(a) Put labels on the borescope plugs that you removed.
SUBTASK 72-00-00-296-048-G00
(5) Use the borescope to examine the 1st-stage LPT nozzle (Figure 617, Figure 618).
(a) Examine all the areas on the nozzle vanes for the conditions that follow:
Condition Maximum Serviceable Limit
Cracks One crack that is less than 0.25 inch (6.4 mm) in length is permitted on a vane.
Nicks and dents Permitted if the metal has no tears.
Burned areas Burned areas that are less than 1.0 square inch (6.45 square cm) are permitted.
One burned vane must be adjacent to a minimum of two vanes that have no burns.
Tears One tear that is less than 0.5 inch (13 mm) in length is permitted on each vane. One
stage must have less than 0.5 square inch (3.2 sq. cm) of total area that is torn.
SUBTASK 72-00-00-296-049-G00
(6) Use the borescope to examine the LPT stator vanes (2nd through 4th-stage) (Figure 619):
(a) Examine the leading edge of the fillet radius of the LPT stator vanes for the conditions
that follow:
Condition Maximum Serviceable Limit
Cracks One crack less than 0.50 inch (12.7 mm) in length is permitted on a vane. Two vanes
on each nozzle segment are permitted to have a crack.
SUBTASK 72-00-00-216-050-G00
(7) Use the borescope to examine the LPT rotor blades (Figure 620).
(a) Examine all the areas of the LPT rotor blades for the condition that follows:
Condition Maximum Serviceable Limit
Cracks Not permitted.
(b) Examine the leading and trailing edges of the LPT rotor blades for the conditions that
follow:
Condition Maximum Serviceable Limit
Nicks Less than 0.04 inch (1.0 mm) in depth are permitted.
Dents (small) All small dents are permitted if there are no distortions (that go out) on the
opposite side of the blade. Five small dents are permitted if they have distortions
that are less than 0.05 inch (1.3 mm) on the opposite side of the blade.
Dents (large) or pieces of metal that
are gone
Two damaged areas are permitted on each blade. The damage must be 0.50 inch
(12.7 mm) from the leading edge and 0.375 inch (9.53 mm) from the trailing edge.
The damage must have a radial separation of more than 0.50 inch (12.7 mm).
Cracks in the dented areas Cracks less than 0.380 inch (9.65 mm) are permitted in dented areas. The cracks
must not be in other areas.
Cracks that go out from dents,
broken areas, or the root fillet
Not permitted.
(c) Examine the concave and convex surface of the LPT rotor blades for the conditions that
follow:
767
AIRCRAFT MAINTENANCE MANUAL
CF6-80A SERIES ENGINES
72-00-00
NoC
Page 621
D633T1B7 Dec 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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