sentences:  Their existing HR2S fleet had a ground pressure of about , and proved to blow people about on the ground and stir up considerable amounts of debris.The C-142 was predicted to have an even higher loading of , which they believed would limit it to operations to and from prepared landing pads and was therefore unsuitable for assault operations.The first prototype made its first conventional flight on 29 September 1964, first hover on 29 December 1964, and first transition on 11 January 1965.