For our military aviators here, I have a question about how the military actually replaces aircraft. The only AC I have experience with was obsolete and no longer produced by Grumman at the time I was around it.

When an aircraft is in common usage, do you get new replacement aircraft every so often? Or do they just keep getting parts from depot level, and rebuild the old airframes as long as they are serviceable?

I was watching some FA-18s doing touch and goes over the weekend, and one looked so much newer than the others. I'd never considered this in the past that squadrons might get new production AC every so often.

Both.

Procurement of airframes and spares (spares being the components that would be used to maintain the aircraft in service that are equal to an additional airframe "logically" speaking).

Any aircraft written off due to Class A mishap may be replenished, if the airframe block is still being produced, or transferred from another unit.

All of these logistics are dependent on the current needs, availability and other factors.

There is no "hard fast rule", but is predicated on a multiple of factors.

Aircraft procurement can be like the F-4, that saw more than 6000 manufactured over nearly 25 years.

To the F-117 that was under 10 years for less than 70 airframes (and spares).

All I ever saw was rebuilding of old airframes, and airframe reclassification due to G limitations on airframes. Just curious.

I'm sure the purchase contract covers new planes plus spare parts of enough quantity to rebuild the planes many times over plus a commitment to maintain a supply of those spare parts for some time plus a commitment to maintain production capability for some time after.

Every aircraft contract is different. Our KC135 tankers are in common usage but they’re all from the 1950s and 60s. However, portions (avionics, engines) are upgraded and replaced periodically. Some aircraft designs are really good, like the C130, so when a new aircraft is built under a new contract it looks very similar to the old ones despite being a totally different aircraft C130J).

Our fleet is a hodgepodge mix of old and new, both on a macro and micro scale.

The "Newer" looking aircraft could have simply been an older airframe that had gone though rework. With MH-60's every 3 years they go though major overhaul and with everyother rework they get a new paint job.

Replacement aircraft would generally require authorization and appropriation of funds from Congress.

I know that for the Air Force, all replacement AC must be a Energy Star rated central forced air system and not individual window units.



< ducks and runs >

quote:

Originally posted by Sig2340:
I know that for the Air Force, all replacement AC must be a Energy Star rated central forced air system and not individual window units.

< ducks and runs >

I pulled this thread up while having lunch at LRAFB and showed it to some senior enlisted guys. They loved your response!

I worked at Pensacola NAS at the Naval Aviation Rework Facility, NARF, some years ago when I was young. (They changed the name to NADEP but I like NARF)

There I converted combat A-4 to trainers. Later, I worked converting H-53s to Pave Low, and H-60s to Pave Hawk. It’s been a long time ago so I can’t remember the designations.

Basically, you can almost replace any component that comprises the airframe. In theory, we could have manufactured brand new aircraft on site. Not feasible, but possible. The A-4s wings were basically the fuel tanks, along with a bladder behind the seat.

Any part of the wing tank was replicable or orderable. We would remove the skin, fabricate a replacement, and then replace all the ribs. Anything larger would undergo NDI to see if it was structurally sound. Almost the entire structure was aluminum. It could be annealed, or heat treated as specified.

Basically with a new engine and components, the rest of the monocoque is completely repairable, or replaceable. That’s why you can get so many years out of an airframe.

FYI, for anyone that has been to the Naval Aviation Museum, the F-14 out front on the pedestal, I was one of the sheet metal mechanics that converted it from a combat aircraft to a museum piece.

It's my understanding, and this may be wrong, but as long as you have the data plate, which has the serial number and other such manufacturer info, as long as you have this then you can replace every other single part of a plane. You literally could build a brand new plane out of the parts available, just make sure you have attached that original data serial number plate. Of course cost and parts availability might be the huge deciding factor.

I see most of it has been covered, but in the FA-18 community, FLE (Fatigue Life Expenditure) is a hot topic and tracked very closely by the aircraft and maintenance personnel.

The airframes have flight time limits, but also specific stress limits (overall G's experienced) and arrested landing limits. After so many of each, they either need to receive specific maintenance that is approved by the manufacturer or cease that kind of flying - for awhile certain aircraft had lower G limits, or could no longer land at the boat - basically useless except for initial training, etc.

The big thing on older A-D Hornets was the "center barrel", basically the center structure which pretty much everything attaches to - when aircraft reached a certain limit, they had to have it replaced, which was expensive and time consuming.

But engines and other components are replaced / overhauled on a periodic timeline / flight hours / etc.

Also squadrons get aircraft back from maintenance and they can look factory fresh / new, even though they are older. Like a new paint job from MAACO on your car.

Or they can be getting a new "Lot" of aircraft (term used in the F18 community to distinguish different production years / capabilities). It's usually a wholesale change, they turn in all of their old planes and get new ones.

Because if your squadron is flying 10 year old F-18s, that kind is no longer made, with all the new production models being more advanced in some regard - so it's not conducive to maintenance to have a wide mix of "Lots" - similar to "Blocks" of F16s for the USAF types. They can and do have different engines, avionics, systems, etc as the aircraft has matured over time.

quote:

Originally posted by smithnsig:
I worked at Pensacola NAS at the Naval Aviation Rework Facility, NARF, some years ago when I was young. (They changed the name to NADEP but I like NARF)

They changed the name again a few years ago to Fleet Repair Center or FRC

I was an engineer on the F-15 at McDonnell Douglas and we always said not to worry about what we sold the basic airframe for, we will make up for it on change orders, enhancements and spares. Probably not too much of an exageration.

quote:

Originally posted by Flyboyrv6:
I was an engineer on the F-15 at McDonnell Douglas and we always said not to worry about what we sold the basic airframe for, we will make up for it on change orders, enhancements and spares. Probably not too much of an exageration.

I worked on every one of them, from A-E, and everything in between.

You have not exaggerated, not a single bit.

But, damn. That bird is one bad assed platform.

quote:

Originally posted by smithnsig:
I worked at Pensacola NAS at the Naval Aviation Rework Facility, NARF, some years ago when I was young. (They changed the name to NADEP but I like NARF)

I also am a former employee of NARF/NADEP.