(3) 1st-stage fairing is a single 360° piece. It houses the 1st-stage vanes which hook into slots on
forward inner diameter of fairing. Fairing forms splitter between fan discharge air and core
engine inlet air. 1st-stage contains 78 vanes while 2nd and 3rd-stages contain 112 vanes.
Purpose of vanes is to slow down speed of the air coming off fan rotor blades thus increasing
pressure. Interstage seal segments at each stage forms inner diameter of fan stator vanes.
C. High Pressure Compressor
(1) Compressor rotor features a unitized spool/disk structural concept. By use of circumferential
dovetails and a smooth-spool rotor structure, several stages of blades can be installed on a
single piece of rotor structure.
(2) There are five major structural elements and two main bolted joints. 1st-stage disk, 2nd-stage
disk and integral with front stub shaft, and 3rd thru 9th stage spool are all joined at one bolted
joint. These are followed with 10th-stage disk and 11th thru 14th-stage spool integral with rear
shaft bolted joint at 10th-stage. Interfering rabbet flange joints are used for proper positioning
of parts and rotor stability.
(3) Cooling and pressurizing air is provided by using shaft as air duct. The rotor lands are coated
with an abradable material to allow for close vane-to-spool clearances.
(4) 1st and 2nd-stage blades are installed in axial dovetail slots and are held by individual blade
retainers. 3rd thru 14th-stage blades are stacked circumstantially and are held by two locking
lugs. 6th thru 9th-stage blades have one additional locking lug. 1st-stage blades feature a
mid-span shroud to provide blade stability and reduce vibratory stresses.
(5) Rotor drives accessories by means of a splined adapter that is fitted into internal splines of
front stub shaft.
(6) Compressor discharge air is sealed from sump area by a 6-tooth rotating seal. Seal support is
integral with 11th thru 14th-stage spool/shaft.
(7) Compressor stator assembly consists of casing halves, inlet guide vanes, and 13 stages of
vanes. Stator assembly provides structural support between fan frame and compressor rear
frame.
(8) Stator casings are matched halves machined from forged steel. Halves are bolted together
horizontally at 3 and 9 o'clock splitlines. Alignment is maintained by 8 body-bound bolts on
each flange and clamped additionally by 29 more bolts on each flange. Three bleed manifolds
are welded to casing: bleed air extracted from 7th-stage vane is used for turbine 1st-stage
nozzle cooling, 8th-stage bleed air is for airplane services, 10th-stage bleed air is used for
turbine 2nd-stage nozzle cooling. Borescope ports are provided on right side of stator at all
vane stages for internal inspection of compressor.
(9) At the high pressure end of the compressor stator, an insulating liner shields the case
structure, including aft flange, from effects of high temperature air. The insulating liner also
permits closer rotor-to-stator clearances. There are two configurations of stator cases. One has
liners at the twelfth and thirteenth stages. The other configuration has a liner at the thirteenth
stage only.
767
AIRCRAFT MAINTENANCE MANUAL
CF6-80A SERIES ENGINES
72-30-00
NoC
Page 2
D633T1B7 Dec 22/2016
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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