reported earlier 3PTS Landing Grades - Why the pitch down just before touchdown?

[Stearmandriver]

Hello,

 

This has been raised many times, but mostly in the Supercarrier bugs forum, in the context of incorrect LSO grading.  It was recently (in the past few days) dismissed as "correct as is", because it was determined that the LSO correctly issues the 3PTS critique when the approaching aircraft's pitch attitude drops below a certain value.  That seems completely reasonable to me.

 

...Which is why I think it's time to look at this from an aircraft-specific standpoint, instead of a Supercarrier standpoint.  The Hornet DOES pitch down by itself just before touchdown.  Take a look at this short track I've attached.  Pull up the controls indicator, and pay attention to these two things as we cross the ramp:

 

1.  Just before touchdown, the aircraft pitches down several degrees.  Watch the waterline symbol on the HUD; it drops from 5 degrees nose-up to about 2.5 degrees nose-up, almost instantaneously.  At the same time, the AoA indexer switches to a "fast" indication.

 

2.  On the controls indicator, you'll see no control inputs that could cause this.  There is no longitudinal stick input at all, and no throttle reduction that could cause the nose to drop.

 

I believe that this unexplained pitch-down is what's causing the 3PTS landing grades.  The Supercarrier LSO is correctly grading flat landings.  The question is: why do they occur?  Most of us have figured out that to avoid the 3PTS and EGIW landing critiques (which typically push you into a Cut pass grade), you have to make a significant power ADDITION just before touchdown whether you need it or not, in order to counter this pitch-down.  If you've got a stable pass going, this unnecessary power addition pushes you high... thus you end up choosing between a properly-flown but incorrectly graded pass, or a 4 wire in search of a better grade.

 

Could one of the community managers run this by the team?  Specifically, if this is intentional, what aerodynamic or FCS phenomenon do they believe they're simulating with this pitch-down?  I've never flown a jet that did this.  The two former Hornet pilots (one of which was also an LSO) that I've run this by claim that of course the Hornet doesn't do it either.  So... what is it?  Why does it happen?

 

Thanks!

3wireC.trk

[BIGNEWY]

Hi,

 

I am going to mark this as reported earlier, we do have some touch and go issues that will get tweaked soon. My best guess currently is that this is related. 

 

I will show the team and see what they say.

 

thanks

[Stearmandriver]

Thanks Bignewy.  Just to clarify: this behavior occurs with every touchdown of the plane.  It's not touch n go related. 

[BIGNEWY]

Yes but I think there is a pull down of the nose, it looks related to me. 

 

The team will know for sure. 

[Mistermann]

Adding my support for this to be fixed.  Here's a thread that I started the other day with some tracks and research ...