Operating in Unsafe Airspace

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Operating in Unsafe Airspace

45TH ANNUAL CONFERENCE, Kaohsiung, Taiwan, 27-31 March 2006

WP No. 164

Operating in Unsafe Airspace

Presented by PLC


1.1  There are situations, in regard to “unsafe airspace”, that are causing great concern among air traffic controllers around the world. Examples of this situation included the use of unqualified personnel in :

  • Costa Rica in mid 2004,
  • Guatemala in early 2005.

In both these cases ATCOs were replaced by unqualified personnel. In the Guatemalan case controllers were forcibly transferred from another nation to work in unfamiliar airspace within another nation.

1.2  In such airspace and/or at aerodromes where air traffic services are provided by unlicensed or unqualified personnel (not licensed or qualified in accordance with ICAO Annex 1), there might be an unreasonable risk to aircraft and passengers safety.

1.3  ”Unsafe airspace” is not defined in any of the professional international publications and there is no means to warn of the risk associated with flying through this kind of airspace.

1.4  PLC has been tasked to formulate the criterion needed to define the risk associated with flying through unsafe airspace and to create a recommendation relating to the use of such airspace/aerodrome by airlines. The main thrust of the policy is to support the maintenance of a legal, safe and efficient aviation system.


2.1 An airspace and / or aerodrome can be defined as unsafe whenever there is an unacceptable risk to an aircraft and / or passenger safety.

2.1.1  The definition of a Danger Area according to Annex 2 Ch 1:

“An airspace of defined dimensions within which activities dangerous to the flight of aircraft may exist at specified times”

does not cover all the aspects of air traffic management and air traffic safety and therefore must be expanded. According to PLC the main purpose of this definition is to emphasis that commercial and general aviation operation in this area increases the probability of severe incidents or in the worst case an accident.

2.1.2  In order to define unsafe airspace in a way that will cover most future cases, we need to classify/categorise the different factors.

2.2 Professional Factors

Professional factors (including human factors issues) include: unqualified personal, inadequately trained staff, insufficient staff and associated workload issues, inadequate language skills to provide air traffic services, inadequate rest hours between shifts resulting in fatigue issues, etc.

2.2.1  IFATCA policy on the use of unqualified personnel states that:

“For the purpose of guaranteeing safety, ATCO’s shall not be replaced by personnel who do not hold ATC licences in accordance with ICAO Annex 1, with the ratings, recency and competency appropriate to the duties that they are expected to undertake. In addition, the functions, which are contained within ICAO Annex 1, as being ATC functions, shall not be added to the work responsibilities for unlicensed personnel.”


2.2.2  ICAO Doc.9750 p. 1-4-20 states:

“Planning and implementation of improved ATM capabilities should include consideration of human factors impact and requirements. the goals listed for the future ATM should be qualified in relation to human factors at least in terms of the following Consideration:

  • the level of safety targeted for the future system should be defined not only with reference to various system statistics ,but also with reference to error including mechanisms related to human capabilities and limitations as well as important individual cases.
  • the definition of system and resource capacity should include reference to responsibilities, capabilities and limitations of ATM personnel and air crew who must retain situational awareness and understanding in order to carry out all of their responsibilities.”

2.2.3  Unqualified personnel for this purpose are also air traffic controllers that are working in airspace that they are not familiar with and/or without proper training.

2.2.4  Air traffic control work is based on verbal communication between the controller and pilot using Standard English phraseology. Inadequate language skills might cause a misunderstanding leading to incorrect interpretation of the controller instructions, especially in non routine and emergency situations that may compromise safety.

2.2.5  Rest hours between shifts are a key element to maintaining high concentration levels. Fatigued air traffic controllers may suffer performance degradation.

2.2.6  Considering the above are but some of the professional issues, it is appropriate to say that any airspace/aerodrome that is controlled in whole or in part by unqualified personnel, or personnel that are not fit for duty, may be deemed ‘Unsafe Airspace’. The events in Costa Rica and Guatemala are perfect examples.

2.3 Technical Factors

Technical factors, such as: inadequate or inappropriate equipment can render airspace to which it is applied unsafe.

2.3.1 Radars that do not match the ICAO requirements and standards; coverage is inadequate for the ratings held, intermittent and / or unreliable; non consecutive “mode A” and “mode C” readout, frequent radar failures.

2.3.2  Unreliable radio communication caused by inadequate and old equipment or by illegal radio stations.

2.3.3  Airport layout and control towers location that do not allow the controller the sight view needed to control both ground and air movements.

2.4 Airspace factors

Airspace factors, such as: flawed airspace design, non standard procedures, unsafe aerodrome practices, reduction of separation, airspace subject to known unauthorized military activity.

2.4.1  There is considerable action by ANSPs worldwide to reduce services and to amalgamate functions of several ATC positions. However, commercial considerations must always be preceded by conducting a thorough safety case to validate any such proposals. The following are examples of intentions or actions employed by ANSPs to reduce costs to the detriment of safety.

  • Current initiative of the Federal Aviation Administration to close a number of regional control towers overnight or in periods of low aircraft movements
  • National Airspace System (NAS) implementation in Australia in the absence of a safety case
  • Implementation of temporary de-activated airspace to permit operations during industrial disputes
  • The use or consideration of remote control towers
  • Airspace re-classification and removal of services to achieve cost reduction without an established safety case.

2.4.2  There are numerous sightings of unidentified aircraft operating illegally within CTA (Civil Controlled Airspace). In most if not all instances these are assumed to be covert military operations. If they can be assessed to compromise safety, operations should be suspended. Political sensitivities aside, all available intelligence on such activities should be processed to determine and publicise those involved. (See Doc.4444 definition/ aircraft proximity/safety not assured)

2.5 Political & security factors

Political & security factors, such as: hostile airspace; airspace subject to concurrent terrorist acts; airspace subject to re-entering of intercepting fighters without coordination.

2.5.1 The cases of the” DHL” Airbus 300 freighter in proximity to Baghdad Airport and the “Arkia Israeli airlines” B-757 in Mombassa, Kenya that were nearly hit by anti aircraft missiles demonstrate, with the portability of such weapons, that such a terrorist attack is possible at most if not all airports worldwide. In the aftermath of such a missile firing, who will determine the resumption of normal operations? If it left to the State or ANSP (Air Navigation Service Provider) there is a possibility that commercial pressures may override safety.


3.1 Our main focus is to create a policy that would assist in initiating action from the Airline industry to limit or withdraw services from unsafe airspace. Not only would this address the safety aspect, but PLC believes known shortcomings will be more likely to be resolved in the shortest possible time frame.

3.2  The first step is to define unsafe airspace and to categorize it to various aspect of air traffic management.

3.3  The second step is to define measurable criteria that support the determination of “unsafe airspace”

3.4  The third step is to define a series of measures to the criteria such that they can support a scale to determine the level of safety associated with a given airspace or aerodrome

3.5  The policy should include “warning airlines, air navigation service providers and all other relevant bodies concerning the aviation industry and users of the risk of operating in unsafe airspace according to the unsafe airspace definition and criterions”.


4.1  It is recommended to add the following definition:

Unsafe Airspace/Aerodrome

An airspace/aerodrome is deemed unsafe whenever there is an unacceptable risk to the safety of aircraft.

4.2 It is recommended to add the following paragraph:

IFATCA should issue a warning to airlines, air traffic service providers and all other relevant bodies concerning the aviation industry and users of the risk of operating in unsafe airspace according to the unsafe airspace definition and criterions.

4.3  The Executive Board informs ICAO about this policy.


IFATCA Manual.

ICAO Annex 1.


ICAO Annex 2 – RULES OF AIR – Chapter 1 Definitions.


ICAO Doc. 4444 – AIR TRAFFIC MANAGEMENT – definition/aircraft proximity/safety not assured.

ICAO Doc. 9689 – MANUAL OF AIRSPACE PLANNING METHODOLOGY FOR THE DETERMINATION OF SEPARATION MINIMA – Chapter 3 – description of current airspace and the CNS/ATM system.

ICAO Doc. 9426 – AIR TRAFFIC SERVICES PLANNING MANUAL – Section 1 – paragraph 1.2 factors affecting planning, paragraph 1.5 objective operating factors.

Australian DOTARS (Department of Transport and Regional Services) https://www.dotars.gov.au/airspacereform/nas.aspx.

Last Update: September 29, 2020  

March 29, 2020   751   Jean-Francois Lepage    2006    

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