75-23-08 R5 CESSNA: Amendment 39-2419 as amended by Amendment 39-
2687, 39-2830, 39-3298, and
39-3609, are further amended by Amendment 39-5451. Applies to 
T310, 320, 340, 401, and 411 series
airplanes and Models 402, 402A, 402B, 414, 421, 421A, 421B and 
421C (S/N 421C0001 through
421C0683) airplanes, certificated in any category.
This AD is issued to combine in one document inspections and 
parts replacements required by
previous ADs and require modifications now available which will 
increase the reliability of the exhaust
systems on the affected airplanes.
Compliance: Required as indicated, unless previously 
accomplished.
To detect incipient failure and improve reliability of the engine 
exhaust systems installed on the above-noted
airplanes, accomplish the following:
I. Repetitive General Exhaust System Inspection
A. On all new and in-service airplanes listed above, visually 
inspect the exhaust system
components per procedures hereafter specified in accordance with 
the following schedule:
50 HOUR INSPECTION
Inspect components not listed in Table II or III within 50 hours 
time-in-service after
the effective date of this AD or last inspection per AD 75-04-01 
and within each 50 hours time-in-service
thereafter.
100 HOUR INSPECTION
Inspect components listed in Table II within 100 hours time-in-
service after the
effective date of this AD or last inspection in accordance with 
this AD and within each 100 hours time-in-service
thereafter.
EXEMPT COMPONENTS
Components listed in Table III are exempt from these inspection 
requirements.
1. CLEANING - In order to properly inspect the exhaust system, 
components must be
clean and free of oil, grease, etc. If required, clean as 
follows:
a. Spray engine exhaust components with a suitable solvent (such 
as Stoddard
Solvent), allow to drain, and then wipe dry with a clean cloth.
WARNING
NEVER USE HIGHLY FLAMMABLE SOLVENTS ON ENGINE EXHAUST SYSTEMS.
NEVER USE A WIRE BRUSH OR ABRASIVES TO CLEAN EXHAUST SYSTEMS OR 
MARK
ON THE SYSTEM WITH LEAD PENCILS.
b. Remove the heat shields from the turbocharger in accordance 
with heat shield
removal procedures in the Service Manual.
c. Remove shields around the exhaust bellows or slip joints, 
multisegment "V"
band clamps at joints, and other items which might hinder 
inspection of the system.
NOTE
Do not remove clamps.
2. VISUAL INSPECTION OF COMPLETE SYSTEM
NOTE
Conduct this inspection when the engine is cool
a. Visually inspect exhaust stacks for burned areas, cracks and 
looseness. Insure that
attach bolts are properly torqued in accordance with the aircraft 
Service Manual.
NOTE
During this inspection give special attention to condition of 
bellows and welded areas along seams and
around bellows, and weld seams around exhaust system components.
b. Visually inspect the flexible connection between the waste-
gate and overboard duct
(when applicable) for cracks and security.
c. Correct any major leaks in all areas of the exhaust system 
except waste-gate to
tailpipe flexible coupling (when applicable) by replacement of 
defective parts or by repair in accordance with
Part 43 of the FARs.
d. Visually inspect exhaust joint springs for correct 
compression. If the joint is
disturbed or if springs are obviously loose, proceed with the 
following inspection. (See Figure 1).
i. Before removal of exhaust joint springs, measure installed 
length of each
spring. Those compressed to less than 0.45 inch must be replaced.
ii. Remove all springs and measure free length. Springs having a 
free length of
less than 0.57 inch must be replaced.
NOTE
Add AN960-10 washers under head of joint bolts as required to 
obtain correct dimension. During
installation, joint bolts should be tightened gradually and 
spring length checked frequently to prevent over
compression of springs.
iii. Reinstall springs and measure installed length. Length must 
be 0.51 plus .00,
-.03 inch.
e. If installed, visually inspect the slipjoint(s) for bulges 
beyond normal manufacturing
irregularities of .03 inches and/or cracks. If any bulges and/or 
cracks are present, replace bulged or cracked
slipjoint(s) (refer to Service Manual). See Figure 2.
NOTE
This inspection was previously required on Model 421B airplanes, 
S/N 421B0001 through 421B0935
by AD 75-17-38 effective August 22, 1975.
f. Inspection of multi-segment "V" band clamp(s) (Between engine 
and turbocharger).
i. Using crocus cloth, clean the outer band of the multi-segment 
"V" band
clamp(s). Pay particular attention to the spot weld area on the 
clamp(s).
ii. With clamp(s) properly torqued:
(1) Visually inspect the outer band in the area of the spot weld 
for cracks
(see Figure 3). If cracks are found, replace the clamp(s) with 
new multi-segment "V" band clamp(s).
(2) Visually inspect the corner radii of clamp inner segments for 
cracks
(See figure 3). This inspection requires careful use of 
artificial light and inspection mirrors.
AD 75-23-08 R5
AD 75-23-08 R5
NOTE
When replacement is required, install the new multi-segment "V" 
band clamp over the exhaust flanges
and torque to the correct value (see Torque Value Chart, Table 1 
to this AD). As the clamp is tightened,
lightly tap it circumferentially in a radial direction with a 
rawhide or soft plastic mallet.
(3) Visually inspect flatness of the outer band, especially 
within two
inches of the spot welded tabs which retain the T-bolt fastener. 
This can be done by placing a straight edge
across the flat part of the outer band as shown in Figure 4, then 
checking the gap between the straight edge and
the outer band. This gap should be less than 0.062 inch. If 
deformation exceeds 0.062 inch limit, replace
clamp(s) with new multi-segment clamp(s). (See Note preceding 
this step).
g. One-piece "V" band clamp inspection (Overboard exhaust to 
turbocharger).
Visually inspect with a light and mirror, the clamp surfaces 
adjacent to the
intersection of the "V" apex and bolt clips, and the entire 
length of the "V" apex of the clamp for signs of
cracks or fractures. If cracks or fractures are visible, replace 
the clamp. (See Figure 5).
NOTE
The above inspections, except for Paragraph e. and f., were 
previously required by AD 75-04-01
effective February 11, 1975. Inspections per Paragraph e. were 
previously required by AD 75-17-38 effective
August 22, 1975. Inspections per Paragraph f. were previously 
required by AD 75-04-01 as amended by
Amendment 39-2338 effective August 15, 1975.
75-23-08 R5 TABLE I
EXHAUST COUPLING APPLICABILITY CHART
AIRCRAFT APPLICABILITY
Single Piece “V” Coupling
Coupling
Part Number
Qty
Per
Acft
Torque
In-Lbs
T310P
Q, R
320 320A,
B,C
320D
E, F
340
340A
401/402
A, B
414 421
A, B
421
C
Location Life
Limited
NH1000897-20 4 40
*
X X Collector
(Wye)
Inlet
No
NH1000897-30 2 40
**
X Wastegate
Inlet
No
NH1000897-40
or
V57A4234
or
41195AA423
2 40
*
X X X Turbine
Outlet
No
NH1000897-50
or
V57A5019
or
41195AA502
2 40
*
X X X X Turbine
Outlet
No
Multi-Segment “V” Band Clamps
51394H250
(51134-2505
Gasket)
3 35 X Collector
Inlet
Yes
838037 3 35 X Collector Yes
AD 75-23-08 R5
Alternates:
4309AL
4309AF
Inlet
MVT64832
Alternates:
4309AL
4309F
3 35 X X X Collector
Inlet
Yes
MVT68892-250
Alternate
4301BT250
4 45 X X Collector
(Wye)
Inlet
Yes
4256AB200
Alternate
MVT68892-200
2 45-50 X X X Wastegate
Inlet 340A
(414) &
Wastegate
Exit (421)
Yes
4356AA300 2 70-90 X
Wastegate
Inlet (421)
Yes
* Initial installation of single piece couplings must be made in 
strict adherence to the specified 40 inch-pounds torque value. 
However, periodic retorquing
is required only if coupling shows torque values below 30 inch-
pounds.
**The 24096-300-N gasket is not required at the exhaust wastegate 
inlet of 421, 421A, and 421B aircraft when the NH 1000897-30 
Single-piece coupling
is installed.
NOTES FOR TABLE II
GENERAL NOTES:
0850XXX and 5654XXX dash numbers shown in parentheses are earlier 
part numbers for the
corresponding 9910XXX dash numbers..
Ball joint attaching parts (springs, bolts, nuts, washers and 
cotter pins) are subject to the 100-hour
inspection instead of the 50-hour, only if installed in 
combination with the components listed in Table II.
1. Components incorporate formed sheet metal coupling flanges.
2. Components incorporate external safety ring.
3. Components incorporate internal safety sleeve.
4. Components require seals at coupling flange.
5. Alternate for MVT68892-250 and 4301BT250 couplings.
6. NH1000897-30 supersedes 4356AA300. Gasket P/N 24096-300-N is 
not required with the
NH1000897-30 clamp.
7. Exhaust stack assemblies are sealed type, and the part numbers 
shown include risers for both
cylinder banks and the crossover pipes.
75-23-08 R5
TABLE II
100 HOUR INSPECTION EXHAUST SYSTEM COMPONENTS
Description &
Part Number
Qty
Per Eng
T310
P,Q,R,
320
D,E,F
340 340A 401/402
A,B
414 421
A,B
421
C
Notes
Exhaust Stack Assy
9910379-1 L.H. Eng
(Inconel 601)
1 (LH) X 7
9910379-2 R.H. Eng
(Inconel 601)
1 (RH) X 7
9910295-11 L.H.
(5155184-1)
1 X
9910295-12 R.H.
(5155184-2)
1 X
Aft Slip Joints
9910314-1
(Inconel 601)
1 X
Aft Elbows
9910299-3 L.H.
(5654551-5)
1 X X X 1 & 4
9910299-4 R.H.
(5654551-6)
1 X X X 1 & 4
9910301-1
(0850712-39)
1 L.H. X X X 1
9910301-3
(0850712-41)
1 R.H. X X X 1
9910301-5
(0850712-40)
1 L.H. X X X 1
9910379-19
(Inconel 601)
1 L.H. X
9910379-20
(Inconel 601)
1 R.H. X
Wye Collector Assy
9910299-8
(Inconel 601)
1 X 1,3, & 4
9910301-4
(0850732-3)
1 L.H. X X X 1 & 2
9910301-6
(0850732-18)
1 R.H. X X X 1 & 2
9910341-1
(Inconel 601)
1 X 1,3, & 4
9910300-6
(5155100-1)
1 X
Wastegate Inlet Elbow
9910299-5
(5654551-4)
1 X X
Couplings (One Piece)
Wastegate Inlet
NH1000897-30
1 X 6
Wye Collector Inlet
NH1000897-20
2 X X X 5
NOTES FOR TABLE III
GENERAL NOTES:
5155XXX, 5355XXX, and 5654XXX dash numbers shown in parentheses 
are earlier part numbers
for the corresponding 9910XXX dash numbers.
Ball joint attaching parts (springs, bolts, nuts, washers and 
cotter pins) are exempt from mandatory
inspections only if installed in combination with the components 
listed in Table III.
1. Exhaust stack assemblies are seal-less type, and part numbers 
shown are complete bank
assemblies.
2. On aircraft prior to 1979 Models, the initial replacement must 
include the aft elbow, wye
collector assemblies and clamps since they are not 
interchangeable with earlier components.
3. Attach 5155156-5 Elbow to overboard stack using one each 
5155157-1 Flex Joint and two
each U84C200 SH Clamps.
II. Parts Replacement
A. Replacement of multi-segment "V" band clamps between aft 
engine cylinders and
turbocharger inlet.
On all airplanes listed above within 50 hours time in service 
after February 11, 1975,
for those clamps having more than 350 hours time in service as of 
that date or prior to 400 hours time in
service for those clamps having less than 350 hours time in 
service as of that date, and at or prior to each
additional 400 hours time in service thereafter, replace existing 
multi-segment "V" band exhaust system
clamps located between aft engine cylinders and the turbocharger 
inlet (except for waste-gate to exhaust
overboard pipe clamp on 421 airplanes) with new parts having 
Cessna part numbers in accordance with
Attachment 4 to Cessna Service Letter ME-75-17 dated July 14, 
1975, or later revisions. Use aircraft total
time for clamp time in service unless aircraft maintenance 
records establish location and time in service on
previously replaced clamps. See Figure 3 for multisegment type 
clamp configuration.
NOTE
The above clamp replacement was previously required by AD 75-04-
01 effective February
11, 1975.
B. Replacement of multi-segment turbocharger to overboard tail 
pipe clamps.
Within 200 hours time in service after August 15, 1975, replace 
presently installed
multi-segment type turbocharger to overboard tailpipe clamps on 
Model T310, 320, 401, 402, 340, 414 and
421 airplanes with the clamps specified below:
75-23-08 R5
TABLE III
EXEMPT EXHAUST SYSTEM COMPONENTS
Description &
Part Number
Qty
Per Eng
T310
P,Q,R,
320
D,E,F
340 340A 401/402
A,B
414 421
A,B
421
C
Notes
Exhaust Stack Assy
9910295-13 L.H.
(Inconel 601)
or
9910295-9 L.H.
(5155166-1)
1 X X X X X X 1
9910295-14 R.H.
(Inconel 601)
or
9910295-10 R.H.
(5155166-2)
1 X X X X X X 1
9910295-15
(Inconel 601)
1 X
9910295-16
(Inconel 601)
1 X
Aft Slip Joints
9910296-2
(Inconel 601)
or
9910296-1
(5355108-4)
(Stainless Steel)
2 X X X X X X X
Aft Elbows
(Inconel 601 mat’l,
seal-less style
machined coupling,
flanges & internal
safety sleeves)
9910299-15 L.H. 1 X X X 2
9910299-16 R.H. 1 X X X 2
9910301-14 1 L.H. X X X 2
9910301-16 1 L.H. X X X 2
9910301-17 1 R.H. X X X 2
Wye Collector Assy
(Inconel 601 mat’l &
seal-less style
maintained coupling
flanges)
99102099-9 1 X X 2
9910301-15 1 L.H. X X X 2
9910301-18 1 R.H. X X X 2
9910341-2 1 X 2
9910300-7 1 X
75-23-08 R5
Description &
Part Number
Qty
Per Eng
T310
P,Q,R,
320
D,E,F
340 340A 401/402
A,B
414 421
A,B
421
C
Notes
Overboard Exhaust
Stack Assembly
0850711-33 & -31 1 L.H. X X X
0850711-34, -40, -42 1 R.H. X X X
9910299-1
(5654551-7)
1 L.H. X X X
9910299-2
(5654551-8)
1 R.H. X X X
5155156-3 1 L.H. X
5155156-4 1 R.H. X
9910300-1
(5155100-7)
1 L.H. X
9910300-2
(5155100-8)
1 R.H. X
Wastegate Inlet Elbow
9910299-10 1 X X
Wastegate Overboard
Pipe
0850713-1 1 X X X
5355100-64 1 X
9910299-6
(5654551-3)
1 X X
Wastegate Outlet
Elbow
5155156-5 1 X 3
9910300-3
(5155100-20)
1 X
Turbo Shield
0850902-1 1 X X X
5155154-3 1 X
5354005-1 1 X X X
Couplings (One Piece)
Wye Collector Inlet
NH1000897-60
2 L.H.
(All)
2 R.H.
(340,414)
1 R.H.
(T310,
320 &
401/402)
X X X X X X 2
Wastegate Inlet
NH1000897-70
1 X X 2
Turbine Outlet
NH1000897-40
1 X X X
Turbine Outlet
NH1000897-50
1 X X X X X
On T310 (all aircraft through S/N 310Q0600), 320D (all aircraft), 
320E (all
aircraft), 320F (all aircraft), 401 (all aircraft), and 402 (all 
aircraft through S/N 402B0300 series airplanes,
replace the existing multisegment "V" band turbocharger to 
overboard tailpipe clamp with a new Part Number
V57A4234 or 41195AA423 clamp. These new clamps are not "life 
limited".
On 340 (all aircraft through S/N 3400150, 414 (all aircraft 
through S/N 4140350),
and 421 (all aircraft through 421B0396) series airplanes, replace 
the existing multi-segment "V" band
turbocharger to overboard tailpipe clamp with a Part Number 
V57A5019 or 41195AA502 clamp. These new
clamps are not "life limited".
NOTE
The above clamp replacement was previously required by AD 75-04-
01 as amended
by Amendment 39-2338 effective August 15, 1975.
III. Special Inspections
A. Unless previously accomplished, within 25 hours time in 
service after August 15,
1975, the inspection described below is to be conducted on the 
following aircraft on which the one-piece "V"
band tail pipe clamps have been installed. (Clamps bearing a 
Cessna inspection stamp on the back side (a large
C with a number) and installed on airplanes exempted from this 
inspection on Attachment No. 2 of Cessna
Service Letter ME-75-17 have been inspected by the manufacturer 
and comply with this requirement).
T310 (All aircraft S/N 310P0001 through 310R0275)
320D, 320E, 320F (All aircraft)
340 (All aircraft through S/N 3400550)
401 (All aircraft)
402 (All aircraft S/N 4020001 through 402B0912)
414 (All aircraft through S/N 4140648)
421 (All aircraft S/N 4210001 through 421B0927)
1. Remove upper cowling from LH and RH engine.
a. (Aircraft Turbo 310, 320, 401, 402, and 421 series equipped 
with
metal heat shield). Detach heat shield from turbocharger turbine 
housing by cutting safety wire and removing
hinge pin located at top of shield assembly securing shield 
halves together.
b. The heat shield does not need to be removed on 320, 340 or 414 
and
any aircraft equipped with insulation blanket shield.
2. Clean and visually inspect with a light and mirror, the clamp 
surfaces
adjacent to the intersection of the "V" apex and bolt clips (see 
Figure 5) for signs of cracks or fractures. If
cracks or fractures are visible, replace clamp. (This step allows 
inspection of the clamp under tension).
3. Remove nut, washer, and bolt from clamp, unseat coupling, and 
slide clamp
down exhaust stack to gain adequate visibility.
CAUTION: DO NOT REMOVE EXPANSION LIMITER.
4. Visually inspect for cracks and fractures the entire length of 
the "V" apex of
the clamp (see Figure 5), and pay particular attention to the 
surfaces adjacent to the intersection of the "V"
apex and bolt clips.
AD 75-23-08 R5
NOTE: The use of artificial light and at least a 10-power 
magnifying glass is
necessary to detect minute cracks or signs of incipient failure.
Do not use dye penetrant inspection procedures since noncritical 
metal
forming folds yield misleading failure indications.
5. If clamp is found to be defective, replace clamp.
6. If clamp has no defects, steel stamp or using a vibrating 
pencil, mark an "X"
on the back side of metal torque tag.
7. Reinstall clamp on turbocharger turbine housing and overboard 
exhaust stack
and install bolt, washer and nut. Torque nut to 40 inch-pounds.
CAUTION: DO NOT EXCEED NUT TORQUE BY MORE THAN 5 INCH-POUNDS.
8. Resecure heat shield on turbocharger turbine housing when 
detached, by
aligning shield hinge halves and reinstalling pin previously 
removed. Secure lower halves of shield using two
pieces of .032 monel safety wire twisted together, through 
opposing eyelets of shield halves, draw shield snug
on turbine housing, and safety by twisting end of wire together. 
Insure heat shield is snug on housing.
9. Reinstall upper cowling on LH and RH engine.
NOTE
This inspection was previously required by AD 75-04-01 as amended 
by Amendment
39-2338 effective August 15, 1975. Previous inspection per this 
AD or accomplished by the manufacturer
satisfies the above requirement (IIIA).
IV. Modifications
A. On the following aircraft within 50 hours time in service 
after the effective date of
this AD inspect/modify the overboard exhaust stack flange 
(turbocharger and exhaust stack interface) in
accordance with the instructions below.
T310P0001 through T310R0230, T310R0232 through T310R0254, 
T310R0256,
T310R0257, T310R0259 through T310R0263, T310R0265, T310R0266, 
T310R0268 through T310R0272,
T310R0274, T310R0275, 320D0001 through 320F0045, 3400001 through 
3400550, 4010001 through
401B0221, 4020001 through 402B0630, 402B0632 through 402B0909, 
402B0911, 402B0912, 4140001
through 4140643, 4140645 through 4140648, 4210001 through 
421B0889, 421B0891 through 421B0918,
421B0921, 421B0922, 421B0924, 421B0926 and 421B0927.
1. Remove any existing overboard support clamps, and remove 
overboard
exhaust stack.
NOTE
Take precautions to prevent collection of any dirt or foreign 
particles in opening of
turbocharger turbine housing during modification.
2. Visually inspect the mating surfaces of flanges of overboard 
exhaust stack
and turbochargers for uniform contact over their entire 
perimeter.
3. If such contact is not evident, remove excess material (shaded 
area) of
overboard exhaust stack as required, and as shown typical in 
Figure 6, by grinding, to allow mating surfaces
of flanges of overboard exhaust stack and turbine housing to have 
uniform contact over their entire perimeter.
Exercise care to prevent damage to flange surface of overboard 
exhaust stack when grinding off excess
material.
4. Reinstall overboard exhaust stack and secure clamps in 
accordance with
turbine outlet exhaust stack one-piece "V" band clamp inspection.
NOTE
This one-time inspection/modification may be performed in 
conjunction with the one-piece
"V" bank clamp 25-hour inspection and redundant tail pipe support 
installation required by IV. B.
below.
B. On the following aircraft, prior to but not later than 
December 31, 1975,
install redundant tail pipe support clamps and brackets in 
accordance with Cessna Service kits specified
below.
T310 (All aircraft through S/N 310Q0600)
320D0001 through 320F0045
3400001 through 3400150
4010001 through 401B0300
4020001 through 402B0300
4140001 through 4140350
4210001 through 421B0300
1. Kit Number and Applicability
a. SK402-31 - Turbo 310P0001 through Turbo 310Q0600
320D0001 through 320F0045
4010001 through 401B0300
4020001 through 402B0300
b. SK414-9 - 3400001 through 3400150
4140001 through 4140350
c. SK421-67 - 4210001 through 421B0300
V. Any equivalent method of compliance with this AD must be 
approved by the Chief,
Engineering and Manufacturing Branch, FAA, Central Region.
VI. The time in service between the repetitive inspections 
required herein may be adjusted up to plus
10 per cent of any specified inspection interval required by this 
AD to facilitate accomplishing these
inspections concurrent with other scheduled maintenance on the 
airplane.
Cessna Service Letter ME75-17 dated July 14, 1975, Cessna Service 
Letter ME77-1 dated January
24, 1977, and Supplement 2 thereto dated June 26, 1978, and 
Cessna Multiengine Service Information Letter
ME79-32 dated August 17, 1979, pertain to this subject.
Amendment 39-2419 supersedes AD 75-04-01, Amendments 39-2083, 39-
2130, and 39-2338, and
AD 75-17-38, Amendment 39-2341.
Amendment 39-2419 became effective November 17, 1975.
Amendment 39-2687 became effective August 12, 1976.
Amendment 39-2830 became effective February 17, 1977.
Amendment 39-3298 became effective September 25, 1978.
Amendment 39-3609 became effective November 13, 1979.
FIGURE 6
AD 75-23-08 R5
This amendment, 39-5451, becomes effective on November 4, 1986.