Mooney M20TN, Service And Maintenance Manual

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MOONEY AVIATION COMPANY, INC.
M20TN SERVICE & MAINTENANCE MANUAL
Date
2006
Rev Date
Page 7
B. REPLACEMENT--STANDARD SIZE RIVETS,
HOLE AND COUNTERSINK OR DIMPLE OVERSIZE.
This repair applies only to original countersunk head
aluminum alloy rivets of 1/16, 3/32, 1/8, and 5/32 inch
diameters. Such rivets may be replaced (as noted and
limited below) when the hole and countersink or dimple
is oversize.
(1) Machine Countersink Joint. If edge distance
is a minimum of two times the diameter of the next stan-
dard size larger diameter rivet and countersink depth is
not beyond thickness of countersunk sheet, it will be
permissible to rework according to paragraph 2, A (3).
(2) Dimpled Joint. If edge distance is a minimum
of two times the diameter of the next standard size di-
ameter rivet and all parts are dimpled, it will be permis-
sible to rework the smaller dimples to a size to match
the oversize dimple and install the next standard size
larger diameter rivet of the same type and material as
original rivet. Dimples in 75S--T6 (7075--T6) must be
hot formed when reworked.
(3) Combined Countersink and Dimpled Joint. If
edge distance is a minimum of two times the diameter
of the next standard size larger diameter rivet, it will be
permissible to rework the smaller countersink or dimple
to a size to match the oversize dimple or countersink
and install the next standard size larger rivet according
to paragraph 2, A (4). Dimples in 75S--T6 must be hot
formed when reworked.
C. RIVET HEAD TOLERANCE.
(1) A rivet head will be considered open if .001
feeler gauge can be inserted between head of flush or
protruding head rivet and top skin.
The top of a flush head rivet must not be below skin sur-
face in which it is installed by a dimension of more than
.004.
D. RIVET HOLE TOLERANCE.
(1) An enlarged hole is defined as having an in-
ternal diametric dimension, in any direction, which ex-
ceeds the sum of the drill diameter normally used, plus
ten percent of the diameter of the rivet shank.
(2) Figure 51--4 specifies the maximum accept-
able diametric dimensions for various rivet sizes that
occur in multiple layer assemblies which are “drilled on
assembly”.
NOMINAL
RIVET SIZE
MAX. ACCEPTABLE
DRILL SIZE
DIAMETRIC DIMENSION
AN470AD3 or AN426AD3 #40 (0.098 dia.) 0.108 in.
AN470AD4 or AN426AD4 #30 (0.1285 dia.) 0.141 in.
MAXIMUM ALLOWABLE DIAMETRIC DIMENSIONS
FIGURE 51--4
(3) When a hole becomes enlarged beyond ac-
ceptable diametric limit and the prescribed rivet cannot
be used, the next larger diameter rivet may be used if:
(a) four--diameter (4D) rivet spacing is maintained and
(b) two--diameter (2D) edge distance is maintained.
3. BLIND RIVET INSTALLATION. Ordinarily, where
rivet bucking is impossible, cherrylock (CR--2248 and
CR--2249) rivets may be substituted for AD rivets to re-
pair skins and structural members. However, consult
Mooney Aviation Company, Inc., Product Support De-
partment or a representative of the Federal Aviation
Administration before using blind--type or hollow rivets
in primary structure.
Check existing rivet hole size before installing blind riv-
ets. When hole is marginal, use next larger size rivet to
assure firm attachment.
4. “AN”-- BOLT, NUT AND WASHER INSTALLA-
TION. To compensate for material thickness toler-
ances, the length of AN bolts may be increased or de-
creased by one dash number from prescribed length.
AN960 regular washers and AN960L thin washers may
be used interchangeably for proper bolt and nut instal-
lation.
One regular washer or one thin washer may be added
to any bolt installation. Washers may be used under the
bolt head and/or under the nut. AN365 and AN363 nuts
may be used interchangeably. The AN363 nut is ac-
ceptable for higher operating temperature installations.
5. HI--SHEAR RIVET INSTALLATION. When a hi--
shear rivet pin of the prescribed length is not available,
the next longer length pin may be used with cadmium--
plated steel washers to adjust pin grip length. The com-
bined washer thickness shall not exceed .096 inch.
6. MS20470--AD4 or MS20426--AD4 rivets may re-
place spot welds in aluminum structures, (1) per spot.
Head side and/or double flush requirements deter-
mined by form, fit & function of assembly.
51--11--00 -- RESERVED
51--12--00 -- FUSELAGE REPAIR
51--12--01 -- TUBULAR STRUCTURE REPAIR
Check tubular structure annually for corrosion and
damage. Refer to Service Bulletin M20--208( ). Interior
panels may require removal to gain access to areas
which are difficult to inspect.
Refer to AC 43.13--( ) for general, tubular frame repair
procedures. Warped or bent tube members can often
51--11--00