If I understand your question correctly, not really. There is some cable stretch and lost motion in the connections between the throttle and the fuel control, but we're talking the equivalent of maybe a half knob of throttle movement - so while one engine may lag a bit, it shouldn't be enough to cause a serious issue.
With cable engines, there is normally some throttle stagger between the engines - in addition to what I noted above, there are differences in the fuel controls and their 'trim' settings, and (IIRC) on the CFM56-3 engine, the fuel control controls to N2 - not N1 - so to align N1s might require slightly different throttle positions (there is also an analog electronic supervisory control that trims the fuel control to attempt to keep N1 constant as the conditions change). However even with all that, there should be less than a knob of throttle stagger with equal N1s (and maintenance action taken if it gets that large).

td. Thank you; my thoughts relate to the need for meaningful instrument displays re thrust asymmetry, and crews prioritising these over thrust lever position.
Also, considering a range of scenarios, indications, analysis, and action:-
- AT clutch slip could involve two cues; instruments and TL. ~ AT malfunction; disengage AT.
- Engine/FCU fault; probably only instruments. ~ Engine malfunction; review other engine instruments and related systems.

Presumably modern FADEC controlled engines have the capability for cross monitoring and alerting displays; e.g. similar to air data instruments ‘disagree’.
Are there any aircraft which have such a system?

Associated refs;
https://www.faa.gov/aircraft/air_cer...ne_psm_icr.pdf
“Although the vast majority of propulsion system malfunctions are recognized and handled appropriately, there is sufficient evidence to suggest that many pilots have difficulty identifying certain propulsion system malfunctions and reacting appropriately”.

https://www.aia-aerospace.org/wp-con...ITT_Report.pdf
Powerplant Indications Task Team Report;
‘… opportunities for safety improvements’, para 1.4 onwards.

Investigation of (Automatic) Asymmetric Thrust Detection
https://core.ac.uk/download/pdf/42702866.pdf

Further to td's explanation, there's a controlling circuitry in the Classic called PMC, I seem to recall. It's job is to fine-tune everything controlling the N1s and if operational the engines behave very gracefully.

BananaJoe somewhere near?

I.e. most likely in your scenario the PMC would feed inputs to A/T for matching N1 first, resulting in the stagger described and not the other way around. The governing input is the N1, not throttle angle.

safetypee

It was found that flight crew would often start troubleshooting things like low oil pressure or an IDG dropping offline when the actual problem was the engine had quit. So starting with the 747-400, Boeing implemented an "ENG X FAIL" message on EICAS - the logic was pretty basic (N2/N3 well below idle) - Similar ENG FAIL logic was included in the 767 EICAS but for reasons I never understood it was never turned on...
777 took it a step further - partly due to the implementation of TAC (Thrust Asymmetry Compensation) which could hide a thrust asymmetry caused yaw, they implemented L/R ENG THRUST which indicated an engine was producing less than commanded thrust (by at least 10% IIRC) and not recovering. I think the ENG THRUST logic was in the FADEC but I wouldn't swear to it. The 777 also has L/R ENG FAIL with somewhat more sophisticated logic than the 747-400.
The 787 and 747-8 have the ENG FAIL and ENG THRUST messages.

There's always the case where the engine doesn't annunciated a failure condition at high altitude or at low power during approach, yet over time the drag asymmetry can lead to an unstable aircraft mode (pitch and/or roll) which can manifest itself and confuse the crew if they fail to note such changes.

So just how far to you go with engine controls or instruments, either in design or annunciating to the crew?

That is a great question.
Case in point and a very subtle failure that happened to a friend. When leaving FL360, on descent, the thrust levers were at idle and the number 2 engine flamed out. At that time the only caution that the crew saw was the engine generator message indicating an "off line" condition.
If the descent had an intermediate level off, then that would have been interesting.

Yes ! Well, I certainly would anyway. (Sometimes you want both hands on the yoke for finer control, but you can always see the engine gauges).

Some pilots say that non moving Airbus FBW thrust levers are a bad thing, yet there have been several accidents in recent years with Boeing thrust levers that didn't move when they should have, but the situation was not noticed by the pilots.

The Airbus system requires the pilots to look at the N1/EPR gauges every instrument scan to confirm what the engines are doing. This is a very GOOD thing, and avoids getting caught out.

You are of course required to monitor the engine instruments in a Boeing as well, thrust lever movement is not the primary engine indication. They add an element to the monitoring. It is very easy to get lazy when it comes to engine monitoring in an Airbus.

Yes, my point was that several recent Boeing crashes have been a direct result of pilots NOT looking at the engine instruments, but assuming - from the proxy of the thrust lever position(s) - what the engines were doing. But even then, the wrong thrust lever position - for example an asymmetry - has not been noticed. In particular, a common theme seems to be not noticing when the thrust lever(s) don't move, but should have moved.

The danger is that some use the moving thrust levers as their engine monitoring and get out of the vital habit of checking the engine instruments in every scan,

In Airbus FBW, pilots must look at the engine instruments to know what the engines have been commanded to do and are doing, (apart from large accelerations felt through the body).

Are you trying to sell the lack of tactile feedback in Airbus FBW design (both thrust levers and sidestick) as positive?

It's not. The fact that you have to stare inside the flightdeck to monitor what automation is doing, instead of being able to look outside and feel with hands on controls that the autopilot is starting to do something silly, isn't a positive in my book.
​​​​​

The danger in an Airbus is that engine instruments are not included in the scan. You can use BIG letters as much as you want, but movable levers are not dangerous.
If thrust is assymetric, thrust levers split, aircraft in a yaw/roll and the pilots fail to notice, they are not doing their job.

It's two different planes with different operating philosophies... Stop arguing whether one of them is better. In either of them you should be trained for and know about the traps you can fall into, and in either of them you are not doing your job properly if a major thrust asymmetry goes unnoticed. Whether you don't pay attention to thrust levers that have moved or to engine instruments, you are not doing your job. If anything, autothrust is the danger as it brings out the lazy part in any pilot. Bring back manual thrust only, wohoo! /sarcasm

Following through the history of this crash up to present date, it looks increasingly like the scene in the 737 simulator described by Centaurus at Post 309 date 18 January 2021, is uncomfortably close to that of what really happened.

Sheppy, totally agree! Cockpit gradient is some countries is staggering and zero CRM . Add to that complacency, lack of skill and the holes line up quickly.

It was required in Naval Aviation and in the airline where I worked.

It is also covered under FAR 91.103 in the US:
Recent maintenance history and recurrent maintenance problems certainly are relevant to the flight!

Any open defect, no mater how far back , was and is the captain's responsibility. No excuses for not knowing what you are signing for.

Intruder

"Recent maintenance history and recurrent maintenance problems certainly are relevant to the flight!"

So how many previous sectors' log entries should a crew expect to have to trawl through when accepting an aircraft ?

You nailed it Intrance. The convenience of autothrottle may have tipped the balance in the wrong direction where control of the airplane is concerned. Too much automation has disengaged the pilot.

DaveReidUK

That's an easy one: About last 3 flying days' worth, or back to the previous WY check. When a new logbook is started the old one remains on-board, officially.

The real dilemma behind your question is understood, but it's one of those few that fortunately do not need a lawyer-proofed solution. Working the job does it.

DaveReidUK

3 days at my company

fatbus

Things may have changed, but way back, it wasn't acceptable to have an open defect. If it couldn't be cleared, it went as an ADD "Acceptable Deferred Defect", which was in a separate section of the log. If not acceptable, the aircraft wasn't airworthy.

It could be aa simple as "Recurring defect not detectable on the ground. Crews are requested to monitor", but it would be there; right in your face.

DaveReidUK

Depends on the history. If the airplane has several clean flights in a row, I go back to the last flight with a squawk. If there are many deferred items or recent maintenance actions, I will go all the way back to the flight of the earliest deferred item, or to the last previous series of clean flights.

By "open defect " I meant differed and or MEL release . Good on ya for the pick up .

DaveReidUK

As required by my company, look back until the last weekly inspection. I’ve had to look at the last page, or for our more hypochondriac 319s, up to 40 pages. But it’s at least dictated by company policy.

FlyingStone

Well I am wondering why the thrust asymmetry was missed even with moving thrust levers, (that many claim are so essential).

FWIW I have flown many different types, including the B737 classic, and I have no problem at all with Airbus FBW lack of tactile feedback. Nor do I have a problem with scanning the instruments, which is what all pilots should be doing anyway - even with moving thrust levers - this was my point really.

There is no need to "stare inside the flight-deck" - a quick glance every 10 secs or so at the PFD and the N1/EPRs is all that is required. I reckon it takes about 2 seconds to look at the PFD and the engine gauges to assimilate the situation. Easy peasy ! :ok:

Our company provides us with a maintenance log history based on items. Either the last 20 items which have been closed or all items closed in the last 14 days, whichever is less.

And of course the maintenance release document which addresses currently known defects.

Confused by coupla posts before, discussing jammed cables,clutch, servo

I read from the interim report for press: While climbing, Throttle 1 slowly reduced. Not at the point at level off, but in climb. And Throttle 2 even increased N1 to hold speed. No stuck things, both moved. Right? Or did I miss something?
And if they take a look at the A/T system, that N1 reduction rather was by itself. Controlled most propably from A/T, not from the Pilot Flying.
Throttle 2 and Engine 2 haven't been an issue at all.

A repetitive technical fault
And Maintenance failed
And Pilots failed
Cockpit situation analyzed from CVR for contributional factors.

I’m fearing the notion that these fellows watched the split throttles and just hoped the AP would get them out of it. Ugh...

I suggest you read the interim report. The right throttle did not increase. Thrust/speed control in jets doesn't work like that in a normal climb.

I've been reading this 'thread' since the start, but sorry to note it's no longer getting updated "information" pieces such as normally contributed and commented on by the cognoscenti.
Have any more facts from the flight and/or cockpit recorders been revealed please ?

IIRC the CVR was downloaded 2-3 weeks ago. Things have indeed been quiet since.

It's been a month since the KNKT reported that all relevant data from the CVR was successfully downloaded (the data from the FDR was successfully dowloaded earlier). So it is very likely -- though not a certainty -- that the KNKT now understands what happended and why (root cause(s) and contributing causes). In due time (release of the Final Report) we will all know what they know.

From reuters:

The Federal Aviation Administration (FAA) said on Friday it was requiring U.S. operators of 143 Boeing Co (BA.N) 737 Classic series airplanes to check for possible wire failures stemming from an investigation into an Indonesia crash in January.

waito

Around 1,000 aircraft potentially affected by the issue, though probably well under half of those still flying.

Some of the articles I saw on this mentioned that the FAA specifically said that while the issue stemmed from the Indonesia investigation, that this was *not* the cause of the accident. So, still a mystery.

At some third world operators, pilots are “not encouraged” to write up defects, particularly for what’s perceived as minor issues but would be expensive to fix. A culture of different standards is sometimes evident with “Everyone knows it does that, you just need to …….”, being ingrained. This is worse if the owner is closely involved in the day to day running.

A pilot can easily cost the company tens of thousands of dollars in a few minutes with a cheap Biro.

flight cat

It's "still" a mystery but not because of what FAA has said or not said in announcing that action. The final KNKT report is what is still missing. And FAA won't be making its own cause analysis and findings in this instance, in any event.

It's not really a mystery - the terms "latent failure" and "identified unsafe condition" are both readily understood across the industry.

It is perfectly normal for an investigation involving an aging aircraft to pick up issues unrelated to the cause, but still requiring remedial action. Investigators will be able to examine parts which are normally inaccessible.

Is this seriously embarrassing or are they just deadly slow?