(a) This system of accounts and reports is designed to permit limited contraction or expansion to reflect the varying needs and capacities of different air carriers without impairing basic accounting comparability as between air carriers. In its administration three air carrier groups, designated Group I, Group II, and Group III, respectively (see section 04), are established by the BTS. This grouping will be reviewed from time to time upon petition of individual air carriers or by initiative of the BTS with the view of a possible regrouping of the air carriers.

(b) Under the system of accounts prescribed, balance sheet elements are accounted for by all air carrier groups within a fixed uniform pattern of specific accounts. All profit and loss elements are accounted for within specific objective accounts established for each air carrier group resulting from dual classifications, designated for each air carrier group, which are descriptive of both basic areas of financial activity, or functional operation, and objective served. The profit and loss elements of the three air carrier groups can be reduced to broad objectives and general or functional classifications which are comparable for all air carrier groups. Both balance sheet and profit and loss accounts and account groupings are designed, in general, to embrace all activities, both air transport and other than air transport, in which the air carrier engages and provide for the separation of elements identifiable exclusively with other than air transport activities. Profit and loss elements which are recorded during the current accounting year are subclassified as between

(c) In order to afford air carriers as much flexibility and freedom as possible in establishing ledger and subsidiary accounts to meet their individual needs, a minimum number of account subdivisions have been prescribed in this Uniform System of Accounts. It is intended, however, that each air carrier, in maintaining its accounting records, will provide subaccount and subsidiary account segregations of accounting elements which differ in nature of accounting characteristics, in a manner which will render individual elements readily discernible and traceable throughout the accounting system, and will provide for relating profit and loss elements to applicable balance sheet counterparts.