Watch a 737 built in 136 seconds.

a reply to: Voyager1

Ultrasound is one way. Many years ago they had to do a special NDI check of our C-135s. They took an ultrasound probe and oscilloscope, and circled every rivet on the aircraft. Where any cracks were the scope would show a spike.

a reply to: Zaphod58

That's interesting Zaphod58. If a crack is found how is it repaired?

a reply to: Voyager1

There are various ways. They can run stringers across it to strengthen the area, all the way up to cutting that section out and putting a small plug into place.

a reply to: Zaphod58

Ultrasound: Is there anything it can't do?™

Coming from a completely different field (Hint: It's kind of like being a mechanic, but the machines you fix are lot squishier and more temperamental), it's nothing short of amazing to see the capabilities that ultrasound has given us in the past 5-10 or so years. It's so useful for so many different things that you start to wonder how the industry ever got by without it.