Jump to content

Manual Control Of Fuel Management


Ray Proudfoot

Recommended Posts

Ray Proudfoot

I now feel I've reached the point where I would like to ease the workload of the VFE and handle Fuel Management.

However, despite reading the manual and watching Mark's excellent video I still seem to be doing some things wrong and have to switch the option back on for CoG to be corrected.

It may be because I'm not flying the tutorial route - EGLL-KJFK - but a shorter route - EGCC-LPPT. I have used CPS to work all the numbers out but I'm still unsure of certain settings.

Here is a link to the data produced by CPS - EGCC-LPPT

My questions are:-

1. Tank 11 contains 2333Kg to which a further 143Kg has to be pumped from tank 9 during the taxi. But given that more fuel will be transferred to 11 during the climb I don't know what value to set for Tank 11 Load Limiter. How is it determined?

2. Same question but this time for Tanks 9 & 10 Load Limiter before descent?

3. Finally, the Fuel Balance chart in the CPS documentation shows a CoG in red of 52.08%. I mistakenly took this to be the take-off CoG. I set CoG before take-off to this value but it was forward of the forward bug and I had to pump more fuel to tank 11 to achieve CoG within the limits. CPS stated I only needed to pump 143Kg to 11. But after doing that the CoG bug was not between the limits. Why?

I'd appreciate some guidance which hopefully will be useful to others wanting to master this tricky aspect of Concorde.

Link to comment
Milton Kuser

I'll do my best to help, but someone with some more knowledge might want to chime in as well if I have any errors. First of all, this flight is a little different than normal because you have ballast fuel in play. That means that fuel must be loaded, but not used. It is there to assist in your CG control of the aircraft.

So with that in mind, based on your CPS data, tank 11 has 2333 kg initially loaded at the gate. To achieve your proper take off CG, you need to transfer 2600 kg into tank 11 during the taxi to reach a final level of 4933 kg. (This value includes the ballast fuel in tank 11.) You can set your load limit controller to 4930 prior to engine start, then during taxi you can use the trim transfer auto switch. It will start to transfer fuel from tank 9 to tank 11 until approx 4930 kg is present, then stop. Once it is complete, you can turn off the transfer switch and re-guard it. All of these numbers are present on the flight plan just below where it lists all of the fuel amounts for your trip, alternates, reserves, final block fuel, etc. Once your take off CG has been achieved, you can reset the tank 11 load limit controller to the amount needed for your supersonic cruise flight. (10500 or 10200 kg is common, but it will depend on your flight.) I usually pull that number off the FSL aircraft load page. Just choose the CPS load, verify the fuel amount and other numbers, and your 59% CG cruise tank 11 amount should be present at the bottom.

The aircraft ZFW CG was calculated to be 51.97 based on your loading. The ballast fuel in tank 11 adjusts (or corrects) the aircraft ZFW CG to a new value of 52.08. This is the value (52.08) you set into the CG computer, along with the ZFW of 89.1. These are the numbers that will allow the computer to accurately compute your CG as you go.

The tank 9/10 load limit controller is left at zero until your fuel transfer has been completed. This obviously occurs well into the flight when you normally reach FL450+. Once tank 9 and 10 are empty, you can turn off the trim transfer auto switch and re-guard. (Usually you will start the 5a and 7a transfers at this time.) According to the ITVV video, the flight engineer advised 8000 kg was usually set in the tank 9/10 load limit controller at this point in case an emergency descent was required.

When you reach top of descent, you can reset the tank 9/10 LLC to zero. As you decelerate and descend, you are going to transfer fuel into the main collector tanks, primarily 1 & 4, until tanks 1 - 4 are approximately the same level. Depending on your fuel load, it is not uncommon for almost all of the fuel to be in these tanks at the end of the descent/deceleration. Usually as you make your approach to the airfield and prepare for landing, a small amount will be needed in tank 9 to achieve a proper landing CG. After landing (or just before) set the tank 9/10 LLC to 4000 kg to prepare for after landing checklist procedure.

After landing, it is not uncommon to have to pull fuel from tanks 2 & 3 to transfer forward since everything else is normally empty. To do this, you will have to open the tank 2 & 3 jettison valves, open the tank 11 main inlet valves, and turn on the trim transfer auto switch to forward. It will then take fuel out of tanks 2 & 3, put it into tank 11, then transfer forward to tank 11. It will stop moving forward at 4000 kg, but tanks 2 & 3 will continue transferring into tank 11 until you turn the jettison valves off or the tanks are empty. Just be aware!

As I understand it, if you have a ballast fuel situation like you do here, that ballast fuel is supposed to stay in the appropriate tank (tank 11 in your case) for the entire flight. Therefore, you should always have 143 kg in tank 11 until you are back on the ground. (Someone might need to correct me here.) To assist you in doing this, you can leave the tank 11 LLC at 140 kg after your fuel transfers are complete in cruise climb flight, instead of resetting it all the way back to zero like normal. If you use the trim transfer auto switch to transfer the fuel during the decel/descent into the main collector tanks, it should stop transferring fuel at 140 kg. Of course, if you do it manually without the trim transfer auto switch, then it will not stop until the tank is empty.

The take off tank 11 LLC can be calculated manually if desired. You will need your aircraft gross weight, aircraft ZFW CG, desired take off CG, and the initial tank 11 level numbers. Subtract the aircraft CG value from the desired take off CG gravity and divide by 100. Take that result and multiply it with the aircraft gross weight value. The result should give you the tank 11 LLC value for reaching the take off CG.

I hope this covered what you were needing. I would recommend trying a flight without any ballast fuel requirements since that should make it a little easier until you feel more comfortable with the whole process. With a little practice you'll find it is not too hard to manage the fuel and CG requirements. I have never seen a fuel panel that has more ability to control what you have where in the aircraft. Pretty impressive stuff! (And of course it's perfectly modeled by FSL!)

  • Like 2
Link to comment
Ray Proudfoot

Hi Milton,

That's a tremendously helpful post so thank you very much for providing it. I had missed the 2600Kg of fuel to be transferred to tank 11 in the CPS documents. I usually just glance over most of that page as the info is provided elsewhere but with manual fuel handling it's now critical to getting a good CoG.

Regarding the tank 11 LLC calculation I might ask Pierre if this can be provided in CPS2016 which he is currently working on. If all the data is available at the planning stage it seems reasonable CPS could calculate it to save our brains. :)

Once again, thank you for that. I shall try that flight again this morning and report back.

Link to comment
Ray Proudfoot

I've just completed my test flight EGCC-LPPT with manual control of fuel and it went a lot better albeit still with a couple of issues.

After transferring the correct amount of fuel to 11 the CoG was 52.1 for take-off. During the climb I started transferring fuel rearwards and this was also okay although I probably left it too late as the pumps were struggling to pump it fast enough to keep CoG within limits.

The real fun started with the transonic climb. With a light fuel load it was climbing at 8000fpm or more and the pumps definitely struggled. CoG went out of limits before eventually recovering.

Once stable beyond M1.7 Tanks 1, 2, 3 and 4 displayed low fuel warnings (not all together) and I had to check the manual to see what to do. Worked out that I needed to pump fuel into them from their relevant feeder tanks and that solved that problem.

By the time I started the descent all available fuel was in 1-4 and 11. I hadn't realised until now that 11 also feeds 1-4. I just thought it was pumped back to 9 and 10.

By the time I landed CoG was 53.3 and all bar 140Kg of fuel in 11 had been moved to 1-4. 5a and 7a had transferred their contents earlier in the flight.

I didn't move fuel after landing. That will come later once I'm confident with fuel handling airborne. I have to say the workload increases quite a bit once you're handling fuel yourself. I hardly had any time to look out of the windows! :)

Thanks once again Milton. Great advice. :)

Link to comment
Ray Proudfoot

I have a couple of questions after a second longer flight today.

I didn't pump fuel from 5a and 7a to their parent tanks early enough and found that I couldn't do it later in the flight. Is this only possible at certain stages in a flight?

The second problem was I had too much fuel in tanks 2 and 3 and wanted to pump some to 1 and 4. The instructions say to open Jettison Valves but they didn't respond to clicks. What am I doing wrong?

Link to comment
Jean L. Leborne

Salut Ray,

Mouse “right-click” to open (unguard) and
close (guard) transparent plastic cover.
Transparent Covers
The jettison panel transparent covers can only
be closed when the collector tank jettison valve
switches are at SHUT and the JETTISON MASTER
VALVES switches are at OFF.
from page 157 Flying Manual "Jettison & Temperature"
Have a try et tout ira bien
Brgds
  • Like 1
Link to comment
Fraser Gale

Ray,

It sounds like you are getting the hang of it now.

As I'm a visual type of person, I generally look at the fuel panel and think "from top to bottom" for climb, opening the transfer valves from 5a and 7a into 5 and 7 when they are around one third full. Once 5 and 7 are empty, switch off the pumps in those tanks and turn on the second pump in 6 and 8 - you will have had one of them on already to de-air the fuel.

Before or at the same time as all this you will have transferred fuel from 9 and 10 down to 11. 11 has a preset value in the LLC for 59% CG at the start of cruise which is on a chart (if I find it I shall post it here). The rest of the fuel from 9 and 10 goes into 5 and 7 so it may be some time before you transfer from 5a and 7a but that is good as it stops the wings bending too much (these tanks are in the tips).

During this transfer you may need to select the aft trim switch to keep your CG at the optimum 59% due to the wing tips being aft of the main 5 and 7 tanks. This can remain selected until you notice the CG creeping aft of 59% at which point select it back to normal.

When 6 and 8 get down to around one quarter full, transfer some fuel up from tank 11 into tanks 5 and 7 to help wing cooling. Your CG will be forward of the optimum and close to the upper bug but this helps at the decel as it takes time to transfer forward!

When it comes time to leave the super cruise I then think "bottom to top" as its time to pump forward from tank 11 (set LLC to 0 unless you have a subsonic cruise to fly like heading to LHR in which case set 5000kg) up into tank 5 and 7 again. Depending on your zero fuel weight there may be ballast fuel required in tank 9 - this is also available on a chart that I have somewhere which if I find...

The fuel panel is the most time consuming bit really but I enjoy playing with it, it is a constant job and will be slightly deifferent on every flight!

I maybe haven't helped but I tried!

Frazz

Link to comment
Ray Proudfoot

Thanks Frazz. Lots of info there and it will take time for me to absorb it. I do have a printed copy of the tutorial but because it's recommended VFE is engaged for it the text is quite small and not easy to read when things are happening quickly. I may create my own notes for the various stages of the flight for fuel transfer.

The other problem is that on shorter flights the climb rate is significantly higher than the EGLL-KJFK route so things have to be done more quickly.

As with all things Concorde-related familiarity is key. The more I try this the easier it will become. I had the same learning curve with Concorde itself but I'm now reasonably competent. The next level up just takes time especially when you're not in the first flush of youth! :)

Link to comment
Fraser Gale

Plus, also remember that you are essentially doing the job of three people now...!

At light weight, it was common to start the rearward fuel transfer a bit before the accel point because, as you have discovered, you can't get it back quick enough otherwise!

The thing is, as you already know, the fuel wasn't just fuel. It was ballast, coolant for air conditioning, coolant for hydraulics and oils and coolant for the wing surface itself. Due to all this there were levels in certain tanks that would dictate when certain transfers would occur. I think it was not only extremely well engineered but shows how busy and important the FE was!

An amazing machine.

Frazz

Link to comment
Milton Kuser

Ray,

On a flight with a light fuel load, and therefore higher climb rates, I always start the fuel transfer aft a little early. Remember the check list calls for this to begin at Mach 0.7, but if needed you can do it early.

As a rule of thumb, the order for the fuel transfer is from tank 9 to 11. When 9 is empty, tank 10 will start transferring to tank 11. Sometime during this transfer tank 11 will reach its LLC setting, and the system will automatically start transferring fuel to tanks 5 & 7. Once tank 10 is completely empty, you can turn off the trim transfer auto switch and re-guard. Tanks 5a & 7a can now be transferred into tanks 5 & 7 respectively. About this time, keep a close eye on the CG and select the aft trim switch as needed. For the most part, the aft trim setting and transferring the 5a & 7a tanks cancel each other out as far as CG movement is concerned. But pay attention to it because you will be floating around 59% CG +/- a little and reaching cruise climb all at the same time.

*** "After transferring the correct amount of fuel to 11 the CoG was 52.1 for take-off. During the climb I started transferring fuel rearwards and this was also okay although I probably left it too late as the pumps were struggling to pump it fast enough to keep CoG within limits." ***

This appears to me that your CG still wasn't correct for takeoff. 52.1 % should have been your corrected ZFW CG taking into account your ballast fuel while still at the gate. Tank 11 should have been showing a load of 2333 kg before you began transferring the 2600 kg from tank 9 into tank 11 to reach your planned takeoff CG. The total of tank 11 should have been approximately 4930 kg when the transfer was complete. Your planned takeoff CG was 53.5 % according to you takeoff form.

This fuel panel has so much control that you can literally move fuel from any tank into any tank - almost. The only exception is putting fuel into tanks 5a & 7a while airborne. Otherwise anything else is possible. It is just a matter of setting the correct intake valves and turning on the correct pumps.

The main transfer tanks (tanks 5-8) feed the engine feed tanks (1-4). As the engine burns fuel, tanks 5 & 7 will transfer fuel into the engine feed tanks if both of the fuel pumps are turned on. Once they are empty, tanks 6 & 8 will take over.

You also want to make sure you have the panel set up correctly before take off. This includes the inlet valves set to auto for tanks 9, 5/7, and 11. The fuel pumps should be set to auto for tanks 9, 10, and 11. The pumps for tanks 5a & 7a and 5-8 get turned on for de-air purposes along with the dedicated de-air pumps for tank 10 and 11 either before or shortly after takeoff. (I usually do it before takeoff.)

Two areas of the panel that are very helpful are the standby inlet valves just above tanks 5a & 7a respectively. When you open one or more of these valves, fuel will start flowing into the selected tank regardless of any other settings on the panel. This is very useful during the decel and descent to aid in moving fuel directly into tanks 1 & 4, or anywhere else as needed from tank 11 as long as a fuel pump in tank 11 is on. You can manually turn a fuel pump from auto to on to assist in this instead of trying to use the trim transfer auto switch. Just don't forget to turn it off when appropriate!

The other very useful area is the jettison panel. The upper section can directly remove fuel from the individual engine feed tanks into tank 11, just manually open the tank 11 inlet valve. From tank 11 it can be moved anywhere else as needed. The lower section of the jettison panel are the valves that actually activate the jettison system to dump fuel overboard. To open the guards, right click on the panel hinge.

Tanks 5a & 7a will transfer into tanks 5 & 7 respectively as long as the fuel pumps are on and the transfer valves are open. However, it can be a slow process. Typically, the system will open the valve as needed and moves fuel in batches. Just give it some time and you will see that it will transfer.

As I said in the other post, a longer flight will probably be easier for you until you get the hang of it better. When the aircraft is light, everything happens faster due to less weight and the power of the engines! The operation of the fuel panel and monitoring of the CG is a constant job throughout the flight. When I was learning the fuel panel, I loaded up the plane with a partial load and started transferring fuel all over the plane while sitting on the ground until I was comfortable with it. The other thing that was very helpful to me was paying close attention during the ITVV Concorde video - especially on the flight back from New York. The flight engineer gives an excellent explanation of what he is doing throughout the flight.

Link to comment
Ray Proudfoot

Thanks Frazz and Milton. I did post a reply earlier but it was deleted due to the new forum software.

All advice duly noted. Thank you. :)

  • Like 1
Link to comment
Ray Proudfoot

Probably my most satisfying flight today. EGCC-KMCO. 3770nm, close to Concorde's limit. But first of all I spent over an hour with CPS trying to get an acceptable payload. In the end the best I could do was 8 pax and 3 empty galleys and even then the CG was too far aft.

I couldn't do anything about that so took off with a CG of 54.3. Ouch! The climb-out was okay and I engaged max climb as soon as possible so I could concentrate on fuel management. At Mach 0.7 I started moving the fuel rearward and even though the CG moved within the two bugs there was a red/black diagonal over the CG gauge which I couldn't understand.

That eventually cleared itself and fuel continued rearwards until CG reached 59.2 where it stayed for most of the flight. I even managed to move fuel around to even up the amount in tanks 1-4. I had to pump fuel out of 11 early as some tanks were getting a bit low. Once I crossed the Florida coastline at FL280 I knew I'd have enough for the remainder of the flight. The weather at KMCO was horrible. Thunderstorms and heavy rain. 8/8 at 1500ft.

I was going to autoland but at 800ft the runway was visible so I turned off AFCS and landed manually. Taxied to the gate and let off my grateful passengers. All 8 of them! :D

The fog is beginning to lift on fuel ops and longer flights definitely help with a less hectic schedule. I've sent my plan to Pierre so he can understand my frustrations trying to get an aceptable TOW and rear ballast.

Here are the docs as calculated by CPS and my flight plan. EGCC-KMCO pdf  Flight Plan

Link to comment
Fraser Gale

Glad you enjoyed your trip today, even if it was only for the Queen and her helpers haha! 

I would have to check but I'm not convinced that route would have been done with a normal passenger load anyway. I could be wrong but it looks a bit too far.

Your takeoff CG was actually within limits as there was always a 0.3 allowance either side to allow for small errors in the CG computers or errors in the burn off/transfer fuel figures. I assume you selected the "take-off CG switch" to 54% so you didn't get CG warnings? 

The red and black flag is an instrument error/power failure sign.... Not sure why you would have seen it unless you had failures in the gauging system...? 

I remembered the other day that I had made myself a "training booklet" with diagrams of fuel transfers, if I get time at the weekend I'll send you a copy.

 

frazz

Link to comment
Ray Proudfoot

Hi Frazz,

The reference to the Queen is lost on me, sorry. :huh:

Maybe it is too far. Must be close to EGLL-TBPB though.

No, forgot you can switch CG to different settings. May try that on the return leg.

I wasn't aware of any failures. I won't lose any sleep over it.

Appreciate the training booklet, thanks. :D

Link to comment
Milton Kuser

Glad to hear your making progress, it sounds like an interesting flight. I'll try and duplicate it this weekend if I have time and let you know it turns out for me.

Milton

Sent from my SM-T537V using Tapatalk

Link to comment
Fraser Gale

The Queen reference was purely to the fact that you ended up with so few pax on board and I guess on royal flights the number on board would have been a lot less than usual. Just my silly humour. 

I will have a look for my booklet at the weekend.

 

frazz

  • Like 1
Link to comment
Milton Kuser

Ray,

I completed the same flight this weekend.  I altered the route slightly, using the SM concorde track to cross the pond instead of a normal NAT.  It gave me a distance of 3737nm.  I used Mopat as my accel point.  I had a few errors on my part during the flight (got interrupted during the accel/climb and the reheats stayed on until mach 1.83) and put the wrong departure subsonic distance in CPS, but otherwise it was close to matching yours.  I was able to get 15 pax aboard and still stay within the PLTOW.  With all that said, including my errors, I was able to make it - just barely!  I used the same weather in ASN as your date and time of takeoff, but arrived just prior to you.  The storm you arrived in was just to the south of the airport and the winds had not shifted, so I had to make a 35R spproach.  By the time I completed the long taxi in, I had a total of 140 kg of fuell on board!  Definitely an all time low record!  The storm hit while I was taxiing to the gate.  It was a little tricky on the CG management and fuel comsumption vs decal. Interesting flight.  I'll try and make the flight back when I get a chance to see how that one goes too.

Link to comment
Ray Proudfoot

Got it, thanks. My only question is why did you wait until reaching MOPAT before accelerating beyond Mach 1? You should have reached FL260 by the Welsh coast assuming you flew the MONTY SID out of EGCC. The path on my flight plan leaves enough distance between Wales and Ireland not to lay the sonic boom over land.

This is longer than EGLL-TBPB so will become my long-range test flight. Assuming the wx stays nice at KMCO.

Link to comment
Milton Kuser

I might have miscalculated the sonic booms distances. When I was trying to plan that, I got pulled away several times.  (One of those weekends.)  I was looking for established waypoints in PFPX that were 20 miles off shore, and might have missed a better one then what I eventually used.  As I said, I had a few errors in this flight for sure. 

Link to comment
Ray Proudfoot

I planned the route carefully to ensure sonic boom didn't overlay land. I didn't use listed waypoints - I used my own.

My route up to LESLU is fine. You could use SM track from there. When you plan the return flight may I see your plan?

Link to comment
Milton Kuser

Sure no problem. Not sure when I'll be able to get to it, but I'll try to get it this weekend. Unfortunately I have to work a large part of it so we'll see how it goes.

Sent from my SM-T537V using Tapatalk

Link to comment
Milton Kuser

Well, the return flight went well.  I landed with 3320 kg of fuel left and was airborne for 4:01 hours with 8:53 of reheats during the acceleration and climb.  I took off later than I wanted, but managed to get wheels up at 2328 Zulu on 4/10/16.  (It made for a very early arrival at EGCC local time!)

 

For some reason I can't get the CPS report attached, but here are the specifics and the flight plan:

ZFW 80386, ZFW CG 53.24, 15 PAX, release fuel 94762

 

FLIGHT LOG

| ICAO | ID | ICAO | ID | Latitude | Dist | Notes

| Freq | | TR | | Longitude | | Remain Dist.

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

| KMCO | 0 | OMN | 1 | N 29*18.2 | 54 | Load KMCO to EGCC-1.1.AWC

| | | 12° | | W 081*06.8 | 54 | 3752

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

| OMN | 1 | KJ90U | 2 | N 30*00.0 | 72 |

| | | 54° | | W 080*00.0 | 126 | 3680

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

| KJ90U | 2 | KJ09W | 3 | N 31*30.0 | 137 |

| | | 49° | | W 078*00.0 | 263 | 3543

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

| KJ09W | 3 | KW30A | 4 | N 35*00.0 | 290 |

| | | 43° | | W 074*00.0 | 553 | 3253

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

| KW30A | 4 | SN1 | 5 | N 40*25.0 | 464 |

| | | 44° | | W 067*00.0 | 1017 | 2789

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

| SN1 | 5 | SN2 | 6 | N 41*40.0 | 118 |

| | | 50° | | W 065*00.0 | 1135 | 2671

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

| SN2 | 6 | SN3 | 7 | N 43*07.0 | 238 | Load KMCO to EGCC-1.2.AWC

| | | 67° | | W 060*00.0 | 1373 | 2433

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

| SN3 | 7 | SN4 | 8 | N 45*10.0 | 345 |

| | | 67° | | W 052*30.0 | 1718 | 2088

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

| SN4 | 8 | SN5 | 9 | N 45*54.0 | 114 |

| | | 67° | | W 050*00.0 | 1832 | 1974

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

| SN5 | 9 | SN6 | 1 | N 48*10.0 | 431 |

| | | 68° | | W 040*00.0 | 2263 | 1543

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

| SN6 | 1 | SN7 | 2 | N 49*26.0 | 402 |

| | | 76° | | W 030*00.0 | 2665 | 1141

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

| SN7 | 2 | SN8 | 3 | N 49*49.0 | 389 |

| | | 83° | | W 020*00.0 | 3054 | 752

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

| SN8 | 3 | SN9 | 4 | N 49*41.0 | 194 |

| | | 91° | | W 015*00.0 | 3248 | 558

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

| SN9 | 4 | LULOX | 5 | N 50*22.0 | 273 | Load KMCO to EGCC-1.3.AWC

| | | 79° | | W 008*00.0 | 3521 | 285

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

| LULOX | 5 | GATRA | 6 | N 51*17.9 | 76 |

| | | 43° | | W 006*37.9 | 3597 | 209

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

| GATRA | 6 | BAKUR | 7 | N 52*14.5 | 67 |

| | | 32° | | W 005*40.8 | 3664 | 142

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

| BAKUR | 7 | MONTY | 8 | N 52*53.6 | 99 |

| | | 66° | | W 003*10.4 | 3763 | 43

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

| MONTY | 8 | EGCC | 9 | N 53*21.7 | 43 |

| | | 50° | | W 002*15.6 | 3806 | 0

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

If you don't have the SN waypoint coordinates, they are listed above in the flight plan and the rest are available with a quick search online.  I added the SM, SN, SO, and SP waypoints and tracks into PFPX just for my convenience when building a route before moving into CPS.  The accel point was 50 nm after OMN and decel was complete by Gatra.  ATC took me around to the north before bringing me back for a 23R approach.  I'll try the EGCC-KMCO flight again when I have a chance to see if it turns out better then my first attempt.

Link to comment
Ray Proudfoot

Thanks for the report Milton. Delayed reply as I've been in London for a long weekend.

As you had so much fuel on landing I'm curious how many pax you loaded. And one minor point. MONTY is the end of a SID but not the start of a STAR. You need to head north up the gap between Ireland and Wales and pick up the arrival route via LYNAS and WAL ending at MIRSI. That's one of the holds for EGCC with ATC directing based on winds.

Thanks for details of the SN waypoints. I'll amend my plans.

Link to comment
Milton Kuser

I used the Mirsi 1A STAR, it's initial point is MONTY.  The LYNAS approach is the MIRSI 1B STAR.  At least that is what is present on my chart through Navigraph effective 3 March 2016 (chart #6-30).  I went with 15 PAX since I couldn't really handle any more weight.  3320 kg is not much fuel divided between four engines on landing plus a little bit in tank 9 for the CG landing requirement.  Overall it was a nice flight.

Link to comment
  • 3 weeks later...
Ray Proudfoot

On a flight from LEBL to KJFK today I had a problem with CG and remaining fuel. Tanks 1 and 4 were getting low but because they're quite far forward pumping fuel into them from 11 would cause CG to move out of limits.

In the end I turned on Fuel handling for the VFE and let him sort it out. But how do you handle this situation manually?

Link to comment
Steve Prowse
10 hours ago, Ray Proudfoot said:

On a flight from LEBL to KJFK today I had a problem with CG and remaining fuel. Tanks 1 and 4 were getting low but because they're quite far forward pumping fuel into them from 11 would cause CG to move out of limits.

In the end I turned on Fuel handling for the VFE and let him sort it out. But how do you handle this situation manually?

Hi Ray,

Not that I'm trying to tell my granny how to suck eggs, but, and I guess, you're on the cruise/climb stage of the flight.  If so, and as far as I understand, collectors 1 and 4 will be low if the aft switch is in the aft position.  The action of the aft switch is to limit the fuel flow to collectors 1 and 4, until the fuel level in transfer tanks 6 and 8 reach around 4000kg in anyone of them.  At that point the aft switch will go back to normal,  and normal fuel flows will resume to collectors 1 and 4 you should see a rise in fuel  level.  If you find that the CG is getting to close to aft limit you could always pump from 11 to transfer tanks 5 and 7, not forgetting to switch on their respective pumps.  Now I do hope this helps and I'm sure one of the other guys will come in on this to help both of us;) I also seem to remember reading that is you find yourself with a forward CG and no fuel anywhere to counteract then the procedure was to slow down and go down, as I remember.  I'll try to find the actual  quote from the 'Concorde bible'.

Interesting to note on this point:

Providing that tank pressure is satisfactory the minimum permissible contents in the collector tanks for continuing supersonic cruise is as follows:-  1000kg for tanks 1 and 4,  1000kg for tanks 2 and 3.

When these minima can no longer be maintained by further transfer from tank 11 because the forward CG limit has been reached supersonic  cruise should be discontinued.

Anyway I hope some of this helps, if I've misunderstood the problem altogether, sorry!

 

Edit just found this: (07.02.17)

ABNORMAL CG POSTION:

AFT LIMIT

MACH NO.                                                               INCREASE IF POSSIBLE

FUEL FWD TRANS SW                                          O/RIDE

TRIM TRANSFER PUMPS AND VALVES              AUTO

TRIM TRANSFER AUTO MASTER                         OFF

 

FORWARD LIMIT

MACH NO                                                                       DECREASE IF POSSIBLE

FUEL FWD TRANS SW                                                 OFF AND GUARDED

TRIM TRANS AUTO MASTER                                       OFF

 

IF TANKS 9 OR 10 CONTAIN FUEL:

TRIM TANSFER PUMPS AND VALVES                           AUTO

TANKS 9 AND 11 LLC                                                      ADJUST

TRIM TRANS AUTO MASTER                                         REARWARD

 

IF TANKS 9 AND 10 EMPTY:

TANK 11 INLET VALVES                                              OPEN

TANKS 2 AND 3 JETTISON VALVES                           OPEN

WHEN NORMAL CG POSITION ACHIEVED

TANK 11 INLET VALVES                                             AUTO

TANKS 2 AND 3  JETTISON  VALVES                       SHUT

 

 

 

 

 

 

Link to comment
Ray Proudfoot

Thanks sharky. Whilst I'm an old hand flying Concorde handling fuel is a relatively new experience.

The problem was during cruise-climb but quite close to ToD. Reading through the info you supplied my only option was to slow down. But perhaps there are ways around the problem of low fuel in 1 and 4 in the latter stages of the flight. I don't recall having this problem when the VFE handled the fuel so I might enable him and see how he does it.

The only way of moving fuel into 1 and 4 without the CG moving forward is to pump from 9 and 10 but of course they're empty so that's not possible. Let's see how Roger handles things and I'll report back.

Link to comment
Steve Prowse

Ray,

If you're very close to the TOD I don't see there is a problem because you will soon start pumping forward.  If you find 1 and 4 are low you could cross feed.

All the best

 Steve

 

Link to comment
Ray Proudfoot

Hi Steve,

My earlier remark that I was close to ToD wasn't quite right. I can remember the CG moving too far forward some time before I was due to start down.

I'm currently flying RJTT-PHNL and have just reached FL500. Tank 10 has just emptied and CG was 58.8. The instruction is to set Transfer Switch to OFF when either 10 is empty of 59 CG has been reached.

I suspect I may have allowed CG to go too far rearward on previous flight, possibly beyond 59. I should learn more this time. Currently 5a and 7a and pumping into 5 and 7 and CG is 58.6.

I'll update this as the flight progresses. It will give me a record to refer back to.

LATER: FL504. Tanks 5a & 7a empty. CG 58.5. Tanks 1&4 switch in AFT mode.

Penny has dropped. The Tank 1&4 AFT switch controls the fuel flow into Tanks 1 & 4. Didn't spot that yesterday. I kept it at Norm for a while to increase 1 & 4 capacity and when CG started to move forward I switched it to AFT. Fuel into 1 & 4 has now ceased and CG is moving AFT. Should now be able to handle situation better.

EVEN LATER: Tanks 5 & 7 are now empty and 6 and 8 are pumping fuel into 1-4. However, 2 & 3 contain far more fuel than 1 & 4 but if I pump too much into 1 & 4 then CG starts to move forward of 59. The key appears to be using Tank 1&4 AFT switch to control flow into those tanks to ensure CG remains at 59.

Current capacity is:-

1=2460; 2=4620; 3=4620; 4=2660. 1700nm to Honolulu.

LATER STILL: Tanks 1-4 contents have remained unchanged. It would appear tanks 6 & 7 are feeding them at the same rate fuel is being burnt. CG remains at 59, Tank1&4 switch is set to AFT. 1260nm to Honolulu.

TOD: CG is 58.8; Tanks 1 & 4 = 1740; Tanks 2 & 3 = 3820. Tanks 1&4 Switch at NORM. CG has stayed between 58.8 and 59.1 with use of T1&4 Switch.

Landed and parked. I gave up trying to get fuel to move forward from tank 11 and engaged VFE to take over. Noted the position of switches and should be able to work it out next time. But in all honesty the descent takes a lot of your time so I might choose to leave the fuel to Roger.

Very enjoyable flight which took 3hr 35m. Learned a lot about fuel management. :D

Link to comment
Fraser Gale

Ray,
The AFT trim switch controls the fuel level in tanks 1 & 4 to around 2500kg as you had there. This is left in the AFT position even after the transfer from the "a" tanks is completed to maintain the CG at 59%. When CG begins to creep beyond 59% you should set the trim switch back to NORM which then replenishes tank 1 & 4 back to normal levels from tanks 6 and 8.

This should happen a bit before TOD. Also before TOD, some fuel was transferred from T11 to T5 and T7 manually by switching on the T11 pumps and opening the T5 & 7 inlet valves. This was to help keep the wings cool when the fuel level was substantially lower and the aircraft had been hot soaked during the cruise. This would naturally cause the CG to move towards the forward limit for the last part of the cruise.
This is beneficial as it gives you time to do the descent checks, retard the throttles etc before you have to start moving fuel forward again - although as soon as this is done you should start moving it as the CG moves quite fast.

If you get to the point that you have no fuel in T5,6,7,8 then you should move some from T11 as above., this can then be transferred to the collectors to prolong the cruise slightly.

Hope this helps.
Frazz

  • Like 1
Link to comment
Milton Kuser

When I start to run into a rear CG issue and it is toward the end of the supersonic cruise with still a ways to go, my fuel situation should be this:  all tanks empty except 1 - 4 and tank 11.  Tanks 1 & 4 should be at low level since the AFT Trim switch has been selected AFT.  Since transferring fuel from tank 11 has a drastic impact on CG, I will first take fuel from tanks 2 & 3 and move it into tanks 1 & 4.  This accomplishes two things.  First, it will even out the engine collector tanks in preparation for decel/decent, and it gently moves the CG forward compared to moving fuel out of tank 11. 

 

After completing this, and the CG still reaches the forward CG limit before your TOD, then you pretty much have no option other than to decelerate and descend.  By balancing out the engine feed tanks you can stay in cruise mode longer than by moving the fuel from tank 11.  This has happened on a few of my flights depending on the length and temperatures encountered while enroute. 

 

If I have a rear CG issue during the early part of the cruise, then instead of playing with the AFT Trim switch, I'll just move fuel from tank 11 forward into tanks 5 & 7.  Once the CG has stabilized after tanks 9 & 10 and 5a & 7a have reached zero, then I'll move fuel back into tank 11 as needed.  In theory, this should not be needed if the tank 11 LLC has been correctly calculated before the climb to cruise; however I have had issues on more than a few occasions concerning this!

 

Remember as a guideline, your cruise CG should be reached about the time tanks 9 & 10 empty or slightly before.  The transfer of tanks 5a & 7a and selecting the AFT Trim switch to the AFT position should keep your CG approximately static. 

  • Like 1
Link to comment
Steve Prowse
13 hours ago, Ray Proudfoot said:

 

Landed and parked. I gave up trying to get fuel to move forward from tank 11 

Ray

Glad you enjoyed the flight, your issue with tank 11, did you dial back the LLC to zero or there abouts?   

Also great info from Frazz and MiltonSST.

All the best

 

steve prowse.

 

 

13 hours ago, Ray Proudfoot said:

 

Landed and parked. I gave up trying to get fuel to move forward from tank 11 

Ray

Glad you enjoyed the flight, your issue with tank 11, did you dial back the LLC to zero or there abouts?   

Also great info from Frazz and MiltonSST.

All the best

 

steve prowse.

 

 

  • Like 1
Link to comment
Ray Proudfoot

Frazz & Milton,

Thanks for your feedback. Can I ask where you acquired this knowledge? I only have the tutorial notes to refer to. You appear to have a greater understanding of fuel handling so where did you learn it from?

I should add that CG was fine throughout the flight until the descent when I couldn't get it to transfer forward. I suspect Sharky has provided the answer as I didn't zeroise the LLC beforehand. I'll try another longish flight this afternoon and take on board the tips provided above.

I agree that having the CG near the forward limiter before descent will be helpful as it gives more time to handle the fuel transfer although doing this manually has to be balanced with flying the aircraft as the fuel panels occupy virtually all the screen.

Link to comment
Ray Proudfoot

Just completed a flight from Ben Gurion, Israel to Barcelona. 1hr 59m. :)

Fuel handling was much improved and Roger's position is looking a bit shaky. Landed with CG of 53.2 and Tank 9 had 3500Kg in it.

Low pressure lights on 1-4 so I suppose I could have moved the remaining 3120 in 11 to them. Still, hell of a lot better than yesterday. Thanks all.

Link to comment
Fraser Gale

Hi Ray,

you should land with no fuel in T11, it should all be transferred forward into 5 & 7 then into the collector tanks to be used. If you have your fuel calculations bang on and you get a straight in approach you will be landing with 10 to 15 tonnes left so (depending on the ZFW and ZFCG) you may need some balls fuel in T9 to achieve the landing CG but once you get down to minimum landing fuel (6500kg) you will probably find all your fuel can be in the collector tanks to give you the landing CG. You also need the fuel in the collectors as you ain't got long left!!

There is a chart to calculate the ballast fuel in T9 for landing that I have but maybe CPS has a function for this? I don't know as I don't use it.

I have all the flying manuals (although they aren't that detailed for fuel transfer), the load and balance manual which has a lot of detail on CG obviously and many of the training notes and engineering notes. Plus if you watch the ITVV and all the other DVDs enough you tend to pick things up. 

Plus I have been "flying" her for a long time and I'm rather geeky about it as I like to do everything as in the real world including paperwork etc. 

I'm so sad I have put myself through the simulator training course as per the training manual which details every session, although I did it over a longer period of time than the BA guys would have done!

Frazz

Link to comment
Ray Proudfoot

Frazz,

Is there some reason why the contents of 11 need transferring to 5 and 7 rather than straight to 1-4 especially during the descent? If in 5 & 7 wouldn't they just need pumping to other tanks? Sorry, but I don't understand the logic behind this.

The only requirement in the tutorial is for CG to be forward of 53.5 for the landing. I stopped transferring fuel forward once that had been achieved.

CPS only mentions the tank 11 requirement in the program. It's not transferred into the documents. I'll be speaking to Pierre about that.

You are clearly smitten and have access to docs that give you far more info than the rest of us. But my learning curve is levelling out now and I'm reasonable happy I can move fuel around without resorting to 'Roger'. I salute your enthusiasm! :D

  • Like 1
Link to comment
Steve Prowse

Ray,  glad to see you are giving Roger the boot  :D, though keep him around for when you're not ie tea breaks, WC breaks etc.  Regarding landing fuel weight for tank 9 CPS does calculate it.  I use the French TO/landing forms, ( they seem better than ours) and the fuel weight for tank 9 is given on the landing form. 

Frazz; where did you get the load and balance manual?   I'd love to get my hands on that! Thanks for all the info.

 

Steve Prowse

 

  • Like 1
Link to comment
Fraser Gale

As stated before Ray, I am a geek! 

You transfer to 5 and 7 because the inlet valves to these tanks are controlled by the TRANSFER AUTO MASTER switch. 

At TOD you should switch off the hydraulic fuel pumps in T11 (unless you have an electric pump failure of coarse haha!), set the T11 LLC to 0kg (if you have a subsonic cruise to do after descent set this to around 3,500kg to stop transfer around 55% CG) and switch the TRANSFER AUTO MASTER switch to FWD. If you had 8000kgs set in the T10 LLC (set in case of emergency descent when the FO would use his override switch to start fwd transfer) you should set this to 0kg so that fuel doesn't enter it. 

The fuel is now transferred into 5&7 and you can get on with flying the descent. Once you get a minute to check it, switch on the pumps in T5 and T7 to pump fuel into the collector tanks - you might have to do this soon after descent as you will probably have emptied T6 and T8. If you need ballast fuel in T9 for landing (hopefully you can get this sorted in CPS) then you have to open the inlet valves to T9 manually to transfer some from T11. I usually do this at the start of the forward transfer so I don't forget but I suspect the real guys used to do it later in the flight - but there were three of them sharing the duties!!

For example, with a ZFCG of 53.8 and a ZFW of 88000kgs the chart says you need 720kg in T9 for landing. This figure increases with a further aft ZFCG and/or higher ZFW. 

You also have to remember that the T5 & T7 have a larger surface area in the wings compared with T1-4 so I suspect they were more critical for wing cooling, plus if you ever have 0 fuel in T1-4 (hence no wing cooling) you are in a lot of trouble anyway! 

I must use say it's not until I've been typing all this out to attempt (probably with little success due to my ramblings) to help you that I have realised just how complex the system is. I'm just used to doing it rather than thinking about it if you know what I mean?

In a nutshell, the standby inlet valves that go direct to T1-4 are just that, standby. They were only used for certain things rather than as part of normal fwd-aft fuel movement.

frazz

 

  • Like 1
Link to comment
Ray Proudfoot

Frazz,

Your knowledge and level of commitment amaze me. Thank you for clearing up the tank 5 & 7 mystery. I'm about to embark on EGLL-TBPB and Roger has never satisfactorily controlled the fuel transfer for this flight. I shall see if I can do a better job! :D

Sharky, thanks for the tip on using the French option. As you probably know Pierre is working on CPS v2 so at an appropriate point I'll mention the tank 9 thing is missing on the English version.

Link to comment
Fraser Gale

Steve, 

Ebay is a wonderful thing! I've had the manuals for some years and I have to say that there was lots of them floating about then, it's rather slow now. 

Ray,

some days I wonder where I picked up all this information myself, I can only assume that being a teacher by day my brain is programmed to retain information. I nearly became a pilot but my school and parents weren't sure how to get me into it back in the late 90's and I'm not an RAF style person. I was humbled the last time I did the sim at Brooklands when after my first landing my captain asked if I flew real planes, when I said I didn't he said it was a shame as I had something in me that meant I could "just do it". I don't regret not being a pilot as I'm rather stuck on Concorde and I think I would become bored with the glass cockpits haha! 

Saying that, I'm looking forward to flying the A320 when it is released. 

Anything else you want to know just ask and I'll try to help, I think I'll be flying New York - London today :-) 

Frazz

Link to comment
×
×
  • Create New...