Global CNS/ATM Policy General Aviation and Aerial Work Requirements
Prepared by the
International Council of Aircraft Owner and Pilot Associations

IAOPA was founded in 1962 to provide a voice for general aviation and aerial work activities in the international aviation arena. Since that time it has been working with ICAO and regional aviation authorities to present and promote GA/AW needs and requirements. IAOPA represents the interests of affiliate organizations in 61 ICAO States, incorporating more than 470,000 pilots and aircraft operators. Each affiliate regularly works with State regulatory authorities to accomplish the goals stated above.


When the name general aviation is mentioned most members of the public conjure up a mental image of a small single-engine piston-powered aircraft, operating for recreation out of a small rural aerodrome. This image is correct for only about one-quarter of worldwide general aviation and aerial work activities. The other three-quarters of the roughly 40 million annual GA/AW flight hours are occupied with flight instruction, business travel, agricultural application, emergency medical services and other gainful pursuits. In fact, the diversity of GA/AW is so great that ICAO defines general aviation operation by exception: those flight activities not involving commercial air transportation (CAT) or aerial work. Similarly, aerial work may only be generally defined as operations used for specialized services such as agriculture, construction, photography, surveying, observation and patrol, search and rescue, aerial development, etc.(ICAO Annex 6, Operation of Aircraft, Definitions)

In sheer numbers GA/AW is impressive: Approximately 350,000 aircraft and 1,000,000 pilots are involved in these activities worldwide. On balance, roughly 60,000 aircraft and 500,000 pilots are employed in commercial air transportation (including cargo and charter). The significance of GA/AW becomes greater when it is realized that every airline and most military pilots must begin their journey to professional competence in the cockpit of a general aviation aircraft. Further, the essential services provided to the public by GA/AW for police, emergency medical services and search and rescue make all of our lives safer and more productive. Aerial survey, agricultural application and pipeline/powerline patrol add significantly to many aspects of the economy. And, for the many remote areas of the world, life and civilization would not be possible without the benefits provided by GA/AW operations.

GA/AW activities globally create hundreds of thousands of jobs and tens of billions of dollars for the countries and small business enterprises these activities serve. Without this activity essential transportation functions would be eliminated and the opportunities associated with them would be lost to the economies they potentially serve. Therefore, GA/AW needs and desires should be taken seriously as a worldwide economic engine.

General Aviation and Aerial Work Operational Needs

The Secretariat's principal working paper for the 11th ICAO Air Navigation Conference, entitled "The Global ATM Operational Concept," states:

The ATM operational concept seeks to bring benefits to the international civil aviation community. From an airspace user perspective, greater equity in airspace access, greater access to timely and meaningful information for decision support and more autonomy in decision-making including conflict management, will provide the opportunity to better deliver business and personal outcomes, within an appropriate safety framework. In particular, system harmonization and integration will provide high levels of assurance of predictability to airline operators and their customers.

While the omission of GA/AW operations from the assurances afforded the airline community may have been an oversight, it must be emphasized that we too desire these assurances. While we acknowledge that the ATM system was designed principally to accommodate the needs of the airlines and military, a significant amount of GA/AW traffic regularly participates in this system worldwide. Therefore, the system must "bring benefits to the entire civil aviation community."


CNS/ATM requirements for GA/AW are similar to those of commercial air transport: safe and reliable on-demand access to the air traffic system and efficient routings and handling by air traffic service providers, all at the lowest possible cost. Yet, there are differences.

The majority of the world's GA/AW operations are conducted under visual flight rules (VFR) and in visual meteorological conditions. This provides us with great flexibility and a variety of options not available to those operating under instrument flight rules (IFR). Yet, our activities still need large portions of the airspace in which to operate, particularly in the low altitude structure, and to be able to gain access to airports located in closely controlled airspace.

The point being that while closely controlled airspace, especially in busy terminal areas, is designed primarily for high speed IFR air traffic, slower VFR traffic also requires access to or around or under these areas, either to operate into major airports or to peripheral reliever airports. As control constraints escalate in airspace along busy routes and equipment requirements to operate in that airspace grow, VFR operations are effectively eliminated in favor of well-equipped IFR operators.

GA/AW IFR traffic constitute approximately 20 percent of the total in North America and less that 10 percent in Europe. While these percentages will probably not grow appreciably in the near future, access to the IFR system is increasingly important to those who use this service. General aviation IFR users are those who employ their aircraft in pursuit of legitimate business and personal goals, making access to the system vital. And, this category of user incorporates an increasing number of turbine-powered aircraft, currently more than 29,000 worldwide or about half the size of commercial air transport fleet.

Because of the diversity of GA/AW operations and the differing capabilities of their diverse elements, it is important not to consider this segment of aviation as a homogenous group; the intercontinental Gulfstream 550 has very different needs than the Robinson R22 helicopter employed to muster cattle. Yet, each of these lay a legitimate claim to CNS/ATM facilities and services.

Communications, Navigation and Surveillance

VHF Data Link (VDL), Global Navigation Satellite Systems (GNSS) and Automatic Dependent Surveillance (ADS) systems offer great promise for civil aviation, yet with that promise comes two considerations:

  • as use of this equipment becomes the price of access to the system, will the benefits provided be adequate to offset the costs, and,
  • will those who cannot equip be excluded or delayed from entry into vital airspace and airports?

GA/AW operators readily embrace new technology when a clear benefit is apparent. For instance, it is estimated that more than two-thirds of the world's GA/AW fleet uses a GPS receiver of some sort, either panel-mounted or hand-held. No one mandated these devices; it was the clear benefit available to the user that led them to embrace this technology. However, GPS receivers requiring a sophisticated Technical Standard Order (TSO) pedigree to be used for IFR enroute and approach applications bring a less certain and well defined cost-benefit ratio.

An IFR-capable single-engine Raytheon (Beechcraft) Bonanza valued at $100,000 can ill-afford to install $50,000 worth of Space Based Augmentation System (SBAS), certified GPS, enhanced Mode S transponder, PRNAV and VDL equipment that may be required to operate in some locations within the near future. Similarly, it may require as much as $500,000 of equipment to properly equip and configure an older million dollar Learjet. Moreover, even if this equipment is not mandated, will access to desired routes, altitudes and terminal areas continue to be available without it?

An IFR-capable single-engine Raytheon (Beechcraft) Bonanza valued at $100,000 can ill-afford to install $50,000 worth of Space Based Augmentation System (SBAS), certified GPS, enhanced Mode S transponder, PRNAV and VDL equipment that may be required to operate in some locations within the near future. Similarly, it may require as much as $500,000 of equipment to properly equip and configure an older million dollar Learjet. Moreover, even if this equipment is not mandated, will access to desired routes, altitudes and terminal areas continue to be available without it?

The timing of required equipment changes is an important consideration for GA/AW operations. For instance, does it make sense for an IFR operator to install a Mode S transponder that may be eclipsed by ADS-B just a few years later? That is, will existing Mode C transponders provide adequate surveillance signals until ADS becomes a mature technology. Therefore, single-step solutions are preferable to costly and disruptive multi-step solutions.

Air Traffic Management

While ATM is designed to accommodate and direct IFR traffic flows, it also indirectly affects VFR traffic, as well. In order to safely control IFR traffic ATM designers must designate certain portions of the airspace for varying degrees of access and control. In doing so, VFR traffic, especially in busy terminal areas, is constrained and restricted from access to increasingly valuable portions of the airspace. Airspace and procedures designers must become familiar with the unique performance characteristics and capabilities of light aircraft if efficient and effective integration of GA/AW into the air traffic system is to take place.

Over-classification of airspace segments appears to be a natural tendency for ATM specialists seeking the most suitable conditions for controllers. Yet, in doing so access to valuable airspace is lost to the VFR trained and equipped pilot. More importantly, in over-classifying airspace designers may unintentionally overload both surveillance equipment and the controller's ability to accommodate additional traffic generated by excessive amounts of closely controlled airspace.

It is clear that increasing amounts of managed airspace will be required as more flights continue to crowd into a finite amount of sky. However, compromises are available to the ATM specialist to properly classify airspace segments, providing VFR entry points and routes in terminal areas and imposing less-controlled airspace segments where possible. Importantly, the equipment required as a precondition for access to managed airspace should be carefully evaluated and minimized for IFR operators. VFR operators can accommodate the detail required to navigate in terminal airspace through the use of elementary GPS units.

Perhaps the most important consideration for air traffic managers to acknowledge that non-airline and non-scheduled traffic exists that have legitimate requirements to use the air traffic system. This is particularly important when devising airspace structures, rules and procedures that impose constraints on the system. GA/AW cannot claim access equal to the mass flow of airline traffic, yet their needs must be acknowledged and accommodated fairly and equitably.

It is useful to note that a principal constraint of on air traffic systems is airport capacity. Unless the runway launch and acceptance rate at key airports can be enhanced airborne capacity improvement efforts may prove to be of little value. Therefore, ATM efforts should be directed at solving airport capacity problems as well as the airborne capacity component. Land-long and land-and-hold-short techniques can provide short-term improvements but a longer view is needed for ultimate solutions. In the medium-term, short off-axis runways installed at major terminals will accommodate both GA/AW and regional CAT. In the long-term, additional major runways and, ideally, airports to relieve terminal area congestion hold the ultimate solution.


There are a number of guiding principles that form an essential structure when contemplating CNS/ATM features for GA/AW. While these are not our only concerns these issues are of critical importance for current and future operations:

  • Safety of the air traffic system must be the principal concern. Safe operations for CAT, State and GA/AW aviation communities takes precedence over any other consideration. To do less would invalidate any solution or system devised.
  • The costs for general aviation users to access and operate in a global ATM system should be equal or less than it is today. With a single ATM system, duplicative infrastructure costs and service provider overhead are minimized, thus reducing operating costs in all regions of the world.
  • With a new ATM system, general aviation aircraft operating under VFR should have increased access to all airspace areas. Because of the ATM system's efficiencies and performance gains, more airspace should be available for VFR general aviation operations. Increasing the access and flexibility of general aviation operations in all airspace areas generates incentives for acceptance of a global ATM system.
  • A global ATM system should be capable of providing equal or better levels of service without expensive avionics upgrades or training. An ATM system should result in improved safety, access and efficiency without costly equipment and training mandates. Any proposed equipment, system or procedure must be subject to segmented cost-benefit analyses that adequately accommodate GA/AW operations.

While a number of these principles may appear to conflict with features prized by air traffic service providers or other airspace users, these principles may be accommodated through the use of early coordination and planning. After safety, these principles may be further distilled to the dual concepts of access and equity — access to airspace and airports and equity in equipment requirements and sharing system resources.

Specific Requirements



  • Voice communications — only 760 channel VHF needed for the foreseeable future for both VFR and IFR traffic
  • Datalink —
    • Communications — when economically feasible
    • Data — an option for GA users
    • Method of delivery — VDL, Mode S extended squitter, UAT — less important than how it is used/imposed
    • Requirements for datalink should be carefully coordinated with the introduction of ADS-B


  • Global navigation satellite system (GNSS) — considered primary means for all users, enroute and terminal
  • IFR — if backup to GNSS required, retain skeletal VOR system until GNSS reliability is assured
  • Minimize precision navigation and sub-RNP-1 requirements — provide alternatives for those not so equipped
  • Remove existing VOR and NDB only after regional feasibility studies have been conducted, including user inputs


  • Provisions for Mode A/C transponder should remain valid as long as possible, pending transition to ADS-B
  • Institute ADS-B for IFR traffic ASAP; establish a permissive transition period for VFR users, as required

Air Traffic Management

  • Provide fair and equitable access to the airspace and airports
  • Provide guidelines for and implement airspace designs that provide maximum access for GA/AW, providing optimized flows VFR and IFR operations
  • Integrate GA/AW IFR traffic into enroute and terminal flows
  • Provide maximum access to terminal airspace for VFR operations
  • Accommodate GA/AW airspace requirements for specialize operations, e.g., flight training, glider operations, sport parachuting, etc.
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