1) Put a label on the borescope plug.
SUBTASK 72-00-00-016-121-G00
(4) Remove borescope plugs B3-1 and B3-2 to examine the 1st and the 2nd-stage rotors and
shrouds, and the 2nd-stage nozzle (Figure 601).
(a) Put labels on the borescope plugs.
SUBTASK 72-00-00-296-031-G00
(5) Use the borescope to examine the leading edge of the vane airfoils on the 1st-stage HPT
nozzle for the conditions that follow (Figure 611):
Condition Maximum Serviceable Limit
Cracks that connect the nose holes Permitted.
Cracks that go out from the nose
holes (but do not connect to the nose
holes)
Permitted.
Burns, erosion or corrosion (can be
fully through the metal)
Permitted, if the area of metal loss is less than 0.20 square inches (129 square
mm) on each vane. A maximum of four vanes in a 90 degree arc can have
damage. If adjacent vanes have signs of damage, replace the three fuel nozzles
that are upstream from the area of the damaged vanes. Refer to the
Continue-In-Operation Limits.
Material that is gone, because of
cracks/impact damage.
Permitted, if the area of the damage is less than 0.10 square inch (64.5 square
mm) on each vane. It is permitted to have some burns around the cracked area.
SUBTASK 72-00-00-296-032-G00
(6) Use the borescope to examine the concave and convex surface of the vane airfoils on the
1st-stage HPT nozzle for the conditions that follow (Figure 611):
Condition Maximum Serviceable Limit
Radial cracks out of the gill holes Permitted.
Other cracks Permitted, if no more than two cracks connect at one point.
Burns or spalls (no holes through the
basic metal)
Permitted.
Cracks in the fillet area adjacent to
the inner and the outer platforms
Permitted.
Burns and erosion Permitted, if the damaged area is less than 0.1 square inch (64.5 square mm) on
each vane. Refer to the Continue-In-Operation Limits.
SUBTASK 72-00-00-296-033-G00
(7) Use the borescope to examine the trailing edge of the vane airfoil on the 1st-stage HPT nozzle
for the conditions that follow (Figure 611):
Condition Maximum Serviceable Limit
Axial cracks that start at the slots
adjacent to the trailing edge
Any number 0.30 inch (7.6 mm) long if they are separated by 0.10 inch (2.5
mm) from other cracks. Two per vane 0.50 inch (12.7 mm) long if they are
separated by 0.30 inch (7.6mm) One 0.70 inch (17.8mm) long if it is separated
by 0.50 inch (12.7 mm) from 0.50 inch (12.7 mm) long cracks.
Buckling or bowing Permitted.
767
AIRCRAFT MAINTENANCE MANUAL
CF6-80A SERIES ENGINES
72-00-00
NoC
Page 612
D633T1B7 Aug 22/2017
ECCN 9E991 BOEING PROPRIETARY - Copyright © Unpublished Work - See title page for details
EFFECTIVITY
ABX 001-007, 011, 012, 016-019, 021, 022, 025, 101,
109, 114, 115, 314-999
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