CS 27.621 Casting factors

• ED Decision 2003/15/RM found in: CS-27 Amdt 10 - Small Rotorcraft (Feb 2023)

CS 27.621 Casting factors ED Decision 2003/15/RM (a) *General*. The factors, tests, and inspections specified in sub-paragraphs (b) and (c) must be applied in addition to those necessary to establish foundry quality control. The inspections must meet approved specifications. Sub-paragraphs (c) and (d) apply to structural castings except castings that are pressure tested as parts of hydraulic or other fluid systems and do not support structural loads. (b) *Bearing stresses and surfaces*. The casting factors specified in sub-paragraphs (c) and (d): (1) Need not exceed 1.25 with respect to bearing stresses regardless of the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) *Critical castings*. For each casting whose failure would preclude continued safe flight and landing of the rotorcraft or result in serious injury to any occupant, the following apply: (1) Each critical casting must – (i) Have a casting factor of not less than 1.25; and (ii) Receive 100% inspection by visual, radiographic, and magnetic particle (for ferromagnetic materials) or penetrant (for non-ferromagnetic materials) inspection methods or approved equivalent inspection methods. (2) For each critical casting with a casting factor less than 1.50, three sample castings must be static tested and shown to meet – (i) The strength requirements of [CS 27.305](#_DxCrossRefBm8893823) at an ultimate load corresponding to a casting factor of 1.25; and (ii) The deformation requirements of [CS 27.305](#_DxCrossRefBm8893823) at a load of 1.15 times the limit load. (d) *Non-critical castings.* For each casting other than those specified in sub-paragraph (c), the following apply: (1) Except as provided in sub-paragraphs (d)(2) and (3), the casting factors and corresponding inspections must meet the following table: <table border="1" cellpadding="0" cellspacing="0" width="528"><tr><td valign="top" width="184"><p><b>Casting factor </b></p></td><td valign="top" width="344"><p><b>Inspection </b></p></td></tr><tr><td valign="top" width="184"><p>2.0 or greater......... </p></td><td valign="top" width="344"><p>100% visual </p></td></tr><tr><td valign="top" width="184"><p>Less than 2.0 greater than 1.5 </p></td><td valign="top" width="344"><p>100% visual and magnetic particle (ferromagnetic materials), penetrant (non-ferromagnetic materials), or approved equivalent inspection methods. </p></td></tr><tr><td valign="top" width="184"><p>1.25 through 1.50...... </p></td><td valign="top" width="344"><p>100% visual, and magnetic particle (ferromagnetic materials), penetrant non-ferromagnetic materials), and radiographic or approved equivalent inspection methods </p></td></tr></table> (2) The percentage of castings inspected by nonvisual methods may be reduced below that specified in sub-paragraph (d)(1) when an approved quality control procedure is established. (3) For castings procured to a specification that guarantees the mechanical properties of the material in the casting and provides for demonstration of these properties by test of coupons cut from the castings on a sampling basis: (i) A casting factor of 1.0 may be used; and (ii) The castings must be inspected as provided in sub-paragraph (d)(1) for casting factors of 1.25 to 1.50 and tested under sub-paragraph (c)(2). CS 27.621 Casting factors ED Decision 2003/15/RM (a) *General*. The factors, tests, and inspections specified in sub-paragraphs (b) and (c) must be applied in addition to those necessary to establish foundry quality control. The inspections must meet approved specifications. Sub-paragraphs (c) and (d) apply to structural castings except castings that are pressure tested as parts of hydraulic or other fluid systems and do not support structural loads. (b) *Bearing stresses and surfaces*. The casting factors specified in sub-paragraphs (c) and (d): (1) Need not exceed 1.25 with respect to bearing stresses regardless of the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) *Critical castings*. For each casting whose failure would preclude continued safe flight and landing of the rotorcraft or result in serious injury to any occupant, the following apply: (1) Each critical casting must – (i) Have a casting factor of not less than 1.25; and (ii) Receive 100% inspection by visual, radiographic, and magnetic particle (for ferromagnetic materials) or penetrant (for non-ferromagnetic materials) inspection methods or approved equivalent inspection methods. (2) For each critical casting with a casting factor less than 1.50, three sample castings must be static tested and shown to meet – (i) The strength requirements of [CS 27.305](#_DxCrossRefBm472493264) at an ultimate load corresponding to a casting factor of 1.25; and (ii) The deformation requirements of [CS 27.305](#_DxCrossRefBm472493264) at a load of 1.15 times the limit load. (d) *Non-critical castings.* For each casting other than those specified in sub-paragraph (c), the following apply: (1) Except as provided in sub-paragraphs (d)(2) and (3), the casting factors and corresponding inspections must meet the following table: <table border="1" cellpadding="0" cellspacing="0" width="528"><tr><td valign="top" width="184"><p><b>Casting factor </b></p></td><td valign="top" width="344"><p><b>Inspection </b></p></td></tr><tr><td valign="top" width="184"><p>2.0 or greater......... </p></td><td valign="top" width="344"><p>100% visual </p></td></tr><tr><td valign="top" width="184"><p>Less than 2.0 greater than 1.5 </p></td><td valign="top" width="344"><p>100% visual and magnetic particle (ferromagnetic materials), penetrant (non-ferromagnetic materials), or approved equivalent inspection methods. </p></td></tr><tr><td valign="top" width="184"><p>1.25 through 1.50...... </p></td><td valign="top" width="344"><p>100% visual, and magnetic particle (ferromagnetic materials), penetrant non-ferromagnetic materials), and radiographic or approved equivalent inspection methods </p></td></tr></table> (2) The percentage of castings inspected by nonvisual methods may be reduced below that specified in sub-paragraph (d)(1) when an approved quality control procedure is established. (3) For castings procured to a specification that guarantees the mechanical properties of the material in the casting and provides for demonstration of these properties by test of coupons cut from the castings on a sampling basis: (i) A casting factor of 1.0 may be used; and (ii) The castings must be inspected as provided in sub-paragraph (d)(1) for casting factors of 1.25 to 1.50 and tested under sub-paragraph (c)(2).