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wain

JARDESIGNS A320 SPEED ISSUE

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I am currently having an issue where after takeoff the aircraft is showing that I can only get to about 240kts before it gets to the red overspeed line and that will then disconnect the AP, I have gone through all my initial inputs setting up and all seems ok. Currently having to manage the AC at about 235kts to avoid overspeed.

 

This is the JARDESIGNS A320, XP 10.51, checked on JARS web but cant see this issue, all other things are running as expected, however when Autothruster gets above FL100 and wants to power on it cant because of the overspeed warning. If you need anymore info please ask as I am not sure what you would need....

 

Thanks

Edited by wain
heading change

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Just to make it clear... the ipper speed limit on pfd sets to 240 the whole flight.. would it be a cost index error by me or fuel input....any help be appreciated...

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I'll take a look at it Wayne this week. Hopefully I'll have some answers for you. What version of the A320 are you using and can you give me the flight details so I can replicate it? 

Out of curiosity, check your flaps and gear settings. Those would lead to a constant speed restriction in flight. 

Best wishes,

Jess 

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I do not have that aircraft, but as far as I am aware, cost index is used in determining flight levels and speed to determine the fuel burn, but the only thing that affects the overspeed indicator on the PFD is the flight level.  The higher you go, the higher that rises.  Are you remembering to set it Mach when you get above 25,000 ft?  Could also be a bug in the aircraft.  Have you checked the forums for the developer?

 

This is from my MD-80 operating manual

 

The cost index is used in the computations of
ECON speed. A low cost index means lower
speed and lower fuel consumption. A higher
cost index means higher speed and higher
fuel consumption. 0 makes ECON speed the
same as MAX RANGE speed. 999 is used for
maximum speed and minimum flight time.

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ok thanks for the replies, I have since done 2 short flights, one from Bristol and one from Nice, this was where the original was that had the issue. I have followed the instructions regarding the Cost Index and have topped up the fuel, both times all was ok so I am guessing it was operators error (ME!!!!).....I did have an overspeed issue but that seems common acording to XP forums....I have also updated to 2.7 which seems to be the latest version....I am guessing I was rushing through the prep and not inputing the correct figures once again thank you for all your suggestions....

 

Can someone please change to resolved as I can never remember how to....cancel that sussed it.....

Edited by wain
update

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Glad to hear you've solved the issue Wayne. As a little follow up, it's unlikely that the cost index would be causing the overspeed issues. The cost index covers the projected speed at cruise. I use 35 for my normal flights which equates to Mach.77 in the cruise, whilst a BA virtual flight sees me use a C I of 0 which brings in a cruise speed of Mach.74

 

if you were seeing a red speedbar above 240kts in the cockpit, the most likely cause would be a flaps issue. The standard max flaps 1 speed is 235kts. From what you've described, that fits the bill perfectly. The JAR airbuses can be strange at times. 

 

Jess 

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Thanks for getting back Jess, I use a cost index of 30 as per a tutorial I have for this Bus.

 

You may have something regarding the flaps, I do remember getting airborne and setting up for the climb, then realising I had the flaps extended still, so that sounds like the culprit.

 

The overspeed was not really an issue, I used the speedbrake to keep under the red and came in with manual throttle, landing was fine and very controlled.

 

I seem be to be OK with this one now, can set it up and go through most phases without the need to check my list, pactice, practice....also seem to be leanimng more toward XP most days too, XP11 has gone on my Christmas wishlist.......

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A cost index of 30? Wow! On most of my aircraft (MD-80, DC-10, EMB 190) I use typically use a cost index of 500.  I find it  a nice compromise between speed and efficiency.  30 will save a lot of virtual fuel but will take a long time to get there assuming that you use the calculated speeds from the FMC

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