FMC question. Please read. Thank you.

[DOGANG KIM 8]

Airplanes in my country have to fly below 250knot under 10000feet. It is about noise problem maybe.In climb page and devent page of FMC, there are 2 lines about those speed limit and altitude.First one is SPD TRANS.Second one is SPD REST (speed restriction).Both format is sss/aaaaa like 250/10000.SPD TRANS number is flexible and changed by plane's performance.Defualt number is 250/10000, but if airplane is light, it can be more high number like 255/10000.Yesterday, I started flgiht with light 747, the number was 254/10000.So I need to maintain 250know below under 10000 feet, and I inputed 250/10000 at SPD REST line.And~I did take off, My 747 was accelating.The auto pilot's "SPD BUG" in PFD was not 250. It was maybe 254.I watched speed exceed definitely.How can I do control allowed speed under certain altitude? (Sorry my poor English. I spent 8 month to read manual)

[Paul_Smith 92]

The 250kt below 10,000ft limit is a request not a demand. It is fine for a cessna which can not do 250kts anyway, but a loaded 747 can not safely fly with those restrictions. ATC will always put safety of flight before other restrictions.

[DOGANG KIM 8]

The 250kt below 10,000ft limit is a request not a demand. It is fine for a cessna which can not do 250kts anyway, but a loaded 747 can not safely fly with those restrictions. ATC will always put safety of flight before other restrictions.

OK. I can control speed of 747 by hit SPD nob on MCP panel.But FS ATC is not cleaver.So I want control speed via FMC useing auto pilot.Anyway, my question is how to control speed not to exceed 250knot under 10000 feet.

[scandinavian13 5,192]

You would insert 250/10000 in the spot that says 255/10000, just like you said you did. You need to make sure that the Autothrottle (AT) is on, and you are using either FL CH or VNAV mode for a speed-based climb.It's better not to use FSX ATC. It's very poor. To be honest, ATC can't really tell exactly how fast your airspeed is, only groundspeed.

[DOGANG KIM 8]

You would insert 250/10000 in the spot that says 255/10000, just like you said you did. You need to make sure that the Autothrottle (AT) is on, and you are using either FL CH or VNAV mode for a speed-based climb.It's better not to use FSX ATC. It's very poor. To be honest, ATC can't really tell exactly how fast your airspeed is, only groundspeed.

SPD TRANS line is not able to be modified number .I tried it already.If you are running FSX, please test it.It can't change SPD TRANS line .

[downscc 1,327]

Really? Don't fly 250 below 10,000 in a heavy 747-400. Simple answer. It's not realistic, and in real world is it not safe or economical.

[bamboofats 0]

You just input 250/10000 under the speed restrictions. And use delete on speed transition. Now the FMC will follow whatever you put under the res row, whether or not it is economical or safe. it will look spd trans ---/----- spd res 250/10000 rmb to press exexThis can be done with the descent page as well. If you want absolute control over the restriction speeds and altitude,delete the trans, input your choice into the res, if you left the res blank with trans deleted the plane will just accelerate to its climbing speed of about 300+kts

[Matt2218 4]

Dogang Kim;I have nothing to add to the technical answer to your question...but your English sounds good to me!Good Luck...

[skysurfer 76]

Hola. I agree with everybody here. I just want to add something. When virtual air controllers do a goofy things just simply go to their forum and speak out. Also speed restrictions 250 kts below 10,000f is not for noise procedure. When you descend below 10,000ft you are approaching to the Terminal area and there is no much room for air controllers to play with. ATC slows down the air traffic for spacing, because separations are reduced other than en route. So speeds are slower, radius of turns are smaller and ATC would be able to handle more traffic and restricted airspace and so on. When I controlled air traffic in reality we preferred 250 kts below 10,000 but if a crew said it was unacceptable due to weight it had never been an issue. All air controllers know that. Some of those virtual air controllers who force you to keep 250 kts below 10,000 even if you die are not smart enough and I am more than sure they have no idea why crew are required to keep 250 kts below 10,000. If they force you to do it once again just tell em it is very unprofessional and reportable event. Good luck.

[Matt2218 4]

Hola. I agree with everybody here. I just want to add something. When virtual air controllers do a goofy things just simply go to their forum and speak out. Also speed restrictions 250 kts below 10,000f is not for noise procedure. When you descend below 10,000ft you are approaching to the Terminal area and there is no much room for air controllers to play with. ATC slows down the air traffic for spacing, because separations are reduced other than en route. So speeds are slower, radius of turns are smaller and ATC would be able to handle more traffic and restricted airspace and so on. When I controlled air traffic in reality we preferred 250 kts below 10,000 but if a crew said it was unacceptable due to weight it had never been an issue. All air controllers know that. Some of those virtual air controllers who force you to keep 250 kts below 10,000 even if you die are not smart enough and I am more than sure they have no idea why crew are required to keep 250 kts below 10,000. If they force you to do it once again just tell em it is very unprofessional and reportable event. Good luck.

Good post Ed.Likewise, in the real world not everybody is on an IFR flightplan under ATC control. Keeping the speed down under 10,000' gives people more time to 'see and avoid' VFR traffic.

[wanabflyer 53]

Just a dumb question from rookie: Forgeting the real world, i have Radar contact and many times they have taken me down to say 9,000ft. and said 'Speed not to exceed 250". Does this meen i have to fly flaps # whatever before i normally would be using flaps?

[scandinavian13 5,192]

"Normal" time for flaps is whenever you're at a speed which requires their use. So, yes.

[skysurfer 76]

Just a dumb question from rookie: Forgeting the real world, i have Radar contact and many times they have taken me down to say 9,000ft. and said 'Speed not to exceed 250". Does this meen i have to fly flaps # whatever before i normally would be using flaps?

Hello back.I was jump-sitting in the flight deck yesterday into Memphis, TN, and our ETA was right in the middle of FedEx push and our flight were raped by a Memphis Center. The flow control began over Texas which is 300 nm away from KMEM. We were instructed to reduce speed to LRC for additional traffic and than we had to reduce speed to 220 kts about 100 nm from the airport. Crew had to throw flaps to comply with ATC and we didn't even enter the STAR transition. At the end of the story Approach wanted us to keep at least 180 kts till 4 DME on final which did not make any sense but we had to, otherwise we might have ended up with only 2 options, either keep that crazy speed or be eaten by FedEx MD11..When things get wild in the air you have to forget about "Normal" procedure. If you have to use your flaps, you have to use your flaps. Not much you can do.