AMC E 70  Castings, Forgings, Welded Structures and Welded Components

ED Decision 2007/015/R

(1)     Castings

The means of maintaining the required quality of all castings should be established by such methods as analysis for correct chemical composition, tests of mechanical properties, microscopic examination, break-up examination, strength tests, radiographic examination, etc. While other forms of examination may be adequate for most parts of castings, radiographic examination, where practicable, should be carried out on the more highly stressed portions in order to establish that the foundry technique is satisfactory.

When radiographic examination is called for, this should be continued until a satisfactory standard of quality has been established. Subsequent relaxation may be introduced, in quantity production, at the Engine constructor's discretion using a system acceptable to the Agency.

All castings should be subjected to a suitable flaw-detection process. Such processes should be completed subsequent to any heat treatment.

The drawings of each casting should contain information sufficient to identify the relevant means of manufacture and quality control, either by detailing the necessary information, or quoting the relevant documents. Where necessary, areas of high stress should be identified, but this may be done by a separate drawing.

No change of foundry (i.e. castings constructor) or significant change of foundry technique should be made without the agreement of the Engine constructor, and such agreement should involve review of the need for the repetition of certain tests and/or a revision of the method of quality control.

(2)     Forgings

(a)      Forgings should be classified as Class 1, Class 2 or Class 3 parts in accordance with the following:

—         Class1 Those parts, the Failure of which could hazard the aircraft.

—         Class 2 Stressed parts not covered by the terms of Class 1.

—         Class 3 Unstressed or only lightly stressed parts, not covered by the terms of Class 1.

The means of maintaining the required quality of all forgings should be established by such methods as analysis for correct chemical composition, tests of mechanical properties, microscopic examination, fracture examination, strength tests, radiographic examination, etc.

On the drawings of Class 1 parts, the direction of grain required should be indicated clearly in a manner which will ensure that it is brought to the notice of the person responsible for deciding the forging technique to be adopted. The agreed material properties should also be identified.

All forgings should be subjected to a suitable crack-detection process at an appropriate stage. Additional crack-detection tests should be made after any subsequent heat treatment has been completed. Where the level and location of residual stresses in forged Engine Critical Parts could be significant in relation to the intended loads, and cannot be assessed by experience on similar designs using similar materials and forging methods, sufficient physical tests should be carried out to give adequate assurance of the level of residual stress likely to be present and of freedom from unacceptable variability.

When radiographic or ultrasonic examination is called for, this should be continued until a satisfactory standard of quality has been established. Subsequent relaxation may be introduced in quantity production at the Engine constructor's discretion using a system acceptable to the Agency.

The drawings of each forging should contain information sufficient to identify the relevant means of manufacture (e.g. the optimum fabrication method and sequence to obtain the desired level of residual stress and the correct grain flow in the finished forgings) and quality control either by detailing the necessary information or quoting the relevant process control documents.

The strength of forgings classified as Class 1 or Class 2 parts should be proved to be satisfactory by calculation, by test, or comparison with a forging of similar design already proved to be satisfactory.

(b)     Tests

Each Class 1 and Class 2 forging should normally incorporate one or more projections which, after heat treatment of the forging, can be used as test piece(s) to establish that the material qualities of the forging are satisfactory.

The location(s) and dimensions of the test piece(s) should be decided in consultation with the forging manufacturer. The forging manufacturer should certify that the test piece(s) achieve the required material properties.

In cases where the incorporation of test pieces is unpractical, or would adversely affect the design, the drawing should indicate that such test pieces are not required. In such cases a suitable technique of sample testing should be agreed.

(c)      No change of forging constructor or significant change of forging technique should be made without the agreement of the Engine constructor and such agreement should involve review of the need for the repetition of certain tests and/or a revision of the method of quality control.

(3)     Welded Structures and Welded Components

Fusion and resistance welds should be classified in accordance with the following:

—          Group 1 Those welds the Failure or leakage of which could hazard the aircraft.

—          Group 2 Highly stressed welds the Failure or leakage of which would not hazard the aircraft.

—          Group 3 All other welds.

The necessary means of maintaining the required quality of all welded structures and components should be established. This may involve the verification of correct application of the approved preparatory and welding techniques, by destructive and non-destructive inspection of representative test specimens, at prescribed intervals during weld production, visual inspection of each weld produced, and pressure testing of welds, where applicable, etc.

All welds should be subjected to a suitable crack-detection process at an appropriate stage. Additional crack-detection tests should be made after any subsequent heat treatment has been completed.

When radiographic examination is called for, this should be continued until a satisfactory standard of quality has been established. Subsequent relaxation may be introduced in quantity production at the Engine constructor's discretion using a system acceptable to the Agency.

The drawings of each welded structure or component should contain information sufficient to identify the relevant means of welding to be used and the quality control method either by detailing the necessary information or quoting the relevant documents.

No significant change of welding technique should be made without the agreement of the Engine constructor and such agreement should involve review of the need for a revision of the method of quality control or even modification approval action.

[Amdt. No.: E/1]