Stall warning while not being in a stall.

[JRSchiphol 0]

Hi!

I am busy with a video this week and there are some scene's with landings.
What I am used to is make a circuit around the airport with low fuel. I will in all the data in the FMC and I take off to get prepared for landing.

Most of the time my VREF is around the 130 to 137 knots.
When I am about to land I try to keep my speed at that VREF. But I keep getting the stall sound after going lower than 140 knots. FS doesn't say I am in a stall... neither do I fall onto the ground and I can continue with the landing.

For a video it is fine... I just mute the sound since it is cinematic. But when I am going to do real flights with it... it can get quite annoying.

Is this a bug or is this normal in a 777? Or am I doing something wrong that I don't know yet?

Thanks!

Kind Regards,
Jonah

[scandinavian13 5,192]

 

 

Is this a bug or is this normal in a 777? Or am I doing something wrong that I don't know yet?

 

Check to ensure you're entering the proper weights for the plane.  Sounds like you've entered pounds when the aircraft is expecting KGs, or something like that.

[JRSchiphol 0]

Well I am not going to land with full fuel of course. I give it like a random number  or put the fuel on short range. Should be enough. And my VREF is around the 137knts at that point. But it gives me a warning when under 140. Which is weird cuz I am not in a stall at all. It just gives the sound when I am in the red lines at the speedindicator.

 

[FLEX1978 373]

Well if you are below minimum maneuvering speed and into the red band (minimum speed) then you will get the stick shaker. As Kyle has pointed out something is up with your weights and your calculated Vref.

 

What is the actual Vref displayed on your PFD? And no you won't be in a stall, a buffer is built in, you will be at stick shaker speed when you hit the red band, in other words start reacting or you will stall if speed bleeds of further.

 

Not much of a warning if it tells you once you are already stalled... One last thing to rule out the ridiculously obvious, you are using the correct flap setting for the calculated Vref?

[JRSchiphol 0]

The VREF is correct so it should be something else. Maybe because I am not really doing a complete flight but more like a circuit. I will test it out next week in a normal flight to be sure I am not doing something wrong.

I will let you know.

[FLEX1978 373]

Correct according to what? Vref & Vapp is calculated on weight and wind corrections, doesn't matter if you fly from Tokyo to LA or do a circuit around Gatwick.

[JRSchiphol 0]

What I always do is looking at the flap speeds in my Approach REF page. 30 is around 140 so I am guessing the landing speed will be something like that too. And it is. Cuz when going faster, I am getting a long landing. So I just guess something since I don't know (yet) how to calculate the VREF correctly.

You got any calculation for that? Or am I doing it on a sort of good way?
I am not a pro.. I agree. I just like to fly it and doing it the way I am always used to. And I keep learning every day. But this is something I have never had before. Probably because I don't know how to do it correctly.

 

[downscc 1,327]

Use the Vref given by App Ref page for given flap, assuming you have setup ZFW and CG values. Fly final approach at Vref+5 with the flaps at 25 or 30 and land at about Vref with power idle. Please don't forget the FCTM training manual. Lots of good info in there.

 

 

 

[scandinavian13 5,192]

 

 

You got any calculation for that? Or am I doing it on a sort of good way?

 

How about this:

Can you post a screenshot of your CDU with the PERF INIT page displayed, with the upper EICAS also visible?

[3-2-1-Now 126]

I just thought - you don't inadvertently have FS displaying TAS instead of IAS in the FSX options do you?

 

Best regards,

Robin.

[ericbgee 4]

It's a stall warning, not a stall indicator... if it went off after you had already stalled, it wouldn't be much of a warning...  lower the nose a little, give it a little gas, or continue to fly on the edge of stall... sounds like it's doing its job.

[lexsis 1]

I don't think this has anything to do with VREF calculations or weight issues.

 

If your calculated and inserted VREF is calculated by the FMC and this speed is used, than it should be correct. I think what Jrschiphol means is that the VREF is far in the red band while flying in a normal landing config. So if you try to get to your VREF or VAPP speed, you get all the warning bells that tell you you're stalling while actually you are not.

 

Regards,

 

Sonny A.

[FLEX1978 373]

it's late here and I'm not getting it Sonny, if his Vref is in the red band then it is a weight or Vref calculation error.

[JRSchiphol 0]

It is exactly the problem as lexsis says.

My VREF gets in the red band... but that is sometimes. But still...

 

And if it is a VREF calculation error... while an FMC must be correct about these values... You know where I am going to?

[Tabs 2,790]

Jonah,

 

Can you do screenshots of this please? Show the PFD and show the FMC PERF INIT and PROG pages please. We've been totally unable to reproduce this here so far.