DLH 781

[Cbf]

It looks like that Lufthansa is the last airline to operate 744 with PAX
SIN/FRA flight duration is approx 12H30 (5700NM). The aircraft seems to be heavy as cruise begins at FL 300.
Estimated minimum ZFW with full PAX on board is 185T (OW) + 37T (371PAX with luggages) = 222T
Estimated fuel including reserves 145/150T
Estimated minimum TOW 367/372T
What is the strategy for such flight? I think they add cargo in the holds (increasing fuel)
I saw D-ABVW/VX registration. Are they equipped with STAB tank? If yes, do LH uses it?
Do LH uses RCF procedure?

[andrej]

For D-ABVW it seems that STAB tank is not fitted.
https://www.planespotters.net/photo/1451987/d-abvw-lufthansa-boeing-747-430
Not sure about VX, but most likely not?

Having reviewed DLH's AOM OM-A, only 747Ls and TD, TE, TF, TH had STAB tank installed.

Edit 2:
OM-B states that there are two different MTOW classes:
1. 394,600 kgs
2. 385,600 kgs

Lower MTOW are:
-VA -VC, -VL -VP, -VR -VU, -VW
-TA -TC

[Mawea]

Hi,

the strategy is to not leave anything behind. But as you discovered already, it is a heavy task to not leave cargo or even passengers behind. They just switched the flight number from 778/779 to 780/781, we used to fly the route with B748. The first 9 748 had no tail tanks, the newer ones all have tail tanks.

With the 744 it is the opposite, the older ones had tail tanks the newer ones don't. VM is the last remaining 400 with tail tanks. If you are interested I updated the LH fleet models and it is available for download, tanks, setup, call outs etc

https://aerowinx.com/board/index.php/topic,7567.0.html

These listed ones are the last remaining ones in service.

*edit: 
- if installed tail fuel is used when >130t and trim situation allows.
- RCF is basically used but never had a reclearance flight plan in 10 yrs on the 747

[Cbf]

Thanks for your answers. As takeoff fuel is below 160T, I read that stab tank fuel is not recommanded with an aircraft equiped. Furthermore, if used, the takeoff CG margins are very restrictive when reaching MTOW.
For DLH 781, if aircraft is full of passengers and their luggages, I think that 10T of freight can be loaded with 150T of fuel (MTOW 385T? and MZFW 246T?). If more fuel is required, freight must be less or disembark airline staff passengers
Concerning B747-800, on which flight does DLH (or other airline) use stab tank?

[Mawea]

..takeoff fuel is below 160T, I read that stab tank fuel is not recommanded with an aircraft equiped.....

Don't know where your 160tons not recommended comes from, our standard fuel distribution would be wings full first followed by CWT and HST in this exact ratio to the capacities 52t : 10t so in the case of 150t you would expect 110t (wings full) + 40t (33,5t CWT + 6,5t) with HST. With 15,8t in CWT HST starts to fill (3,03t) and that's the area when the CG starts to move aft.

I didn't check in psx but I expect Hardy is filling the tanks this way (even more precisely than my rule of thumb way 😉). Buttom line for you as pilot is to check on your loadsheet if tail fuel is used and calculated and that the ratio is ok. There are also other rules but to keep it easy it gives more flexibility with the T/O CG to get an CG which is more aft. Helps with performance, minimizing the downward lift of the stabilizer. Sounds negligible but it really matters at a few high and warm airports.

Other aircrafts have the ability to really trim by pumping the fuel back and forth (A340) continuously during flight. On the 747 the fun of having tail fuel is gone shortly after reaching cruise level 2-3 hrs (~36t in cwt) or if the stab pumps would fail and the fuel would be trapped.

Best regards

[Cbf]

160T is airline specific recommandation. Real aircraft HST filling begins at 125T, same with PSX.

[jawomba]

...

Edit 2:
OM-B states that there are two different ZFW classes:
1. 394,600 kgs
2. 385,600 kgs


...

Hi Andrej,

regarding the values of the ZFW classes, what is the relation to ZFW or why ZFW and not MTOW?

regards,
Jan

[andrej]

Jan,
thanks for your message.

I reviewed the OM-B again, and I have to make a correction. The weights I referred to were indeed, MTOW not ZFW (I will amend my post above as well).

OM-B states that there are two different MTOW classes:
1. 394,600 kgs
2. 385,600 kgs

ZFW are also different:
Combi -430M (D-ABTA - TH): 256,300 kgs
Regular - 400 (D-ABVA - D-ABVW) 242,700 kgs

I am sorry for the confusion.
 

[jawomba]

Thank You Andrej,

if I resolved it properly, it should be:

Code Select Expand

FIN#  ZFW       MTOW      FC
TF    256300    394600    173056 HST, Combi
TK    242700    394600    163027
TL    242700    394600    163027
VC    242700    385600    173056 HST
VM    242700    394600    173056 HST
VN    242700    394600    173056 HST
VU    242700    385600    163027
VW    242700    385600    163027
VX    242700    394600    163027
VY    242700    394600    163027
VZ    242700    394600    163027
regards,
Jan

[Mawea]

Hey Jan, hi andrej,
I'm not sure what you mean by the mentioned ZFWs. ZFW (zero fuel weight) differ for each flight, as they are based on the Basic Weight (BW) plus crew and pantry, which results in the DOW. The ZFW is then calculated as DOW plus payload. BW of VM is ~180t vs BW of VU ~178t. Maybe you refer to Max ZFW? In this case I understand and it is equal for all remaining 744 planes with LH,  MZFW 242671t. 

As mentioned above in my post VM is the last remaining 400 with a tail tank installed. MTOW is the same for all tail numbers. Only the fuel capacity with installed HST is increased, in all tanks btw not only in the tail tank itself. So the actual fleet would look more like this:

  MTOW.  Fuel capacity (block fuel)
TK 385,550 162,400
TL ..
VM 385,550 174,430 (HST)
VU 385,550 162,400
VW ..
VX ..
VY ..
VZ ..


Cheers jay

[jawomba]

Hi Jay,

yes, thank you and yes, I mean MZFW.

I impelemented the data in simbrief airframes models (edit: and shared them):
- D-ABTF   
- D-ABTK
- D-ABTL
- D-ABVC
- D-ABVM
- D-ABVN
- D-ABVU
- D-ABVW
- D-ABVX
- D-ABVY
- D-ABVZ

Unfortunately they don't appear in the new airframe selection list.

They are basically based on your data. For airframe equipment I used what I found
for a certain airframes "flight" on EDI-GLA (edit: real world flightplan database) for MLW I used 295740 kgs. Any feedback is welcome.
For the active fleet I also entered the Drag/FuelFlow inputs from your model-files.

A short personal story and the VC: I had the chance to fly from FRA to BKK and back on the jumpseat already 25 years ago and during the stay over in Bangkok also to fly on a shuttle to MNL where we only spent one hour before we went back to BKK where I we got a beautyfull midnight landing. One flight was in the VC.

Cheers Jan

[Mawea]

Hi Jan,
I can understand why you keep the VC — especially with memories like that. Those jumpseat flights sound fantastic.
Unfortunately, there are no shuttle flights anymore due to codeshare agreements, so that part has changed quite a bit over the years.

Regarding the weights, use 285.5t as MLAW if you want to be precise. For SimBrief, I have to admit I don't have a lot of experience yet, so I hold back on inputs there.

Bis dann

[jawomba]

Hi Jay,

thank You for your info and feedback, I updated the airframe MLAW to 285.5t.

Bis dann