The communication process encompasses every single part
daily being. The use of both verbal and non-verbal communication is the
basis of how we converse, both on a personal and on a business level.
introduces the concepts of the communication process and then uses the
domain to exemplify how barriers to effective communication may
themselves. Two specific areas in aviation are discussed; barriers to
communication between pilots, and, barriers to communication between
air traffic controllers (ATC). The combination of case examples,
research, and studies of literature, is combined to give the reader a
picture of the effects of deficient communications processes in the
to the Problem
Effective communication is an important process in
life. People must be able to communicate effectively with each other on
personal as well as business level. Breakdowns in the communication
can lead to benign misunderstandings, or worse, a major disaster.
Nowhere else is the communication process more important than in the
an aircraft. As history has repeatedly shown, a breakdown in the
process often leads to less than desirable events that can be
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 passengers perished.
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 people.
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 problem.
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.
(Aviation Today: Special Reports, 2004)
All of the above examples are the result of "language
barriers." But, barriers to effective communication can come in other
as well, including noise, vibration, radio clutter, distractions, and
cultural differences between crew members. This list is not
does depict some of the more common problems in today's cockpits.
is Effective Communication?
In order to facilitate effective communication, one
understand how the process works. In its most basic model, two-way
involves a sender, a message and a receiver. In some communications
communication might be one-way, but for the purpose of this paper, only
two-way process is identified. The following illustration shows the
(Encodes) >Message> Receiver (Decodes)> Receiver Becomes
Sender and Encodes> Message> Receiver (Decodes) (Zastrow,
When effective communication is at work, what the
decodes is what the sender sends (Zastrow, 2001). A breakdown in the
communication process may occur if the intended message was not encoded
decoded properly. Comments may be taken the wrong way, a compliment may
as an insult, or a joke might be interpreted as a put-down (p.130).
also be barriers in the transfer process; these barriers may include:
Lack of credibility
Lack of rapport
Think in personal terms
Further examples of barriers to effective communication
extracted from the flight instruction domain. Dynamicflight.com (2004)
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.
2. Confusion between the symbol and the symbolized object- Results when
a word is confused with what it is meant to represent.
3. Overuse of abstractions- Overdependence upon words that are of a
general nature rather than specific.
4. Interference- Includes physiological, environmental, and
With this basic understanding of the communication
its limitations, let us take a look at how all of this plays into the
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
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).
Empirical evidence shows that specific language variables are
moderately to highly correlated with individual performance, individual
error rates, and individual communication ratings. Use of the first
person plural (we, are, 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.
Communications may 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 don't seem right, does it? Uh, that's not right
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. Easy, vee-two
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.
16:00:59 CA Stalling, we're falling!
16:01:00 F/O Larry, we're going down, Larry....
16:01:01 CA I know it.
16:01:01 [Sound of impact]
In this example, the First Officer notices that
wrong with the engine instruments (highlighted in black), but the
disregards the F/O's concerns and continues with the takeoff. In fact,
addresses the issue of something "not being right" six times, with one
of those six almost an acceptance of the problem. The captain, for
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
(as the message sender, his message was not being received). Typically,
something does not look right by the pilot not flying (in this case the
"abort" callout should be made and the pilot flying (in this case the
Captain) should unquestionably abort the takeoff as per the takeoff
Would a more assertive F/O have prevented this catastrophe? Was the
of job repercussions a factor in not speaking up to a superior (and
experienced) Captain? Would the captain have even performed an abort
if the F/O were more assertive? We will never know these answers. But
purest form, there was a lack of communication.
All aircraft accidents provide us with an insight and hopefully an
as to what went wrong and why. Accidents are also investigated to make
controls are established or modified to prevent that type of accident
happening again. The Air Florida crash was no exception. This example
deficient communicative ability has been used as a case-learning
example to this
very day in crew resource management (CRM) airline training programs to
crews understand their roles and communicative requirements in the
Another example of barriers to effective communication may be found in
pairing process, and specifically the cultural differences between
In this world of cultural diversity, it is not uncommon to have two
a completely different cultural background flying as a crew. Verbal and
nonverbal communications may be interpreted differently, and this may
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
societies (Hofstede, 1980). Societies with a low PD believe that, among
things, inequality should be minimized, all people should be
hierarchy is an inequality of roles. Conversely, societies that believe
high PD feel that inequality is a fact of life, hierarchy is something
exists and is accepted, and power gives privileges (Helsinki
In practical terms, PD reflects the fact that there is an unequal power
relationship in the cockpit, and a subordinate should not question the
or actions of their superiors (Helmreich, Wilhelm, Klinect and Merritt,
The results of a cross-cultural study, conducted by Helmreich et al.
showed that in cultures with a high PD, safety might suffer from the
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
the highest PD scores, or a culture based on the acceptance of
distributed power. Countries such as Ireland, Denmark, Norway, and the
States scored at the extreme low end of the PD scale.
Traffic Control Communications
The previous discussion covered some of the inherent
pilot-to-pilot communications. This segment will highlight the
the communication process between pilots and air traffic controllers
Referring back to the beginning of this paper, one should note that out
six accident scenarios illustrated, five of them had implications of
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
foreign pilots is deficient, compounded by dialects, accents, and
misinterpretations. The lack of English proficiency is apparent from
ATC, as well as the pilot side of the spectrum. This problem is not
however, because just as foreign carriers are required to be proficient
aviation English phraseology, US crews flying to other countries must
able to understand controllers' limited, staccato, and sometimes
incomprehensible English instructions.
Another area of concern in pilot/controller communication addresses
and "hearbacks." Readbacks are very important because they confirm
that the instructions given by the controller have been understood and
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:
is not unusual for a pilot climbing out to readback 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 readback, is
In this case, the controller must evaluate the pilot's readback to make
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
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
(p.141). Masking occurs when speech is difficult to understand because
unwanted noise. For example, the cockpit of an aircraft (particularly
takeoff and climb phases) can be quite noisy. This masking of important
pilot/controller instructions can lead to misunderstandings or having
repeated instructions a number of times.
Clipping occurs when a speaker does not use a microphone properly. A
inadvertently begin to speak before keying a microphone, or, unkey the
microphone before finishing his or her transmission. This can lead to
communication, clutter, and frustration for others using the frequency.
Blocking is a very common problem in ATC communications. If two pilots
trying to inadvertently transmit at the same time, the transmission
blocked and everyone listening on the frequency will hear an ever
"screeching" or irritating "whistle". A "stuck"
microphone can literally prevent everyone from talking or listening on
Blocking may have been a contributing factor in the worst aviation
history. In 1977, at Tenerife in the Canary Islands, two 747's (one
KLM and the other by Pan Am) collided on the runway, killing 583
addition to factors such as improper terminology and weather
following extraction from the official accident investigation report
that a critical part of a takeoff clearance transmission may have been
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
form of similar sounding words and numbers. Misunderstanding of words
numbers is exacerbated by the environmental factors prevalent in the
(i.e., noise, vibration, chatter, etc.). Anecdotally speaking, the
understands the difficulties in sorting out words and numbers,
high workload and high ambient noise situations (i.e., just after
"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
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
communications in this paper, it is by no means exhaustive. There are
examples of how the process of communication works (whether good, bad,
indifferent), which can fill a 500-page book.
Aviation happens to be one of the best models for studying the
process and its inherent flaws. This paper may have brought to light
magnitude of the communication problems in aviation; a problem for
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
easier to "understand!"
Aviation Today: Special Reports (2004). Report on
safety. Language barriers. Retrieved May 31, 2004 from
CNS Outlook (1996). Indian Air Disaster Raises Concerns About ATC
Communications. Cited in Aviation Today: Special Reports.
Code of Federal Regulations (2004). Federal Aviation Regulations
version]. Available at http://ecfr.gpoaccess.gov
Connell, L. (1995). Pilot and controller communications issues. In B.G.
& O.V. Prinzo (Eds.), Proceedings of the Methods and Metrics of
Cooper, G. E., White, M. D., Lauber, J. K. (Eds.). (1980). Resource
on the flightdeck: Proceedings of a NASA/Industry workshop (NASA CP
Moffett Field, CA: NASA-Ames Research Center.
DynamicFlight.com (2004). Effective communication. Retrieved May 31,
Helmreich, R. L., & Sexton, B. J. (n.d.). Analyzing cockpit
The links between language, performance, and workload. The University
at Austin. Department of Psychology.
Helmreich, R. L., Wilhelm, J. A., Klinect, J. R., & Merritt, A. C.
Culture, error, and Crew Resource Management. The University of Texas
Department of Psychology.
Helsinki University (author unknown) (2004). Culture-Power Distance.
May 29, 2004 from http://www.hut.fi/~vesanto/ihfudge/culture-part2.html
Hofstede, G. (1980). Culture's consequences:
differences in work-related values. Beverly Hills, CA: Sage
Kirby, J (1997). Crew Resource Management (CRM) PowerPoint
presentation of the Salt Lake City Flight Standards District Office
Murphy, M. (1980). Review of aircraft incidents. Cited in Cooper et al.
Orlady, H. W., & Orlady, L. M., (1999). Human factors in multi-crew
operations. Brookfield, VT: Ashgate.
PlaneCrashInfo.com (2004). Cockpit Voice Recording transcript of Air
Flight 90. Retrieved May 14, 2004 from http://www.planecrashinfo.com/cvr820113.htm
Secretary of Aviation Report on Tenerife Crash (1978).
B-747, PH-BUF and Pan Am B-747 N736 collision at Tenerife Airport Spain
March 1977. Retrieved from http://www.aviationcrm.com/TENERIFE.htm
Zastrow, C. (2001). Social work with groups: Using the
a group leadership laboratory (5th ed.). Pacific Grove, CA: Brooks/Cole.
Robert Baron is the president and chief consultant of
The Aviation Consulting Group, an aviation consulting firm with a core
specialization in CRM/Human Factors training and research, and expert witness
support for aviation law firms. He holds an Airline Transport Pilot
Rating and has over 16 years of aviation experience, including a Line Captain,
Instructor and Check Airman in Learjet aircraft. He's also type-rated in the
Cessna Citation and holds a Flight Engineer Rating for Turbojet aircraft. His
academic achievements include a Bachelor's Degree in Professional
Aeronautics/Aviation Safety, a Master's Degree in Aeronautical Science with
dual specializations in Aviation Safety/Human Factors, and is currently
working towards a PhD in General Psychology with an emphasis on
Aviation/Aerospace Psychology. Mr. Baron is also an adjunct professor at
Everglades University, where he teaches Graduate and Undergraduate courses in
Aviation Safety and Human Factors. Mr.
Baron can be reached at 1-954-803-5807. Company website is http://www.tacgworldwide.com.
Robert J. Boser
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The Editor of this Web Page, now retired, was an
airline pilot for 33 years and holds 6 specific Captain's type-ratings
on Boeing Jet Airliners.