When I was first asked to take part in this Colloquium I declined on the grounds that there had been too many reliability conferences already, and I feared that another would only take the time of good engineers off their day to day tasks of improving the reliability of British products. Having heard some of the contributions, I think I should revise that opinion. We have heard some good material. I was prevailed upon to say a few words on the problems of military aircraft and this I will do. I shall omit almost entirely references to equipment because, as I see it, the problems on the equipment side are fairly similar whether the aircraft is a military or a civil one.