JohnB wrote:
I'm pretty sure the B-52 tooling no longer exists...I could be wrong, if I am, let us know.
IIRC, beginning in the 70s-80s, Congress mandated that contractors retain production tooling for military types (they got tired of hearing from contractors that producing parts would be expensive or they didn't have the ability to make a new batch of aircraft, like the C-5B or TR-1). I've read that's why the Skyraider wasn't put back into production during Vietnam.
On a working visit sit to D-M, I was shown some. Also, I believe some of the tooling was occasionally sent to the AFMC depot responsible for the overhaul and logistical support for the type so they could build or repair sections such as wings or control surfaces.
Congress mandates but does not fund. The C-17 just went out of production and some tooling was retained, but not the entire wish list. Tooling also wears out and requires replacement or refurbishment. I'm sure there is plenty of B-52 tooling out there, but almost none of it is original '50s and '60s Boeing tooling.
The big problem is finding a supplier willing to build 1-5 spare parts. The Original Equipment Manufacturer (OEM) is generally out of the picture building new planes, so they won't be interested (Diminished Manufacturing Sources, or DMS). Now you have to find another supplier with no expertise in building that exact part. Their processes will not be the same as the OEM and in many instances the processes used are proprietary to the OEM. You also have obsolescences where sub-tier suppliers no longer make the IC chips used in circuit cards or the sensing elements needed for oxygen flow sensors. Now the new supplier has to design the part and do all the qualification testing to prove the part is suitable for long-term aviation use. All this for the 5 parts that will be needed over the next one or two years. You can't amortize the start-up cost over 100 parts because all the seals would dry up sitting on the shelf for the next 40 years. Thus you have the $150K bleed air valve or $300K hydraulic pump. Then you may only get 5 or 10 parts out of your supplier because 3 years later they go out of business or merge with another company that doesn't want to make those products any longer.
Avionics obsolescence is a huge problem as well.
BTW, a USAF Depot is probably the most expensive place you could find to manufacture spare parts.