dave ward wrote:
On the face of it keeping 45 year old airframes operational is pretty daft, but the old Comet derived Nimrod did have one trick up its sleeve that modern replacements don't appear to offer. As the engines are close in to the fuselage and comparatively well cowled in, they can shut 1 or 2 of them down for long periods, when a low level "loiter" capability is required. This can considerably increase the endurance, which would be particularly useful on the sort of maritime emergencies you mention in this post.
Although modern engines are extremely reliable, having 4 of them when you're engaged in low level work in the middle of the Atlantic is preferable to the 2 fitted on aircraft such as the modified B737's which are being touted as replacements. I also suspect that the airframe is a lot stronger than newer designs. Things tended to be over engineered back then...
As far as I know, this is true. Modern civil aircraft are built to incredibly fine tolerances that just wouldn't be suitable for military use, which is part of the reason the US still uses 707s for its AWACS airframes.
I find it odd that they felt it necessary to essentially rebuild the entire jet in order to keep it. For that money they could have designed an entirely new replacement that used a similar configuration (engines in wing near the root and so on), with much better performance than the rebuilt nimrods and with much better quality control, as well as providing a large number of jobs in the UK.
I recall one of the problems with the MR4 was that they had to custom-build each one as each airframe was a slightly different shape, which drove the cost through the roof. I bet they could have built a comparable new aircraft for about two thirds of the price and had the option to build many more for other purposes if needs be.