747/777 minimum safe speed at MTOW below ten.
 

Good evening guys and gals.

First I don’t fly either airplane, I’m a bus guy and I was having a friendly discussion on a FB group about the max speed allowed below ten, now someone brought up the scenario were a 747 and 777 at MTOW has to fly faster than 250kts after clean up below ten. I have never heard ATC approve a clearance like that before and I know that FAR 91.117 states no aircraft will fly faster than 250 below ten “unless authorized by the administrator” so my question is, are some US cargo company authorized by the administrator for this? Or is there another FAR that allow you guys to fly faster below ten when heavy? Or do you guys never takeoff at MTOW?

Again, I am clueless about both aircrafts and their operations and I appreciate the clarification.

Hope everyone is well :)

The last part of that far reads “(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”.

This is the case for Military aircraft such as fighters as well

At least to the best of my knowledge.


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I guess I need to read the whole paragraph before asking questions lol so that answers that, so my next question is, because most cargo flies at night I have never really heard a clearance like that before, is that pretty normal?

Yes, it’s allowed per the FAR, did that at Atlas often. And when in doubt, just ask ATC for relief.... they know you’re a heavy and usually approve.

I’ve always just stated “request min speed 260 KIAS” and typically get a “cleared as requested”. The controllers probably won’t have an issue as it’s usually only happening on climbout and a short event.


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Thank you guys for answering my questions! :)

Yes, it's very normal. You don't hear it because, in the US there is no need to request the higher speed if you need it. MD-11s at max TOGW often have clean speeds at 280 or higher. Even 767 freighters sometimes need greater than 250. However, outside the US there is no relief unless requested specifically from ATC.

ATC can not approve it, only administrator can.

If your min safe speed is higher than 250, you may fly the higher speed. You do not need need administrator approval in that instance.

https://www.law.cornell.edu/cfr/text/14/91.117

See paragraph d.

Also, some countries do not require 250 KIAS below 10,000’ or their ATC can waive the requirement. Your FOM/GOM should have an explanation.