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Wannabeaswapilot

Approach VREF issues

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After setting my approach VREF and flap setting in the FMC, for some reason on approach the aircraft is warning me that my airspeed is too low when the speed is well above my VREF speed. For example, my VREF is 140 with flaps full, at 155 I will get an "airspeed low " indicator, and at about 145 I will get the stick shaker stall warning. Also on almost all my flares I get the stall warning. I hope I explained this correctly. Anyways thank you.

 

- Max Ortiz

P.S. I love the 777, nice job!!!!!:)

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Need more info, what was your weight? Please provide more information about the flight. Are you sure the flaps where down?

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I guess that your actual weight is not the same (but higher) as the weight you calculated the Vref for.

 

On the approach speed you can enter your estimated landing weight.

You then get a Vref30 speed for that entered weight.

Normally you would calculate this by substracting expected fuel burn till landing from current weight.

(note:When you leave the approach page and return to it....it will have the current actual weight in there again, but the entered Vref30 speed will stay)

Maybe you did that wrong, and entered a too low weight. (lower than actual landing weight)

 

Try updating the Vref page on final and see if that gives you the correct speed for your weight.

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For example, my VREF is 140 with flaps full, at 155 I will get an "airspeed low " indicator, and at about 145 I will get the stick shaker stall warning.

 

This is going to sound like a stupid question, but you didn't indicate it for certain in your post, so I'm asking it:

 

You're using a full flap VREF, but have you put your flaps down to full?

 

Additionally, are you entering pounds when the plane is expecting KG?  Remember that each livery has its settings for the operator in question: if it's a Euro carrier, it'll probably be using KGs.  If you give it pounds, the aircraft will assume it's really heavy and trigger warnings out of place.

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I had a similar issue the other day on my first flight, I had no load, 8 tons fuel and with flaps set to 30, it wouldn't let me go below 180 knots with out protections kicking in...  :mellow:

 

Hasn't happened since though so I just put it down to the first time the aircraft was loaded.

 

Regards,
Ró.

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Hasn't happened since though so I just put it down to the first time the aircraft was loaded.

 

It was getting pissy because it knew what you normally fly...  :P

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It was getting pissy because it knew what you normally fly...  :P

And there was me hoping it'd be really nice to me try and convince me to come back to the other side... :blush:  Oh well, looks like it's one of those contrary aircraft that holds a grudge... :rolleyes:  :P 

 

Regards,

Ró.

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flaps set to 30,

 

I was gonna ask whether you knew flaps went past "3" on the 777, but you wisely specified... :P but I shall taunt you either way. ;)

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I was gonna ask whether you knew flaps went past "3" on the 777, but you wisely specified... :P but I shall taunt you either way. ;)

It may be 19 years since I sat at the pointy end of a Boeing, but I'm not that forgetful...  :P

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