First photo had Walter flying the Queens Own into the Narrow Water ambush site
Second had the much larger second IRA bomb going off, obscuring the Wessex in dust, bricks and other debris
The third has the old girl, still in the hover, shaking off the blast like a dog just out of the water.
The cynical would probably say that the explosion wasn't that close, but that's what the Wessex was like, you felt it would always look after you.
I think it was close enough to have its windows blown in. The Captain, an ex-colleague of mine, once told me that he is certain that if he had been flying anything else that day he would not be alive. He got an AFC for his part in the aftermath and is still flying today.