Originally Posted by
misd-agin
^^ x2. 10,000+ hrs on the 757/767. I can recall at least 3 incidents of inadvertently activating the G/A switches in 15,000+ hrs on Boeing's with G/A switches. 'Click, click' to deactivate the auto throttles is the rapid response.
It's typically a non event because the FO, with their hand on the throttles, feels an uncommanded forward movement and physically restrains the thrust levers while using the push buttons to disconnect the auto throttles.
And, in my observation, even if you leave the autothrottles engaged it's easy to overpower the automation and pull the power back manually. At 6000 feet the plane hand flies just fine so if you went up off altitude just pop off the autopilot and ease back down. Would selecting FLCH also bring you back to the altitude in the window? It probably would but there may be some inhibit above 2500 feet RA with flaps out in G/A mode on alternate Thursdays etc. So just pop off the automation and make the plane do what you want then 'Autopilot Center to Command' to recover from the inadvertent go-around switch activation would be my suggestion.
Some folks would have their hands on the throttles at 6000 feet with the autothrottles and autopilot on, others would not. I've seen it done and taught both ways.
In the docket file of interviews starting on page 305 an Atlas FO recalls a possible earlier automation glitch incident with the accident aircraft.
3 Q. Okay. Tell me what it is you want to share with us. You had
4 some information about the accident airplane.
5 A. Well, I don't know if it does. The -- I had an incident
6 coming out of Stockton on -- and I'm not actually sure that it was
7 that date. I think I believe it is. It very well could be --
8 Q. What date are you talking about?
9 A. 11/2 of '18.
10 Q. Got it.
11 A. And I had a incident coming out of Stockton on one of our
12 aircraft. It was -- we departed there in the middle of the night
13 it was 0730Z VFR and normal departure. It was heading off
14 departure with a climb -- a left climbing turn to 7,000 feet and
15 when we went through 1,000 we engaged the center autopilot and
16 somewhere before 2,000 we got a Flight Director command full down,
17 nose down. And the airplane tried to start leveling off and I
18 disengaged the autopilot, hand flew it, we reset the autopilot in
19 the climb out and it was all systems were normal after that.
20 And we did not do an FTR on it. We just took it as a anomaly
21 of the autopilot and it reset and we just continued on.
22 And I can't say if Laz, the guy I was flying with, remembers
23 the incident, you know, if we could verify that that was one
24 hundred percent it but when I was looking through my logbook I was
25 like, “Oh, that's -- that tail number was on that flight.” So it
1 just kind of concerned me.
2 Q. Okay. So when it nosed over did you happen to notice what
3 the flight motor enunciator was telling you at the time?
4 A. I do not.
5 Q. Okay. And was it a hard over or was it just trying to level
6 off and kind of go to a normal reduced pitch?
7 A. No, it felt like it was pushing over and I'm sure that the
8 command bars being all the way as far down as they could go.
9 Q. Okay. And when you reengaged --
10 A. I wouldn't say it was so abrupt -- it wasn't so abrupt like
11 it was trying to push us out of our seats or anything but it was
12 definitely heading into a pretty good dive. But -- and, you know,
13 we kicked the autopilot off, we kept flying the airplane and, you
14 know, corrected it but it was, you know, very noticed, very
15 pronounced.
16 Q. Okay. When you reengaged the autopilot do you reengage that
17 second or the center autopilot?
18 A. Yes.
19 Q. Okay.
20 A. We reengaged the center autopilot.
21 Q. And anything happen after that?
22 A. No. It was Flight Director was all normal, everything was
23 normal. It flew all the way to CVG with no problems.
24 Q. Okay. Was this written up in the logbook?
25 A. I do not recall.
1 Q. Okay. Any irregularity reports or anything like that filed
2 in conjunction with this event?
3 A. No.
4 Q. Okay. And how certain are you that this was 1217 Alpha?
5 A. I would say really only talking about 80 percent. If Laz
6 cannot verify that he was on that and that was the -- then I would
7 have to look elsewhere but it was -- I'm about 80 percent sure
8 that that's what it was.
9 Q. Okay. You said earlier it was pushing over toward a dive.
10 It never got into a dive or did it actually start to descend?
11 A. It started to descend. We went -- it -- level come off
12 immediately and it started to descend down and we probably got a
13 little bit vertical descent and immediately kicked off and
14 reinitiated the climb.
15 Q. Yeah. I'm trying to visualize this so you turned the
16 autopilot on during the climb then it started to level off and
17 then it continued past the level off into a descent before you
18 disconnected the autopilot. Did I get that right?
19 A. Yes.
In the preamble to this interview conducted over the phone the FAA disclaimer mentioned in my earlier post is given.
19 MR. LAWRENCE: Okay. Oh, by the way, FAA is in the room
20 here. They're a representative on our group but they're not here
21 for certificate action or anything. It's just like a safety --
22 this is just a safety investigation, okay. Just to let you know.
23 MR. ANDREWS: Right.
24 MR. LAWRENCE: Okay. Cool.