"Adjusting Gross Weight"

[Hold West]

So the other day I'm working a fighter drag out of here, and one of the tankers needs to RTB for a non-emergency problem. I get him turned around, and he makes a request that stumped me for a sec. I was having a hard time understanding him out near the fringe of our VHF radio coverage, but I finally figured out he was saying he needed to "adjust gross weight". OK, so I ask does that mean he wants to fly around for a while and burn off fuel, or dump? He says he wants to dump. Fine, we get that going.

My question is, what's up with the request to "adjust gross weight"? With oil pushing $70/bbl, is it politically incorrect now to say "I need to dump fuel"? I thought it was an awful long series of transmissions just to figure out he wanted to dump fuel. Can anyone enlighten me?

 

[RampFreeze]

The term has been around and used for years, it's not a new PC phrase. I've got nothing to base this on other than what I've always been told, but I'm guessing the reason we use that term is to keep from raising flags with the uninformed every time we need to dump fuel. (i.e. no need to highlight every event to each Greenpeace member and news crew with a scanner) With as many non-events becoming "Breaking News" lately, the more we can do to keep from raising eyebrows the better.

 

[Hold West]

The term has been around and used for years, it's not a new PC phrase. I've got nothing to base this on other than what I've always been told, but I'm guessing the reason we use that term is to keep from raising flags with the uninformed every time we need to dump fuel. (i.e. no need to highlight every event to each Greenpeace member and news crew with a scanner) With as many non-events becoming "Breaking News" lately, the more we can do to keep from raising eyebrows the better.

OK, makes sense, just be aware that next thing I'll do is broadcast that fuel dumping's in progress, so the secret'll get out pretty quick:

9-4-5. INFORMATION DISSEMINATION
a. If you are in contact with an aircraft when it starts dumping fuel, inform other controllers and facilities which might be concerned. Facilities concerned shall broadcast an advisory on appropriate radio frequencies at 3-minute intervals until the dumping stops.
PHRASEOLOGY-
ATTENTION ALL AIRCRAFT.
FUEL DUMPING IN PROGRESS OVER (location) AT (altitude) BY (type aircraft) (flight direction).
b. Broadcast a terminating advisory when the fuel dumping operation is completed.
PHRASEOLOGY-
ATTENTION ALL AIRCRAFT.
FUEL DUMPING OVER (location) TERMINATED.​

 

[AlbieF15]

Adjusting gross weight is also a common pre-step ritual...

 

[AdlerDriver]

OK, makes sense, just be aware that next thing I'll do is broadcast that fuel dumping's in progress, so the secret'll get out pretty quick:

9-4-5. INFORMATION DISSEMINATION
a. If you are in contact with an aircraft when it starts dumping fuel, inform other controllers and facilities which might be concerned. Facilities concerned shall broadcast an advisory on appropriate radio frequencies at 3-minute intervals until the dumping stops.
PHRASEOLOGY-
ATTENTION ALL AIRCRAFT.
FUEL DUMPING IN PROGRESS OVER (location) AT (altitude) BY (type aircraft) (flight direction).
b. Broadcast a terminating advisory when the fuel dumping operation is completed.
PHRASEOLOGY-
ATTENTION ALL AIRCRAFT.

FUEL DUMPING OVER (location) TERMINATED.​

Seems like the "adjusting gross weight" thing has been in vogue for the last 10-ish years (at least in the USAF). Probably in an effort to avoid the above "thrash" on the radio. I always thought it was fairly stupid since ATC usually is going to abide by the above and not play "lets talk in code and keep a secret from the rest of the world".
I'd guess conservatively that I've dumped at least 100K lbs. from various F-15s. Not once did I bother to tell ATC. Sometimes for an emergency - sometimes because I didn't want to land as heavy as I was. It just ain't that big a deal. There's not an Eagle driver on the planet that hasn't RTB'd from a deployment and been fat on gas off the tanker upon arrival at home base. It doesn't even take a radio call. Lead just starts dumping and #2 through #8, 10, or 12 just follow their lead. Nothing like a 12-ship "conning" at 10,000 MSL 20 miles from the field.

 

[RampFreeze]

just be aware that next thing I'll do is broadcast that fuel dumping's in progress, so the secret'll get out pretty quick

Yeah, good point, although I've found ATC hit or miss on actually following the guidance you quote. From our end, it's just one of those things that I've heard/used over the years. With the ATC broadcast, it really makes you wonder why this came about, which in perfect flightinfo.com thread circular routing, leads us back to your original question...

(I guess I should delete my original post... )

 

[SIG600]

I'd guess conservatively that I've dumped at least 100K lbs. from various F-15s.

One of my best friends is a KC-10 guy... he said they dumped 100K #'s of gas last week, two days in a row. :bawling:

 

[Flyerjosh]

One of my best friends is a KC-10 guy... he said they dumped 100K #'s of gas last week, two days in a row. :bawling:

That's about 1/2 a years worth of fuel for my flight department! It's also about $140,000 worth at my local FBO... Ouch!

 

[Huggyu2]

"Adjusting Gross Weight" goes back a long ways. My guess is that it's a holdover from SAC. I got into SAC in '89, and the term was well established back then.

 

[tomgoodman]

Use it or lose it

I hope this has changed since I was on active duty, but some flying units used to "adjust gross weight" of their fuel storage tanks near the end of each fiscal quarter. They would schedule extra flying to use up their fuel allocation, lest it be cut in the next quarter.

 

[SIG600]

I hope this has changed since I was on active duty, but some flying units used to "adjust gross weight" of their fuel storage tanks near the end of each fiscal quarter. They would schedule extra flying to use up their fuel allocation, lest it be cut in the next quarter.

Haven't seen it personally, but I've heard it still goes on. You'd think saving gas/money would be a good thing, not get punished for it in the next FY.

 

[Russ]

My understanding the term when I was in is that it doesn't always mean dumping. Can be flying in a high drag configuration and thus a high power setting to adjust gross weight.

Yes/no?

 

[Huggyu2]

My understanding the term when I was in is that it doesn't always mean dumping. Can be flying in a high drag configuration and thus a high power setting to adjust gross weight.

Yes/no?

From my military experience, I'd say "no".

 

[Bobo135R]

Adjusting..

The "adjust gross weight" thing has been around a while. I use the term to request fuel dumping from command post or talking to other military folks...not ATC. If it's due to an emergency we tell ATC what's going on....but, FYI, ATC won't always know if we do or not...
BTW, over 16 million pounds of JP-8 was dumped by tankers during the Kosovo conflict from March-June of '99.

 

[Hold West]

Yeah, good point, although I've found ATC hit or miss on actually following the guidance you quote. From our end, it's just one of those things that I've heard/used over the years. With the ATC broadcast, it really makes you wonder why this came about, which in perfect flightinfo.com thread circular routing, leads us back to your original question...

(I guess I should delete my original post... )

Well, you're right there on the hit or miss. I didn't deal much with fuel dumping until I got to Hawaii - something about us being the most isolated populated land mass in the world, with a minimum 5 hour flight over water to the next stop, makes pilots much more circumspect about aborting a flight back to the departure point, and having to dump a bunch of gas to do it. We're pretty proficient at all the little details now.

 

[kc135ang]

I will say that "adjusting gross weight" sounds a lot better over the radio then just coming out and saying I have to dump 40k. Typically we only dump as a last resort and that's after attempting to find a reciever to take the off load or if it's an emergency. Otherwise I would love to have the gas I dumped because my car is a diesel.