Arlington Municipal Airport Development Plan Arlington Airport Development Plan | Page 99

craft which are currently using or are expected to use an airport. The critical design aircraft is used to
define the design parameters for an airport. The design aircraft may be a single aircraft type or, more
commonly, is a composite aircraft representing a collection of aircraft classified by three parameters:
Aircraft Approach Category (AAC), Airplane Design Group (ADG), and Taxiway Design Group (TDG).
FAA AC 150/5300-13A, Change 1, Airport Design, describes the following airplane classification sys-
tems, the parameters of which are presented on Exhibit 3B.
Aircraft Approach Category (AAC): A grouping of aircraft based on a reference landing speed (V REF ), if
specified, or if V REF is not specified, 1.3 times stall speed (V SO ) at the maximum certificated landing
weight. V REF , V SO , and the maximum certificated landing weight are those values as established for the
aircraft by the certification authority of the country of registry.
The AAC generally refers to the approach speed of an aircraft in landing configuration. The higher the
approach speed, the more restrictive the applicable design standards. The AAC, depicted by a letter A
through E, is the aircraft approach category and it relates to aircraft approach speed (operational char-
acteristic). Aircraft in AAC A and B include pistons, turboprops and small general aviation jets. Aircraft
in AAC C, D, and E include medium-sized general aviation jets up to larger commercial jets. The AAC
generally applies to runways and runway-related facilities, such as runway width, runway safety area
(RSA), runway object free area (ROFA), runway protection zone (RPZ), and separation standards.
Airplane Design Group (ADG): The ADG, depicted by a Roman numeral I through VI, is a classification
of aircraft which relates to aircraft wingspan or tail height (physical characteristic). When the aircraft
wingspan and tail height fall in different groups, the higher group is used. The ADG influences design
standards for taxiway safety area (TSA), taxiway object free area (TOFA), apron wingtip clearance, and
various separation distances.
Taxiway Design Group (TDG): A classification of airplanes that is based on outer-to-outer Main Gear
Width (MGW) and Cockpit to Main Gear (CMG) distances. The TDG relates to the undercarriage di-
mensions of the design aircraft, and the TDG standards are based on the MGW and CMG distances.
The taxiway design elements determined by the application of the TDG include the taxiway width, tax-
iway edge safety margin, taxiway shoulder width, taxiway fillet dimensions, and, in some cases, the
separation distance between parallel taxiways/taxilanes. Other taxiway elements, such as the TSA,
TOFA, taxiway/taxilane separation to parallel taxiway/taxilanes or fixed or movable objects, and taxi-
way/taxilane wingtip clearances are determined solely based on the wingspan of the design aircraft
utilizing those surfaces. It is appropriate for taxiways to be planned and built to different TDG stand-
ards based on expected use.
Exhibit 3C summarizes the aircraft classification of the most common aircraft in operation today. Gen-
erally, recreational and business piston and turboprop aircraft will fall in approach categories A and B
and airplane design groups I and II. Business jets typically fall in approach categories B and C, while
commercial aircraft will fall in approach categories C and D.
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