GENERAL

Only such markings and identifying insignia as outlined herein will be used on AAF aircraft except as specifically authorized by the Commanding General, AAF.

11. PARTS.

Each part and assembly will be permanently and legibly marked the same number as the drawing number in such lo­cation that it can be read after assembly in the unit. (Refer to Specification No. 98-24105.)

12. DETAIL.

Various detail and code markings for the cockpit, fuselage, oil lines, etc., as required in latest revision of Specification No. 98-24105, will be maintained except that paragraph E-19 need not be complied with on airplanes to which fluid line iden­tification decals were not applied in production. In addition, Jet No. 622 finishes (on metal and wood) surfaces will be stenciled in yellow on an upper surface with code number of the approved Jet 622 of the paint manufacturer under the two applicable specifications (Bulletin 102 for lacquer, and 148 for enamel), two dashes, followed by the symbol for the material as “L-29” or “E-3.” Example: D-800-L-29.

13. RADIO CALL NUMBERS.

a. Radio call numbers of not less than four numerals will be maintained on all AAF aircraft, except as stated in paragraph 17.c„ utilizing both sides or each outboard side, as applicable, of the vertical stabilizer and rudder assembly. These call numbers, or designators, will be of a size discernible at a distance of 150 yards. The suggested size is 8 x 12 inches. They will be derived by deletion of the first numeral of the serial number (4) and the hyphen (-), and the combination of the remaining four or more numerals. In case of serial numbers of type 41-7, use zero as necessary to make four numerals, as 1007. Colors will be black for uncamouflaged surfaces, and yellow for camouflaged surfaces except that jet camouflaged planes will have insignia red call numbers. Decaicomania are authorized if available.

b. On all airplanes operating solely within the continental limits of the United States the radio call numbers will also be placed with the top forward on the lower surfaces of wings, except as stated in paragraph 17.g. The size of the number to be painted on aircraft and the matter of whether the numbers will be painted on the left wing only or both wings, will be determined by the local using agency in accordance with the space available and the desired usage. However, the suggested method is to apply 16 x 24 inch numerals on the lower left wing.

c. Radio call numbers in neither location are required, however, on primary trainers not equipped with radio and which bear field identifying numbers.

14. PROPELLER MARKINGS.

American propeller blades, design Nos. A-2721107, A2891100, and A2891106, used in sets in Aeroproducts propellers and design Nos. С-27212Ш) and C-3821306, used in sets in Curtiss propellers, respectively, will be identified by a yellow stripe, 3/8 inch in width and 3/8 inch inboard of the yellow tip. A. O. Smith propellers, design No. Prefix “SPA” used in sets in Curtiss propellers will be identified by two 3/8-inch yellow stripes; one 3/8 inch inboard of the yellow tip, and the other stripe 3/ 8 inch inbdard front the first. These stripes will extend completely around the blade section. The stenciled markings between the 18- and 24-inch stations on the cambered side of the propeller blades wilt be retained. When the exact location of the blade reference station is known, a stripe of yellow paint 1/8 inch wide, 2 inches long, and spaced equally distant between the leading and trailing edge of the blade, will be placed on the thrust face at the reference station.

CAUTION Unless the exact location of the reference station on the blade is known no attempt will be made to identify

this location by the afore-mentioned stripe.