Fuel Management Question

[SonnyJ]

Is there anything preventing a herk from flying normal missions if one aux tank is out and the other is full and they are abiding by fuel unbalance limits listed in the FM?

[WxFE]

Is there anything preventing a herk from flying normal missions if one aux tank is out and the other is full and they are abiding by fuel unbalance limits listed in the FM?

Nope, not unless there's been a change since I last flew in August 2005. That's the one sets of tanks (other than Bensons) that you can fly with one full and one empty.

[Muff Millen]

Right...no restriction.

Muff

[ldschmidt29]

Aux tanks are basically cargo weight, the are so close to CG that it won't throw off you weight and balance.

[C130CC]

I concur.

[SEFEGeorge]

Aux tanks are basically cargo weight, the are so close to CG that it won't throw off you weight and balance.

Is that so close to CG or so close to centerline that they won't affect the wing load balance?

[Skip Davenport]

It's been a long time since I have flown a Herk. BUT my memory says like everyone else the Aux tanks have no effect on weather one is full or one empty

[ldschmidt29]

centerline! thanks for catching that...

[Old Fella]

Is there anything preventing a herk from flying normal missions if one aux tank is out and the other is full and they are abiding by fuel unbalance limits listed in the FM?

Just a question. Why would you want to fly with one aux tank full and the other empty. Are you asking about commencing a mission in this condition or continuing?

[DC10FE]

Just a question. Why would you want to fly with one aux tank full and the other empty. Are you asking about commencing a mission in this condition or continuing?

Had to do it a few times at Transafrik for either a leak or an inop boost pump. Lose $$$ if it sits on the ground waiting for repair.

Don R.

[C130CC]

Just a question. Why would you want to fly with one aux tank full and the other empty. Are you asking about commencing a mission in this condition or continuing?

This is not uncommon at all. Main tanks on the other hand are a different story, but aux tanks are just that, auxiliary.

[AMPTestFE]

I wouldn't have a single issue with flying like this for any reason.

[SEFEGeorge]

Is there anything preventing a herk from flying normal missions if one aux tank is out and the other is full and they are abiding by fuel unbalance limits listed in the FM?

I've flown missions like this, both operational, mission support, and pilot pro. The only in was given any real consideration was how long the mission was. Wouldn't want to fly a 10 hr overwater nav out of LRF this way, or a trip from EDF to Hickam, out an actual recovery mission out of Hickam.

There could be any number of things to fly this way - tank leak, inop boost pump, fuel quantity problems (even though the 1 full-1 empty doesn't need any consideration with fuel qty problems, just use the "dip stick").

[Ronc]

I've flown missions like this, both operational, mission support, and pilot pro. The only in was given any real consideration was how long the mission was. Wouldn't want to fly a 10 hr overwater nav out of LRF this way, or a trip from EDF to Hickam, out an actual recovery mission out of Hickam.

There could be any number of things to fly this way - tank leak, inop boost pump, fuel quantity problems (even though the 1 full-1 empty doesn't need any consideration with fuel qty problems, just use the "dip stick").

I read enough of SEFEGeorges report, he knows the aux tank can't be dipped in the conventional way and you have to use the fuel tank gauge on the bottom of the wing

[WoodysDiscoPalace]

I agree - mostly because of leaks in the aux (bladder) cells. There was a period of time where it seemed like we had a aux cell leak on almost every aircraft. Standard fuel load at the time was 36K for a trash hauler, and config was either 8-7-3, or 7-6-5 (outboard to inboard) keeping as much fuel in the outer wings as possible, for as long as possible (to lessen wing stress). The externals were not used unless necessary for a higher fuel load. If you had one aux cell out, you would try to squeeze 8.5 in the outbd's, 7.5 in the inbd's, and 5 in one aux (and hope the aircraft wouldn't start venting before take-off). 40K was standard on HC/MC's, but you had the Benson tanks so no worries even if both aux cells were leaking.