Smart throttle

[tcasblue]

A single throttle lever that controls both engines with reverse thrust and airbrake controls integrated into the lever.

This is what the Falcon 10X will have.

[dixi188]

WHY?
If it ain't broke, don't fix it.

[tdracer]

I foresee a problem complying with 25.903(b):(b) Engine isolation. The powerplants must be arranged and isolated from each other to allow operation, in at least one configuration, so that the failure or malfunction of any engine, or of any system that can affect the engine, will not -

(1) Prevent the continued safe operation of the remaining engines; or

(2) Require immediate action by any crewmember (https://www.law.cornell.edu/definitions/index.php?width=840&height=800&iframe=true&def_id=d3d24a831020443b5f202a681f24e446&term_occur=999&term_src=Title:14:Chapter:I:Subchapter:C:Part:25:Subpart:E:S ubjgrp:103:25.903) for continued safe operation.

With a single lever, how will you provide isolation for a failure or jam of that lever assembly?
It would also make intentional asymmetric thrust rather difficult (such as setting a malfunctioning engine at idle to provide electric and hydraulics, while actually flying the aircraft with the other)
As dixi notes, what problem are they trying to solve?

[Private jet]

dixi188

The same could be said about living in a cave I suppose...

[Moo Driver]

Or having someone in a control tower

[Private jet]

tdracer

On the aircraft type I used to fly there was a "sync switch" that would make one of the thrust levers the controlling one and you could move the other anywhere and it makes no difference, same principle can be applied here.

[tdracer]

Yea, but that's with two levers.
What we are talking about is:A single throttle lever that controls both engines with reverse thrust and airbrake controls integrated into the lever.
So there is nothing to separate...

[Check Airman]

WiFi reception will be bad in caverns without a router. That’s reason enough to not live in a cave.

[Private jet]

tdracer

lol. I'm sure it will be thought through though, with reversion and abnormal procedures in place..

[Pugilistic Animus]

They've lost their minds again.

[ScepticalOptomist]

Private jet

Why would that be useful? Most of my time is on heavy twin jets, and I don’t know why I would want that setup?

[tdracer]

Private jet

So, like the original implementation of MCAS :ugh:

Aside from falling afoul of the regulations - in addition to the 25.903(b), there is 25.901(c) - no single failure shall result in an unsafe condition (at best, it's going to require an "Equivalent Level of Safety" finding), I fail to see any advantages aside from a slight reduction in manufacturing costs. OTOH and can see numerous drawbacks.
What problem are they trying to correct?
We moved out of caves and into buildings because it was a better solution. I fail to see how going to a single thrust lever for a twin engine aircraft is in anyway a better solution.

[Check Airman]

What problem would this new setup solve?

[megan]

Dassault have experience with the system through the same set up in the Rafale fighter. Details are elusive, other than this comment from a pilot report.Taxi speed is easily controlled, because the residual ground thrust is limited by keeping both "mini-throttles" (acting as low-pressure cocks) in the "idle" position before setting them to "normal" for take-off

[stilton]

In a single seat fighter I suppose there’s some rationale for this gadget


In a civilian biz jet it’s just technology for its own sake

[slacktide]

Check Airman

Kegworth is the first thing that comes to mind. We'll be at the pilot+dog cockpit team before you know it. Touch a flight control, that mutt will bite you HARD.

Further details on the implementation here. https://www.ainonline.com/aviation-news/business-aviation/2021-02-01/dassault-adds-more-smarts-falcon-autothrottles

[Check Airman]

Wasn't that the accident where the wrong engine was shut down?

[Denti]

I believe they want to move to a PFD-HUD which makes the space in the panel for the former PFD usable for other things. Will be interesting to see if that works.

[FullWings]

There are many occasions where differential thrust is useful/required, such as turning on the runway. How do you do that with only one lever?

[swh]

tdracer

The single lever will be the primary method to control the thrust in normal operations, there are secondary controls which will enable individual controls in non normal situations, it will also feature the auto recovery to straight and level like the Avidyne DFC90 autopilot.

[alf5071h]

As I recall - experience from ‘have a go flying’; the Bereguet 941 only had one ‘throttle’ (power inceptor) controlling all four engines.

Fightdeck photo halfway through the article; interesting history and background, and opportunities for photo captions.
Video at the end as ‘MD188’

http://histaero.********.com/2014/11/breguet-940941-linvention-de-ladac.html
[ replace ***s by blog_spot, but as one word without underscore]
http://histaero.blog _spot.com/2014/11/breguet-940941-linvention-de

[Vessbot]

swh

The article says that backup individual levers are there only in the test version, while the final installation is expected to have the single lever only.

[FMS82]

FullWings

Not much use with tail mounted engines, so not really a factor for this particular model.

[Private jet]

Exactly...

[Private jet]

tdracer

It's always difficult trying to imply irony on an internet forum and as you are a resident of the "western colonies" I should have known better than to attempt it.
All I know about Falcons is what they look like. "Give way to the Falcon" is the limit of my interaction with them. I don't have any experience of MCAS either, so I can't comment on it, but I'm sure the rot set into Boeing long before the 737MAX was contemplated. (Even the 747 had multiple "hair raising" issues, my Father was one of the early FE's, so i know) If you were really so unhappy with the slide back then why didn't you quit at the time? Don't lecture me on operating an aircraft and I won't lecture you, or anyone else, on how to design them. Aviators have been putting up with both design and commercial "comprimises" as long as aviation has existed. You are an obviously experienced fellow but you are not solely the truth and the light, sorry pal, it's very easy to become a preacher in retirement, and there's quite a few on here! haha.

[stilton]

swh

You could have a set up with two separate levers controlling the thrust to each engine, I think that’s been done before

[oceancrosser]

WHY?
If it ain't broke, don't fix it.

This (american) saying is what has stifled progress in a lot of areas in the US, who amongst other things still produce busses that look and feel as leftovers from the Korean War era… totally unfit for cattle transport, let alone humans.

[Zeus]

Had a problem when one of the engines was starting to run low on oil. "No, don't shut it down" said Maintrol. "Just throttle it back until the oil loss is OK".
Wonder how you will reduce power on one engine using this set up.

[tdracer]

Private Jet
I try to avoid personal attacks, so I'm going to ignore the overt patronizing in your last post.
But to the point, the reason I brought up MCAS is because of this post:
lol. I'm sure it will be thought through though, with reversion and abnormal procedures in place..
The MCAS designers went through the failure modes, and had "reversion and abnormal procedures in place.." They looked good on paper, maybe even in a simulator, but in the real world they failed miserably and 300 people died. Simply having "reversion and abnormal procedures in place.." isn't always enough when things don't work...
As a designer, you don't just design for when things work - you have to design for when they don't work. If everything always worked, we wouldn't need redundant systems. But they don't always work (or don't work per design intent) and redundancy is needed.
We have two (or more) engines for redundancy. We have multiple Air Data and Inertial Reference systems for redundancy. We have multiple electrical power systems for redundancy. We have individual thrust levers for each engine for redundancy. Eliminating redundancy has to be done very, very carefully.
Many years ago I did several Failure Mode and Effects Analysis (FMEA) for thrust lever assemblies. One of the failures was "Lever Seizes" - effect was "Loss of Thrust Control on the affected engine, if necessary affected engine can be shutdown". So what are you going to do with that fancy smart throttle if the it seizes or jams?

I've noticed with all the smart ass replies comparing having redundant thrust levers with living in caves and crappy buses, I've yet to see anyone mention any advantage to having a single, non-redundant thrust lever. If you want the levers to move together, a simple link that can be readily removed seems like a far simpler and safer solution.

[FlightDetent]

I've long suspected "if it ain't broke" is another way of saying "you're not re-inventing the wheel here, are you?". Similar to saying "Occam's razor" instead of K.I.S.S., both really mean the same thing.

The determination to misunderstand what's being said ... it must be an internet thing, right?

[hans brinker]

If you really insist on reinventing the wheel, could you please make sure it is round??

[Denti]

tdracer

That is actually one of the things where the airbus non-moving thrust levers have a slight advantage: if the lever seizes or jams, one still has autothrust available on that engine up to that thrust lever angle (if it is below the CLB detent). I have no idea how Dassault plans to implement its system, but that may be a way of working around that particular issue.

It will be interesting to see how they will implement that system and how it works in its final version.

[fab777]

In the ainonline article above, the test pilots make it very clear that, since pilots do not hand fly a lot, they are creating "aircraft for the dummies". Training, anyone? Ever heard of "automation dependency"?

[vilas]

All I can see is that except there's one lever there's absolutely no more information. Armed with only that all objections actually they are queries are natural. At the same time they are so basic that the manufacturer can also foresee that and must have provided the answers. Only they can provide satisfactory answers.

[Private jet]

tdracer

Well, You've said what you want to say, and avoided what I asked. I suggest you run for political office, you obviously have a talent for it.

[tdracer]

If I'd responded what you wrote, I'd be banned...
Now go troll someone else. :mad:
Oh, and I'm still waiting for someone to explain the benefits of getting rid of one throttle per engine...

[john_tullamarine]

Gents,

Tech Log is not for battleground antics - there are other forums where such is appropriate.

Normally, I don't see any great need to wield a stick in this forum but, if needs be, I can do so.

Let's play the ball, please, and not the player.

regards,

John

[ShyTorque]

Those with any knowledge of twin turbine engined helicopters will realise that this is completely normal. The collective lever controls main rotor blade pitch and the engines respond together to maintain rotor RPM. Admittedly, there is only one main rotor on most helicopters but obviously the Chinook and Tilt Rotor have two.

Individual control of the engines is done by separate controls. These are not normally moved because there is no need in normal use.

[fab777]

Oh, and I'm still waiting for someone to explain the benefits of getting rid of one throttle per engine...

automatic engine failure management. Thus less training needed. Also, no need for cross check on thrust lever management, in an aircraft that is being developed with single pilot cruise in mind.

[Vessbot]

Why does that need a single thrust lever? The airplane can automatically pull back the individual lever for the failed engine, if they want to design it to do so. My plane does that for an unlocked thrust reverser, and it doesn't even have autothrottles.

The earlier linked article also talks about them integrating thrust more tightly into the control law, and automatic upset recoveries. But it doesn't say why either of those need a single thrust lever.

edit: OK, I can see one case: a descent where both levers are at idle. Then the single lever could prevent a misidentification and shutdown of the wrong engine. (second edit: changed "would" to "could." The computer could display "LEFT engine failed, shut down the LEFT engine, note: that is the same side of the airplane as your wristwatch and the side the guy with 4 stripes is sitting on" and someone could still get it wrong, unless they go one step further and change to a single shutoff button :ok:)

[Pugilistic Animus]

Do that to the B-52, one throttle, that is....Also, combine all the electrical circuits on one Bus.:}

[pineteam]

I agree with some posters here. Why trying to improve something that works perfectly fine.
For the A320 Neo drivers did you see the new FOT on the NEO? By adding this new rotation mode they have potentially created a new threat at rotation and now we have extra workload during the takeoff roll. This new flight control law is ridiculous IMHO. Something as basic as a rotation they feel the need to assist the pilots… smh

[stilton]

Could you elaborate on this ?

[pineteam]

If you Pm me, I can email you the pdf document.

FLIGHT OPERATIONS TRANSMISSION - FOT
TO: All A319-100N, A320-200N, A321-200N, A321-200NX Operators
SUBJECT: ATA 00 – OEB 59 REINFORCE SPEED CHECK FOR ROTATION MODE OUR REF.: 999.0042/21 Rev 00 dated 21-JUN-2021
CLASSIFICATION: Airworthiness or Safety
APPLICABLE AIRCRAFT: This FOT is applicable to all A319neo/A320neo/A321neo Airbus aircraft.
Notice: This FOT provides information about a significant operational issue that is related to airworthiness or safety. It is each Operator’s responsibility to distribute this FOT or to distribute the information contained in this FOT, to all of their applicable flight crews without delay. Failure to apply this FOT may have a significant impact on safe aircraft operations.
REFERENCES
1. FOT 999.0041/21 ATA 00 – WEBINAR - OEB 59 REINFORCED SPEED CHECK DURING
TAKEOFF of June 3, 2021. 1. PURPOSE
The purpose of this FOT is to inform all A319neo/A320neo/A321neo Operators that the Red OEB number 59 Reinforced Speed Check for Rotation Mode has been published. OEB 59 and the associated webinars were announced via FOT [REF 1].
2. DESCRIPTION
Between January 2020 and March 2021, several events of unreliable airspeed indication during takeoff were reported to Airbus. Most of the reported cases were due to pitot obstruction by insect contamination. In one of the reported cases, probe cover removal was not completed before flight.
Based on those in-service experiences, Airbus decided to analyze and understand this specific increase of unreliable airspeed indication events and published several recommendations.
Airbus has performed an additional study, and has identified the following: in the case of an unreliable airspeed situation, defined by an erroneous and consistent airspeed on at least two ADRs, the Rotation Mode computation may be degraded. This degradation may result in an unstable flight path after rotation on A319neo, A320neo and A321neo aircraft.
3. CAUSES / CONSEQUENCES
3.1 Cause
The aircraft airspeed is an essential parameter for the flight controls computation during takeoff, particularly when the Rotation Mode is operating.
FOT ref: 999.0042/21 Rev 00 Page 1 of 3 Date: 21-JUN-2021 © AIRBUS S.A.S. 2021. ALL RIGHTS RESERVED. CONFIDENTIAL AND PROPRIETARY DOCUMENT

FLIGHT OPERATIONS TRANSMISSION - FOT
The Rotation Mode is an ELAC function that has been included in the most recent Airbus aircraft types, and particularly on the A320neo family. This function provides an homogeneous rotation for all possible weights, CGs and configurations, while it minimizes a possible tail strike. The Rotation Mode is a flight control law that makes a sidestick input become a pitch rate demand. The principle of the law is based on the fact that the elevator deflection is dependent on the airspeed:
 At low airspeed, it corresponds to a large elevator deflection
 At high airspeed, it corresponds to a low elevator deflection.
This design enhances the rotation phase and requires a reliable airspeed. If the airspeed considered by the Rotation Mode is erroneous, the elevator deflection may not be appropriate for a correct rotation.
The Rotation Mode computation relies on the airspeed monitoring function. By design, the airspeed monitoring function keeps airspeeds, when they are below a certain threshold of difference one from the other. Therefore, the airspeed monitoring function may:
 Keep the two airspeeds, because they are below the threshold
 Reject the remaining airspeed, because it is above the threshold.
In the case of an unreliable and consistent airspeed on two ADRs, the following may occur:
 The correct airspeed is rejected, because it is above the threshold
 The two erroneous airspeeds are kept, because they are below the threshold.
Then, the airspeed considered by the Rotation Mode is erroneous and the Rotation Mode may be degraded.
3.2 Consequences
The Rotation Mode may be degraded and may result in an unstable flight path after rotation with the combination of all of the following conditions:
 A double erroneous ADR airspeed indication
 Both affected ADRs provide a similar erroneous airspeed indication
 The erroneous airspeed is underestimated by at least approximately 30% of the real aircraft
airspeed
 The takeoff is continued.
From an operational point of view, the “approximately 30 %” of error is difficult to monitor during the takeoff roll. Therefore, this “approximately 30 %” parameter has been translated into a fixed operational parameter. The value of 20 kt airspeed error is kept based on:
 Simulation studies
 Margins: instrument uncertainties and crosswind effect on airspeed indications.
4. AIRBUS ACTIONS
Although there were no in-service case reports, Airbus decided to mitigate the possible degradation of the Rotation Mode via the Red OEB 59 Reinforced Speed Check for Rotation Mode, applicable to A319neo, A320neo and A321neo aircraft.
OEB 59 aims to ensure that, during the takeoff roll, the two PFD airspeed indications are not consistent in an erroneous way. In order to achieve that, the airspeed check during the takeoff roll before V1 is reinforced as follows:
 The two PFD airspeed indications must be crosschecked with the ISIS airspeed indication
 A value of 20 kt of airspeed error is to be considered
 An additional airspeed crosscheck is added at 80 kt
 The current SOP 100 kt crosscheck is reinforced.
FOT ref: 999.0042/21 Rev 00 Page 2 of 3 Date: 21-JUN-2021 © AIRBUS S.A.S. 2021. ALL RIGHTS RESERVED. CONFIDENTIAL AND PROPRIETARY DOCUMENT

FLIGHT OPERATIONS TRANSMISSION - FOT
In addition, OEB 59 requires the ISIS airspeed indication. Therefore, ISIS becomes a “must be operative item”. The MMEL was updated accordingly.
5. FOLLOW-UP PLAN
OEB 59 and MMEL update will be released to Operators with an unplanned major event revision. An advanced copy of the operational documents are attached to this transmission.
In addition, the associated AFM Temporary Revision TR 787 is approved by the authorities. The AFM TR 787 will be released in the June 2021 AFM revision.
OEB 59, the associated AFM TR and MMEL impact will be cancelled by ELAC L103+ planned fourth quarter 2021.
For any questions about the operational content of this FOT, please use TechRequest on AirbusWorld.
Best regards,
Capt. Yann LARDET
Vice President, Flight Operations Support & Training Standards
FOT ref: 999.0042/21 Rev 00 Page 3 of 3 Date: 21-JUN-2021 © AIRBUS S.A.S. 2021. ALL RIGHTS RESERVED. CONFIDENTIAL AND PROPRIETARY DOCUMENT


OPERATIONS ENGINEERING BULLETINS
RED OEB – RED OEB – RED OEB – RED OEB – RED OEB – RED OEB – RED OEB
A318/A319/A320/A321
18 JUN 21
59.01A
QUICK REFERENCE HANDBOOK
REINFORCED SPEED CHECK FOR ROTATION MODE - PROCEDURE
ECAM ENTRY
None
PROCEDURE
Apply this procedure at each takeoff:
 AT ANY TIME during the takeoff roll before V1, in the case of an
unreliable airspeed indication: ABORT TAKEOFF  At 80 kt:
PFD/ISIS SPEEDS...................................................... .............CROSSCHECK
The PM must silently reinforce the IAS scanning by crosschecking own PFD speed and ISIS speed.
 In the case of an airspeed difference of more than approximately 20 kt: ABORT TAKEOFF
 At 100 kt:
PFD1/PFD2 SPEEDS...................................................... ........ CROSSCHECK
Apply this check as per the Standard Operating Procedures/100 kt crosscheck.
 In the case of an airspeed difference of more than approximately 20 kt: ABORT TAKEOFF
OEB59 Issue 1

OPERATIONS ENGINEERING BULLETINS
RED OEB – RED OEB – RED OEB – RED OEB – RED OEB – RED OEB – RED OEB
ROOT CAUSE
The aircraft speed is an essential parameter for the computation of flight controls during takeoff. In the case of an unreliable and consistent airspeed on 2 ADRs, the Rotation Mode computation may be degraded.
OPERATIONAL CONSEQUENCE
The Rotation Mode degradation may result in an unstable flight path after rotation.
END OF OEB59
A318/A319/A320/A321
18 JUN 21
59.02A
QUICK REFERENCE HANDBOOK
REINFORCED SPEED CHECK FOR ROTATION MODE - EXPLANATION
OEB59 Issue 1

A319/A320/A321
TEMPORARY REVISION TR787 issue 1
TR 787 - A320NEO FAMILY REINFORCED SPEED CHECK FOR ROTATION MODE
AIRPLANE FLIGHT MANUAL
The content of this document is the property of Airbus. It is supplied in confidence and commercial security on its contents must be maintained. It must not be used for any purpose other than that for which it is supplied, nor may information contained in it be disclosed to unauthorized persons. It must not be reproduced in whole or in part without permission in writing from the owners of the copyright. © AIRBUS 2005. All rights reserved.
REFERENCE: TR787 Issue 1 AFM ISSUE DATE: 17 JUN 21

PRELIMINARY PAGES

A319/A320/A321
AIRPLANE FLIGHT MANUAL
PRELIMINARY PAGES TABLE OF CONTENTS
APPRO APPROVAL DATA
APPRO-TR TEMPORARY REVISIONS
Reinforced Speed Check for Rotation Mode........................................................ .................................................. A
NORM NORMAL PROCEDURES
NORM-TO TAKEOFF
Takeoff Procedure................................................... ............................................................ .................................... A
TR787 Issue 1 PLP-TOC P 1/2 AFM 17 JUN 21

A319/A320/A321
AIRPLANE FLIGHT MANUAL
APPROVAL DATA TEMPORARY REVISIONS
TR787 Issue 1
REINFORCED SPEED CHECK FOR ROTATION MODE
Ident.: TDU / APPRO-TR-00024785.0001001 / 17 JUN 21 EASA APPROVED Criteria: (319-100N or 320-200N or 321-200N or 321-200NX)
Impacted DU: NONE
APPROVAL REFERENCE
Do not remove this Temporary Revision until instructed to do so.
Reason for issue: This Temporary Revision (TR) is issued in order to reinforce the speed check during take-off.
Applicable to: All A319neo, A320neo, and A321neo.
This Temporary Revision is made up of the following Temporary Documentary Units:
APPRO-TR-00024785.0001001/17 JUN 21 NORM-TO-00024786.0001001/17 JUN 21
APPROVED BY: EASA
Approval date: 17 JUN 21 Approval reference: 10076715
TR787 Issue 1 APPRO-TR P 1/2 AFM A 17 JUN 21

A319/A320/A321
AIRPLANE FLIGHT MANUAL
NORMAL PROCEDURES TAKEOFF
TAKEOFF PROCEDURE
Ident.: TDU / NORM-TO-00024786.0001001 / 17 JUN 21 EASA APPROVED Criteria: (319-100N or 320-200N or 321-200N or 321-200NX)
Impacted DU: NONE
Belongs to TR787 Issue 1
In addition to the normal Takeoff Procedure, apply the following reinforced speed crosscheck at each takeoff.
Anytime during the takeoff roll before V1, the takeoff must be aborted in the case of:
‐ An unreliable airspeed situation, or
‐ An airspeed difference of around 20 kt (and above) between any of the ASI (PF ASI, PM ASI and
ISIS ASI).
TR787 Issue 1 NORM-TO P 1/2 AFM A 17 JUN 21

[Check Airman]

If it ain’t broke…:ugh:

[vilas]

pineteam

This is not exactly a case of it ain't broke. All the Airbus varients mentioned react differently to rotational inputs at different CG locations, especially rearward CG. There was an instruction also to keep some rear seats vacant. Since there is no aerodynamic feel in the stick Airbus deviced this rotation mode so pilots don't need variable techniques or judgement. Now something has turned up so they will modify the software. Till then the OEB or FOT will remain operational. It's more of a proactive measure.

[SignalSquare]

Is it really so difficult to move multiple levers at once that one needs a single lever?

[Commander Taco]

Private jet, can you clear your PMs please?

[stilton]

vilas

If I understand this correctly Airbus is attempting through software to ‘augment’ the pilots pitch inputs on take off to provide a uniform rotation rate regardless of the actual stick movement ?

Seems to be unnecessarily complicating things and causing more potential problems in their quest to automate anything and everything !

[pineteam]

Agreed with you Stilton. I love the NEO but I don’t like very much the rotation mode on it. You know you are flying a NEO when you rotate. You can feel the « kick » when that take off law engages and it feels like you are not 100% in control of the rotation rate. Never had issue on the classic. It just feels like a conventional aircraft. Yes it might rotates faster or slower than expected but well we are pilots after all; Only small basic pitch inputs required.

[vilas]

Not augment but standardise rotation response would be more correct. Actually the problem is due storage and blockage/contamination of ADRs impacting in particular this mode.

[stilton]

Semantics,

Just like any other system that inputs into the flight controls without pilot action it is augmenting their control movements

[vilas]

Sorry! If we are speaking English then to Augment means to increase. While that's not what is exactly happening here. The pilot input is being controlled by doing whatever it takes to a standard response. In certain models and CG positions it could be decrease also.

[Vessbot]

If we are speaking English about aircraft, then to augment control means to increase it - not necessarily in force, authority, or surface displacement; but in stability, precision, aid toward certain tasks, etc. (including when displacement is decreased compared to the same input without augmentation). Think "Stability Augmentation System." In short, any FBW control law other than direct, is augmented control.

[cattletruck]

There's something ideologically wrong with having a singe lever to control multiple engines. The primary reason for having multiple engines in the first place is for redundancy, perhaps the reliability of jet engines is such that manufacturers feel the need to take it to the next level and letting the engine management computer (fadec?) manage each Bunsen burner and the parameters that go with running it.

Under normal operating conditions, giving the responsibility of the management of the burners to the IT nerds (ok, maybe I'm being harsh, the engine developers) can realise new efficiencies and operating envelopes beyond the abilities of a mere pilot. Heck, it may even be able to compensate for the weight of a pilots watch. One immediate advantage I can see is the ability for the engines to augment stability when reverse thrust is engaged - all computer controlled of course, and all pre-programmed beforehand in a lab.

But there's the rub... computers as we know are well known to fail miserably, even catastrophically, for reason that are later revealed to be obscure and well hidden from those in command and control.

It shouldn't be that way. In my mind the single lever facility should be an option that is available to exploit conditions when they are favourable, and an ability to disengage that facility and revert to manual override should always remain to maintain command and control, and ultimately safety.