The document summarizes an analysis of the 2005 Helios Airways Flight 522 accident using the TRIPOD incident analysis methodology. It identifies five "tripods" or causal factors in the accident: 1) multiple warning systems on the Boeing 737 aircraft created challenges for the flight crew, 2) missing or failed barriers allowed the cabin altitude to exceed hypoxic thresholds, 3) organizational cultures where checklists are seen as ways to assign blame, 4) a lack of following checklists properly, and 5) latent failures remaining undiscovered prior to the accident. The analysis found nine missing barriers requiring changes and eight failed barriers that could be addressed more easily. It aims to shed light on organizational issues rather than blame individual pilots.

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| Written by Dimitrios Soukeras
ORGANISATIONAL
DIAGNOSIS LTD
A TRIPOD VIEW OF HELIOS ACCIDENT

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HELIOS accident, a catastrophic event that claimed 121 souls
onboard a Boeing 737/300 heading to Athens, occurred back in time on
August 14th 2005 but still, from time to time, attracts International Media
interest, as the whole story is thought to be shrouded by a veil of mystery and
undisclosed details. According to the official final accident report, prepared
and released by the Greek AAIASB, this tragedy was directly attributed to
human error ; an estimation supported by the application of HFACS model for
the investigation of this accident. Nowadays, there might still be a call for
attempting to shed additional light to such a complex accident, as it is widely
thought that more discoveries are waiting to come into light.
While in prehistory years, in Greek Mythology only Ariadne was thought to
have been the expert in labyrinths, today many others, among them, air
accident investigators, might also encapsulate the art of “applying thread”, as
a means of finding their way out from a difficult to solve situation, like an
aviation accident. In this scenario perhaps, it is most important to share a new
viewpoint, by applying another form of methodology in order to interpret this
accident. In this occasion TRIPOD Beta is believed to have the credibility
into further submitting useful Analysis hints and opening pioneer paths in
Accident Analysis.
The intentions of this Marketing Edition for TRIPOD demonstration are to
abstain from disputes that may arise from the fact that this graph depiction
intentionally will deviate from the official (The Greek AAIASB’s opinion).It is
true that as it was being drawn up so much time after the disclosure of the
original accident report, the chances were in favor for this new attempt to also
have gained insight from other papers or the opinions as presented by other
experts, among them even those in opposition to the so called “Tsolakis
Report”.
A TRIPOD VIEW OF HELIOS ACCIDENT

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Prior to starting working with TRIPOD in sorting out valuable data of HELIOS
accident, it is worth mentioning that by applying this methodology there is the
option of disregarding the “relative position” of the pressure system’s control
switch (either in AUTO or in MAN) or who left it that way. TRIPOD BETA can
be applied without taking into account the comments, either in favor or
against, of the role of the pair of F-16s on the accident, or even of survivability
aspects for passengers, flight and cabin crew, after remaining for nearly 2 ½
hours in an altogether hypoxic and also extremely cold environment and its
consequences as they are thought to have been, which created the “Accident
Environment”, as the cabin undoubtedly “followed” the airplane in the height of
34000 ft.
Tripod Incident Analysis Methodology
Accidents or Incidents are unpleasant events of a kind that no one wishes to
continue speaking about after they have occurred. In High Risk Entities at
least, there is a growing tension of investigators struggling to uncover real
and latent “Causes” that had led to them. The primary reason for doing so had
always been the need of human nature to move further down rather than just
continuing picking up the easy option, that of casting blame upon the most
obvious victims instead of bringing over the catharsis, by letting fresh air
coming in, by new concepts and new investigation methodologies.
What is the TRIPOD Incident& Accident Analysis Methodology?
The birth of the “Safety Culture” era and its dominance over the previous
“Socio-technical Period” in accident causation had forever altered the
prevailing axioms that drive accident investigation. In Safety Culture Era, it is
profound that people form teams and carry common characteristics that play a
substantially important role into the way that accidents are created and thus

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investigation moves down to organisational issues rather than just
apportioning blame to certain humans.
Therefore Tripod methodology delves into the new advents and fresh tools
segment, which aim at pinpointing and analyzing the reasons for failure of a
Barrier, via the application of the Human Behavior model. That is why this
Analysis looks at what had caused the sequence of events in an incident, the
sequence of events themselves, how the incident happened and also of
which Barriers had failed, no matter if they had been in place or not.
The most important factor examined is the reason why those Barriers failed.
The construction of a “tree” diagram forms a graph representation of the
incident mechanism which describes the events and its relationships. The
event in a TRIPOD Beta Diagram is the result of the Hazard acting upon an
Object. A Barrier is something that was made to prevent the meeting of an
object and a hazard.
When such a Barrier fails, a causation path is made to explain how and why
this happened. The TRIPOD Beta method presumes that incidents are
caused by human error, which can be prevented by controlling the working
Environment. The Causation path displays this by starting with the Active
Failure of the Barrier, then investigating under what Precondition or in what
contextual state this happened and finishing up by identifying the Underlying
Causes that led to the Accident.
By delving into the “Preconditions” World , emanating after the accident,
investigators have the opportunity to deepen their knowledge about the Safety
Culture segment of the Organisations involved into the accident and reliably
identify both Behavior Norms and Shared Values that dictated the established
patterns of actions that have driven the Causes of Accident.
The aim of TRIPOD Beta is not only to uncover the hidden deficiencies in an
Organisation, the Latent Failures, but also to offer a solid starting point to
depict all subsequent changes in the Organisational Cultures suffered by the
accident. Those flaws are classified into eleven Basic Risk Factors (BRFs),
categories that represent distinctive areas of management activity, where the

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solution of the problem lies. All the items of the TRIPOD Diagram are shown
below:
Benefits from the Application of TRIPOD Methodology
Tripod Methodology assists investigators:
• To easily structure an investigation,
• To distinguish all relevant facts
• To make causes and effects explicit
• To encourage team discussion
• To reduce the report writing task
• To increase the quality of corrective actions

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• But most importantly to offer the Organisation the opportunity to create
a link between previous Risk Analysis and accident aftermaths that
profoundly assists the creation of a Learning Organisation Entity.
THE HELIOS ACCIDENT
From early noon on August 14th 2005, it was known that a flight of an aircraft
in a hypoxic and extremely cold Environment for quite some time would have
by all means led all HELIOS Crew & Passengers into an “Incapacitation”
status. Therefore, there was not much left to be done to protect “Our Object”,
into the Red-Green Box, (Crew & Passengers) from fatality , which was the
subsequent event after the action of the Change Agent (Fuel Starvation of the
Engines ) on the still intact hull of the aircraft.
In starting a TRIPOD Beta Investigation it is important to be able to create
“trios”, Tripods, which are formed by three elements. (a) The Object which
has the potential of “receiving” change -mostly unwanted- from (b) the
change agent and which, if the “Barriers” are not proved effective will lead to
an (c) outcome-event which will definitely be in favor of no one. The
Investigation that follows an accident aiming at Barriers identification, which
are afterwards categorized, either as “Failed” ,“Missing” or “Effective”, if they
did succeed in stopping the accident sequence.
Μissing Barriers require enormous changes and consume time, while Failed
Barriers are easier for mitigation.
The Fifth TRIPOD

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Failed Barriers owe their failure to stop the accident from happening to an
Active Failure that can easily be spotted. The important part of the
Investigation commences with the “hunting” after Preconditions,
environmental, situational, psychological ‘system states’ or ‘states of mind’
that promote Immediate Causes.
The necessity to distinguish Preconditions while investigating is the
“whistleblower” speaking up about the Organisational Cultures involved into
the accident. Therefore, not only can we reach the underlying Causes behind
the failure more efficiently but also we have enough hints and raw data about
corporate cultures that definitely need change.
Back to “HELIOS Accident”
The First TRIPOD

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While the formation of the first TRIPOD, from the maximum five that we can
manage in an Accident Analysis, might be easy, all the rest require effort and
a definite knowledge of who requested the investigation, since his array of
interests we need to take into account upon examining the accident’s data.
Soon after HELIOS take off, the flight crew faced a challenge as they had
found themselves faced with the task of dealing with multiple warnings, a
combination of at least two of the elements of the Warning System of the
aircraft (either OFF & Intermittent Horn or Aux Fail & Intermittent Horn) as
they had been active in short time intervals or almost simultaneously. That
challenge had been the change agent of this first in session TRIPOD while the
Object that had been chosen to be guarded is “The Boeing 737/300 integrity
of the design over time”.
According to Sidney Dekker (unknown), the EICAS (Engine Indication and
Crew Alerting System) technology was available at the time that Boeing
737/300 came out but still it is unknown why this system had never been
applied on the prototype. Sidney Dekker argues that for that reason “B737
lags behind the industry standard on warning and alerting systems”.
A thorough study of Boeing’s 737/300 model in 2005 reaches the conclusion
that the designer of the aircraft had decided not to follow the simple rule of
putting in place a unique warning per grave emergency. Additionally,
international aviation community had long ago been informed about the
necessity to also take human factors principles into account in the design of
flight checklists, Degani &Wiener (1990) state, but unfortunately a
mechanism, either driven by an International Regulatory Body or the
Manufacturer itself, failed to lead these changes.
While the Barriers that are identified as “Missing” were reported in good faith,
still there are also others that had failed to protect the Object and had led to
the unwanted event of “letting HELIOS Cabin Altitude cross the hypoxic
threshold with the aircraft operating in a non normal situation”.
Reality states that it is highly likely that nothing might have happened if the
flight crew had correctly interpreted and effectively applied the Boeing flight
checklists, before and after takeoff. Although many were found to apportion
blame on the professionalism and the capabilities of pilots, in general
experience has shown that during the past, in other relative accidents again,
in only two cases out of ten flights, crew had reacted effectively. That alone
shows that “evil” is always hiding behind the details and therefore it is worth
mentioning that “Soldiers in Battles should be sent equipped with the best
available weapons if later on we intend to cast blame upon them for any loss”.
TRIPOD investigation spotted several preconditions shown below that need to
be counterbalanced if the relative Barrier is to become effective:

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Organisational cultures in airlines unfortunately still carry some of the
characteristics which are presented by the statements above and indeed
those are the prevailing axioms around aviation professionals. For as long as
pilots insist on declaring that they think of checklists as the means of the
manufacturer to cast blame upon them, in case of an accident and
international community fails to root out the evil, we should expect more
occasion where pilots will be the scapegoats and latent failures will remain in
dark.
On the other hand, there are signs that relative knowledge had been found far
beyond in time, before HELIOS accident occurred, but unfortunately till the
time of the accident it had remained on the shelf.
TRIPOD methodology had been designed to draw the attention away from
single failures of first line personnel (pilots, engineers, ATC controllers, etc)
and instead shed light on organisational issues, which are the breeding
mechanism for latent failures and far more complex issues to be dealt with.
Below are depicted the rest of the TRIPODS which are included into the
investigation:
Active Failure & Preconditions

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The Second TRIPOD
DD
The Third TRIPOD

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In the event of this accident investigation being transformed into a short
business oriented report, the fact that during this -demonstrative only- attempt
there were discovered nine Missing barriers that require immediate concern
and careful study and another eight Failed barriers indicates that for the
former we should expect time consuming solutions, while for the latter, things
might get better more easily.
On the other hand, the magnitude of the gaps found explains the safety
breaches that took place and in addition offers absolution for the pilots, at
least in the eyes of common people who initially might have thought that the
obvious is also the real.
FURTHER DETAILS CAN BE DISCUSSED VIA EMAIL AT:
info@o-diagnosis.com or directly reaching out Dimitris Soukeras at :
Mobile: +306947006664
The Fourth TRIPOD

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REFERENCES
1. AAIASB (2006), “Aircraft Accident Report Helios Airways Flight
HCY522 BOEING 737-31S AT Grammatiko, Hellas on August 14
2005”.
2. Asaf Degani & Earl Wiener (1990), “Human Factors of Flight-Deck
Checklists: The Normal Checklist”, NASA, Ames Research Center.
3. Asaf Degani & Earl Wiener (unknown), “Cockpit Checklists: Concepts,
Design, and use”,
4. Sidney Dekker (Unknown), “Expert Opinion-Human Factors”, retrieved
from the internet.
5. R. Key Dismukes & Ben Berman (2010), “Checklists and Monitoring in
the Cockpit: Why Crucial Defenses Sometimes Fail”, NASA/TM ,Ames
Research Center.
6. Jop Groeneweg (2002), “Controlling the Controllable Preventing
Business Upsets”, Global Safety Group, Fifth Edition.