Ramp safety is a critical issue in the aviation industry due to the complex interactions among various personnel and equipment in the airport ramp area. The document discusses the importance of open reporting of safety issues to prevent accidents and provides an overview of different types of adhesives used in aircraft repairs, emphasizing that certain adhesives, like casein and plastic resin glues, are now considered obsolete. It also defines key terms related to adhesive bonding processes, highlighting the need for proper application to ensure durability and efficacy.

1. Ramp
operation
safety

2. RAMP SAFETY
2
× Ramp safety is a significant safety concern in the aviation industry. The
airport's ramp area involves a vast number of activities and movements
from aircraft, vehicles, equipment and people. More so, it
accommodates personnel and contractors from different organizations
such as airport operations and maintenance staff, airport police and
fire, airport and airline engineers, planners, regulatory and security
personnel, as well as ground handlers, caterers, and fuelers - all
performing different activities and tasks every day. Owing to the level of
aircraft activity, the complexity of work tasks, and the equipment used
in servicing aircraft, ramp operations and workers can face a variety of
safety concerns and hazards.

3. Encouraging the Reporting of Safety
Information
There is growing realization in
the aviation industry that
encouraging prompt reporting
of safety issues actually reduces
the number of accidents and
incidents. An environment of
“open reporting” is a key
element in fostering a “just
culture” for the systematic
reporting, collection, analysis
and dissemination of safety
information that will be used
solely to prevent accidents.
3

4. 4

5. Adhesives play a critical
role in the bonding of
aircraft structure. The
product must be used
strictly in accordance with
the aircraft and adhesive
manufacturer’s
instructions.
5

6. All instructions must be
followed exactly, including
the mixing ratios, the
ambient and surface
temperatures, the open
and closed assembly times,
the gap-filling ability, or
glue line thickness, the
spread of the adhesive,
whether one or two
surfaces, and the amount
of clamping pressure and
time required for full cure 6

7. “Adhesives meeting the requirements of a
MIL-SPEC, Aerospace Material Specification
(AMS), or Technical Standard Order (TSO) for
wooden aircraft structures are satisfactory,
provided they are found to be compatible
with existing structural materials in the
aircraft and fabrication methods to be used
in the repair.”
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8. Casein Glue
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× Casein is made from curd
from milk (when milk sours, it
separates into curd and
whey). It can be easily
identified by both smell and
appearance. In its natural
form, casein joints take the
appearance of a milky-white
glue, often of a thick
consistency.

9. Casein Glue
9
× Casein-glue joints can be
expected to prove
permanently durable,
therefore, only if the
moisture content of the
wood does not exceed
about 18 to 20 percent for
prolonged or repeated
periods.

10. Casein Glue
10
× Casein glue is now
considered obsolete for all
aircraft repairs. The adhesive
deteriorates when exposed
to moisture and
temperature variations that
are part of the normal
operating environment of
any aircraft.

11. Casein Glue
11
× If a joint that has previously
been bonded with casein is to be
reglued using another type
adhesive, all traces of the casein
must be scraped off before a
new adhesive is applied. If any
casein adhesive is left, residual
alkalinity may cause the new
adhesive to fail to cure properly.

12. Casein Glue
12
The new AC43-13 states “Casein
adhesives should be considered
obsolete for all repairs.”

13. Plastic Resin Glue
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also known as a urea-
formaldehyde adhesive. It
is a powdered glue that is
mixed with water prior to
use. This type of glue is not
waterproof but does have
much better water
resistance than casein
glue.

14. Plastic Resin Glue
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However, plastic resin
glue has been shown to
deteriorate in hot, moist
environments. Prolonged
exposure to heat has a
cumulative effect on the
glue.

15. Plastic Resin Glue
15
AC43-13 now contains a warning
concerning the use of plastic
resin glues. It basically states
that you should consider this
type of glue obsolete for aircraft
wood repairs and any proposed
use should be discussed with the
appropriate FAA office prior to
use on a certificated aircraft.

16. 16
Resorcinol Glue
Was first introduced in
1943.
These glues consist of a
2-part mixture that is
very thick and also is a
dark purple color. The
glue consists of a resin
and a hardener.

17. Resorcinol Glue
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It has better wet-weather
and ultraviolet (UV)
resistance than other
adhesives.
Because of its color it is
easily recognized after
being applied on aircraft
structures.

18. Epoxy Adhesive
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Epoxy adhesives consist of
a resin and a hardener that
are mixed together just
prior to use.
A popular glue used by
many amateur builders is
called T-88 and FPL-16A

19. Epoxy Adhesive
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The pot life (working time)
of epoxies varies with the
type of adhesive and with
the temperature where you
are working.
Generally, you will have 30
minutes or more to
complete the gluing process
before the epoxy begins to
gel.

20. Epoxy Adhesive
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All epoxy adhesives should
use minimal clamping
pressure to avoid starving
the glue join

21. Process
1. Wood surfaces must be
clean (free of oil, grease,
varnish, paint, etc.) prior
to gluing. It is best not to
sand the pieces prior to
assembly.
2. After joining the wood
pieces together you will
want to apply pressure.
The amount of clamping
pressure does vary
depending upon the type
of glue to be used and
the type of wood. 21

22. Definition of Terms Used in the Glue
Process
× Close contact adhesive—a non-gap-filling
adhesive (e.g., resorcinol-formaldehyde
glue) suitable for use only in those joints
where the surfaces to be joined can be
brought into close contact by means of
adequate pressure, to allow a glue line of
no more than 0.005- inch gap.
22

23. Definition of Terms Used in the Glue
Process
× Gap-filling adhesive—an adhesive suitable
for use in those joints in which the surfaces
to be joined may not be close or in
continuous contact (e.g., epoxy adhesives)
due either to the impracticability of
applying adequate pressure or to the slight
inaccuracies of fabricating the joint.
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24. 24
Definition of Terms Used in the Glue
Process
× Glue line—resultant layer of adhesive
joining any two adjacent wood layers in the
assembly.
× Single spread—spread of adhesive to one
surface only.
× Double spread—spread of adhesive to both
surfaces and equally divided between the
two surfaces to be joined.

25. 25
Definition of Terms Used in the Glue
Process
× Open assembly time—period of time
between the application of the adhesive
and the assembly of the joint components.
× Closed assembly time—time elapsing
between the assembly of the joints and the
application of pressure.

26. Definition of terms used in the
glue process
26
Pressing or clamping time—time during which the
components are pressed tightly together under
recommended pressure until the adhesive cures.
Caul—a clamping device, usually two rigid wooden bars, to
keep an assembly of flat panel boards aligned during glue-
up. It is assembled with long bolts and placed on either
side of the boards, one on top and another below, and
parallel with the pipe/bar clamps. A caul is usually finished
and waxed before each use to keep glue from adhering to
it.