Maximum operating speed (at cruise altitude)

[Endevour]

Hi
Could anyone please tell me what the maximum operating speed at cruise altitude is for the A 380 and the 777. Also another dumb one, does this maximum cruise speed exist for the structural integrity of the plane?

[Old Smokey]

For the B777-200 series, MMO = M0.87

For the B777-300 series, MMO = M0.89

Having said that, TYPICAL (and Boeing recommended) Max Cruise Mach number is M0.85, fuel costs steeply rise after that.

Nothing to do with structural limits at high altitude, it's an Aerodynamic limit.

Regards,

Old Smokey

[Endevour]

Thank you Smokey. Is this aerodynamical limit the "Redline Airspeed"

[BOAC]

Endevour - there will be an IAS limit for structural reasons, but as OS has said, at cruise altitude one is nowhere near that, so Mach effects govern the limits.

[Endevour]

Thank you kindly