Aaron Marko 10:00-12:00
Mahboobin, L06
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SG-25 RADIAL ENCODERS/TEST FAILURES
Aaron Marko (adm120@pitt.edu)
This is written to bring forward a potentially
significant problem within the lower landing gear in several
military aircraft. Companies such as Boeing and Lockheed
Martin may be required to be notified upon further tests. Our
other clients whose names are classified should also be
informed if the problem is found significant. The component
in question is the SG-25 Absolute Radial Encoder found in
the lower landing gear section of newer prototype aircraft
commissioned by the US Navy. None of the components are
in passenger or active duty aircraft, however, there are
approximately 110,000 units sold for the use in landing gear,
and several thousand units waiting departure this Wednesday
October 29.
SG-25 Absolute Radial Encoders are our newest
version of our optical encoder line. The program dates back
to the previous November when funding for the project was
granted by the US Military for a new series of precision
sensors for the newest line of aircraft. The SG-25 encoders
were developed to give a new fidelity of the movement in
the landing gear. They use micro optic technology to
determine the precise location of the landing gear. This
technology has been modified from previous versions of
encoders to create a finer analysis of movement. The device
is air and water sealed and pressurized to prevent any
contaminants entering.
During the past two weeks of testing the encoders
were being cycled through the atmospheric testing chamber.
The atmospheric testing chamber regulates the humidity,
pressure, and temperature levels above and below thresholds
to emulate extreme exterior conditions. The four hour cycle
consists of bringing the humidity up to near saturation while
changing the temperature from -30 degrees Celsius to 100
degrees. During this rise in temperature and humidity the
pressure within the chamber regulates between a full
vacuum and three time atmospheric pressure. This
fluctuation holds at each pressure for ten minutes and takes
10 minutes to fluctuate. The SG-25 component was given an
input position and the output was monitored for errors.
During the last week of testing a discrepancy was shown
within the data retrieved. Small sections of data was missing
indicating that there was an internal issue.
After the issues were discovered within the
chamber, isolation tests were used to find out the cause for
problem. Sunday October 19 the first set of isolation tests
were operated. The testing team operated the chamber by
increasing the humidity first. We did not find any water
within the casings however the micro optics are very
sensitive to particulate disruption throughout all of the tests
the test SG-25’s performed as designed. The team then
moved onto a pressure test. These also came out negative on
100 tests. Monday October 20 the test team tested the same
modules in a temperature chamber from the same range as
tested within the multi condition chamber. Halfway through
the tests 15 of the 100 encoders stopped responding on
several positions. One of the data analysis graphs is shown
below. The data points should be present across the curve
however there is missing data after the 70 degree Celsius
mark.
Rotational reading E-57
POSITION
THE SITUATION
2.5
2
1.5
1
0.5
0
60
65
70
75
80
TEMPERATURE IN C
These encoders were taken apart in a secure
environment and examined for the cause. The optical ports
on the encoder disk seemed normal under regular light
however when applied with an ultraviolet spectrum the disks
appeared to be coated in an ultra violet reflective substance.
The untested disks did not have this property of reflectance
indicating a coating of photo-reflective substance.
On Wednesday October 22 the testing team sent out
for a chemical analysis of the SG-25 disks and encoder
casing. While those tests were being accomplished a
dimensional analysis was taken on the tested disks. The
disks were shown to have decreased mass after the heating
test had occurred. The disks also were shown to have be
more brittle only deflecting two centimeters in the deflection
tests versus the normal five centimeters of deflection seen
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Aaron Marko 10:00-12:00
Mahboobin, L06
from unheated and cooled disks. The chemical analysis
showed a coating of a carbon resin in the inside of the
casings. Under a microscope the disks seemed to be pitted.
The 15 tests that were shown to have inhibited the use of the
encoders had the resin deposits blocking the optical ports.
COURSE OF ACTION
The test ratings for these specific optical encoders
are rated for up to 80 degrees Celsius with a window of error
of 20 degrees. This window is not being met through our
tests of the latest batch of encoders and there is a fear that
the SG-25s in the field are also compromised if they become
heated. I feel as though it is necessary to consider a recall for
all devices or at the minimum retest several previous batches
to verify that they have met all safety standards.
I believe that this should be paramount due to
several cases of poor ethical decisions and testing in the past
in other companies using the same types of technology. This
company has not had any issues in terms of poor product
quality and safety issues and this could be a situation where
public safety and a large monetary loss may be imminent.
Although tests may be severely disruptive towards our
clients it is necessary to consider the potential problems if
the problem remains unfixed.
REASONING
One of the most prominent examples of
temperature having a significant role in components was the
Challenger space craft accident in 1986. The accident was
originally caused by an o-ring failure which allowed for
gasses to escape creating in essence a bomb. The o-rings,
after being super cooled from the liquid hydrogen would not
do their job and conform to the gap. This created a leak and
lead to the disaster. This example directly applies to this test.
Both occasions are result from a thermodynamic issue with
the materials. The difference with this particular case is
through tests we have discovered a potentially fatal issue
with the SG-25 encoders where the testing data for the orings were not available prior to the launch [1]. If this is any
indication of how failure to a small degree can cause
extreme harm I do not know what does. Although acting on
this problem is not in my authority to manage, as the head of
the testing department I am obligated by several ethical
codes to report these findings and report to my authorities.
The danger of allowing problem to go unchecked or
ignored can be very hazardous and expensive. A seemingly
minor problem can be magnified into a huge problem if the
right conditions are present. As depicted in an ethics case in
the Texas Technical University, “repairing the damage may
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exceed the amount of the [project] itself” [2]. The
underlying issues that are associated with a product that does
not meet its technical specification can extremely dangerous
to the consumer. Left unchecked a simple disregard to a
small issue suck as a flaw in the heat capacities seemingly
insignificant components can cause a much larger impact
than thought. This ethical dilemma has urged me to suggest
that there should be more work done to remedy this problem
now instead of after the distribution of potentially bad
encoders.
Although this company is an independent member,
the predominant client base is in the military specifically
within the navy. In this regard I am bound by the Naval
Engineering Code of Ethics which states that engineers shall
“conduct business and advertising in a restrained manner…
avoiding any misinterpretations” [3]. This in itself requires
me to report any test failures and urge my fellow engineers
to disclose said information when it is required. In this case
the encoders that are currently being tested do not meet the
advertised temperature standards without failure. I do not
believe that this is an advertising problem even though the
product cannot perform as advertised. I do not believe that
the product can perform to its full potential if it cannot meet
the current standards set before it. In this way the best option
would be to analyze the problems and make a correction to
the product while informing the public.
The Engineering Code of Ethics do not legally bind
the owner to address the issues conflicting with the ethics.
Shown in an abstract of the case between Terra Energy v.
Kilbourne Engineering a breach of the code of ethics results
in judicial penalty. The breach of the code was a false
advertisement and patent fraud for company profit, not
taking into account for the safety of the machine operators or
the environment surrounding the project. This represents a
scenario where the code of ethics is not taken into account
but is instead is the precursor to a disciplinary hearing where
a sentence was drawn and not an actual sentence based on
the Code of Engineering Ethics. I however feel it’s my duty
to adhere to the ethical codes to the highest of my authority
as the consequences of not obeying these guidelines could be
more significant than disregarding them [4].
DIRECT CODES
The fundamental canons of the Code of Ethics
according to National Society of Professional Engineers
(NSPE) describe six major points. All of these canons are
important in this case however the first canon is paramount
in this situation. The first canon states that engineers shall
“hold paramount the safety, health, and welfare of the
public” [5]. In terms of holding the safety of the public
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paramount, if these encoders were to fail aircraft landing
gear may not fully deploy leading to not only millions of
dollars of mechanical and property damage but could be life
threatening to people inside of the aircraft and bystanders.
The NSPE is most commonly accredited with the
codes of ethics however the ASCE uses a modified version
of the same ethical codes. The NSPE stresses sustainable
development where these other agencies “such as ASCE,
ASME, and IEEE do not mention sustainable development
in their ethics”[6]. This is to prevent engineers to focus on
any kind of production profits over the ethics of their
practices. I feel as though this is important in this specific
case due to the lack of sustainable development within this
problem itself. This is a problem based on the ethical
dilemma to recall or seek testing of already distributed
products, and to cease shipments until this problem has been
rectified.
In accordance to these alternative ethical laws is
many statements about integrity especially on technology.
The Institute of Electrical and Electronic Engineers states
that professional engineers should “accept responsibility in
making decisions consistent with safety…” [7]. Although
this may cost significant backlog and money the safety of
the operators and people near to the aircraft these encoders is
of primary concern with this paper. The use of these specific
devices are not recommended until the situation has been
corrected regardless to the operating temperatures. As far as
being physically unsound further tests will need to be
enacted to verify the usage of the previous batches of SG-25
encoders are performing as designed.
The issue of solving this problem as quickly and as
effectively as possible is dependent of the responsibility to
act in accordance to what will be the best outcome. Although
“the responsibility is dependent on the different contexts” of
the application of the application of ethics [8]. In this context
the outstanding dilemma should be to act in accordance to
all of the applicable ethical guidelines. Based on the
importance for the product to perform there can be no room
for error. Further research on the cause of the failure will be
identified in the next few days and corrections can be made
to the products currently in facility and in future production.
Recalling products is highly advised in the current events or
at the minimum send an advisory and set samples from all
previous batches into heat testing to verify that there is not a
problem.
FINAL NOTE
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upon the issues within the testing of the last batch of
encoders and that it is not meant to be a disregard to the
company. Full support by myself and my team is available to
determine the origin of the issues and correct them if at all
possible. Further testing will be done prior to official public
notification. The previous codes of ethics are designed to be
followed by the individual engineer however they are not
limited to the individual [9]. The SG-25 encoders were not
up to this point problematic however the procedure of
creating the encoder disks have not changed. On the side of
caution the retesting and full analysis of these components
should be taken into effect as soon as possible to be certain
there are no fatal flaws within the system.
Chemical analysis of the disks are in progress to
determine why the reaction takes place with high
temperatures. Possible causes will be included in daily logs
however the first case we are isolating is improper curing of
the disks. This we believe would cause the reaction and
cause the brittle nature of the post heated disks. The tests
will isolate the problem and we are confident that this
process will be streamline if no further complications are
found. The devices will be retested to verify that the
problematic components of the manufacturing process has
been fixed.
REFERENCES
[1] "Challenger O-Ring Data Analysis" Online Ethics Center
for Engineering 2/16/2006 National Academy of
Engineering Accessed: Sunday, October 26, 2014
<www.onlineethics.org/Resources/Cases/ORingAnalysis.asp
x>
[2] Brenner, B. (n.d.). Ethics Cases. Texas Tech University.
Retrieved October 25, 2014, from
http://www.depts.ttu.edu/murdoughcenter
[3] (2005). NAVAL ENGINEERING - Code of Ethics.
Naval Engineers Journal, 117(2), 8-8.
[4] Sidnell, J. (2005). The code of Ethics. Engineers and the
law, 1, 31-35.
[5] Code of Ethics. (2007, June 1). National Society of
Professional Engineers. Retrieved October 27, 2014, from
http://www.nspe.org/resources/ethics/code-ethics
[6] Michelfelder, D., & Jones, S. A. (2013). Sustaining
Engineering Codes of Ethics for the Twenty-First Century.
Science and Engineering Ethics, 19(1), 237-258.
I feel as though at this point it is important to
understand that this document is meant to be shine light
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Aaron Marko 10:00-12:00
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[7] IEEE IEEE Code of Ethics. (n.d.). IEEE. Retrieved
October 26, 2014, from
http://www.ieee.org/about/corporate/governance/p7-8.html
[8] “Operations research and ethics: Responsibility, sharing
and cooperation, European Journal of Operational
Research”, Giorgio Gallo, Volume 153, Issue 2, 1 March
2004, Pages 468-476, ISSN 0377-2217,
http://dx.doi.org/10.1016/S0377-2217(03)00167-X.
[9] Davis, M. (2001). Three myths about codes of
engineering ethics. IEEE Technology and Society Magazine,
20(3), 8-14.
ACKNOWLEDGEMENT
I would like to thank my family for supporting my education
and helping my find encouragement. I would also like to
thank my class mates for helping me in proof reading.
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