I am having a most annoying problem. I use the autothrottles for takeoff (n1 mode). 50% of the time, I get part of the way down the runway, the FMA says THR HOLD, and after a few seconds, the engines spool down and I am forced to abort my takeoff. What could cause this to happen? I am not using RTO. Is there something built into the PIC that would abort the takeoff. An aircraft configuration issue? If so, why is there no EICAS message?

Sounds to me like joystick noise.Two solutions are possible:a) in the PIC Preferences window select the option "A/T inhibits thrust".:( Use the joystick to add full thrust, then at 70% N1 press the N1 button on the A/T panel. Should joystick noise occur again, it will give full thrust instead of idle thrust. Not nice but you won't get as much adrenaline pumped into your blood as right now :-)Regards,Mark

" I am not using RTO" In my office mister!Best Wishes,Randy J. [email protected]" A little learning is a dangerous thing"AMD XP 2100 |MUNCHKIN 512 DDR RAM |ECS[/b ] K7S5A MB |[b]GF3 64 MEG |WIN XP PRO |MITSUBISHI DIAMOND PLUS 91 19"

I'm not using it because I wanted to eliminate that as the problem.

LOL Randy!Anyway, back to the issue at hand. I gave up using autothrottle on the TO roll back in the days I used to fly default aircraft (I know - the shame of it!), because of the very issue you describe. It seems the autothottle sees an impending overshoot of you MCP selected speed while accelerating for take off and takes this drastic action to reduce the overshoot, thus making you think your virtual copilot has gone for the V1 cut throttle back. I'm not sure if this is what is happening with PIC, but the workaround used to be to set your MCP speed to a ridiculously high setting such that it never sees the impending overshoot. Then you just have to worry about resetting it to a reasonable level afer rotation. Personally, I don't think it's worth the bother so I go manual throttles for the TO roll.Gary

Guys, please... :)First. ALWAYS use RTO in takeoff.. always.Then to the issue itself.It is because if you use N1 mode, the throttles will initially advance to T/O thrust setting, UNTIL at 80 kts the A/T will engage in THR HOLD mode, which basically means, that it will HOLD whatever throttle is SET on the throttles themselves. Now, IF you don't have the throttles firewalled by 80 kt, you WILL get the engines to spool down to just whatever setting you might have them in.The solution:1. Advance manually throttles to 70% N12. wait for the engines to stabilize3. press N1 and also set the max thrust from your joystick/yoke/throttle console (or whatever)PIC A/T logic will spool engines DOWN if the manually set throttle is BELOW the EEC T/O thrust setting at 80 kts. If it is ABOVE it (ie. max thrust for example), it will continue on THR HOLD and keep the predefined T/O thrust setting (for example derated thrust) from then on. It will not increase the throttles to max thrust, although you firewall the throttles after pressing N1.Now, IF you have RTO armed, and the engines spool down at 80kts, due to the fact that you haven't firewalled the throttles, the RTO will detect deceleration which automatically engages RTO mode, and you will abort the takeoff.So, all you need is to ensure your throttles are firewalled BY 80 kts, and the EEC & A/T will take care of the rest, and you will not see the engines spool down ever again in the t/o roll :) (unless of course they burn hehe)regardsTero

Thanks for explaning, I had this problem too and it almost drove me crazy!

I just want to add to this conversation to hopefully add some extra real world information on this subject. In the real aircraft, when the aircraft hits 80 knots thr hld is displayed exactly as it is in pic. In the real aircraft this mode disconnects the autothrottle servo from the throttles, so if the throttles did not reach max takeoff thrust by 80 knots, the pilot has to push them the rest of the way up. This is designed this way because once the aircraft hits 80 knots it is in the high speed abort region and the pilot will only abort for engine failure, or warnings, not for cautions. If the autothrottle did not disconnect the servo at 80 knots, when the pilot aborts, by pulling the throttles back, the autothrottle would push the throttles back up to takeoff power, and this would be very bad when the end of the runway is coming up very fast. I hope this adds to your flight simming experience and gives you more information then you ever wanted. If you want to see this in pic, sit at the end of the runway with the parking brake on, with the peadastal view open, push the n1 button and watch the throttles go up. Then press F1 and watch the throttles come to idle and then go back up to takeoff thrust. Now do the same after you are above 80 knots and the throttles should stay at idle after pressing f1. Do this with your joystick disabled to see the full effect.