Charts without the new designation will continue to be guided by the old, smaller-radii criteria. The government plates will show an inverse “C” in a black box in the approach minimums area of the plate, while Jeppesen will use a “C” inside a black diamond. Terminal Procedures and Jeppesen both plan to use new chart symbology to identify the updated approaches. Under the new criteria that radius will increase by 65 percent, to 2.7 nm. Previous versions of the FAA’s terminal instrument procedures (Terps) used a radius of 1.7 nm from the end of the runway for a Category C aircraft such as a Hawker 800. The higher the speed of the aircraft, the larger the arc. The boundaries of protected airspace for circling approaches are defined by arcs drawn from the threshold of each runway at an airport. The new airspace also offers pilots additional obstacle clearance while considering their MSL altitude above the MDA, which affects true airspeed. Table 3: TERPS 8260.3C - Criteria for circling approach areas Circling MDA in feet MSLĪpproach Category and Circling Radius (NM)įrom May 2, 2013, the FAA started publishing new instrument approach plates that include an enlarged segment of airspace to protect aircraft during circling approaches. These distances, dependent on aircraft category, are also based on the circling altitude which accounts for the true airspeed increase with altitude. TERPS 8260.3C - Circling approach areas for approach procedures use the radius distances (in NM) as depicted in Table 3. As a result, circling minima at certain airports may increase significantly. The circling approach area has been expanded to provide improved obstacle protection. The FAA has modified the criteria for circling approach areas via TERPS 8260.3C.
ICAO PANS-OPS uses a varying MOC which increases with aircraft category as shown in Table 2: Table 2: Minimum Obstacle Clearance (MOC) - PANS-OPS Aircraft category Table 1 shows the lowest value of visibility assumed by each method: Table 1: Minimum Visibility at OCA Aircraft category These values are calculated differently and therefore, may result in different AOM. Circling Approaches Minimum Visibilityīoth PANS-OPS and US TERPS assume values of minimum visibility available to the pilot at the lowest obstacle clearance altitude (OCA). This is especially true in respect of Circling Approaches where the assumed radius of turn and minimum obstacle clearance are markedly different (see below). Pilots should be aware that there are differences in obstacle clearance criteria between procedures designed in accordance with ICAO PANS-OPS and US TERPS. Some NATO military procedures are also based on US TERPS standards. These include Canada, Korea, Saudi Arabia and Taiwan. US TERPS are used in USA and in certain other countries.
United States Standard for Terminal Instrument Procedures (TERPS), described in FAA Order No 8260.3C.
PANS-OPS procedures are the international standard and are used throughout Europe and in many other countries world-wide. ICAO Procedures, described in ICAO Doc 8168 Procedures for Air Navigation Services (PANS-OPS).The procedures themselves are based on obstacle clearance domains constructed using internationally accepted standards. This information typically consists of approach and departure procedures which assure safe separation between the aircraft and known obstacles located close to the intended flight path of the procedure in question. Comparison between ICAO PANS-OPS and US TERPSĪerodrome operating minima (AOM) are calculated by operators based on information supplied by national authorities in their AIPs.