My purely speculative guess would be that this is less of an issue for tankers than for fighters.
Fighters are designed to be able to take off with both weapons and fuel that they are supposed to use up before landing again.
Big passenger/transport jets may have to dump fuel to be able to get to their landing weight, but they normally don’t drop their cargo or passengers during the flight. So for all of the “cargo weight” that is taken up by fuel in the KC-135, it should be possible to bring that back without dumping it.
But maybe @ST0RM can say something about this if he’s allowed
The USAF website states that the max ferry range is as follows:
ferry mission, up to 11,015 miles (17,766 kilometers)
The USAF website has this number for MTOW:
Maximum Takeoff Weight:** 322,500 pounds (146,285 kilograms)
And a doc on the USAF website has this for max landing weight:
The maximum landing weight for the KC-135 is now 235,000
So it would need to lose 87 500lbs of weight if loaded to MTOW before it can land. However, its empty weight is 98 465lbs while its maximum fuel capacity is 200 000lbs. So to reach MTOW you’d need to max out on fuel and still add 24 035lbs of cargo to it. If you would only fuel it, you’d only need to dump 63 465lbs to reach maximum landing weight.
This is all based on public info I could find, thanks for the little sidequest Someone like @ST0RM will obviously know better than me.
Ladies and Gentlemen, we have experienced a technical problem that forces us to turn around and land. Sadly we are too heavy to land right now, so we will dump 100 passengers.
Please remain in your seats for now, and wait for the crew to hand you your personal chute and give you further instructions.
Thank you for your understanding.
We used to have a 225k max landing weight limitation, but that has been increased to 235k and possibly more. I need to check.
But yes, we’d have to dump, or “adjust gross weight”, to bring us to that number.
EDIT: Apparently it can be landed at full max load (emergency), but is limited to a tight sink rate of 240ft per minute instead of the more common 700-800.
Ok, so semi related, a million years ago I was doing the whole security forces thing at a guard base. They had a 135 that landed for that exact reason (had a problem and overweight landing). The poor crew chief would come in every morning at about 04:30 to do the hard landing inspection (somehow I was always at the gate when he came in) but we had to do fire watch checks on the hangar.
So I walked in one night and saw that he and the mx crew had the parts marked on racks but also on the ground, inside of squares they made with tape, marked with p/n and location. Now, I grew up with a KC/EC/RC-135 crew chief dad, on SAC and USAFE bases. We did this same thing working on cars. I knew why they were doing this and how important it was. (this was reinforced when I went to A&P school years later)
Well, my mischievous brain got hold of me and the next day I grabbed some spare nuts, bolts, and washers from my garage before I came to work. Sure enough, I was at the gate when he came in. We started talking like we did every morning. This guy was old school- started on the A models back in the late 80’s. One of the coolest guys ever. Then, acting like I had just remembered, I reach into my pocket and pull out the hardware and said “Hey, I found these in your hangar. Did you need these?” His eyes became saucers and I could see the panic on his face. I managed to keep a straight face for all of about 10 second and then started laughing. Told him the whole story. Luckily he laughed and thought it was funny…but he DID ask me if I was SURE I had brought them from home.