Re: Splashproof?

Date:         18 Mar 97 03:14:49 
From:         "Brian A. Reynolds" <>
Organization: Rockwell Avionics - Collins
References:   1 2
View raw article
  or MIME structure

Reid Fairburn wrote:
> At 02:45 AM 3/1/97, you wrote:
> >This came up in a discussion I was having with a friend.  How
> >resistant are the electronics in a typical airliner cockpit to
> >spilled drinks?  What sorts of procedural and deesign safeguards
> >are there?
> The airplane manufacturer usually specifies the needed level of resistance
> to cockpit fluids that a requested piece of equipment must have.  Coffee,
> water, and food type liquids are for sure tested on most all of the
> displays and control panels on the pedestal, and probably in other places
> also.  Don't know what the FAA requires for cert but it probably includes
> some resistance to normal cockpit environmental fluids.

The accepted standard (almost world wide - the Russians have their own
version which they are working to harmonize) is RTCA DO-160 (currently
at revision C).  This document provides various equipment categories,
then presents the test case for each category.

Two sections could be relivent to this discusion:
	Section 10 Waterproofness
	Section 11 Fluids Susceptibility

The purpose of Section 10 is to "Determine wheterth the euipment can
withstand the effects of liquid water being sprayed or falling on the
equipment.  Four categories of equipment are defined:
	Category X "Equipment (that) will be installed in locations where it is
not subjected to falling water (generally the result of condensation,
rain or sprayed water in the course of normal aircraft operations.
	Category W installed in locations where it is subjected to
falling water (generally the result of condensation)...
	Category R installed in locatins subject to driving rain
or where water may be sprayed on it from any angle..
	Category S installed in locations where it may be
subjected to the forces of a heavy stream of fluid such as would be
encountered in aircraft de-icing, washing, or cleaning operations...

My information for the MCDU (aka the coffee cup holder) is category X.
(The MCDU is used as the primary flight deck interface for the Flight
Management Unit and consists of a small CRT display, an alphanumeric
keyboard, and line select keys adjacent to the CRT.  In some cases the
MCDU is also capable of performing standby naviagtion functions.  Newer
aircraft typically have three installed in the center pedestal.  The
ideal place to set drinks :)

Section 11, Fluids Susceptibility, has the stated purpose of:
	"These test determine whether the materials used in construction of the
equipment can withstand the deleterious effects of fluid contaminats.
Fluids susceptibility tests should only be performed when the equipment
will be installed in area where fluid contamination could be commonly

The section goes on to provide tests for determining the susceptibility
to fuels, hydraulic fluids, lubricating oils, solvents and cleaning
fluids, de-icing fluid, fire extinguishants, insecticides, and sullage
(what the heck is sullage ?)

[Moderator's Note:  The American Heritage Dictionary's second
definition appears to be the relevant one: "waste materials or refuse;
sewage."  Karl]

Again, the MCDU is category X, or not expected to be susceptible to the
listed fluids.

Soft drinks and coffee are not listed, hence testing is not required.

It should be remarked that DO-160 listed the tests which are expected by
the requlatory agencies.  Product Quality may or may not use these tests
to ensure customer happiness.  :)

Section 10 is waterproofness