The profit and loss accounts are designed to reflect, through natural groupings, the elements entering into the derivation of income or loss accruing to the proprietary interests during each accounting period.

The prescribed system of accounts provides for the co-ordinate grouping of all revenues and expenses in terms of both major natural objectives and functional activities and for subdivision of both to provide varying degrees of detail for air carriers of differing accounting capacities and/or requirements.

The detailed objective accounts established for each air carrier group, by the dual subdivision of profit and loss elements in terms of both natural objectives and functional activities, are set forth in section 7, Chart of Profit and Loss Accounts.

The prescribed system of accounts provides generally that profit and loss elements shall be grouped in accordance with their inherent characteristics within the following primary classifications:

Operating revenues. (i) This primary classification shall include revenues of a character usually and ordinarily derived from the performance of air transportation and air transportation-related services, which relate to services performed during the current accounting year, and adjustments of a recurrent nature applicable to services performed in prior accounting years.

Operating revenues shall be subclassified in terms of functional activities as provided in section 9.

Operating expenses. (i) This primary classification shall include expenses of a character usually and ordinarily incurred in the performance of air transportation and air transportation-related services, which relate to services performed during the current accounting year, and adjustments of a recurring nature attributable to services performed in prior accounting years.

Operating expenses shall be subclassified in terms of functional activities as provided in sections 10 and 11.

Nonoperating income and expense—net. This primary classification (8100) shall include income and loss incident to commercial ventures not inherently related to the performance of the common carrier air transport services of the accounting entity; other revenues and expenses attributable to financing or other activities which are extraneous to and not an integral part of air transportation or its incidental services; and special recurrent items of a nonperiod nature.

Income taxes for current period. This primary classification (9100) shall include provisions for Federal, state, local, and foreign taxes which are based upon the net income of the air carrier for the current period together with refunds for excess profits credits or carryback of losses and increases or reductions of income taxes of prior years of a magnitude which will not distort net income of the current accounting year. Income taxes applicable to special income credits or debits recorded in profit and loss classification 9700 Extraordinary Items, and other material income tax items not allocable to income of the current accounting year, shall not be included in this classification but in profit and loss classification 9700 Extraordinary Items.

Discontinued operations. This primary classification (9600) shall include earnings and losses of discontinued nontransport operations and gains or losses from the disposal of nontransport operations the result of which are customarily accounted for through profit and loss objective accounts 86, 87 and 88.2.

Extraordinary items. This primary classification (9700) shall include material items characterized by their unusual nature and infrequent occurrence.

Cumulative effect of changes in accounting principles. This primary classification (9800) shall include the cumulative effect of material changes in accounting principles.