Engaging FLCH on the ground

[Hardy Heinlin]

Last time you checked FLCH did engage. Just the A/T didn't engage.

[Britjet]

Yes, you're right. It did. Hmmmm.
Recheck required..
Peter.

[Hardy Heinlin]

Have you been in a different* 744 sim? Are the 744 sims all identical, equipment-wise?


* English lesson: "different" or "another"?

[Britjet]

One of the 4 sims is usually configured as a GE for third-party work. The others are standard BA config.
I will check back and see which one I was using last time. I try to avoid testing on the GE sim though..
Edit - just checked. They were both BA sims.
It is probably something I did - I am working like a one-armed paper-hanger when I do this, trying to keep the aircraft right way up with a beginner flying it, answering questions about one thing while talking about another, trying a test agenda while allowing them free rein - it's a madhouse! Not an ideal test situation :-(
Peter

Ps edit - either...:-)

[John H Watson]

FLCH didn't engage?

Do you mean THR didn't appear on the FMA in the A/T slot? Or FLCH SPD didn't appear in the A/P vertical slot either?

[Britjet]

Nothing happened at all. I will retest it when I next get chance.
Peter.

[Will]

I'm sure it would be an unacceptable violation of the students' privacy, but were it not to be so, then you could stick a GoPro digital camera to the ceiling and record the session. Alas...

[John H Watson]

Nothing happened at all. I will retest it when I next get chance.

Much appreciated. This doesn't quite align with my real aircraft tests. FLCH was shown on the FMA and the pitch bar responded (but the engines weren't running).

[Britjet]

Tested again today on BA sim. As per my originsl post.
Aircraft set up on runway for departure, with 6000 in ALTSEL. Flaps 20.
FLCH SPD on vertical mode. No autothrottle engagement.
Peter.

[Will]

Thanks, Peter. That's starting to sound pretty conclusive.

[John H Watson]

Re FLCH, you didn't happen to notice the pitch bar did you, Peter?

[Hardy Heinlin]

As usual, it most likely commanded maximum nose down in order to increase the airspeed above 30 knots :-)


(It also does so when engaging V/S and setting -8000 fpm. I just noticed in version 10.0.9, when on the ground, the FD bar won't go below 0° if the new option "IDLE on non-autoland" is selected. This is an unwanted side effect. But it's just cosmetics.)

[emerydc8]

I just noticed in version 10.0.9, when on the ground, the FD bar won't go below 0° if the new option "IDLE on non-autoland" is selected.

Not even cosmetic if you don't use that option. Thanks, Hardy.

Jon

[Britjet]

The pitch bar - sorry - yes, it moved to zero pitch.
Peter.

[Hardy Heinlin]

Not to -15°? Are you sure? Surely it moved down from the TOGA +15° position; perhaps it moved further down below the horizon? I think I once saw -15° on a Qantas aircraft :-)


|-|ardy

[Britjet]

Definitely zero.

[John H Watson]

That's a worry... That's one of the methods we used to check the A/P after we replaced an FCC. Engaging V/S (from TOGA) V/S = 0000 (synching with current V/S)...  pitch bar goes to zero.  V/S down, pitch bar down. V/S up, pitch bar up. With hydraulics engaged, the column moved in the direction of the bar.

[Hardy Heinlin]

Maybe FLCH is different to V/S regarding the ground test? Peter tested FLCH, not V/S.

[Britjet]

I'll try VS next time I'm in.
Peter.

[John H Watson]

Maybe FLCH is different to V/S regarding the ground test? Peter tested FLCH, not V/S.

My mistake.. I thought the topic had switched to V/S.

As per the video I posted earlier (on a real aircraft), the bar does go down with FLCH on my old airline. This applies whether the MCP altitude is above or below the aircraft altitude (with airspeed zero and engines off)