Output file created by MSC Nastran, a structural analysis program that enables you to test the integrity of different structures such as spacecraft or buildings; contains different types of data output depending on the card (similar to a command) that is run.
An example of a card is XYPUNCH, which will create an output of the X and Y-axis data, e.g., magnitude vs. frequency. The contents of the PCH file created from this card would consist of two types of data. The first type would resemble the .F06 file, with mode shapes, static displacements, and grid point stress data, but in alternate format from the F06 file. The second type of output would display magnitude vs. frequency, which helps plot the response curve in a spreadsheet.