Autothrust with Autopilot OFF

[HAMFAN73]

Please excuse a question from a piece of SLF.

I have a question about autothrust use at landing, specifically the policies of its use with EasyJet versus those of (I believe) Lufthansa.

Re. the (late) Capt. Warren Vanderburgh, -- in his masterful lectures for American Airlines in and around 1997, where he legendarily references ‘children of the magenta’ in the context of ‘maintaining flying skills’ – in this he explains the virtue of flying with autothrust/autothrottle off, when flying with autopilot disengaged. His reasons for this practice seems to make abundant sense, even to this non-pilot.

My question is this: accepting that what he propounds is good airmanship, how does this square with use of autothrust (bringing the added benefit of Ground Speed Mini) on approach, in good visibility at the point where autopilot is disconnected? When he gives his advice, do you suppose that he is talking about other stages of flight (perhaps excluding the cruise), as opposed to approach to landing? Or is he advocating that whenever the autopilot is off, then so should be autothrust (presuming we are in an Airbus)?

I think I read somewhere that Lufthansa mandates autothrust off in manual flight, but I don’t believe this is the case with all airlines? So, following the wise words of the late Captain and acknowledging that Lufthansa know exactly what they are talking about too, does this mean that, for example, on an approach with gusting winds, a Lufthansa PF should disconnect autothrust (and so disable Ground Speed Mini*) because this is SOP, whereas an EasyJet PF will leave autothrust engaged?

If so, which airline’s policy is better airmanship or doesn’t it matter?

I pax short haul across Europe most weeks, almost always with EasyJet, so A319/20, and accordingly have enough time to be curious!

With thanks for any insight.

*I am unclear whether Ground Speed Mini existed in 1997?

[AerocatS2A]

Airbus recommend using auto thrust when manually flying. The children of the magenta line lecture was by a 1990s Boeing pilot to 1990s Boeing crews. Different philosophies from different manufacturers.

Ground speed mini is an Airbus function and is not tied to autothrust. There is nothing preventing a pilot from using manual thrust and targeting the speed bug which may be influenced by GS mini. In other words, you are incorrect when you say “disconnecting auto thrust disables GS mini.”

Where I work (A320) we leave auto thrust on unless it’s not working adequately or we feel like turning it off for practice, most pilots leave it on for most approaches.

[HAMFAN73]

AerocatS2A

Many thanks indeed for your reply and explanation which clears things up nicely for me. Appreciated and my curiosity is duly satisfied. Tks again.

[FlightDetent]

You have LH who presumably suggest A/THR off with manual flight.
You have BA who presumably mandate A/THR on at all times.

Go figure.:ouch:

Since this question is on the use of A/THR in particular, it is worth noting that your understanding of GS mini being lost without A/THR is a gross error. It's just an (automated) speed bug on the dial. No harm done, but uncovering how this mistake happened during your research might unearth a few more.

Take care, feel free to ask.

[safetypee]

AerocatS2A, #2
An alternative origin of CofML was that it was an AA specific video with the introduction later series of MD80 aircraft with FMS and uprated autopilot / auto thrust.
The message was ‘Click Click’, do not over-rely on the automatics, disconnect the automation if situations became confusing. Unfortunately it failed to answer how crews were to identify such situations.
Subsequently the video and phrase has been mis quoted in several areas relating to flying skills and automation, generally out of context and without further justification.
The phrase was used, possible originated by Don Bateman of GPWS fame, re pilots’ over-concentration on the EFIS track line (Magenta).

Re auto throttle in manual flight, autopilot off. Many older automated systems were not well integrated, thus some auto throttles would hunt about the set speed or be out of phase with pilot flight control inputs; mild pitch instability.
Depending on system design, many shortfalls in older systems were tolerated because the overall workload in manual flight with auto thrust was perceived to be lower; arguments continue as the truth of this and need for more practice with everything off.

New generation aircraft have much improved levels of automatic integration, applying to manual and autothrust operation; thus the ease of flying is generally unaffected, and the perceived lower workload - having to think about speed control, is argued as a benefit.

Alternatively … the debate continues re effect on flying skills

[HAMFAN73]

You have LH who presumably suggest A/THR off with manual flight.
You have BA who presumably mandate A/THR on at all times.

Go figure.:ouch:

Since this question is on the use of A/THR in particular, it is worth noting that your understanding of GS mini being lost without A/THR is a gross error. It's just an (automated) speed bug on the dial. No harm done, but uncovering how this mistake happened during your research might unearth a few more.

Take care, feel free to ask.

Thank you FlighDetent. Yes, I had entirely misunderstood GS mini and goodness knows what else. I have since found a thread from back in 2010 where Norman Stanley Fletcher's explanation (plus your contribution and others') neatly explains things clearly, so I have learnt --if not entirely understood-- a lot.

I note, also, that I have conflated too separate issues: #1: being differing policies between airlines as regards A/THR use in manual flight and how this may relate to manually handling skills, and #2: GS Mini being a standalone Airbus aid to help manage the relationship between energy/TAS/IAS/VAPP. In the cae of 1#, the fact that Airbus 'recommends' something, but that some airlines interpret this recommendation differently, is something that a binary soul like me struggles with. Nevertheless, as I inform myself more and more on this website, so I come to understand that many things are open to interpretation in aviation! It seems paradoxical sometimes but I guess that's the nature of the beast.

My questions arise --with limited understanding but unlimited curiosity-- as to how pilots manage energy on approach in gusting winds. Goodness knows how many times I have sat there in seat 3C, listening to engines spooling up and down on approach and then, hearing the noise of the autopilot disconnect, wondering how a pilot can simultaneously keep one eye on IAS (which engine noise suggests is fluctuating significantly); manage thrust (or not if A/THR engaged -- hence the question) to maintain VAPP/VREF; stay on the glide-slope/glide-path....and at some point look up and out at the PAPIs, assuming they are there. Anyway, all I can say is that on a winter's day in a howling gale, it's pretty impressive from a PAX perspective.

Thanks for your patience and explanation.

[FlightDetent]

The main instrument cluster is arranged in a characteristic T-shape, the artificial horizon and its airplane pitch reference being at the joining point. The proper instrument scan, trained the same everywhere, is to focus the attitude indicator and jump to the other ends of T but always coming back. Google for the term.

Pitch(centre) - airspeed(left) - pitch(centre) - heading(down) - pitch(centre) - altitude(right) - pitch(centre). For the daily ILS approach, the LOC deviation scale is conveniently placed low, close to the HDG information. Likewise GP and VSI to the right, near ALT.

This applies as well if you need to take your eyes and/or mind somewhere else, such as the engine instrument, ATC command or co-ordinating gear/flaps with your colleague and reading/responding to checklist. Perhaps at the very late stages when visual, you'd go Speed(left) - VSI(right) - runway outside(up) - heading(down) - speed(left) - VSI(right) - runway outside (up). That's a solid base for an approach at reduced visibility and crosswind. Whenever I make a mess of the flying on a demanding day, it is most likely for not keeping spinning through these loops due to distractions and lack of trying.

-> POINT 1 - know what's going on.

Gusting winds. If you dumped a large barrel of rainwater across the front yard you could see the whirls and uneven speed of the flow, but in general, the water is moving in a well understandable motion. Same for the wind. What we call gust are just protuberances in the flow of air, magnified by the effect of orography. Google turbulent layer flow. The message here is that while it is very dynamic at times, the whole movement of air is somewhat sustained and if you work STEP 1 above well, you can read through it. Once a gust knocks you off the perfect ILS alignment surely the second will not put you back, but it is doable. Like riding a friends bike for the first time, or arguing with a kid who doesn't want to go to school. Keep calm and manage.

-> POINT 2 - It's not beyond average ken, although learning is required. Exposure with attentiveness create experience. Experience with honest work and talent create skill.

Another cool buzzword is to stay ahead of the aeroplane. Applied here it means to sequence the tasks and try to finish them one by one before a need to deal with the next becomes imminent.
(*)
Level off, maintain altitude.
Join the localizer, establish the necessary offset heading.
Some flaps out and perhaps the gear too before the Final Approach Point.
Shove the nose down when glideslope arrives, check your speed and reduce/increase thrust for Vapp
Memorize your stable parameters (drawing on previous experience a lot)
When a gust arrives, correct the displacement with thrust and pitch for speed/GS deviation or with bank for tracking error
Come back to the stable parameters, perhaps re-aligning the sights a somewhat.

-> POINT 3 - Work with small and well-defined targets, allowing no single one to escape too far. The effort of correcting a large deviation will have the cost of some other parameter running loose. And even if you manage to notice, the capacity to contain multiple at the same time is very small. It is a sliced multi-tasking, imagine herding sheep to pasture.

-----

Over the years most of this becomes second nature and moves to the subconscious. When the image of perfect ILS alignment burns itself to the back of the skull, low-level brain functions will alert you to a deviation and gut feeling slowly develops.

(*) = this is not how we fly on the line. It would be overly conservative, slow and costly. With the active A/P following a pre-programmed trajectory, A/THR for the speed control and your colleague who scans and thinks in parallel, we even target multiple things happening at the same time for effectiveness, to conduct ourselves professionally. But any time you'd be left to your own personal resources, for instance when all electrics die in the SIM and you only have the engines and few battery-powered instruments to go with, that is EXACTLY the only recipe for success. Not sure if I had mentioned this already: Keep scanning, keep scanning and then keep scanning. :D

Cheers.


Last word on GS mini, the most overcomplexized tool of Airbus aircraft, and such a simple one in reality.

During the final descent, you carry a bit of speed additive on top of your approach speed - a wise man would anyway. The size of that additive equals to the headwind component you are going to lose between what's now and the threshold. GSmini is a cryptic name for = (automatic) approach speed additive against a headwind loss at landing.

[HAMFAN73]

Thanks so much for that FlightDetent. Fascinating and informative in equal measure. Your time explaining much appreciated!