autothrottle will not mainatin MCP speed

[WilloW_737 5]

Hello:I hope someone can help here. Everything was perfect until I installed FS GLobal 2005 (although this is a coincidence I think) as FS Global is onlty scenery.On approach in the 737 (all series) with the speed activated with auto throttle engaged, as the aircraft decends along the glidepath the speed declines to stall speed. The speed does not maintain the speed as set on the MCP. I've done several tests and the throttles to not spole upwards as the speed goes below the indicated speed on the MCP. The auto pilot CMD A is OFF. I am only using the auto throttle. When flying there isn't an issue. The speeds will follow the dialed MCP commands. It only appears to occurclose to VREF on glidepath to decent.Any ideas?Another glitch which maybe related as it occured at the same time is that on take off after V1 and V2 is reached, the aircraft will not lift off the runway - no matter how far you pull back the yoke. The aircraft becomes airborne V2 + 10!! Once airborne there are no issues with pitch.Once again. ideas?THANK YOU, Iain

[fencer 16]

Hello Iain,Assuming the plane is correctly configured (trim, flaps, generators on etc.), I would check the weight. Do you use the PMDG load manager and what is your GW?Otherwise, maybe you could post a screenshot or two (mainpanel and overhead panel).Hope this helps,BrunoPS : Since you mentioned having installed new software, it never hurts to run the flighone registry repair tool, just in case !

[Guest Wabey]

I was going to say... it does sound ike a weight issue with the V2 plus 10......Have you selected the FMC v speeds for landing when you select the app/runway?I cant think what else.......

[basa 0]

Hi Iain,Q1.- There are two buttons below the A/T switch: N1 and SPEED.Have you pushed the SPEED button and has its light on ?Q2.- Seing the symptoms, I bet your aircraft is not properly trimmed.I hope it helps.

[WilloW_737 5]

HI Everyone;First, many thanks for your replies :)I do use the PMDG fuel and weight managers.I checked the settings and it seems that for whatever reason they were not correct (trim, etc was OK)I did two trial flights using the 800 series - one flight with minimal weight and fuel and a second flight with higher weights.After checking weights and fuel carefully, both take offs and landings were successful.I noted on one flight that the speed selector disengaged (why who knows). But, what is important is to always scan the instruments just to make sure.....Not sure what the hiccup was. Thank you, Iain

[Mats_J 2]

On approach in the 737 (all series) with the speed activated with auto throttle engaged, as the aircraft decends along the glidepath the speed declines to stall speed. The speed does not maintain the speed as set on the MCP. I've done several tests and the throttles to not spole upwards as the speed goes below the indicated speed on the MCP. The auto pilot CMD A is OFF. I am only using the auto throttle.

Iain,What was the mode indications on the Flight Mode Annunciator (FMA. Top of the PFD)? This will tell you the Autopilot mode. The MCP should be trusted for input only.Hope it helps,

[DEINIOLENMAN 0]

I can't help directly except to remark that you are fortunate to have an Autothrottle function! Mine refused to work and no-one on the grup seems to know why. With regard to glide slopes it does seem that the speed has to be pretty precise and it may be that your setting is either too fast or too slow. When I attempt to land the 737 controlling the power manually, it does not take much of a deviation of speed for the glideslop to be lost.BB