§3.304 Casting factors.

For structural castings, the factor of safety prescribed in § 3.172 shali be Multiplied by the casting factors specified in paragraphs (a) and (b) of this section. The prescribed tests and inspections shall be in addition to those necessary to establish foundzy quality control, Castings shall be inspected in accordance with approved specifications. (a) Each casting, the failure of which would preclude continued safe flight and landing of the airplane or which would result in serious injury to occupants, shall have a casting factor of at least 1.25 and shall receive 100-percent inspection by visual, radiographic, and magnetic particle or penetrant inspection methods or approved equivalent nondestructive inspection methods. Where such castings have a casting factor less than 1.50, three sample castings shall be static tested. The test castings shall comply with the strength requirements of § 3.173 at an ultimate load corresponding with casting factor of 1.25 and shall comply with the deformation requirements at 2 load. equal to 1.15 times limit load. Nore: Examples of castings to which this subparagraph applies are: structural attachment fittings; parts of fight control systems; control surface hinges and balance weight attachments; seat, berth, safety helt, and fuel and of] tank supports and attachments; cabin pressure valves, (b) For structural castings other than those specified in paragraph (a) of this section, the casting factors and inspections shall be in accordance with the following table except that it shall be acceptable to reduce the percentage of castings inspected by nonvisuat methods when an approved quality control procedure is established. For castings Procured to a specification which guarantees the mechanical properties of the material in the castings and provides for demonstration of these properties by test of coupons cut from castings on a sampling basis, it shall be acceptable to use a casting factor of 1.0. The inspection requirements for such castings shall be in accordance with those specified in the following table for casting factors of 1.25 to 1.50, and the testing requirements shall be im accordance with paragraph (a) of this section. Casting factor Inspections 2.0 or greater... 10 percent visual. Less than 2.0 greater | 160 percent vusuai, and magnetic than 1.5, particle or penetrant or equivalent nondestructive inspection methods. 1.25 to 1.60........./ 100 ‘percent visual, magnetic Particle or penetrant, and radiographic, or approved equivalent nondestructive inSpection methods. {e) Castings which are pressure tested as parts of a hydraulic or other fluid system shall not be required to comply with the provisions of this section unless such castings support airplane structural loads. (d) The casting factor need not exceed 1.25 with regard to bearing stresses regardless of the method. of inspection employed. A casting factor need not be employed with respect to the bearing surface of a part if the: bearing factor used (see § 3.305) is greater than the casting factor. §3.304-1 [Deletion] 21. By deleting § 3.3041. §3.345-3 [Amendment] 22. By amending § 3.345-3 by inserting between the expressions “ArmyNavy-Aeronautical Standards” and “National Aircraft Standards” the expression “Military Standards”, §3.357 [Amendment] 23. By amending § 3.357 by adding at the end thereof the phrase “on airplanes which are not amphibian”. 24. By amending § 3.359 by deleting from the second sentence the phrase “after the throttle is closed” and inserting in lieu thereof “when one or more throttles are closed” and by adding a note to read as follows: