As a former ground engineer in the late 1970's I paid off my first house loan inside 18 months with the overtime I made doing engine changes & building up 5th Pod engines to fly in & out around the asian area due to JT9D engine failures!!!!!!!!! I reckon they were the best invention since the Super Connie superchargers !!!!! (which would also allow an engineer to pay off a house loan in 18 months due to failures & incurred overtime..,.... ) Technology , you can't beat it!!!!!!! :