So, I've been flying the BUFF quite a bit lately, and I love everything about it thus far.  However, I recently noticed that the amber warning light on the right external tank is always on, even with 100% fuel onboard.  EDIT:  The manual says that this light indicates the external tanks being used out of sequence, but then says nothing more about the CORRECT fuel sequence.

In addition, FSX pesters me every few minutes with a "Fuel is critically low in the selected tank" message at the top of the screen.  Is this the case with everyone, or am I the only one with this issue?

I recently noticed that the amber warning light on the right external tank is always on, even with 100% fuel onboard.
The warning light is a problem, it never goes out for me.

FSX pesters me every few minutes with a "Fuel is critically low in the selected tank" message at the top of the screen.
I only get this one sometimes, and I can't figure out what triggers it. But it also happens in my other, non Captain Sim Add-ons, which makes it difficult to figure out.

Mark

I began to suspect as much when I saw that the light was on in the B-52 Driver banner in my sig.  XD

I've never gotten this message in any other aircraft.  It's got me a bit puzzled.  Plane still flew just fine, but it was a bit irritating after awhile.

You're very observant. I never even noticed that before! :)

I only saw it after I noticed the problem and took a good, hard look at the image.  lol

I as well experience this.

This seems to be a gauge issue to be honest - i've played with the fuel switches and the amount of fuel in the tanks, no luck.

Like HvyEng said once, that light would matter in another situation (if we're talking about the same light lol) as it means something about Center of Gravity balance.

I've been flying it just fine with that light, so don't worry about it now.

Here's the fuel sequence, taken from B-52H Stratofortress Flight Manual.

STEP 1 - TAKEOFF
-aft body tank to engine 1 & 2
-No 2 main tank to engine 3 & 4
-No 3 main tank to engine 5 & 6
-center wing tank to engine 7 & 8
note: for takeoff with main tank No 1 & No 4 above green band and center wing and aft body tank containing 2,000 lbs or more each

or

-mains to all engines (respective)
Note: for takeoff with main tank 1 & 4 above green band and either center wing or aft body tank less than 2,000 lbs

or

-mains to all engines (crossfeed valves open)
note: for takeoff with main tank 1 or 4 in green band. Open all crossfeed valves (9, 10, 11, 12)

---------------------------------------------------------------------------------

STEP 2
-aft body tank to engine 1, 2, 3 & 4
-center wing tank to engine 5, 6, 7 & 8
Note: maintain until center wing tank empty

STEP 3
-aft body tank to engine 1, 2, 3 & 4
-forward body tank to engine 5, 6, 7 & 8
Note:retain 3,000 lbs forward body fuel (ballast) if operating weight center gravity aft of 23% MAC, otherwise fwd body until empty

STEP 4
-mid body to all engines
Note:maintain until mid body empty

STEP 5
-aft body to all engines
Note: maintain until 6,000 lbs left in tank

STEP 6
-aft body tank to engine 1, 2, 7, 8
-No 2 main tank to engine 3 & 4
-No 3 main tank to engine 5 & 6
Note: maintain until aft body tank empty

STEP 7
-mains to all engines (understand each main tank feeds its respective engines)
Note:mains No 1 and No 4 to green band. After this step, mains No 2 and No 3 will be in green band area

STEP 8
-left external to engine 1 & 2
-No 2 main to engine 3 & 4
-No 3 main to engine 5 & 6
-right external to engine 7 & 8
Note: maintain until external tanks empty

STEP 9
-left outboard to engine 1 & 2
-No 2 main to engine 3 & 4
-No 3 main to engine 5 & 6
-right outboard to engine 7 & 8
Note:use 5,000 lbs from each tank

STEP 10
-left outboard to engine 1, 2, 3 & 4
-right outboard to engine 5, 6, 7 & 8
Note:maintain until outboard tanks empty

STEP 11
-forward body tank (ballast) to all engines (not through main tanks, use main manifold)
Note: maintain until forward body tank empty

STEP 12
-mains to all respective engines
Note: when any main is down to 5,000 lbs, open all crossfeed valves (9, 10, 11 & 12)

-------------------------------------------------------------------------------

ALL LANDINGS, TRANSITION AND LOW APPROCHES

-mains to all engines
Note:with main No1 and No4 above green band area, close all crossfeed valves (9, 10, 11 & 12)

or

-mains to all engines (crossfeed valves open)
Note:with main No1 or No4 in green band area, open all crossfeed valves (9, 10, 11 & 12)
Note:with any main down to 5,000 lbs, open all crossfeed valves (9, 10, 11 & 12)

---------------------------------------------------------------------------------

General note
In the fuel sequence above, fuel from auxiliary tanks is transfered directly to the engines through the main manifold and not through the main tanks. During the entire fuel sequence, fuel level control valves switches (19, 20, 21, 22 on fuel panel) are kept closed at all time.

When auxiliary fuel is being used, main tank boost pump switches remain ON. The boost pump in the auxiliary tanks are of higher capacity than boost pumps in the main tanks thus allowing a pressure override condition to exist. When an auxiliary tank runs dry, the main tank boost pumps take over fuel supply to the engines with no interruption in fuel flow.

External tanks when full, act as wing tips oscillation/vibration damper. So make sure before you leave that they are filled up to capacity, even for a short distance flight.   ;)

Thanks

Thank you Rick.

That's an awful lot to try and remember. ;)

Mark

I was going to add a new post but maybe this will suffice. Maybe I'll try this fuel juggleing because I try to fly with minimal loading for my flights. I haven't had the "buff" but 4 days and been running into troubles with engines shutting down in mid flight. If I have enough alltitude I can manage a restart. I've never had a sim to do this. There's plenty of fuel (26%) but some tanks are empty but the switches are driving me nuts. I try to load fuel for a balance but it seems Captainsim has given us a more realistic aircraft than I thought. If I can figure out what was posted and how to cut on and off these switches maybe I'll get my money's worth after all. I'm not going to fill-up every flight.

Also I've had the gauges blacking out after a crash and restart. I couldn't go back into the sim even when restarting FSX. Changing the situation and they were back to normal.

Again one more thing. To turn on the terrain map you press the on button on the EVS monitor not this button on the yokes. I've yet to find out what they do. Usually they've been used for the autopilot on/off on some sims.

Again thanks Rick for the info. I'll print that out for a kneeboard sticky

One more thing. Were can I get that B52 manual without costing me an arm and a leg. I'm a disabled Vietnam Marine that has been flying these simulators since FS 95. Post me a reply Rick. If you can explain all you have posted you seem like a person that knows what he's talking about.

If there's a light on; I want to know why!! >:(

There appears to be an error in the Captain_Sim.b520.L38.cab/L38_013_lt.spb code causing the amber lamp to be ON when there is fuel available with either of the 4 External or Tip tanks and they are selected.

In fact I believe the Amber lamp should only be ON if either of the tanks are empty but selected. I have modified the code to look like this as a remedy:-

xxxxxxxx
                             (A:ELECTRICAL AVIONICS BUS VOLTAGE,Volts) 1 > if{
                                   (A:FUEL TANK EXTERNAL1 QUANTITY,Gallons) 1 < (L:L38_013_SW2,bool) &&
                                   (A:FUEL TANK LEFT TIP QUANTITY,Gallons)  1 < (L:L38_014_SW2,bool) && ||
                                   (A:FUEL TANK RIGHT TIP QUANTITY,Gallons) 1 < (L:L38_036_SW2,bool) && ||
                                   (A:FUEL TANK EXTERNAL2 QUANTITY,Gallons) 1 < (L:L38_037_SW2,bool) && ||
                                   
                             } els{ 0 }
                             if{ 2 } els{ (E:TIME OF DAY,enum) 1 != (A:LIGHT PANEL,bool) ! && }
                             xxxxxxxxxx

Now when I get a RED warning that the tank is Empty and select that tank the Amber Light comes ON.

I would like CS's opinion before telling anyone how to do this.

Dear all,

I posted the fuel sequence, taken from the actual B-52H Flight Manual for the ones who like to fly “by the book” so, this is not a solution for the amber wing tank warning light issue. On my side, I have no problem with that amber light, up to now, it does what it should.

As per the B-52H Flight Manual, the green band on main 1, 2, 3 & 4 fuel quantity gages means “safe to use fuel from outboard wing tanks and external wing tanks”. So, in real life, you do not use fuel from wing tanks and external wing tanks (of a particular wing) unless you have reached the green band on both main tanks of that particular wing.

Another interesting paragraph tells us what could be the reason for this. It goes like this: “Fuel must be used in accordance with normal fuel management sequence to attain maximum airspeed capability. To avoid wing flutter at speed less than 390KIAS and .87 Mach indicated, fuel in the main tanks must be used down to their respective green bands, as marked on the fuel quantity gages, prior to using fuel from full outboard wing tanks or full external tanks”.

The B-52H is available from Mach One Manuals. Usually, I try to read from the first page up to the last, but this manual is 1148 pages. Only one part is missing, Appendix I Performance Data. That part is on a separate document. Appendix I is use to compute S1 speed among others.

Rick

p.s. million thanks to HyvEng, Markoz and TurbofanDude for your support and help and for TFDi BUFF Mods, which I appreciate so much.

rick freedom wrote on Sep 20^th, 2011 at 1:22am:

Dear all, I posted the fuel sequence, taken from the actual B-52H Flight Manual for the ones who like to fly “by the book” so, this is not a solution for the amber wing tank warning light issue. On my side, I have no problem with that amber light, up to now, it does what it should.

Well, that's up to interpretation! The way the code is written the amber light is only associated with 4 selectors, 2 x External tanks and 2 x Tip (Outboard) tanks.

As written the light always comes ON if the tanks have fuel and either of them are selected no matter where any other selector is. Quite meaningless and if your happy with that so be it! I prefer it to light if the tank is empty and selected.

Right or wrong the amber light is not associated with any other selectors or sequencing on the panel in this model.

If the amber light is on your out of sequence supplying fuel to engines initually. If you follow Rick's B52h manual and turn the outboard switches off until you have green bands showig; the light stays off. I still haven't got it right but I've been flying with way less fuel for short flights. I'm trying to estimate the correct range and fuel loads.

It's not all correct because some fuel is used out of the tip tanks even with the switches off.

Dear Garylc1,

You are right, some fuel is still being drawn from the tip tanks even if the booster pump switch is set to the OFF position. I guess we'll have to live with that.

There are interesting views from the B-52 cockpit on the following videos found on you tube.

Regards,

Rick

http://www.youtube.com/watch?v=SlS6q9bnlHY

http://www.youtube.com/watch?v=K-SovN9irY0&feature=relmfu

http://www.youtube.com/watch?v=2g260GpiN3Q

rick freedom wrote on Sep 30^th, 2011 at 11:04am:

Dear Garylc1, You are right, some fuel is still being drawn from the tip tanks even if the booster pump switch is set to the OFF position. I guess we'll have to live with that.

I've noticed the same with the Captain 707, fuel is drawn off the reserve (Tip) tanks with the selectors closed as well. Is it an FSX thingy?

One other thing about fuel. Don't let anyone run dry before switching on other pumps. It'll shutdown in flight or wherever you're at hopefully with enough altitude for a re-start. I know; I've hit the dirt many a time to learn a sequence.

Pull throttle back; switch off autopilot; fly the plane and glide with airspeed enough to not stall and ctrl/shift f4 then ctrl e. While the engines re-start gradually move throttle up back to gain airspeed then altitude if needed and continue with where or what you were doing.

MustanGrande wrote on Mar 6^th, 2011 at 7:32pm:

So, I've been flying the BUFF quite a bit lately, and I love everything about it thus far.  However, I recently noticed that the amber warning light on the right external tank is always on, even with 100% fuel onboard.  EDIT:  The manual says that this light indicates the external tanks being used out of sequence, but then says nothing more about the CORRECT fuel sequence. In addition, FSX pesters me every few minutes with a "Fuel is critically low in the selected tank" message at the top of the screen.  Is this the case with everyone, or am I the only one with this issue?

same problem