English

PANS-OPS: Shaping the Future of Safe and Precise Aviation

PANS-OPS: Shaping the Future of Safe and Precise Aviation

 

 

Enhancing Operational Safety and Accuracy through Air Navigation Service Procedures

 

Air Navigation Services Procedures (PANS-OPS) are an integral part of the modern air navigation regulatory system. Issued by the International Civil Aviation Organization (ICAO), these procedures govern how aircraft operations are designed and managed under low-visibility conditions and through the use of navigational aids. They encompass the design of departure and approach routes, determination of safety altitudes, and monitoring of obstacles surrounding airports.
A comprehensive understanding of PANS-OPS is fundamental for any organization or individual aiming to enhance aviation safety or benefit from advanced airspace planning and obstacle clearance standards. This article provides detailed information on the standards, processes, and best practices for applying these procedures.

 

PANS-OPS – Why It Matters for Aircraft Operations

PANS-OPS, short for Procedures for Air Navigation Services – Aircraft Operations, is a set of rules and standards issued by ICAO for designing and implementing flight procedures. The first part of Document 8168 describes the evolution of these procedures, which cover the departure, arrival, and final approach phases, outlining safe zones to keep aircraft clear of obstacles until the next phase’s criteria are applied. After 1996, standards for the en-route phase, holding patterns, noise abatement, and helicopter procedures were added, making PANS-OPS the most comprehensive global framework for flight operations.

 

The Importance of Adopting PANS-OPS

1.     Ensuring Obstacle Clearance: The document defines protection areas surrounding takeoff and landing paths and sets limits on obstacle heights to ensure safety margins.

2.       Global Standardization: It unifies design criteria across countries while allowing national authorities to adjust minimum altitudes based on local conditions.

3.       Enhancing Airspace Capacity: According to the International Federation of Air Traffic Controllers’ Associations (IFATCA), transferring obstacle-clearance responsibilities to flight-procedure design committees led to more effective standards, improving airspace capacity and inter-sector transitions.

4.       Fuel Efficiency: PANS-OPS procedures help reduce flight time and unnecessary deviations - particularly with Performance-Based Navigation (PBN), which allows more precise routing.

 

How Are Takeoff and Landing Procedures Designed Under PANS-OPS Standards?

Designing departure and approach procedures is the core of PANS-OPS. The document provides the framework, while procedure designers analyze terrain and obstacles around airports to determine optimal flight paths. Key steps include:

1.       Obstacle and Terrain Assessment: Designers identify airport elevations and dimensions, then conduct precise surveys of surrounding terrain. The PANS-OPS annex specifies that departure paths must cover the takeoff and climb phase until the pilot reaches a point where the next phase’s criteria apply.

2.       Determining the Appropriate Climb Gradient: PANS-OPS requires an additional safety margin above the standard climb gradient. Compared to U.S. TERPS standards, PANS-OPS measures from the end of the Clearway rather than just the runway, adding 0.8% to the standard 2.5% climb gradient—resulting in a 3.3% design gradient.

3.       Defining Protection Areas: Three-dimensional protection zones are drawn along the flight path, including initial altitudes, widths, and expanding divergence surfaces. If obstacles are close to the path, designers may increase the gradient or suggest early turns.

4.       Digital Design Tools: Certified design software ensures compliance with ICAO standards, verified through simulation and test flights.

5.       Authority Approval: Once complete, designs undergo regulatory review and approval before official publication.

For example, airports in mountainous areas may require early turns or steeper gradients to achieve safe altitudes before encountering peaks, while coastal airports often allow longer, straighter paths due to lower surrounding obstacles.

 

Minimum Obstacle Clearance Standards

PANS-OPS defines key terms and parameters for determining the minimum altitudes required for safe descent or flight above obstacles.

 

Minimum Descent Altitude/Height (MDA/H):

Defined in Volume II of PANS-OPS as the lowest altitude/height in any 2D or circling approach procedure that must not be descended below unless the required visual reference is established. MDA is measured above mean sea level, while MDH is measured above airport elevation or runway threshold.

 

Minimum En-Route Altitude (MEA), Minimum Obstacle Clearance Altitude (MOCA), and Minimum Sector Altitude (MSA):

·      MEA: The lowest altitude along a defined route ensuring radio communication and obstacle clearance, established by ICAO member states under PANS-OPS standards.

·      MOCA: The minimum altitude ensuring obstacle clearance within a route segment, though continuous navigation signal reception may not be guaranteed.

·      MSA: Provides 25 nautical miles of horizontal obstacle clearance around a reference point such as a VOR or radar station, used primarily for emergency safety.

 

Obstacle Clearance Altitude/Height (OCA/H):

Defined as the lowest altitude or height above mean sea level (OCA) or runway elevation (OCH) that maintains the required vertical clearance above obstacles or terrain. These values allow authorities to determine safe descent limits even in low-visibility conditions.

Additionally, PANS-OPS includes standards for minimum climb gradients and aerodrome operating minima, which integrate aircraft performance, crew proficiency, runway dimensions, ground-based navigation aids, obstacle heights, and weather conditions, as noted by SKYbrary.

 

The Role of Airspace Planning in Implementing PANS-OPS

Airspace planning is the cornerstone of PANS-OPS implementation. While Document 8168 focuses on design, PANS-ATM (Doc 4444) governs air traffic management and minimum separation standards. Eurocontrol’s Airspace Planning Manual recommends:

  • Defining Control Areas: Establishing Control Zones (CTR), Terminal Control Areas (CTA), and Air Traffic Service (ATS) routes in accordance with Annexes 4 and 11 and PANS-OPS to ensure harmonization between airspace planning and flight-procedure design.
  • Defining Protected Airspace: ICAO Annexes and PANS-ATM define types such as Flight Information Regions (FIRs) and Upper Control Areas (UTAs), each with specific vertical and lateral separation requirements.
  • Civil-Military Coordination: Encouraging cooperation between civil and military authorities to optimize airspace use and adopt the Flexible Use of Airspace (FUA) concept, which reallocates sectors dynamically based on traffic needs.
  • Evaluation and Stakeholder Engagement: SKYbrary emphasizes the need for pre-planning, stakeholder involvement, safety impact assessments, use of simulation tools, and sufficient time for training before implementation—ensuring procedures are both practical and safe.

In the Arab region, unique challenges exist - mountainous airports, oil-field proximity, and heavy transit traffic between Asia and Europe. Structured airspace planning and proper application of PANS-OPS enhance safety and prepare for growing air traffic demand.

 

Differences between PANS-OPS and Other Design Systems Such as TERPS

Some countries follow alternative standards, such as the U.S. TERPS. Key differences include:

  • Measurement Units: PANS-OPS uses the metric system; TERPS uses U.S. customary units (feet/nautical miles), affecting slope and distance calculations.
  • Climb Gradient Origin: PANS-OPS begins from the Clearway, offering extra safety margin, while TERPS starts from the runway end.
  • Climb Gradient Requirements: PANS-OPS requires a 2.5% base plus 0.8% reserve (total 3.3%), while TERPS specifies 200 ft/NM (~3.3%) divided between obstacle and reserve surfaces—yielding design variations for steep terrain.
  • Path Width and Divergence: PANS-OPS protection areas start wider and expand gradually, while TERPS areas are narrower. The splay angle and turn-management methods differ.
  • Handling Insufficient Climb Capability: Each system proposes alternatives such as increasing engine power, route modification, or visual procedures, but with distinct criteria.

Understanding these differences is crucial for comparing national procedures or training pilots operating under multiple regulatory systems.

 

Best Practices for Implementing PANS-OPS in the Arab Region

Arab countries increasingly rely on PANS-OPS for flight-path design, yet specific challenges remain - terrain, weather, and regional coordination. Best practices include:

1.       Comprehensive Planning and Assessment

o   Detailed Obstacle Surveys: Aviation authorities should conduct thorough surveys around airports to verify obstacle elevations and update data regularly.

o   Environmental Impact Assessment: Proposed routes must consider noise and community impacts; PANS-OPS includes post-1996 noise-abatement provisions.

o   Integration with PBN: Performance-Based Navigation enables more precise RNAV routes but requires advanced equipment and ongoing maintenance.

2.       Training and Capacity Building

o   Certified Procedure Designers: Designers must undergo accredited training covering Document 8168 and quality-assurance manuals such as Doc 9906. The Bangladeshi Civil Aviation Authority confirms that PANS-OPS and the Procedure Design Quality Assurance Manual form the basis of local design standards.

o   Pilot Training: Understanding differences between TERPS and PANS-OPS is vital for pilots flying internationally. SKYbrary notes that misinterpretation of minima standards can cause incidents, emphasizing careful selection of specialized training courses. The Only Solution for Training and Consulting offers specialized aviation and air navigation courses, including PANS-OPS, targeting air traffic controllers, engineers, and aviation authority staff. The institute provides customized course design  and flexible scheduling options for participants.

o   Development of Labs and Tools: Investment in 3D design and flight-simulation software allows designers to test procedures before approval.

3.       Continuous Review and Updates

o   Risk and Performance Evaluation: Eurocontrol guidelines recommend comprehensive risk and impact assessments when designing or modifying routes, engaging airlines and military authorities.

o   Updating Local Regulations: Each state should align its regulations with PANS-OPS revisions, particularly regarding satellite-based navigation and GBAS/RNP technologies.

o   Regional Cooperation: Coordination among Arab states is crucial for harmonizing procedures in transit regions and ensuring smooth cross-border flight operations.

 

PANS-OPS is not merely a set of technical standards - it is a comprehensive system ensuring flight safety and optimal airspace utilization. By understanding core concepts such as aircraft operations and obstacle-clearance minima, and by applying best airspace-planning practices, Arab countries can enhance aviation safety and efficiency. Given the critical role of human expertise, The Only Solution for Training and Consulting provides specialized PANS-OPS training programs that combine theoretical knowledge with practical application - empowering aviation professionals and contributing to the advancement of the Arab aviation industry.

...