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					                                                                                           The Briefing Room - Learning from Experience

By Anne Isaac, Ph.D.

Anne’s early experience in ATM and airline operation was followed by six years with the
Human Factors team at EUROCONTROL, where she was associated with the development
of tools and techniques to help identify human error and risky performance in the ATM
environment, as well as developing the Team Resource Management (TRM) concept for
European ATM. Anne now heads a team in Human Factors integration within the Division
of Safety in NATS, UK.

Effective communication is a basic           ture which reinforces operational staffs’
human requirement and in the aviation        trust in other colleagues.
environment an essential pre-requisite
to safety. So why do we continue to get      The following graph indicates the most
it so wrong? - and we do get it wrong        numerous problems, however this only
about 30% of the time. In a recent radio     illustrates half the story.
telephony survey it was found that           Perhaps more importantly we should               of the communication process itself. In
80% of RTF transmissions by pilots           ascertain the most serious issues                order to transfer information, both the
were incorrect in some way. However          caused by these activities and the con-          person sending and receiving the
pilots are not the only ones in the com-     text in which they are likely to increase        information must be able to formulate,
munication process, and there are            the risk to the system.                          listen, hear and interpret the message
some startling statistics from the air                                                        correctly as well as verify the informa-
traffic controllers as well:                 The leading events, which encompass              tion for completeness, and at any of
                                             some of the above issues are: mis-hear-          theses stages things could go wrong.
     30% of all incident events have         ing information over the RTF, often
     communication errors, rising to         caused by incorrect pilot read-back of           The most risky situation is when one of
     50% in airport environments.            information (but by the correct pilot)           the parties does not identify or recog-
     23% of all level-bust events involve    and transmission and/or recording of             nise an error, since then they are
     communication errors.                   incorrect information by either the              unable to recover from the situation
     40% of all runway incursions also       pilot or controller. In all cases the prob-      themselves. Some of these risks are
     involve communication problems.         lems are embedded in the complexity              embedded in the way we ascertain
None of these statistics are surprising
when we realise the demand we place
on the verbal communication process,
and most of us know some of the obvi-
ous traps: call sign confusion, the prob-
lems with native language, the use of
standard phraseology and the increas-
ing traffic and complexity leading to
frequency congestion and overload, as
well as a high percentage of technical
failure of the communication system
itself. However, what might not be so
obvious is the complexity of effective
communication and the aviation cul-

HINDSIGHT N°5                                                 Page 31                                                       July
                                                                                                                         January 2007
The Briefing Room - Learning from Experience

information from equally qualified col-

We tend to ask confirmatory questions
to solve a problem when we are unsure
in these situations. The example below
is taken from the Danair 1008 air acci-
dent at Tenerife:

Co-pilot : gosh, this is a strange hold,
isn’t it?
Captain : yes, it doesn’t ............................,
it doesn’t parallel the runway or any-
Co to Engineer : it’s that way isn’t it?
Engineer : that is a 3 isn’t it?
Co : yes, well, the hold is going to be
there, isn’t it?

Captain to Co : did he say it was 150
Co : inbound, yeah
Captain : well, that’s....................................,
I don’t like that
Co : they want us to keep going all                           munication strings. This is particularly       the aircraft waited for take-off clearance,
around, don’t they?                                           risky for both parties since an incom-         several passengers took note of the accu-
                                                              plete transmission is not so easy to pick      mulation of snow on the wings. One of
Another very risky situation, in terms of                     up as an incorrect transmission.               them brought it to the attention of the
the above issues, are conditional clear-                                                                     flight attendant, who assured him that
ances. Conditional clearances are used                        Another example regarding communi-             there was nothing to worry about. Many
on the understanding that both parties                        cation and feedback to colleagues              of the aircraft’s occupants were con-
are assured of the message they hear.                         within the aviation industry is the issue      cerned about the snow, but no one,
Since most of the information which is                        of seniority and expertise. Air traffic        including the flight attendants, thought
found in the conditional clearance                            control assistants as well as cabin crew       it appropriate to say anything to the
information is standard and known by                          believe that it is not their place to          flight crew. When asked about this dur-
both parties, it is very rare for one of                      question or challenge a colleague who          ing the course of the investigation, the
the parties to question part of this                          is more qualified or in a position of sen-     one surviving crew member, a flight
communication. Usually you will hear                          iority. The following example illustrates      attendant, stated that she did not feel it
the person receiving the message say,                         this and had fatal consequences.               was her job to inform the pilots of poten-
“Oh he must have said that, or she                                                                           tial problems. She had never been trained
must mean this” This situation is made                        On March 9th 1989, an Air Ontario              to question an area that in her mind was
more risky when the actual communi-                           Fokker F-27 was getting ready to take-off      clearly a pilot responsibility.
cation is correct but incomplete.                             from a small airport in Northern Ontario.      Moshansky, 1992.
Almost all runway incursion incidents                         Take-off was delayed as the tower waited
which involve conditional clearances                          for a small private aircraft to land. It had   Since then both the development of
are also the result of incomplete com-                        been lost in a spring snow storm. Whilst       Crew and Team Resource Management

July 2007
January 2007                                                                   Page 32                                                 HINDSIGHT N°5
                                                                                          The Briefing Room - Learning from Experience

activities have enabled clarification        phrases have been identified as fol-            tle importance, it is too late to retrieve
and challenge to be an acceptable part       lows:                                           the activity we were engaged in when
of this working environment.                    In turn - intended sequence is               the message or phone call started. This
                                                unclear;                                     results in the two tasks, whether they
One of the most prevalent errors in all         Next exit - who’s next are you refer-        were verbal (receipt of a message) or
aviation communication is information           ring to;                                     another action (scanning, writing)
which is mis-heard or not heard at all.         Pull forward - clearance is not clear;       being incomplete. When two activities
The reasons for this are again many             One hundred and eleven hundred               compete for our limited working
and varied, which is why ICAO and               - as in flight level;                        capacity we usually end up losing all
National Air Navigation Service                 Three digit numbers ending in zero           the communication channels, and have
Providers train their operational staff to      - heading often confused with                to start again.
use standard radio telephony. So why            flight level;
don’t we stick to these rules? Research         Similar sounding letters and num-            This problem is particularly obvious
would indicate that there are several           bers - B,G,C, D and 3;                       when working under a high task load.
human traits which make following               Made a ... interpreted as Mayday;            Task load is dependent on work load
rules more problematic. Firstly people,         Holding position interpreted as              (the sheer volume and complexity of
even controllers, assistants, pilots and        hold in position;                            traffic) and contextual conditions such
aerodrome drivers never believe they            Climb to, two thousand - action, fol-        as:
could be involved in a serious incident         lowed by qualifier.                               Weather;
or accident. The fact that these events,                                                          Experience;
compared to the number of aircraft           Many other errors are made because of                Fitness;
movements, are relatively rare, helps to     the problems of expectancy. Because                  Time on position;
perpetuate this belief. This trait is not    we use standard phraseology, we often                Stress.
exclusive to aviation professionals, we      expect to hear a particular request or
all believe the best when we step out-       reply in a familiar situation. If the mes-      Task load is a personal experience, dif-
side into the hazardous world, not           sage we receive is distorted in some            ferent for everybody and depending
appreciating we could be the victim of       way, such as due to other noise or cut          on many things. The limitations of the
many and varied serious incidents.           off, it is easy to assume we heard what         human information processing system
                                             we expected to hear instead of con-             are first observed in our ability to com-
Secondly, having developed standard          firming the message. Hearing what we            municate. Overloading this system
phraseologies, individuals as well as        want to hear, guessing at an insignifi-         inevitably leads to less effective com-
Centres, Units and even National             cant part of the spoken message, and            munication due to tunnel vision (and
Providers and Airlines believe, because      filling in after the fact, are common-          tunnel hearing), reduction of scanning
they are different, they need to apply       place. We also reconstruct parts of mes-        cycles, less investment in time to exe-
for an exemption or change to the rule.      sages unintentionally - and we do so            cute feedback and a rising temptation
These changes are rarely associated          with the utmost confidence that we              to fall for the trap of expectation bias.
with a study to establish the reason for     hear what we actually reconstructed,            This results in more incorrect informa-
the changes and the best consequent          not what was said.                              tion which leads to further incorrect
solutions. Again it is rare that proce-                                                      communication, and finally decisions
dure specialists would ask the advice of     Another reason for the prevalence of            and actions which are error-prone. We
the human performance specialists            information which is mis-heard or not           all have a tendency to dismiss the need
about how humans process both writ-          heard is associated with interruption           to invest time in effective communica-
ten and spoken information. This often       and distraction. Usually a verbal mes-          tion when it is most needed; under
leads to the use of incorrect phraseolo-     sage or phone call will interrupt almost        high task load.
gies being delivered in the wrong            any activity, and by the time we realise
order. Some of these risky words and         that this interrupting message is of lit-       The main issues which have been iden-

HINDSIGHT N°5                                                Page 33                                                        July
                                                                                                                         January 2007
The Briefing Room - Learning from Experience

tified during incident investigation and       tion to deal with, but also because they      clearance expected;
safety trend analysis are the following:       are constantly tested for their profi-        Both pilots should monitor the fre-
                                               ciency in these skills.                       quency whenever possible;
   Pilot reads back incorrectly and the                                                      On frequency change, wait and lis-
   controller does not recognise and           Well, having explored some of the traps       ten before transmitting;
   correct the error, often since it is        that cause humans to make errors,             ATC instructions should be
   from the correct pilot;                     what are the solutions? These, like the       recorded where possible;
   Pilot reads back correctly, however         traps themselves, are not easy to man-        Use standard phraseology in face-
   this is followed by an incorrect            age and implement since the commu-            to-face telephone coordination;
   action on the flight-deck;                  nication process itself is highly com-        Monitor all read-backs, try to avoid
   Pilot reads back correctly however          plex. However, here are some tips for         distractions - especially the tele-
   the controller records the informa-         both pilots and controllers which may         phone;
   tion incorrectly, resulting in a sub-       help:                                         When monitoring messages - write
   sequent error.                                                                            as you listen and read as you speak;
                                                  Use clear and unambiguous                  If you are unsure, always check!
Statistics would also suggest that con-           phraseology at all times; challenge
trollers can often pick up errors in com-         poor RTF;                               The European Action Plan for Air-
munication more quickly than pilots.              Try to avoid issuing more than two      Ground Communication Safety con-
Cardosi, in her 1997 study, recorded the          instructions in one transmission;       tains more information and advice on
fact that controllers correct 50% of              Be aware that you tend to be less       effective communication. Copies may
pilot read-back errors on ground con-             vigilant when speaking in your          be obtained by completing the form
trol frequencies and 89% on en-route              native language;                        on the EUROCONTROL web-site at
frequencies. The reason for this is pos-          Always insist on complete and           http://www.eurocontrol.int/safety/publ
sibly because not only do controllers             accurate read-backs from pilots;        ic/standard_page/documentation_dis-
have more and varied R/T communica-               Set the clearance given, not the        trib.html

July 2007
January 2007                                                   Page 34                                           HINDSIGHT N°5

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