Flybe AP has a 'Plummet' Mode?
 

As I was only an occasional inhabitant of the Pointy End during flight my knowledge of Autopilot setting is limited to what I had to do to 'fly' the lab in Everett but I don't recall being able to set 'Plummet' mode?
(Edit - looks like the Beeb have decided 'drops' might be better than the original 'plummet' - they could be right but descends could be even better?)

BBC News

As it is reported that the pilot responded to the alarm and disconnected the autopilot = Job Done! OK, there was an error of setting but, despite an uncomfortable dip, the pilots flew the aeroplane. Another useless media item picking something from 11 months ago. However, as if warning were needed, every carrier has to be ready with the correct story and to present it quickly and fairly.

Hmmm. At 1100 ft AGL, ROD was 4300 fpm, one can perhaps understand the BBC's choice of words, however misguided.

Picking up something from an investigation report released a few hours ago.

Mistake was made, very little actual risk unless pilots were asleep, looks good as a headline. Nothing to see here.

The AAIB thought there was something to see!

https://www.gov.uk/government/public...-november-2018

Direct link to Hi-Resolution pdf
https://assets.publishing.service.go...018_Hi_Res.pdf
30MB file. Low res one does not display diagrams well.

DHC-8-402 Dash 8 G-ECOE 11-Jan-18

IMC, autopilot configured and then selected so that aircraft would crash into the ground/sea in 54 seconds unless corrected by crew. Crew oblivious until ...

EGPWS warnings alerted crew who reacted with 36 seconds to spare. Airspeed had been 163 KIAS in climb and reached 235 KIAS in unplanned and unexpected descent. [these times are too generous. Less time was actually available]

After recovery they tried AP again with same settings.

Hardly a benign little excursion I wouldn't have thought.

https://cimg5.ibsrv.net/gimg/pprune....4318582961.png

ALtitude curve interesting

SLF here so please excuse if these are dumb questions - but why is there not some sort of sensible minimum altitude for the autopilot? And why isn't the EGPWS connected to the autopilot to disconnect it or override it and start pulling up?

"Staff reported that the plane had become visual with the ground."

In much the same way that a drunk becomes visual with the ceiling?

"Staff reported that the plane had become visual with the ground."

OMG Johnson! Did you see that? There is a ground underneath us!

For takeoff the Flight director in the Q400 is set with the Vertical Mode ; GA (Go around) and the lateral mode HDG SEL (heading select). Further the assigned altitude for departure is entered with the ALT SEL (alt select) mode armed. In the Flybe case the crew forgot to input the assigned altitude and left it at 0ft. When they armed ALT SEL the flight director captured the assigned altitude of 0ft (as the aircraft was already at approx 0ft) This meant the vertical mode was in ALT. (i.e. the autopilot had been programmed to maintain 0ft. When the autopilot was engaged after takeoff at around 1600ft the flight director pitched down to returned to its assigned level of 0ft. This comes down to basic mode awareness of what the flight director is commanding given the stage of flight.

IMC

So more like: came out of the cloud, realized pointing at the ground.

Every once in a while I encounter a discussion that's a false positive hit against the typical notion of the sensationalist clueless media, and this is one of them. Nobody minding the store while it's plummeting (yes, plummeting) at 4300fpm below 1500 feet, finally to be woken up by WHOOP WHOOP PULL UP. Yes that is indeed a serious incident, and all of you pooh poohing it should imagine yourself in that circumstance, on a dead head or commute! Still "nothing to see here?"

That aside, can you have active FD modes on the Q with the FD hidden? That's the only possibility I can see, that can explain this. If the FD was set in a mode captured at zero altitude, and showing the severe nose down command to achieve that, who in their right mind would engage the autopilot?

It was 15 seconds from AP engagement and beginning of the pitch down to the EGPWS and corrective action. Right now, get out your phone or kitchen timer or whatever is within reach, and start it for 15 seconds. As it counts, close your eyes and imagine flying and/or monitoring the airplane, right after the off, and imagine it continuously pitching down as it develops a 4300 fpm descent rate, over the course of 15 seconds.

Does that feel like "almost immediately?"

What purpose does routinely setting the MCP altitude to 0ft serve on the Q400?

I would guess that the last guy set it to zero after the flight, in an OCD fashion.

SOP, not OCD.

"The first sector was uneventful, and the aircraft landed on Runway 22 at Belfast City. While it taxied clear of the runway, the co-pilot carried out the ‘after-landing’ checks which included setting the autopilot selected altitude to zero."

Interesting...learning has occurred. Then I echo Fursty Ferret's question.

The reason we are given is statistically it is more likely that seeing 0000 in the altitude select window will make you put in the correct number than you correcting the last altitude with the altitude from the departure clearance, and taking off with the wrong altitude in the window would often lead to an altitude bust.
Taking off with 0000 in the window should really not happen, and taking off with the FD in ALT mode instead of GA should not happen, and engaging the autopilot while climbing out with the FD commanding full nose down and ALT hold displayed should not happen, and waiting till you get to 4000+ FPM descent and GPWS before you disconnect should not happen.
There were way too many pointers something was wrong and none were noticed.
I definitely agree with our company policy of resetting to zero, yes, this wouldn't have happened if they had left the last altitude in but they would most likely have ended up at the wrong altitude, and the amount of things that went wrong here makes not setting the altitude the smallest error in the whole debacle.

Question from a long-retired driver. Why?

See my answer to Fursty Ferret's question.

it's not a dumb question at all, I also fly Q400 and in our company the minimum AP engagement altitude is 1000 ASL.. that is the pure minimum and you only follow it if the wx or other circumstances are causing pain. For most of the times we hand fly it until clean and above. Before engagement of AP we have to make sure that your pitch and bank matches the one commanded by the FD, otherwise you shall not engage it. I can't imagine how come a PF can make a decision to engage the AP when the FD is actively pointing down in the brown. That is clearly noticeable and should be a big red flag

oh come on now, dare me asking how many hours you have on a Q400? I smell a lot of BS. The AP as in any other aircraft is doing exactly what you tell it to do. I agree that VNAV and RNAV bits are a bit hit and miss sometimes, but for more basic things, it works beautifully

this is a stupid SOP. Generally the altitude selected would be zero if you start it up from cold and dark. As par of a normal cockpit preparation we set the altitude 100 feet below the SID clearance. Then once the clearance is taken, the PF adjusts it to the correct one. It works out wonderfully because, if not adjusted, the altitude will stay at something like 3900 or 3400 (most SID altitudes are nice round numbers) and it stands out as an eyesore on the PFD and upon taxi/instrument check you immediately notice you haven't done something right. If it is set to zero - you have tinyzero on the PFD and it is easy to miss.

Avherald also says the crew were reading a checklist at 1300 and were not actively paying attention to the monitoring of the flight. In our company you can do it either above MSA or 3000ft whichever is higher. MSA in Belfast City is between 2900 to the north and 3800 to south. Both pilots should have full attention on flying the aircraft below that point, what are you doing with a checklist in your hand just 1000 feet after departure is beyond me

Just made a long post about the merit of setting 0000, and now think you might have me beat. All I can say is in my aircraft the zeros do stand out.

how is ALT SEL a big gotcha?
There is a very good reason why the speed bugs work the way they do, it allows for flexibility in airline SOPs
Can you elaborate what is the right screen that you get to see when pressing the sys button twice? I rather prefer hitting buttons twice on the ground to get to the page I want to see on the ground and only press it once in the air when I'm in the emergency, rather to do it the other way around.. Again, can I ask how many hours you have on the Q400 and what was your previous type? maybe habitation is causing some issues with you?

Hans. I see your point, but I have to disagree. Surely, setting the CLEARED ALTITUDE is part of the SET and CROSSCHECK. Sure, one pilot can miss it, but two?

The answer is really simple ... Routine + the fact the brain is really good to see what he want to see ...

How many accident / incident are due because people after doing the same check and SOP for few years, finally got a day : they think they did it, they looked at what to check, they did the call accordign to SOP but in fact they didn't see the selection / switch position ... was wrong.

You really need to force you to do the check and even we are all Human.
I remember in the SIM few years ago, after a go around, I did the check list, I had a look to the no light of the landing geea and happily called "gear up, light out", during the radar vextov I thought the plane was noisy but it didn't trigger anything in my mind, when PF called for gear down during the funal, I realized the gear was already down with 3 green, I then apologize, the captain and the trainer realised at that time the gear were down all the approach, 3 people in a sim ...

Now I agree with many of you, was a lot of possibility to catch the problems sooner ... When they did the taxi check list, was a check of the AP mode, when they lined up, was again a check of the AP mode engaged, I m sure they did the right call and I m sure when investigator asked the crew, they both remember all was fine and set as they called with GA mode engaged (plane was in alt mode on the ground)

What kind of dash 8 do you fly ? The NG ? Did the alt sel drop out if you touch the cobtcon wheel of autopilot while in alt* ?

I can guarantee you, if you press altsel with 0ft selected and the plane altitude near zero, plane will go to alt locked ...

Martin to clarify, you can arm ALT SEL below 1000ft. We regularly set 500ft ALT SEL on visual approaches as an SOP. But in this case it would not arm ALT SEL but go straight to ALT HOLD as the aircraft was already at it's armed altitude.

Ok, i see the confusion.

In your airline you select the SID alt minus 100ft then press GA, HDG and alt sel.

​​​​​in flybe, the alt is set to zero, clearance is taken then the PF should set the SID altitude, then press GA, hdg and alt set then calling it, PM should check it.
what they did was, they took clearance, then went straight to press GA, HDG, Alt sel then set the SID altitude, so when alt sel with the altitude selector at 0 was pressed, plane went in alt locked mode.
Then now have a FMA saying HDG and alt locked with the altitude selector set at the SID. So you won't have any alt warning and altitude amber ...

Ofc, the FD was showing a horizontal bat at zero pithc in the ground and not +8 degree with GA mode, thet could have spotted it on the taxi checklist and they could have spotted it on the line up check list (check list ask to call FMA mode), was no alt sel arm white at all so it could have been spotted ... then when passing acceleration altitude, they could have seen the FD showing a deep descent and could have spot it there ... We end up about brain is good to see what is used to see and disregard what doesn't fit in his idea of reality.

How you explain the Emirates 777 with 3 crew trying to do a go around with idle ? They were used to have go around power set by autothrottle ... Expect in that case autothrottle was off due to the plane touching rwy...
Or how explain the airbus A320 in "mont Saint Odile" in France, instead of FPA 3degree they selected VS 3000ft/MN, they then we're focused of why the plane was speeding up ? I do remenrem one of the crew convincing himself saying, oh we have little bit of tail wing and plane really light today .... Brain see what he want to see ...

I agree, mind can play tricks and if I remember correctly, Flybe use crosshair FD, while we use chevron type. I never liked the crosshair type, I think it can disappear from your perception too easily. Don't mean to start an AUDI VS BMW or PC VS MAC debate here, just my personal opinion

They have indeed the cross FD, no sure on the Q400 (not Ng) you can have the chevron ...

I m not an expert of the pro / con of each of them.
​​​

Martin and Flocks. I guess your bias depends on what you have the most experience of. 95% of my FD time is on crosshairs, and I never really liked chevrons. I guess someone with the opposite experience would say the opposite.

I once flew for an operator (in the USA) which had a mix of cross hairs and V-bars on the fleet. After a couple of weeks, you don't even notice.

A few separate points:

1. The question is still open: on the avionics in question, can you have active guidance modes with the FD hidden from view? Because my mind boggles at trying to imagine anyone - at any point along the automation dependency spectrum - merrily flying along in an initial climb with a visible FD commanding a pitch into the ground, and then engaging the AP in this state.

2. Prior to engaging the AP, if they were climbing with a visible FD pointing at the ground, I can easily imagine this (unfortunately). One of the aspects of the automation dependent culture is a taboo against not having the FD up, even if it's 100% inappropriate. I remember a sim session where we did a PRM breakout, and in the 90 degree turn away from the airport, (I was PF) I was turning against the FD, which was still commanding a turn back onto the localizer; and the PM was talking on the radio so I couldn't ask him to set it to heading and set the bug. So the FD at that point was counterproductive (i.e., worse than useless) so I reached up and turned it off to avoid the distraction. I got scolded for doing this. Yes, in the instructor's absurd conception, it was better in the interim to have it up and pointing the wrong way than to turn it off. "All available resources," right? :D:ugh::{ (Imagine explaining this scenario to the inventor of the FD.) So if this crew had gotten flogged in the past by instructors in a culture like this, I can certainly see how if they bungled the settings before takeoff, they would have felt more comfortable having a wrong-pointing FD than not having one.

3. Once they engaged the AP and were in (ahem) "plummet" mode, I wonder if they spent those 15 seconds distracted away from noticing the plummet, or were in the often-fatal "what's it doing now" conversation.