Auto throttle question.

Hello All

Although I have been a simulator flier for seventeen years or so ,I still (rather embarrassingly )admit to engagement of autothrottle problems.

I am beginning to wonder if what iam doing on takeoff is incorrect.

I usually do this....Very shortly after iam airborne and climbing out I quite quickly engage the autopilot and then the auto throttle ,but this is were iam having problems on many occasions the autothrottle takes a long time to kick in ,resulting in a soaring airspeed that way exceeds the 250kts below 10000 feet rule.

Sometimes I have to turn the AT on and off a few times before it starts to react.

Can somebody here tell me the correct procedure for flight simming auto throttle engagement after takeoff ,or are the problems iam experiencing some sort of glitch within fs9 or individual aircraft models (Project Airbuses of which I have many seem prone to this behaviour, but not on every occasion.)

I can't wait another seventeen years to solve this as I might well be in the great departure lounge in the sky by then.

 

Cheers Andy

I think it seems to happen with different aircraft models. If you have something like the PMDG 737, I highly doubt you'll encounter the issue at all.

 

In my F-22 it's not the auto throttle that's the issue, but the altitude hold switch. Sometimes depending on what you're doing the plane will climb and climb surpassing the altitude I set. So it seems it all is in how the model was created and maybe the air file. I have no idea.

Hey, Socks, try something for me....before your next takeoff, turn on the A/P, leave heading hold off, turn on A/T (which should already be set for 250KIAS) and let 'er rip. Rotate at your desired V2, stow the wheels adjust flaps and haul arse! You should not be going over 250 knots until you readjust your speed dial.;)

Hey, Socks, try something for me....before your next takeoff, turn on the A/P, leave heading hold off, turn on A/T (which should already be set for 250KIAS) and let 'er rip. Rotate at your desired V2, stow the wheels adjust flaps and haul arse! You should not be going over 250 knots until you readjust your speed dial.;)

 

Thanks Zip

I will give your suggestion a try .

Aren't you actually describing a TOGA takeoff.?

No matter .

I will let you know if my arse gets hauling in the correct manner.. ✈️

 

 

Cheers Andy

Hi,

few things which helped me to avoid this unwanted acceleration when AT engaged:

in aircraft.cfg

[autopilot]

autothrottle_max_rpm= change it to at least 110 (lower doer not work well)

[autopilot]

max_throttle_rate= this is the speed of throttle move, if to slow the speed does not recover enough to slow down. 0.1 is usually a good number.

[TurbineEngineData]

fuel_flow_gain= apparently increasing this will also affect the AT, do not have this tested.

Also in general, steeper take-off angle also helps to decelerate.

Good Luck

Peter

Hi,

few things which helped me to avoid this unwanted acceleration when AT engaged:

in aircraft.cfg

[autopilot]

autothrottle_max_rpm= change it to at least 110 (lower doer not work well)

[autopilot]

max_throttle_rate= this is the speed of throttle move, if to slow the speed does not recover enough to slow down. 0.1 is usually a good number.

[TurbineEngineData]

fuel_flow_gain= apparently increasing this will also affect the AT, do not have this tested.

Also in general, steeper take-off angle also helps to decelerate.

Good Luck

Peter

 

Thank you Peter.

I will give your suggestions a try on tonight's flight.

 

Andrew

Thank you Peter.

I will give your suggestions a try on tonight's flight.

 

Andrew

 

Hello Peter

I notice in your reply that you talk about an unwanted acceleration.

The problem I have is not that ,but a slow response by the autothrottle once selected .This can result in a deceleration and very nearly a stall ,before the autothrottle finally causes the aircraft pick up speed.

On some occasions I have been forced to deactivate the autothrottle as stall speeds approach and shove my throttle fully forward to recover the situation before trying the AT once more.

 

Cheers Andy

Hi Andy,

assuming you tried the aircraft.cfg tweaks to no avail. Sorry for trivia but Auto-throttle engagement would not work without the IAS hold (in some cockpits SPD) button selected.

Just as a test, what I usually do, actually take-off with Auto-throttle:

1/ Select AP runway heading

2/ Select the AP altitude 10000, VSI select lets say 1500 FPM

3/ Select speed dial to 250kts

4/ At this point all AP functions disabled and lined up for take-off, engines running

5/ Autothrottle ON

6/ IAS hold (or SPD) on - aircraft starts to accelerate

7/ Rotate command - rotate to selected VSI

8/ AP engage, AP heading engage, AP altitude engage

9/ Gear up

10/ Flaps up

At this point the speed stays at 250kts and aircraft climbs to the selected altitude maintaining the selected VSI. Then I change the AP heeding and altitude as directed by ATC. Increase AP speed dial after 10000ft.

This always works for me. Occasionally after take-off the speed exceeds 250kts slightly but reduces to the mandated 250.

P.

Edited June 30, 2019 by beroun

Hi Andy,

assuming you tried the aircraft.cfg tweaks to no avail. Sorry for trivia but Auto-throttle engagement would not work without the IAS hold (in some cockpits SPD) button selected.

Just as a test, what I usually do, actually take-off with Auto-throttle:

1/ Select AP runway heading

2/ Select the AP altitude 10000, VSI select lets say 1500 FPM

3/ Select speed dial to 250kts

4/ At this point all AP functions disabled and lined up for take-off, engines running

5/ Autothrottle ON

6/ IAS hold (or SPD) on - aircraft starts to accelerate

7/ Rotate command - rotate to selected VSI

8/ AP engage, AP heading engage, AP altitude engage

9/ Gear up

10/ Flaps up

At this point the speed stays at 250kts and aircraft climbs to the selected altitude maintaining the selected VSI. Then I change the AP heeding and altitude as directed by ATC. Increase AP speed dial after 10000ft.

This always works for me. Occasionally after take-off the speed exceeds 250kts slightly but reduces to the mandated 250.

P.

 

Hello Peter

My apologies for taking so long to reply ,when you have taken the time to try and help me.

Last night I tried your settings as described above ,and it worked very well and all within the correct procedures for the Airbus takeoff ie no overspeeds or near stalls either

I will fly the Airbus all this week just to test that my successful takeoff was not a one off fluke.

 

Cheers Andrew