Avionics News October 57-10 - 15

As we look at the CDC list of disinfectant
compounds, it can be overwhelming. But they
generally fall into the categories of flammables,
solvents, acids and bases.

the National Institute of Health, "Hydrogen peroxide is a very
pale blue liquid which appears colorless in a dilute solution,
slightly more viscous than water. It is a weak acid. It has strong
oxidizing properties and is, therefore, a powerful bleaching
agent that is mostly used for bleaching paper, but has also found
use as a disinfectant and as an oxidizer." It further explains that
"Hydrogen peroxide is unstable, decomposing readily to oxygen
and water with release of heat. Although nonflammable, it is a
powerful oxidizing agent that can cause spontaneous combustion
when it comes in contact with organic material."
Now let us consider alcohol. We know that to be an effective
disinfectant, the CDC recommends a 70% alcohol solution.
While reviewing a Columbus Chemical Industries safety data
sheet for Isopropyl Alcohol 70%, you will notice it is first
listed as a flammable liquid, which should be an immediate
flag for use around aircraft and certainly electrically charged
aircraft systems. Then a bit further, you read in the physical
and chemical properties that the closed-cup flash point is 64.9
degrees Fahrenheit (18.3 degrees Celsius) while the flammability
range (lean/rich) is 2% to 12.7%.
Let's get back to that passenger who wiped down the aircraft.
The aircraft manufacturer (or modifier) had to demonstrate that
the "Materials (including finishes or decorative surfaces applied
to the materials) must meet the applicable test criteria prescribed
in Part I of Appendix F of this Part, or other approved equivalent
methods, regardless of the passenger capacity of the airplane."
(14 CFR § 25.853 (a))
In order to maintain the airworthiness of the aircraft interiors,
the manufacturer produces an instruction for continued
airworthiness that often lists specific cleaning procedures to
not compromise the integrity of the flammability criteria of
the interior materials. When a passenger wipes the aircraft seat
and materials with a solvent with a flashpoint of 64.9 degrees
Fahrenheit, they are, in all likelihood, causing harm. That is,
they are reducing the flammability protections.
So what do you do? And how can you advise your customers?
To begin, there is an FAA advisory circular (AC 43-205)
titled: Guidance for Selecting Chemical Agents and Processes
for Depainting and General Cleaning of Aircraft and Aviation

Products. This AC was written in response to the environmental
drivers of the 1990s. As the AC states, "This advisory circular
contains guidance (test methods, acceptance criteria, and process
changes) for qualifying alternative chemical agents and/or
processes used in depainting or general cleaning of aviation
products."
In particular, contained within paragraph 4 of the AC are the
common tests and acceptance criteria. "This section (Tables
1 and 2) documents the common testing criteria from a select
number of sources for qualifying depainting and general
cleaning agents for aviation products. The sources used for
identifying the common test criteria were taken from applicable
military, Society of Automotive Engineers, and aircraft industry
standards."
The tests for general cleaning materials include: Sandwich
Corrosion Test (ASTM 1110); Immersion Corrosion Test
(ASTM F 483); Hydrogen Embrittlement (ASTM F 519);
Effect on Painted Surfaces (ASTM F502); Acrylic Crazing Test
(ASTM F484); and Residue Test (ASTM F 485).
Notwithstanding the criteria for the aircraft and aircraft
materials, many avionics manufacturers have provided guidance
for cleaning and disinfecting their products.
Garmin International published a Service Advisory 2051:
Cleaning/Disinfecting Guidance. According to the company,
"Garmin would like to provide some general recommendations
for materials and supplies used to clean/disinfect Garmin
aviation products. Not following the recommendations below
could void the warranty." The Garmin Service Advisory can be
found at https://bit.ly/2ZwJnl7.
Likewise, Genesys Aerosystems published cleaning
instructions as a Service Information Letter - Genesys
Equipment Cleaning/Disinfecting. There are two notes of
caution. First, "Genesys Aerosystems recognizes the need for
this guidance in addition to any aviation industry standard
practice for maintaining the cleanliness of cockpit avionics and
the cleanliness of airworthy components in stores." The key
wording here is "in addition to any aviation industry standards."
Continued on page 55
AVIONICS NEWS

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OCTOBER

2020

15
https://bit.ly/2ZwJnl7
Avionics News October 57-10

Table of Contents for the Digital Edition of Avionics News October 57-10
