Deck landing trials apparently for the Sea Knight. The helicopter wears the original naval designation HRB-1, which changed to CH-46A as of 18 September 1962, but the photo must have been taken a little later as the HRB-1 first flew in August 1962 and this was the last of five airframes built in 1962. It was formally delivered in December but stayed at Boeing Vertol flight test department. It later went to Vietnam and crashed into the sea on a medical evacuation mission on 1 May 1967. One of the four crew - the gunner - and seven of the 13 wounded on board perished. Photo from: Boeing