Federal Aviation Administration, DOT

Section 29.625

spaschal on DSK3GDR082PROD with CFR

in addition to those necessary to establish foundry quality control. The inspections must meet approved specifications. Paragraphs (c) and (d) of this
section apply to structural castings except castings that are pressure tested
as parts of hydraulic or other fluid systems and do not support structural
loads.
(b) Bearing stresses and surfaces. The
casting factors specified in paragraphs
(c) and (d) of this section - 
(1) Need not exceed 1.25 with respect
to bearing stresses regardless of the
method of inspection used; and
(2) Need not be used with respect to
the bearing surfaces of a part whose
bearing factor is larger than the applicable casting factor.
(c) Critical castings. For each casting
whose failure would preclude continued
safe flight and landing of the rotorcraft
or result in serious injury to any occupant, the following apply:
(1) Each critical casting must - 
(i) Have a casting factor of not less
than 1.25; and
(ii) Receive 100 percent inspection by
visual, radiographic, and magnetic particle (for ferromagnetic materials) or
penetrant (for nonferromagnetic materials) inspection methods or approved
equivalent inspection methods.
(2) For each critical casting with a
casting factor less than 1.50, three sample castings must be static tested and
shown to meet - 
(i) The strength requirements of
Section 29.305 at an ultimate load corresponding to a casting factor of 1.25;
and
(ii) The deformation requirements of
Section 29.305 at a load of 1.15 times the limit
load.
(d) Noncritical castings. For each casting other than those specified in paragraph (c) of this section, the following
apply:
(1) Except as provided in paragraphs
(d)(2) and (3) of this section, the casting
factors and corresponding inspections
must meet the following table:
Casting factor

Inspection

2.0 or greater ...............
Less than 2.0, greater
than 1.5.

100 percent visual.
100 percent visual, and magnetic
particle (ferromagnetic materials),
penetrant (nonferromagnetic materials), or approved equivalent
inspection methods.

Casting factor

Inspection

1.25 through 1.50 ........

100 percent visual, and magnetic
particle (ferromagnetic materials),
penetrant (nonferromagnetic materials), and radiographic or approved
equivalent
inspection
methods.

(2) The percentage of castings inspected by nonvisual methods may be
reduced below that specified in paragraph (d)(1) of this section when an approved quality control procedure is established.
(3) For castings procured to a specification that guarantees the mechanical properties of the material in the
casting and provides for demonstration
of these properties by test of coupons
cut from the castings on a sampling
basis - 
(i) A casting factor of 1.0 may be
used; and
(ii) The castings must be inspected as
provided in paragraph (d)(1) of this section for casting factors of  - 1.25 through
1.50 -  and tested under paragraph (c)(2)
of this section.
[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29-41, 62 FR 46173, Aug. 29,
1997]

Section 29.623

Bearing factors.

(a) Except as provided in paragraph
(b) of this section, each part that has
clearance (free fit), and that is subject
to pounding or vibration, must have a
bearing factor large enough to provide
for the effects of normal relative motion.
(b) No bearing factor need be used on
a part for which any larger special factor is prescribed.
Section 29.625

Fitting factors.

For each fitting (part or terminal
used to join one structural member to
another) the following apply:
(a) For each fitting whose strength is
not proven by limit and ultimate load
tests in which actual stress conditions
are simulated in the fitting and surrounding structures, a fitting factor of
at least 1.15 must be applied to each
part of - 
(1) The fitting;
(2) The means of attachment; and
(3) The bearing on the joined members.

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