Hi, I've been playing around with SE Flap 15 landings and I've noticed that the GPWS doesn't give a 'TOO LOW FLAPS' warning even if we don't inhibit the GPWS flap warning. Should we not get that warning with less than flap 30 or 40 selected?

 

Now OK, the training manual says that flaps 15, 30 and 40 are 'normal' settings for landing. But the QRH tells you to move the flap inhibit switch to inhibit when doing a flaps 15 landing. Why does the QRH have this action if a flaps 15 landing doesn't generate the aural warning normally? A possible minor bug?

 

Flaps 1,2,5 and 10 all generate the warning....

 

Really looking forward to the FS2Crew Emergency NGX now...

 

Adam Turley

We do flaps 15s in the real plane and we do have to move the switch to flap inhibit. As I understand it you should get the warning at flaps 15 but since we always use flap inhibit we never do. Our company operating manual doesn't actually say at which specific flap settings you will get the warning. It just says landing flaps.

I was not able to find anything on this either. And we always use the switch as well so I never tried landing with F15 without using the flap inhibit switch.

If it is indeed modeled correctly in the NGX could the reason be for a possible go-around. To avoid the warning when going from flap 15 to flap 1, in a SE go-around?

This doesn't really make sense though because you still get the gear warning aural...and that has priority over the flaps warning anyway.

 

Adam Turley

I got this confirmed now. If you do not use the FLAP INHIBIT switch during a F15 landing you WILL get the aural warning.

Thank you for looking that up Kristian, it makes sense for it to work that way.

 

Has Robert or someone else from the dev team seen this thread? Could it go on the SP2 list if it isn't already. I know it's minor for most but simulating non-normals is great fun and little errors do stand out in an otherwise superb representation of the NG.

 

Adam Turley

I haven't tested this in the NGX but if it's not working correctly, I agree it should be fixed with SP2. :-)

The mode 4B is the "too low flaps" message given by the EGPWS in case some conditions are met (landing gears down, low speed under 159kts, 245fts, 1000fts at higher speeds.

Over that the message becomes too low terrain.

Other functions uses the flap input, all of them uses >= 30 as landing flaps on 737.

The inhibit function will give a discrete signal to the computer to tell it that the plane is using landing flaps.

I hope you're not confusing with the aural warning wich is completely indipendent.

 

Other modes that use Flap position:

Mode 2A

Mode 2B

Mode 3

Mode 4

Mode 7

All of them will trigger voice messages in different low altitude conditions.

Forcing it to flap down will activate or disable some sounds.

Excellent, thanks Andrea!

Yes, it SHOULD give you the Warning

The simplified logic is:

The GPWC will know that you're landing by the use of flap position, gears, altitude, speed, glideslope and rate of descend.

For the computer only flap 30 and 40 indicates landing this activating or disabling some messages.

One of them ofcourse is the "too low flaps".

As the procedure tells that flaps 15 landing is possible, the GPWC without an inhibit will not know that you're landing, or will know it only partially. Some messages will be different, some others will not be played. This changing the warning logic to the pilots and possibly confusing them in case of low visibility.

Switching to the inhibit position will do the same as putting the flap lever to 30 or 40 units in terms of gpwc computation, this means that the aircraft will know that flaps are ready for the landing, if aircraft is in a landing condition and other conditions are met, the gpws will trigger other messages that are not avaiable with a non landing config or it will play the same sounds but at different altitudes, speeds, rates.