For a long time I have noticed the MD-11F shows FMS target speeds of around 192, 245, and 270 on the speed tape on the PFD and 280 at 10000 ASL on the magenta track line on the ND when using SIDS. I thought speed was restricted to 250 below 10000 ASL. When the target speed moves from 192 to 245 I dial in 250 in the speed window and right click the speed button. At 10000 I press the FMS SPD button to resume normal acceleration. Why is the MD-11F trying to reach 270 below 10000 and am I using the correct procedure to keep it at 250.Thank youMichael Cubine

It is normal for heavies to exceed 250KIAS below 10,000, and the automation will not slow down for you because it is unsafe. The 747 is similar in this regard.

When the heavies (747, md11, even the 767) are at MTOW or loaded with fuel for long hauls, it's not uncommon for the FMC to dictate a higher than 250 kt "clean manuevering speed" to prevent a loss of lift or stall at those weights. So instead of the 250 max below 10000 on climbout, most airports will permit the plane to accelerate to that higher speed to be within the margin of safety. It's only when the plane has a light load that the FMC will respect the 250kt restriction. In additon to reports from real life pilots on the web, I read about this in a book by a British Airways 747 captain on a flight from EGLL to KJFK titled "Flying the big jets" by Stanley Stewart, he accelerated to 265 kts after flaps retraction on the Compton SID (the maximum speed permitted below 10000 being 250kts OR VREF+100, whichever is greater)

Also worth pointing out is that even if it isn't at MTOW, the FMS doesn't necessarily go down to 250 at 10K. Speed restrictions in SIDs will be there, but otherwise I seem to recall that I have to input a 250 restriction.

I would like to thank everyone for the information. All of the flights in the MD11F were 8-12 hours at about 5000 lbs below MAX TOGW so that would account for the 270 below 10000 ASL.Thank youMichael Cubine

FAA FAR § 91.117 Aircraft speed.(a ) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.).(B ) Unless otherwise authorized or required by ATC, no person may operate an aircraft at or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C or Class D airspace area at an indicated airspeed of more than 200 knots (230 mph.). This paragraph (B ) does not apply to any operations within a Class B airspace area. Such operations shall comply with paragraph (a ) of this section.(c ) No person may operate an aircraft in the airspace underlying a Class B airspace area designated for an airport or in a VFR corridor designated through such a Class B airspace area, at an indicated airspeed of more than 200 knots (230 mph).(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.