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AvA757Pilot

Approach phase and eveything goes to ####

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This has been happening to me a few times recently in the A320.Flight is normal and proceeding nicely. Descent is on schedule, approach has been programmed and once below 8000' I activate APP PHASE on MCDU. Once I do, the speed drops to 140 kts or less (today when it happened I was still 10 mi out) and then the aircraft stalls (which I did not even think was possible in an Airbus) even though A-Floor has activated. I was at 2000' and had no time to recover before the aircraft went in the drink.Am I activating APP Phase too soon? Should I wait until after LOC intercept?The manuals seem to indicate that APP Phase can be activated on the MCDU below 10,000' (although the flight manual says not above 8200' AGL) and I do not recall seeing anything about waiting until after LOC intercept.Perhaps I am misunderstanding the actual procedure that APP Phase initiates.Thanks for any insights.Roger Curtiss

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Guest tymmix

Hi Roger,I had the same problem a long time ago. It was cured when I installed Pedro Oliveiras flight dynamics available with most of the IFDG busses on avsim. Especially with the panel merge on IFDG you get better looking models with all PSS features.Best regardsSt

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Guest FOhagg

Hi,The Approach phase is usually activated during the descend between FL150 and FL100 in real life. The approach phase may not be activated later then 15NM from the landing runway. When you activate the approach phase the speed will drop to "green dot speed" which also is the aircrafts minimum clean speed. When the aircraft has reached the O (green dot) speed it will maintain it util you have selected Flaps config 1, then the speed will drop to the next "step". Lets say that you activated the approach phase at FL 130 then you

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Guest vrandar

It could be that you are activating the approach when flaps are full. If you do then the speed will drop to approach speed. You can activate the approach at about 8000 feet with no problem without this happening providing you are deploying the flaps on the correct schedule. The following approximate target "gates" has been taken from the (real world) British Airways Airbus Flight Training Study Guide:Distance / Height / Speed / Config33/10000/280 max/Clean20/6000/250/Clean12/3800/210 or green dot/Flap 18/2500/180 or S speed/Flap 14.5/1500/160 or F speed/flaps 2 or 3 + gear

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Guest Calum

Many times in real life ,the pilots dont need to activate the approach , when passing the magenta coloured (D) on the flight plan on the Navigation Display , the MCDU automatically changes over to Approach phase , and decelerates the aircraft to green dot speed.That is what the (D) on the flight plan is for , you will notice that it is close to the point where you tunr onto the localizer / runway heading , and so , it times it nicely , slowing the aircraft around 180knts with Config 1 flaps , just perfct before turning.So try not activating it yourself , try letting the AP1 fly you to the purple (D) , then watch the speed reduce automatically , leaving you to deal with Flaps , Gear , and all importan cabin announcements ;)Calum

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You guys have the siituation pretty well nailed. As the last act of a desparate man I went back and read the systems and flight manuals (READ the Manuals?...craziness!)and sure enough the recommendation is not to activate APP mode until below 8000' and preferably not until capturing the LOC as indeed, the speed does automatically go to green dot with that mode selected.

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Guest Calum

great news ,well done and lets us no of any more problems :)Good LuckCalum

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