Archived

This topic is now archived and is closed to further replies.

Guest SuperFortress

Question about auto throttle on PMDG 747 and approach speeds.

Recommended Posts

I have just started flying the PMDG 747 on FSX.One problem I am having is that I problem my MPC, FMC take off and climb to cruize alt but it always keeps speeding up and eventually reads about 405 on the tape and tells me OVERSPEED.This is basically what I am doing at the start of the runway:-1. Click Auto Throttle on2. Click Flight Director on3. Set IAS to 2504. Set Alt 330005. Set FMC as follows:-5a. Origin5b. Dest5c. Route5d. Perf Init, ZFW, Reserve 6.0, Cost Index 100, Crz Alt 330, Flaps 10, , Dept Airport and runway, V speeds6. Set flaps7. Take off8. At 1000ft, enable auto pilot, LNAV and VNAV9. Leave it to climbThis is when the speed keeps going past that recorded in the FMC. I also notice that my throttle on the joystick still affects the 747 throttle.To get around this I have to do the following:-Click FL CHGSet IAS 300Click FL CHGTurn off Auto Throttle and back onPlane then slows to MCP setting. At this point I can switch VNAV back on and it stay correct.Any ideas?Also, just out of interest what would people have their speed set to on approaches for example:-1. 10,000ft2. 5,000ft3. 2,500ft or Capturing the glide slope4. Landing speedI am doing the following at present but wondered if I was right or not:-1. 10,000ft = 250knots2. 5,000ft = 250knots3. 2,500ft = 180knots4. Landing speed = FMC approach ref, say 140knots.Let me know you thoughts.ThanksMark

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Just a check, is your Pitot Heat on? If not, ice could be building up on your Pitot tube, lowering your KIAS measured by the pitot, and thus spooling up your engines to reach your assigned speed.

Share this post


Link to post
Share on other sites

Hi Mark,I think the problem may be that you're not turning the autothrottle on.In your list of things you did you said you turned the autothrottle on ... but how? My guess is that you armed it. In the top left hand side of the PFD is the autothrottle status. Check what that says before you takeoff, my guess is that it's either blank or it says ARM (in white). To takeoff you have to push the TO/GA buttons to actually switch the autothrust on. When this happens it should change from ARM to something else (THR?) in green to show the system is now active.After that everything you said should work.Hope this helps,Ian

Share this post


Link to post
Share on other sites

The TO/GA button is the small screw located on the MCP right around the autothrottle switch.

Share this post


Link to post
Share on other sites