Barriers to Effective
Communication: Implications for the Cockpit
By Robert Baron
Reprinted with permission from
The Aviation Consulting Group
process encompasses every single part of our daily being. The use of
both verbal and non-verbal communication is the very basis of how we
converse, both on a personal and on a business level. This paper
introduces the concepts of the communication process and then uses the
aviation domain to exemplify how barriers to effective communication
may manifest themselves. Two specific areas in aviation are discussed;
barriers to effective communication between pilots, and, barriers to
communication between pilots and air traffic controllers (ATC). The
combination of case examples, empirical research, and studies of
literature, is combined to give the reader a true picture of the
effects of deficient communications processes in the aviation domain.
communication is an important process in everyday life. People must be
able to communicate effectively with each other on both a personal as
well as business level. Breakdowns in the communication processes can
lead to benign misunderstandings, or worse, a major disaster.
Nowhere else is the
communication process more important than in the cockpit of an
aircraft. As history has repeatedly shown, a breakdown in the
communication process often leads to less than desirable events that
can be illustrated as follows:
In 1977, at Tenerife
in the Canary Islands, heavy accents and improper terminology among a
Dutch KLM crew, an American Pan Am crew and a Spanish air traffic
controller led to the worst aviation disaster in history, in which 583
In 1980, another
Spanish air traffic controller at Tenerife gave a holding pattern
clearance to a Dan Air flight by saying "turn to the left" when he
should have said "turns to the left" - resulting in the aircraft
making a single left turn rather than making circles using left turns.
The jet hit a mountain killing 146 people.
In 1990, Colombian
Avianca pilots in a holding pattern over Kennedy Airport told
controllers that their 707 was low on fuel. The crew should have
stated they had a "fuel emergency," which would have given them
immediate clearance to land. Instead, the crew declared a "minimum
fuel" condition and the plane ran out of fuel, crashing and killing 72
In 1993, Chinese
pilots flying a U.S.-made MD-80 were attempting to land in northwest
China. The pilots were baffled by an audio alarm from the plane's
ground proximity warning system. A cockpit recorder picked up the
pilot's last words: "What does 'pull up' mean?"
In 1995, an American
Airlines jet crashed into a mountain in Colombia after the captain
instructed the autopilot to steer towards the wrong beacon. A
controller later stated that he suspected from the pilot's
communications that the jet was in trouble, but that the controller's
English was not sufficient for him to understand and articulate the
On November 13,
1996, a Saudi Arabian airliner and a Kazakhstan plane collided in
mid-air near New Delhi, India. While an investigation is still
pending, early indications are that the Kazak pilot may not have been
sufficiently fluent in English and was consequently unable to
understand an Indian controller giving instructions in English.
Special Reports, 2004)
All of the above
examples are the result of "language barriers." But, barriers to
effective communication can come in other forms as well, including
noise, vibration, radio clutter, distractions, and even cultural
differences between crewmembers. This list is not all-inclusive, but
does depict some of the more common problems in today's cockpits.
What is Effective
In order to
facilitate effective communication, one must understand how the
process works. In its most basic model, two-way communication involves
a sender, a message and a receiver. In some communications processes,
communication might be one-way, but for the purpose of this paper,
only the two-way process is identified. The following illustration
shows the two-way communication process.
>Message> Receiver (Decodes)> Receiver Becomes Sender and Encodes>
Message> Receiver (Decodes) - (Zastrow, 2001)
communication is at work, what the receiver decodes is what the sender
sends (Zastrow, 2001). A breakdown in the communication process may
occur if the intended message was not encoded or decoded properly.
Comments may be taken the wrong way, a compliment may be taken as an
insult, or a joke might be interpreted as a put-down. There may also
be barriers in the transfer process; these barriers may include:
Lack of rapport
Think in personal
Further examples of
barriers to effective communication are extracted from the flight
http://www.Dynamicflight.com (2004) suggests that
misunderstandings stem primarily from four barriers to effective
1. Lack of common
experience - the transfer of
words from the instructor to the student are often misunderstood or
not interpreted correctly. A communicator's words cannot communicate
the desired meaning to another person unless the listener or reader
has had some experience with the objects or concepts to which these
words refer. Many words in the English language mean different things
to different people.
between the symbol and the symbolized object
- Results when a word is confused with
what it is meant to represent.
3. Overuse of
abstractions - over dependence
of words that are of a general nature rather than specific.
- Includes physiological, environmental, and psychological
With this basic
understanding of the communication process and its limitations, let us
take a look at how all of this plays into the realm of cockpits and
air traffic control (ATC).
So big was the
problem with communication in the cockpit that NASA launched an all-
out study of jet transport accidents and incidents between 1968 and
1976 (Cooper, White & Lauber, 1980; Murphy, 1980) and found that pilot
error was more likely to reflect failures in team communication and
coordination than deficiencies in technical proficiency.
Data suggest that
deficient interpersonal communication has been identified as a causal
factor in approximately 70% to 80% of all accidents over the last 20
years (NASA study). Additional data from NASA's Aviation Safety
Reporting System (ASRS) showed that over 70% of the first 28,000
confidential (self-disclosure) pilot reports that were received were
related to communications problems (Connell, 1995).
shows that specific language variables are moderately to highly
correlate with individual performance, individual error rates, and
individual communication ratings. Use of the first person plural (we,
our, us) increases over the life of a flight crew and captains speak
more in the first person plural than first officers or flight
engineers (Helmreich & Sexton, n.d.). When the words (I or me) are
used, there tends to be a separation of individuals leading to a
degradation of the team concept.
also be hindered by subordination problems. Federal Aviation
Regulation (FAR) 91.3 states, "The pilot in command of an aircraft is
directly responsible for, and is the final authority as to, the
operation of that aircraft" (Code of Federal Regulations, 2004). The
First Officer (F/O) must be able to act as both an assertive
individual and as a subordinate in a team atmosphere. This basic
dichotomy establishes the premise of a very fine balance that must be
constantly maintained for proper communication to occur. Speaking up
to a superior can be difficult for some people. However, not speaking
up can have tragic results, as illustrated in the following cockpit
voice recorder (CVR) transcript from the 1982 crash of Air Florida
Flight 90 into the Potomac River in Washington, DC.
Military Time- Local
F/O- First Officer
15:59:51 CA It's
spooled. Real cold, real cold.
15:59:58 F/O God,
look at that thing. That doesn't seem right, does it? Uh, that's not
16:00:09 CA Yes it
is, there's eighty
16:00:10 F/O Naw, I
don't think that's right. Ah, maybe it is.
16:00:21 CA CAM-1
Hundred and twenty.
16:00:23 F/O CAM-2
I don't know
16:00:31 CA Vee-one.
16:00:39 [Sound of
stick shaker starts and continues until impact]
16:00:41 TWR Palm 90
contact departure control.
16:00:45 CA Forward,
forward, easy. We only want five hundred.
16:00:48 CA Come on
forward....forward, just barely climb.
Stalling, we're falling!
16:01:00 F/O Larry,
we're going down, Larry....
16:01:01 CA I know
16:01:01 [Sound of
In this example, the
First Officer notices that something is wrong with the engine
instruments (highlighted in black), but the Captain disregards the
F/O's concerns and continues with the takeoff. In fact, the F/O
addresses the issue of something "not being right" six times, with one
of those six almost an acceptance of the problem. The captain, for
whatever reason, justified those "things" as being "normal" and did
not use any of the conflicting information offered by the F/O.
What the F/O should
have done was voice his concerns in a more assertive fashion (as the
message sender, his message was not being received). Typically, if
something does not look right by the pilot not flying (in this case
the F/O), an "abort" callout should be made and the pilot flying (in
this case the Captain) should unquestionably abort the takeoff as per
the takeoff briefing. Would a more assertive F/O have prevented this
catastrophe? Was the F/O's fear of job repercussions a factor in not
speaking up to a superior (and highly experienced) Captain? Would the
Captain have even performed an abort procedure if the F/O were more
assertive? We will never know these answers. But in its purest form,
there was a lack of communication.
accidents provide us with an insight and hopefully an explanation as
to what went wrong and why. Accidents are also investigated to make
sure controls are established or modified to prevent that type of
accident from ever happening again. The Air Florida crash was no
exception. This example of deficient communicative ability has been
used as a case-learning example to this very day in crew resource
management (CRM) airline training programs to help crews understand
their roles and communicative requirements in the cockpit.
Another example of
barriers to effective communication may be found in the crew pairing
process, and specifically the cultural differences between
crewmembers. In this world of cultural diversity, it is not uncommon
to have two pilots with a completely different cultural background
flying as a crew. Verbal and nonverbal communications may be
interpreted differently, and this may have implications during flight,
particularly in high-workload situations.
Power Distance (PD)
is the distribution of "power" among individuals and groups in a
society, and how inequalities in power are dealt with in these
societies (Hofstede, 1980). Societies with a low PD believe that,
among other things, inequality should be minimized, all people should
be interdependent, and hierarchy is an inequality of roles.
Conversely, societies that believe in a high PD feel that inequality
is a fact of life, hierarchy is something that exists and is accepted,
and power gives privileges (Helsinki University, 2004).
In practical terms,
PD reflects the fact that there is an unequal power relationship in
the cockpit, and a subordinate should not question the decisions or
actions of their superiors (Helmreich, Wilhelm, Klinect and Merritt,
2001). The results of a cross-cultural study, conducted by Helmreich
et al. (2001), showed that in cultures with a high PD, safety might
suffer from the fact that insubordinates may not have the ability to
"speak up" when they should or are unwilling to make inputs regarding
leaders' actions or decisions. It was found that countries such as
Morocco, the Philippines, Taiwan, and Brazil had the highest PD
scores, or a culture based on the acceptance of unequally distributed
power. Countries such as Ireland, Denmark, Norway, and the United
States scored at the extreme low end of the PD scale.
discussion covered some of the inherent problems of pilot-to-pilot
communications. This segment will highlight the deficiencies in the
communication process between pilots and air traffic controllers (ATC).
Referring back to the beginning of this paper, one should note that
out of the six accident scenarios illustrated, five of them had
implications of pilot/ATC miscommunications.
The common thread
among many of the examples appears to be "language barriers." Although
English is the unofficial international language of aviation (CNS
Outlook, 1996), the command of the English language for many foreign
pilots is deficient, compounded by dialects, accents, and semantic
misinterpretations. The lack of English proficiency is apparent from
both the ATC, as well as the pilot side of the spectrum. This problem
is not one-sided, however, because just as foreign carriers are
required to be proficient in aviation English phraseology, US crews
flying to other countries must also be able to understand controllers'
limited, staccato, and sometimes incomprehensible English
Another area of
concern in pilot/controller communication addresses "read backs" and
"hear backs." Read backs are very important because they confirm that
the instructions given by the controller have been understood and will
be complied with by the pilot (Orlady & Orlady, 1999, p.140). The
"expectancy" of further instructions often manifests itself in
pilot/controller communication misunderstandings. The following
example illustrates this problem:
It is not unusual
for a pilot climbing out to read back a clearance reporting at 16,000
ft. when he/she was really cleared to 14,000 ft., and not have the
discrepancy noted by the controller. In one example, the aircraft was
cleared to an altitude of 14,000, and told to expect a later altitude
of 16,000 ft. The pilot expected to hear 16,000 and reported going to
16,000 ft. Because 14,000 was the altitude assigned by the controller,
this altitude was the controller's expected altitude and this was the
altitude he thought he heard. Both the pilot and the controller were
mistaken. (Cited in Orlady and Orlady, 1999, p.142)
Related to, but
slightly different from read back, is hear back. In this case, the
controller must evaluate the pilot's read back to make sure that the
clearance is clearly understood and will be complied with. This may be
viewed as a closed-loop system, or a system that uses redundancy to
verify that what is being said is truly understood and there are no
ambiguities or discrepancies in the communication process.
The process of
pilot/controller communication is further complicated by environmental
variables known as clipping, masking, and blocking/distortion (p.141).
Masking occurs when speech is difficult to understand because of
unwanted noise. For example, the cockpit of an aircraft (particularly
during takeoff and climb phases) can be quite noisy. This masking of
important pilot/controller instructions can lead to misunderstandings
or having to request repeated instructions a number of times.
Clipping occurs when
a speaker does not use a microphone properly. A pilot may
inadvertently begin to speak before keying a microphone, or, unkey the
microphone before finishing his or her transmission. This can lead to
broken communication, clutter, and frustration for others using the
Blocking is a very
common problem in ATC communications. If two pilots are trying to
inadvertently transmit at the same time, the transmission will be
blocked and everyone listening on the frequency will hear an ever
familiar "screeching" or irritating "whistle". A "stuck" microphone
can literally prevent everyone from talking or listening on the entire
Blocking may have
been a contributing factor in the worst aviation disaster in history.
In 1977, at Tenerife in the Canary Islands, two 747's (one operated by
KLM and the other by Pan Am) collided on the runway, killing 583
passengers. In addition to factors such as improper terminology and
weather conditions, the following extraction from the official
accident investigation report indicates that a critical part of a
takeoff clearance transmission may have been blocked:
However, in order to
make their own position clear, they said, "We are still taxiing down
the runway." This transmission coincided with the "Stand by for
take-off ... I will call you", causing a whistling sound in the tower
transmission and making its reception in the KLM cockpit not as clear
as it should have been, even though it did not thereby become
unintelligible. (Secretary of Aviation Report on Tenerife Crash, 1978)
A final example of
pilot/controller communication comes in the form of similar sounding
words and numbers. Misunderstanding of words and numbers is
exacerbated by the environmental factors prevalent in the cockpit
(i.e., noise, vibration, chatter, etc.). Anecdotally speaking, the
author fully understands the difficulties in sorting out words and
numbers, particularly in high workload and high ambient noise
situations (i.e., just after takeoff). Does "five thousand" sound
similar to "nine thousand?" It sure does. Do all pilots and air
traffic controllers always use the proper aeronautical pronunciation
of the number "nine" (it should be pronounced nine-er) to mitigate
this problem? Of course not. Commonly confused words and numbers are
just another part of the barriers to effective communication between
pilots and controllers.
Although there are a
number of examples of barriers to effective communications in this
paper, it is by no means exhaustive. There are many more examples of
how the process of communication works (whether good, bad, or
indifferent), which can fill a 500-page book.
Aviation happens to
be one of the best models for studying the communications process and
its inherent flaws. This paper may have brought to light the magnitude
of the communication problems in aviation; a problem for which there
is no quick cure or magic potion.
Pilots and air
traffic controllers must understand the limitations of communications
and work toward the common goal of making the skies safer and easier
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