'Too Low Flap' on every landing in the A300v2?

[CJ_Reed]

Hi there, In my first few flights in the iniBuilds A300v2 I find I'm getting the 'Too Low Flap' playing during every landing (after disengaging the A/P and A/T from a single channel ILS approach at around 1000ft) the 'too low flaps' audio always starts playing at around 100ft and I wonder if there's something specific I might be missing.

The Approach page in the MCDU is filled-out, Gear is down, Autobrakes set to low, Speed Brake armed, Flap lever set to '30/40' and GPWS Landing Slats/Flaps Switch is set to '30/40'

It seems that on the flap indicator, the white stripes don't go right to the bottom though, is that normal for full slats/flaps?

Also Vapp is within the 'hollow red area' of the speed tape, which seems to suggest the flaps might not be fully extended, despite the lever position (above).

But, Just to check - does the asterisk next to the 15/20 on the Approach page mean that the 30/40 is selected; or does the asterisk highlight the selected flap mode? It seems convention in the MCDU is that an asterisk is used to identify a 'selectable' item, not a 'selected' item.

Any ideas or insights would be greatly appreciated.

Many Thanks,

Chris.

[CJ_Reed]

bump

[jaybird]

On 5/29/2022 at 3:32 PM, CJ_Reed said:

 

But, Just to check - does the asterisk next to the 15/20 on the Approach page mean that the 30/40 is selected; or does the asterisk highlight the selected flap mode? It seems convention in the MCDU is that an asterisk is used to identify a 'selectable' item, not a 'selected' item.

 

I was confused about this also, but finally discovered that the asterisk is NOT what is active, its the alternative 🙂 From your description I'd say you need to keep lowering your flaps. You know, in spite of having documentation, it's the little details like this that don't get explained, just one among many such things.

Still I do love flying them 🙂 Cheers,

 

[Sam]

Hello @CJ_Reed,

Could you confirm, as Jay mentioned above, during your landings, is the asterisk next to the 15/20 setting or 30/40 setting?

[CJ_Reed]

1 hour ago, Sam said:

Hello @CJ_Reed,

Could you confirm, as Jay mentioned above, during your landings, is the asterisk next to the 15/20 setting or 30/40 setting?

hi there, I confirm the asterisk is next to the 15/20 setting.

In later airbus systems the asterisk is used for an unselected option which can be selected (i.e. the A32x MCDU APPR page LDG Conf:

"FULL" and "CONF 3*" when Full is enabled)

(e.g. symbology on the APPR page fo the A32x MCDU)

Also the Flap lever in the sim is fully extended, and speed was below 160knots (in case the A300 has some kind of 'flap load relief' system).

Many Thanks,

Chris.

Enjoying the Vintage Airbus experience (as a child of the eighties) 

P.S. As a workaround, is there a way to inhibit these GPWS warnings in the inibuilds A300/A310?

Edited June 17, 2022 by CJ_Reed

[Cammac]

Hi, 

Thanks for the post.  It seems strange what is happening and I can only think of a few things that might causes it.  But to start with I will go over some logic for the A300/A310 when compared to the A320 as with the flaps and VAPP it's not quite the same. Selecting the flap setting in the FMS will change the target VAPP but that's all it will do. As you need to of course set VAPP yourself manually in the A300. Like the A320 family you need to tell the GPWS that you want to do a reduced flaps landing and need to set that switch to either 30/40 or 15/20. But from your original post I can see these are set correctly. 

You mentioned that the approach speed is always in the red band? Is it possible to show an image of the PFD and the cockpit when on approach when you have these issues? As this might give me more of an idea of what the aircraft thinks is going on. 

Another suggestion / idea which I think is the most likely cause. How are you setting your flaps? Is it with a key command or an axis. If you are using an axis this might be setting the handle to 30/40 but the flaps in the flight model might not actually be coming down to match this. If you are indeed using an axis please try using key commands and see if the issue comes back. 

Finally as mentioned if your speed is above 160kts below 1000ft you might trigger the GPWS warning as that is right on the edge of the envelope for stability. 

Many thanks, 

[CJ_Reed]

Hi There, Many Thanks for getting back on this issue I'm struggling with. I tried it again earlier this week and got the same behavior.

The speed is below 160knots when descending on the G/S; in the most recent occasion (Toulouse ILS 23L, LDG WT:136.4t) I was stable at 164knots, Flaps 15/15 tracking the LOC at 3000ft . Then one dot below the G/S, selected gear down, reduced MCP Speed to vAPP (138) and extended the flaps to 30/40. I disengaged A/P and A/T at 1000ft. The 'Too Low Flap' call was starting at 300ft AGL.

I did notice the green bar on the speedtape on the PFD didn't reduce from 164kts to vAPP (138kts), which does suggest a flap extension issue, even though the lever on the pedestal (in the sim) was in the 30/40 position.

I use a Saitek quadrant and that has a 'keypress detent' at the bottom end of the Flap axis; so I wonder if reaching that portion of the axis stops the flaps extending to full.

I'll certainly try removing the axis and using key commands to raise lower flaps on the next flight.

BTW is there a dataref which could I could monitor to validate what the actual current flap setting is? It would be helpful to have that reading in view when troubleshooting in the pattern.

Best Rgds,

Chris.

[CJ_Reed]

Using the Default Flap 'handl' & 'postn' datarefs, here are the axis readings I see on a ground test:

                  handl        postn         

Flap UP:       0.000     0.000

Flap 15/0:     0.2694  0.2694

Flap 15/15:   0.4843  0.4843

 Flap 15/20  0.7618  0.7618

Flap 30/40 0.9472  0.9472

So flap position IS being moved to the selected flap. Which suggests it isn't the axis causing the issue.

[CJ_Reed]

Using the keyboard, instead of an axis, I get:

                 handl        postn         

Flap UP:       0.000     0.000

Flap 15/0:     0.2500  0.2500

Flap 15/15:   0.5000 0.5000

 Flap 15/20  0.7500  0.7500

Flap 30/40 1.000  1.000

So it seems like it might be a response curve issue, do folks use a linear response for the flap axis, or you you use a 'stepped' response curve?