Restricted cruise speed

[Dicko 3]

Why since the MD11 update when I fly a red band on the speed tape restricts the aircraft's speed to 320 knots? The red band used to come in around 350 knots with exactly the same aircraft configuration and fuel loads. Why would this be?

[Check_Airman 3]

Sure the fuel load was the same? I don't remember the VMO limits, but the MMO limits are M.85 with the wing tanks less that 60% full, and M.87 with greater than 90% fuel in the wings. I believe there is linear variation between these limits.

[KCA9304 0]

Sure the fuel load was the same? I don't remember the VMO limits, but the MMO limits are M.85 with the wing tanks less that 60% full, and M.87 with greater than 90% fuel in the wings. I believe there is linear variation between these limits.

FYI,For wing tank fuel 60%/90%, please read wing TIP fuel as indicated in the Max Speed Graph.Vmo decreases gradually to 320 IAS if fuel from this tip tanks is transfered to inner tank 1 and 3.Harry

[Check_Airman 3]

Thanks for the correction Harry. Where are the wing tip tanks though? I don't recall seeing them in the synoptic.Paul

[KCA9304 0]

Thanks for the correction Harry. Where are the wing tip tanks though? I don't recall seeing them in the synoptic.Paul

They are not on the SD page.Refer to Fuel system, Gravity and Jet pump transfer, in the Systems . pdf, page 10.10 to know how it works.Harry

[Check_Airman 3]

Thanks Harry,I think I have it now. The tips contain 6000lb each, and the fuel is transferred from the tips when the each main falls below 5000; so the transfer will start with 11k in the tanks. Thus you should be on the high speed schedule until 33,000lb.

[Dicko 3]

Thanks Harry,I think I have it now. The tips contain 6000lb each, and the fuel is transferred from the tips when the each main falls below 5000; so the transfer will start with 11k in the tanks. Thus you should be on the high speed schedule until 33,000lb.

Spot on with the fuel loading!!Thanks