Blind Faith

A bloke about to make his first sky dive finds himself sitting next to a blind man in the plane. He comments how brave the chap must be to sky dive given his condition and asks how he copes.
"Quite easily, " says the bloke. "The jump master guides me to the door and places my hand on the rip cord. Then, when it's time to jump, he just taps me on the shoulder and out I go."
"Wow!" says the first chap. "But how do you know when to pull the rip cord?"
"No problem," says the blind guy. "We visually challenged folk have a highly developed sense of smell and when I get to about 300 metres, I can smell the woods and fields and I know it's time to deploy."
"Fantastic!" says the first chap. "But how do you know when to bend your knees just before you hit the ground?"
'Easy," says the bloke. "The dog's lead goes slack."

Pete