BHT-412-MM-2
5-00-00
Page 174 Rev. 16 26 FEB 2013
Export Classification C, ECCN EAR99
c. The maximum acceptable depth of pitting is 0.0005 inch
(0.0127 mm). Depth may be measured by using a dial indicator
with a needle pointed probe. Pitting of measurable depth is
acceptable only in the area on gear or shaft surface outside of
diameter of bolt holes. It is not acceptable within 0.10 inch
(2.54 mm) of edge of a bolt hole. Damage in excess of these
limits is cause for rejection of part.
BHT-412-CR&O 3. Inspect upper flange surface and pilot diameter of ring gear
and mating surfaces of top case fretting and wear.
BHT-412-CR&O 4. Inspect lower flange surface and pilot diameter of ring gear
and mating surfaces of bevel gear support case for fretting and
wear.
5. Visually check index marks on input pinion and inner race
of bearing set for alignment. Inspection may be accomplished
with input quill installed by viewing pinion shaft and bearing
inner race between pinion teeth and main case.
If index marks indicate rotational movement between
pinion and inner race of bearing set, remove quill and
bearing set, and inspect pinion bearing journal for
signs of fretting and bearing inner race spinning.
Visually inspect oil holes in input quill sleeve to
ensure no foreign material is present. Inspect detail
parts to determine cause for bearing inner race
rotation and replace parts as required.
BHT-412-CR&O 6. Inspect bevel gear and main input pinion for general
condition and wear pattern.
BHT-412-CR&O 7. Inspect planetary ring gear, sun gears, and planetary
pinions for general condition and wear pattern. Inspect all parts
of upper and lower planetary visually for excessive wear and
damage. Dimensionally check parts showing evidence of wear
or physical damage.
8. Remove tail rotor drive quill to gain access to accessory
drive and sump gears. Visually inspect accessory case input
quill gear and tail rotor drive quill gear for general condition and
wear pattern.
5-33. EACH 3000 HOURS OF TRANSMISSION (412-040-002) OPERATION (CONT)
DATA REFERENCE INSPECTION TASK DESCRIPTION
INITIAL
MECH OTHER
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