TB 1-2840-229-20-17
(1) Conducting operations at night only for essential missions and/or to maintain proficiency.
Minimum of 1000 feet AGL on night unaided flights, except during takeoff and landings.
(2) Avoiding prolonged operations inside the avoid or caution regions, as defined in the
appropriate height velocity diagram (Figure 9-3 or 9-3.1 of TM 55-1520-236-10), except when both of the
following conditions have been satisfied:
(a) The flight crew has been trained on all AH-1 Spur Gear failure recognition and
emergency actions.
(b) The flight will be conduced in an area which contains suitable landing areas.
(3) Not operating in areas where "land as soon as possible" could not be accomplished (extensive
swamps, forests, etc.).
(4) Not approving flights over water when another land route is available, even if the land route
is longer in distance. Over water flights are considered high-risk missions.
d. Aircraft records shall be annotated to show a recurring vibration screening every 25 flight hours per
the procedure specified in paragraph 8. Aircraft are cleared for flight as long as the aircraft passes the
recurring 25-hour inspection. Unit Level Logistics System-Aviation (ULLS-A) users shall use inspection
code 52 for this recurring inspection.
NOTE
Some engines may have been pre-screened for vibrations using a test cell.
Those engines that have vibrations within an acceptable range may be
installed in an airframe, but the "on aircraft" AVA Vibration Test of paragraph
NOTE
Further information/guidance will be provided in a follow-on SOF
Message/TB concerning the long-term solution to the N2 Spur Gear
problem, which will dear all AH-1 aircraft for flight and eliminate the need
for the 25-hour recurring inspection.
10. Supply/Parts and Disposition.
a. Parts Required. N/A
b. Requisitioning Instructions. N/A
c. Bulk and Consumable Materials.
NSN
QTY. COST EACH
TOTAL $
NOMENCLATURE
2EA
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.03S0.06
Washer, Flat
.71
.71
1EA
0.213 Drill Bit (#3)
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.79
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.79
1EA
1/4 x 28 UNF Tap
Total Cost Per Aircraft = .50
d. Disposition. N/A
e. Disposition of Hazardous Material. N/A
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