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Safety Hazard Alert-Call Sign Confusion
by Larry Lachance, Director, Safety and System Performance,

and Ross Bowie, Director, Air Navigation System Service Design,

NAV CANADA tracks all operating irregularities in an effort to identify safety hazards and find ways to reduce the probability of accidents. Lately, we have seen a disturbing increase in the number of instances where similar call signs have caused confusion among pilots and controllers, leading to situations where there is an increased risk of loss of separation between aircraft. Call sign confusion could also lead to an increased risk of controlled flight into terrain or obstacles.

In a recent typical incident, two aircraft operated by the same airline were approaching a busy airport from the same direction. They had four-digit flight numbers, and the first, third and fourth digits were identical-only the second digit was different. The aircraft nearest to the airport was cleared to 3 000 ft, but the crew in the other aircraft read back that clearance and started descent from 9 000 ft. Fortunately, the controller noted this error and intervened before there was a conflict with another flight.

From the pilot's perspective, the problem is aural confusion. Clearances and instructions already contain headings, altitudes, airway and runway numbers, and if call signs are similar, it is easy to understand how confusion could result. Crews may be completing a challenge/response checklist or other task when a controller issues an instruction, and may react based on hearing just part of the flight number. Add to this the fact that for a given pilot, flight numbers change often.

For the controller, who may be responsible for over a dozen aircraft, the problem could also be visual confusion, because the controller relies on call signs on radar and other displays to distinguish among aircraft.

Regardless of cause, call sign confusion is occurring too often, and airlines, pilots and controllers have to take concerted action to reduce the probability of confusion and the risk of a serious accident.

The root of the problem is the way air carriers assign flight numbers. Ideally, scheduling schemes and the assignment of flight numbers would ensure that flights with similar call signs would not appear in the same controller's sector. Flight number assignment is, however, driven by different considerations, and normally does not address the potential for confusion. Based on incident records, it appears that risk would be reduced by using a maximum of three digits in flight numbers. Even when using three digits, instances where the same three digits are used in different positions (e.g. 461 and 416) should be avoided. Of course there will be instances where different airlines are using the same flight number, but this has less potential for confusion because crews would key on the airline name.

Until air carriers take steps to deal with the root of the problem, awareness on the part of both pilots and controllers is critical to reducing the risk of call sign confusion.

NAV CANADA has recently highlighted the problem in internal communications, reminding controllers to advise affected crews of the existence of aircraft with similar-sounding call signs on the frequency as soon as they become aware of the situation.

Pilots are encouraged to recognize when the potential for confusion exists, and to take extra care to listen attentively. It goes without saying that pilots should take great care to use the proper flight number at all times. It is also very important to use proper phraseology and to pay particular attention to readbacks. Pilot situational awareness is part of the solution. In several recent instances, pilots have incorrectly accepted clearances that were clearly inappropriate-headings or altitudes that did not make sense based on current aircraft position or intent.

Call sign confusion is a worldwide problem and other countries have completed valuable studies with recommendations aimed at reducing the safety risk. NAV CANADA intends to continue its own studies and to incorporate the lessons learned around the world in a comprehensive aeronautical information circular (AIC) that provides more detailed advice to air carriers, pilots and controllers.

Thoughts on the New View of Human Error Part I: Do Bad Apples Exist?
by Heather Parker, Human Factors Specialist, System Safety, Civil Aviation, Transport Canada

The following article is the first of a three-part series describing some aspects of the "new view" of human error (Dekker, 2002). This "new view" was introduced to you in the previous issue of the Aviation Safety Letter (ASL) with an interview by Sidney Dekker. The three-part series will address the following topics:
Thoughts on the New View of Human Error Part I: Do Bad Apples Exist?
Thoughts on the New View of Human Error Part II: Hindsight Bias
Thoughts on the New View of Human Error Part III: "New View" Accounts of Human Error

Bad Apples: Do They Exist?

Before debating if bad apples exist, it is important to understand what is meant by the term "bad apple." Dekker (2002) explains the bad apple theory as follows: "complex systems would be fine, were it not for the erratic behaviour of some unreliable people (bad apples) in it, human errors cause accidents-humans are the dominant contributor to more than two-thirds of them, failures come as unpleasant surprises-they are unexpected and do not belong in the system-failures are introduced to the system only through the inherent unreliability of people."

The application of the bad apple theory, as described above by Dekker (2002) makes great, profitable news, and it is also very simple to understand. If the operational errors are attributable to poor or lazy operational performance, then the remedy is straightforward-identify the individuals, take away their licences, and put the evil-doers behind bars. The problem with this view is that most operators (pilots, mechanics, air traffic controllers, etc.) are highly competent and do their jobs well. Punishment for wrongdoing is not a deterrent when the actions of the operators involved were actually examples of "right-doing"-the operators were acting in the best interests of those charged to their care, but made an "honest mistake" in the process; this is the case in many operational accidents.

Can perfect pilots and perfect AMEs function in an imperfect system?

This view is a more complex view of how humans are involved in accidents. If the operational errors are attributable to highly competent operational performance, how do we explain the outcome and how do we remedy the situation? This is the crux of the complex problem-the operational error is not necessarily attributable to the operational performance of the human component of the system-rather the operational error is attributable to, or emerges from, the performance of the system as a whole.

The consequences of an accident in safety-critical systems can be death and/or injury to the participants (passengers, etc.). Society demands operators be superhuman and infallible, given the responsibility they hold. Society compensates and cultures operators in a way that demands they perform without error. This is an impossibility-humans, doctors, lawyers, pilots, mechanics, and so on, are fallible. It should be the safety-critical industry's goal to learn from mistakes, rather than to punish mistakes, because the only way to prevent mistakes from recurring is to learn from them and improve the system. Punishing mistakes only serves to strengthen the old view of human error; preventing true understanding of the complexity of the system and possible routes for building resilience to future mistakes.

To learn from the mistakes of others, accident and incident investigations should seek to investigate how people's assessments and actions would have made sense at the time, given the circumstances that surrounded them (Dekker, 2002). Once it is understood why their actions made sense, only then can explanations of the human–technology–environment relationships be discussed, and possible means of preventing recurrence can be developed. This approach requires the belief that it is more advantageous to safety if learning is the ultimate result of an investigation, rather than punishment.

In the majority of accidents, good people were doing their best to do a good job within an imperfect system. Pilots, mechanics, air traffic controllers, doctors, engineers, etc., must pass rigorous work requirements. Additionally, they receive extensive training and have extensive systems to support their work. Furthermore, most of these people are directly affected by their own actions, for example, a pilot is onboard the aircraft they are flying. This infrastructure limits the accessibility of these jobs to competent and cognisant individuals. Labelling and reprimanding these individuals as bad apples when honest mistakes are made will only make the system more hazardous. By approaching these situations with the goal of learning from the experience of others, system improvements are possible. Superficially, this way ahead may seem like what the aviation industry has been doing for the past twenty years. However, more often than not, we have only used different bad apple labels, such as complacent, inattentive, distracted, unaware, to name a few; labels that only seek to punish the human component of the system. Investigations into incidents and accidents must seek to understand why the operator's actions made sense at the time, given the situation, if the human performance is to be explained in context and an understanding of the underlying factors that need reform are to be identified. This is much harder to do than anticipated.

In Part II, the "hindsight bias" will be addressed; a bias that often affects investigators. Simply put, hindsight means being able to look back, from the outside, on a sequence of events that lead to an outcome, and letting the outcome bias one's view of the events, actions and conditions experienced by the humans involved in the outcome (Dekker, 2002). In Part III, we will explore how to write accounts of human performance following the "new view" of human error.

Canadian Owners and Pilots Association

COPA Corner-Flying Clubs-Why Bother?
by Adam Hunt, Canadian Owners and Pilots Association (COPA)

The flying clubs of Canada have a long history. Many of today's clubs were formed in the 1920s with the assistance of the Royal Canadian Air Force (RCAF), when it was considered by the government of the day to be in the national interest to get as many Canadians flying as possible. During World War II, many elementary flying training schools that were part of the British Commonwealth Air Training Plan were run by the nation's flying clubs.

Today, many airplane pilots don't belong to clubs-they just go to the airport, fly their own aircraft and then go home again. Many times, they won't even see or talk to anyone else. They aren't undergoing training or renting their aircraft-so why bother belonging to a club?

There are many types of clubs; many do rent aircraft or provide instruction, but some offer other services, such as operating airports or providing guest speakers and organizing aviation events. So if you are not training or renting, then here are some of the benefits of belonging to a club:

  • You can make use of the expertise at the club-learn from the instructors and other senior pilots.
  • You can take part in safety recency seminars and other educational events.
  • Many flying clubs organize aviation speakers from whom you can learn and keep up to date.
  • Being around other pilots will help motivate you and keep you interested in flying.
  • Many clubs hold flying events such as fly-ins and fly-out events, where aircraft are flown on cross-countries to far-off destinations. This will give you experience that you might not pursue on your own.
  • Some clubs organize specific training opportunities, such as survival training or underwater escape training.
  • Some clubs sponsor "mentor programs," where more experienced pilots are paired with students and new licence holders, to help guide them through the learning process and the first few hundred hours of flying.
  • Flying clubs often have members with specific knowledge of local weather and terrain conditions.
  • Flying clubs often have associated aircraft maintenance operations which can be a great source of knowledge and help with aircraft issues.
  • Flying clubs and their members can provide support when there are difficult circumstances to deal with-accidents, injuries or deaths.

Canada's flying clubs have a lot to offer today's pilots, even those who own their own aircraft. Belonging to a club can help connect you to what is going on in aviation in Canada, and just may give you better tools to lower your flying risks. Most clubs have Web sites that list their activities, or you can find most of them at under "Learning to Fly."

CBAA logo

The Canadian Business Aviation Association Column-Training to Bridge the Knowledge Gap

The Canadian Business Aviation Association (CBAA) has recently embarked on a major project to facilitate aviation-oriented training for its members and the aviation community at large. This initiative is the result of observations from the association's management of the Private Operator Certificate (POC) Program.

Gaps were identified in the essential skills and knowledge required for personnel employed at all levels within the Canadian aviation industry. One potential outcome of the management knowledge gap, if not properly addressed, can be ineffective implementation of safety management systems (SMS).

Although CBAA's experience is primarily with private business aviation, its expertise can be useful to other segments of the commercial aviation community, such as: entity charter; air taxi; small scheduled carriers; flight training schools; specialty operations; and maintenance and manufacturing organizations.

There is often limited access for small operators to high-quality essential training for such subjects as human factors, fatigue awareness, high altitude indoctrination, aircraft surface contamination, low-energy awareness, crew resource management, decision making, controlled flight into terrain, and specific navigation operations, etc. CBAA's new training initiative aims to fill that need.

In addition to organizing various seminars, CBAA is partnering with existing training providers to offer valuable training as a service to its members, as well as making this training available to the aviation industry. Visit the CBAA Web site at for the latest information on training seminars.

Transport Canada Update-ICAO Amendment 164-Language Proficiency Rating (LPR)
by Larry Cundy, Chief, Personnel Licensing, General Aviation, Civil Aviation, Transport Canada


In 1998, the International Civil Aviation Organization (ICAO), taking note of several accidents and incidents where pilots' and air traffic controllers' inadequate language proficiency were contributory factors, formulated Assembly Resolution A32-16, and subsequently directed work by the ICAO Council and the Air Navigation Commission. As a direct result of that work, ICAO adopted amendment 164 to the Standards and Recommended Practices (SARPs), Annex I to the Convention on International Civil Aviation-Personnel Licensing, on March 5, 2003, with an effective date of November 27, 2003. This amendment requires language proficiency for pilots, air traffic controllers and aeronautical station operators. It also calls for high-quality aviation-specific language training materials and programs, as well as the development of academically-sound language testing services.

Transport Canada (TC) acknowledges the legitimate safety concerns that ICAO has cited in support of this amendment; however, TC has also noted that there is a significant amount of work required to develop the infrastructure for standardized testing and oversight of the test facilities and services.

The Language Proficiency Study Group (LPSG)

In accordance with the SARPs and guidance material developed by ICAO, the General Aviation Branch of TC is responsible for the development and implementation of language assessment and test standards for pilots. The Air Navigation Services and Airspace Branch is responsible for the implementation of these same standards for air traffic controllers and aeronautical station operators. To achieve a comprehensive plan within the limited time frame for implementation, the General Aviation Branch established the Language Proficiency Study Group (LPSG) in September 2004. The LPSG is comprised of representatives from the TC Licensing Division and the Air Navigation Services and Airspace Branch, as well as industry personnel from the Association Québécoise des transporteurs aériens, Les Gens de l'air du Québec, Air Transport Association of Canada, Canadian Owners and Pilots Association, Air Line Pilots Association, Canadian Air Traffic Control Association, Air Canada Pilots Association, Canadian Aviation Maintenance Council, Canadian Business Aviation Association, NAV CANADA and the U.S. Federal Aviation Administration.

The LPSG has completed a considerable amount of work to date in accordance with the terms of reference required policies, procedures and draft notices of proposed amendment (NPA) to the Canadian Aviation Regulations (CARs).

The LPSG is currently developing formal assessment tools and guidance material for the delegated persons who will be involved in the conduct of testing for the operational language level. TC is also developing informal assessment guidelines for assessing applicants for the expert language level 6. To satisfy the international requirements, these policies and procedures must not only address future licence holders, but also existing licence holders. For Canada, this involves the assessment of some 55 000 current Canadian licence holders.

Details of the work completed to date

  1. In 2004, the LPSG developed a work plan, implementation procedures and NPAs to the CARs that provided a starting point for formal industry consultation. This began with the Special Part IV Canadian Aviation Regulation Advisory Council (CARAC) meeting, which was held on March 31, 2005. The required NPAs were presented, reviewed and accepted with minor revisions. The NPAs are now waiting in the regulatory queue for the opening of a Justice Department file.
  2. A language level 6 file assessment methodology and process has been developed. This process will result in the issue of language proficiency assessments-level 6 French and/or English for the majority of Canadian licence holders who have already demonstrated proficiency through training, flight testing and the completion of written examinations. This process is consistent with the ICAO SARPs and ICAO Guidance Material (Document 9835, Chapter 5), and allows TC to apply the assessment methodology to current licence holders in advance of the 2008 implementation date.
  3. Agreement was obtained through the CARAC process and from the LPSG members to proceed with the approval and publication process of the NPAs to the CARs with the understanding that language levels and validity dates would NOT BE PRINTED on licences. This means that the language rating will be printed on the personnel licence indicating either French and/or English language proficiency; however, the language level and expiry date will not be displayed, thus avoiding any potential discrimination on the basis of language proficiency level.
  4. A document of specifications for an aviation-language proficiency testing system has been developed, and provides a pertinent and specific framework for test development by language professionals. The purpose of the test is to provide reliable, valid and practical evaluation of pilot/flight crew language proficiency in accordance with the ICAO language proficiency requirements criteria, as published in ICAO Annex 1 and the Manual on the Implementation of ICAO Language Proficiency Requirements, Document 9835.

What's next?

A company has been selected to develop the Aviation-Language Proficiency Testing System. Work has begun on the development of the language proficiency test (French and English) and is expected to be completed in the fall of 2006.

TC Civil Aviation Management Executive (CAMX) has approved the design and implementation of a new licence booklet format for pilot and air traffic controller licences (decision record of meeting held on October 27, 2005). This new licence booklet is a security-related document that improves the entire personnel licensing process, with a consolidated and secure pilot and air traffic controller

As a result of this decision, the language proficiency rating (LPR) implementation is now integrated with the licence booklet project. This new booklet will not only be used for the issue of the LPR, but also for the administration of the validity period of the LPR in cases where the document holder has not attained an expert level 6.

Additional NPAs will be required as a function of this decision, not only for the new licence booklet implementation, but also for the changes associated with the simplified endorsement format of the LPR on the pilot and air traffic controller licence. These NPAs are currently under development and will be presented at the next CARAC Part IV Technical Committee meeting.

Where can I get more information?

Further LPR information will be available on the TC, General Aviation Web site later this year, and you can look forward to an in-depth article on the new licence booklet in the Aviation Safety Letter (ASL) soon.

Questions and answers!

  1. Why introduce a new requirement to establish language competency of Canadian pilots? Is it because Canada has an aviation safety problem related to radiotelephone communications?

    As a signatory to the ICAO Convention on Civil Aviation, Canada has agreed to implement and maintain standards in accordance with the ICAO Annexes. ICAO has demonstrated that there have been a number of accidents where a significant factor was the inability to communicate adequately by the pilot and the air traffic controller because of a lack of proficiency in a common language. Although there have been no accidents in Canada related to language proficiency, TC acknowledges this identified safety issue.

  2. Does this new regulation apply to everyone who holds a pilot licence or permit in Canada?

    In accordance with the ICAO standards, these new standards will apply to private, commercial, airline transport pilot and air traffic controller licences, but will NOT apply to any other licences or permits (glider, balloon, gyroplane pilot licences, ultralight, recreational, and student pilot permits).

  3. Are Francophone pilots obliged to have an English language rating in order to be authorized to fly in Canada, other than in Quebec and in the National Capital Region?

    Canadian licences issued after March 5, 2008, will require either a French or an English language rating (or both). There is no airspace restriction attached to the language rating while operating in Canada; French-speaking pilots with a French language rating will have the same freedom to fly in Canada as they do presently.

  4. Will Canadian airspace have designated language zones?

    There are no airspace designations or airspace restrictions, and none are planned in association with this rating.

  5. Do foreign pilots have to speak either English or French before they are allowed to fly in Canada, including Quebec?

    The provisions of the ICAO Convention on Civil Aviation and Annexes apply to foreign operators and foreign pilots operating in Canada. As of March 5, 2008, foreign pilots must be able to communicate with the air traffic services (ATS) facility on the ground in Canada. These pilots must, therefore, hold licences with language ratings appropriate to the service provided by the ATS facility on the ground.

  6. Will the United States also be implementing a language proficiency regulation?

    The United States has indicated their full support for the ICAO SARPs, and is currently developing an implementation plan.

  7. What is the cost to the pilots for obtaining the LPR endorsement on their licence?

    Approximately 96 percent of licence holders in Canada will receive either a French or English (or both) language rating from TC free of charge prior to March 5, 2008.

    Foreign citizens holding Canadian licences, as well as Canadians requiring formal language testing after March 5, 2008, may incur some cost. Details of the implementation are being developed.

  8. Who will be responsible for evaluating language proficiency among pilots-TC or the aviation industry?

    TC will develop the standards for language evaluation and will delegate the application of those standards to the industry.

  9. Will francophone pilots wishing to obtain an LPR in English be charged a fee if they wish to have both an English and French rating?

    Canadian francophone licence holders requesting an English rating before March 5, 2008, may submit evidence of their competency in English to TC. This process will not involve any cost to the pilot. This will apply only in cases where TC has not been able to establish the pilot's English language competency through a review of available records.

  10. Do you not think that, as a result of this new regulation, francophone pilots will be at a disadvantage compared to their anglophone colleagues, with respect to employment opportunities because they have less than a level 6 English language rating endorsed on their pilot licence?

    To address this concern, TC has agreed not to endorse a language level on the licence-only language proficiency in English or French (or both).

  11. In order to avoid the expense of language training, do you think that air carriers will be forced to demand a level 6 language rating from all pilots applying for employment with them?

    Since the pilot licence will only have a rating of English or French or both, it could be a matter of company policy to determine whether further training would be warranted because of demonstrated ability in the use of the language.

Many of you asked for information on this topic. Hopefully this article answered most of your questions. As stated earlier, we will provide further information in the near future.

Ground Collisions Give Us Warning

The photo below shows the result of a spectacular ground collision on July 15, 2006 in Madrid, Spain. The wingtip of a taxiing Boeing 747-400 sliced clean the T-tail of a stationary Embrear 145 jet. Fortunately there were no injuries, but there was significant stress for all involved.

A more tragic ground collision occurred on July 30, 2006, at AirVenture 2006 in Oshkosh, Wisconsin. A small Van's RV-6 homebuilt aircraft was struck from behind on a taxiway by a larger aircraft, a World War II era Navy Grumman TBM Avenger. The Avenger's propeller tore through the tail of the RV and fatally injured the passenger. Both occurrences are still under investigation, but they serve as grim reminders to all pilots to keep an alert eye outside and to mind our distances.

Invest a few minutes in your safe return home this winter...

by reviewing your knowledge on airspace requirements and procedures in the TC AIM, section RAC 2.0.

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