111 percent RPM.
(2) TM 55-1520-240-23, Aviation Unit and Aviation Intermediate Maintenance Manual, CH-47D
Helicopter --
(a) Task 1-91, page 1-284, change the retirement schedule hours for the forward and aft tie
bar assembly, P/N 114R2155-1, to be 4800 hours TSN.
(b) Add the following conditional inspection to Task 1-92 --
1 The inspection frequency shall read -- "When rotor RPM exceeds 111 percent, but
does exceed 115 percent RPM."
2 The inspection requirement shall read -- "Inspect the rotor head tie bar assemblies
per task 5-23.1.1 at the next rotor head removal, but no later than completion of next
phased maintenance."
(c) Task 1-92, Reference 55 -- change "Speed" to read "RPM".
(d) Task 5-23.1.1, page 5-94.2.1, add "Borescope" to tools list.
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