Crab and Lonewolf:
The ground resonance testing ( mechanical stability is the term used in the Engr Dept ) involves depleting the MR damper fluid, the tire pressure and the landing gear strut servicing. The Naval aircraft main gear ( Seahawk ) are quite different than the Army S-70 gear BTW*. In any case neither was conducive to the rapid entry into ground resonance experienced on the S-58.
*The Army gear design was greatly influenced by their very severe crash-worthy requirements, while the USN gear was very influenced by the frigate landing requirements. Those who have been to PXT can still see the 50 x 50 ft pad they built on a 9 degree slope. Landing at 12 ft/sec was “ interesting “. Actually we had asked for a larger pad, but the USN gave us 50. Trouble was that getting the vertical speed under control within 1 ft/sec isn’t easy and we were starting well above 100 ft and I couldn’t see the pad, even after taking the door off. Solution was that Seahwak Test Director CDR Jack Costello put on a flight suit, acquired a prtable UHF radio, stood on that slope and gave us a GCS for the first part of the descent. He was, as you can imagine, pretty close to the ship when we hit the ground.
Jack Costello, in a previous career, had flown Seals into North Vietnam in a UH-2.