AD 47-49-10 ACTIVE

47-49-10 LOCKHEED: (Was Service Note 10 of AD-763-3.) Applies to All Model 49 Airplanes Which Are Equipped With Astrodomes During Pressurized Cabin Operations, Unless Permanently Sealed Off.

(a) Prior to next flight, provide an internal cover plate for the astrodome opening fabricated of 3/16-inch 24ST aluminum alloy or equivalent, with provisions for installing this plate in the astrodome opening in the event of loss of the astrodome.

(LAC Service Bulletin 49/SB-331 covers this same subject.)

(b) Prior to the next flight, provide a navigator's safety harness with suitable attachments to the floor structure beneath the astrodome.

(LAC Service Bulletin 49/SB-264 covers this same subject.)

(c) Prior to next flight, install a placard adjacent to the astrodome opening, reading as follows: "Wear safety harness whenever using astrodome. Check security of harness attachment to floor after each installation".

(d) Prior to each flight, closely inspect each astrodome for cracks, crazing or other defects, with particular attention given to area around radius adjacent to the flange. When any defects are found, the dome should be replaced at least before the next departure from a terminal base.

(LAC Service Information Letter No. 101 covers the necessary inspection procedure.)

(e) If new type laminated astrodome assembly and ring, LAC Parts 298679 and 298735, respectively, are installed with necessary seals and attachments, the requirements of parts (a), (b), and (c), may be disregarded. The preflight inspection called for in (d) should be continued.

(LAC Service Bulletin 49/SB-324, revised April 30, 1947, covers installation of the new type astrodome and mounting ring.)