Aircraft classification number

The Aircraft Classification Number (ACN ) is an International Civil Aviation Organization (ICAO) normative parameter that expresses the relative effect of an aircraft on the artificial surface of an aerodrome runway , used in conjunction with a classification number of coverage .

For the ACN unit, the load is taken, which is exerted by one wheel weighing 500 kg and a pneumatic pressure of 12.5 kgf. ACNs are calculated for various aircraft and published in regulatory and reference documents (for example, Civil Airfield Usability Standards (IEA) ^[1] , as well as in the Jeppesen aeronautical information collection, Airport Directory valve. Aircraft ACNs are calculated for alignment at which the critical load on the critical landing gear is reached. Usually the maximum back alignment is used for calculations with the maximum taxiing weight. However, in some cases, the criterion is reached with the maximum front alignment The load on the nose stance.

For aircraft with a flight mass equal to or less than 5,700 kg (12,500 pounds), ACN is not calculated. For such aircraft, the maximum possible flight weight of the aircraft and the maximum possible pressure in the pneumatics are indicated in the flight plan. For example 4000kg (8800lbs) / 0.50MPa (73psi).

Takeoff and landing operations at the aerodrome with minimal overload are allowed for:

• non-rigid coverage when the ACN is not more than 10% higher than the published PCN;
• hard or combination coatings if the ACN exceeds PCN by less than 5%;
• uncertain coverage if ACN exceeds PCN by less than 5%.

ACN classification numbers of aircraft are calculated in accordance with the ACN determination methodology given in DOS 9157-AN / 901 Part 3, ICAO and are indicated by aircraft manufacturers in the flight operations manual (RLE). In the absence of ACN values ​​in the aircraft RLE, the values ​​indicated in Table 1 are used. 3.15 NGEA. ^[one]