(4) In a given condition if all damages are equal
to or less than the corresponding allowable damage
limits and the distance between damages are equal to or
greater than the corresponding minimal allowable limit,
the aircraft may be released for flight in that condition.
Repair may be deferred although some clean-up and
smoothing of the damage will be required as will
inspection for damage growth after every flight. Special
consideration should be given to damage exposed to the
airstream, particularly to the effects of ram air, rain, and
petaling. Petals may vibrate in the passing airflow,
rapidly creating cracks in the supporting base metal.
Large pieces of metal may peel off and damage other
parts of the aircraft. The distance (D) between damage
sites for most structures has a minimum required
spacing. The spacing requirement is expressed as a
multiple factor (N) of the measured area of damage.
(a) The factor applies to the damage
actually measured not to the maximum damage limit for
(b) The factor applies to the largest
dimension of the largest damage between which
separation is being measured.
(c) The factor applies only if the dimensions
of both damages, when added together, exceed the
single damage limit.
(5) Continuous members. Allowable damage
limits for caps, longerons, webs, floors, decks, and
(6) Damaged fittings, attachments, and splices
are classified as unserviceable and must be repaired,
reinforced, or replaced if any of the following conditions
(a) Damage to the fitting has removed
more than 20 percent of the structural cross section at
any one location.
(b) One or more fasteners connecting the
fitting to a continuous aircraft component are bent,
sheared, stripped, or loose.
(c) The fitting shows signs of overstress or
General Damage Assessment.
(1) Damage Measurement.
(a) Reproduce Figures 2-10 through 2-27
as required, and use to mark up damaged areas.
(b) Refer to Figures 2-10 through 2-27 for
(c) Mark all detected damage on the
appropriate figure, and add remarks to clarify markings
as described in paragraph 2-2.b(9).
(d) Refer to paragraph 2-2.c and for each
damaged element, measure the depth "CD" and the
length (width) "CL" or "WL" of each damage. Count the
number of damages and measure the "D" between
damages. Start with the worst damage. Record the
values on DA Form 2404 (Figure 2-4) and compare
them with the allowable damage limits given in this
section. Select the set of allowable damage limits which
are next larger than the measured damage, determine
the corresponding condition. Consider whether damage
could result in flight failure of other elements. Attempt
to visualize what effect large defections of damaged
member will have on adjacent structure.
(e) Decide on whether repair can be
deferred or whether damage should be fixed and what
the condition of deferred or repaired damage would be.
(f) Determine the priority of the various
required repairs based on repair time, difficulty of repair,
resources available, tactical situation, and need for the
aircraft, etc. The longest repair time normally is given
the highest priority and is most critical.
(g) Enter repair requirements on DA Forms
2404 (Figure 2-4).