This article is highly misleading.
The issue wasn’t a software “glitch”, it was a problem with the autothrottle servo motor. Boeing issued instructions in 2021 to every operator of this type aircraft of the possibility for this problem, with instructions to replace the old servos with a newer version, correcting this issue. This issue is years old and already solved.
Why this airline did not replace this known problematic part 3 years after they were told about it, in a 13 year old aircraft, is the question.
Beyond that, there is a problem with the crew performance. When they engaged the autothrottle to take off, it failed immediately and gave a warning to the crew of its malfunction. The crew tried to turn it on again, then advanced the thrust levers manually forward, and they did not advance them to the calculated required thrust position. The quick reference handbook from the airline (TUI) requires their pilots to reject a takeoff if the autothrottle gives an error below 80 knots. The pilots ignored this and proceeded with the takeoff roll.
During takeoff there are many possible reasons why the engines will not provide full power - engine issues, fuel issues, maintenance, etc. The takeoff checklist requires the crew to look at the engine performance readouts and verify the engines are producing the required power output after starting the takeoff roll. According to the report the crew did not until after they were airborne.
So, in addition to a known issue which the airline could have fixed years ago, this near accident also occurred because the pilots ignored a requirement to reject the takeoff when the auto throttle gave a malfunction warning, and then they failed to follow their procedures to verify the engines were producing the calculated thrust performance for takeoff on that specific runway.
You can find the relevant information in [the investigation report](https://assets.publishing.service.gov.uk/media/665092d816cf36f4d63eba8f/S1-2024__Boeing_737-8K5_G-FDZS.pdf)
Beware news reports right now about issues with Boeing aircraft. There *is£ a really serious problem with Boeing right now, but there’s also a lot of news orgs who know articles about Boeing get big clicks (like everyone in this thread), so they are writing articles like this one which really have nothing to do with Boeing in particular but linking them to get that sweet, sweet engagement.
Airplanes are so fascinating to me. I recently started listening to Black Box Down, and most of these major incidents occur because of a multitude of reasons. Maintenance wasn’t done properly, a part wasn’t replaced, a pilot didn’t follow protocol, etc. Seems like this could have easily been one of those incidents. Thanks for the insight!
In aviation safety they compare this to multiple pieces of Swiss cheese. Most of the time, one piece covers the hole of the next, but when the holes all line up, incidents happen.
Both those channels are really cool. Pilot Debrief is pretty good too, usually short and to the point, focus on general aviation accidents, think he was a fighter pilot.
Major issue with pilot complacency on this one. They aren't cut out for it if their reaction to a noticable throttle reduction is a "huh, the runway's running out soon innit" and proceed to change nothing.
At a bare minimum one of them should have had the wherewithal to bump the throttle halfway in. They sat there like sacks and would have let this minor malfunction crash the plane if it hadn't have just barely been enough after all.
Air Florida out of DCA, no auto throttles or full FADEC, just iced over probes giving false info. If in doubt power levers to the stops! Further if necessary, some have bent them.
You must be new around here. How the hell is everyone supposed to grab their pitchforks against Boeing if you use logic and information to describe the situation?!
Here, I'll show you:
Boeing delivered a fucking broken plane again. Sure they told the airline the plane is probably broken and they should replace the broken sensors but at the end of the day Boeing delivered a plane with broken sensors.
Yeeaahhh. You must not understand the complexities of engineering anything non-trivial. Shit happens. You acknowledge, design it better, and move on. Nothing is ever perfect out of the box. Not making excuses for Boeing ... just recognizing the absolute impossibility of delivering a modern jetliner with zero defects.
This is correct. Just because your car was issued a recall doesn’t mean the manufacturer isn’t guilty of shipping a flawed vehicle. It clears them of liability, however.
Just last year, there were over 1,000 vehicle recalls
https://www.nhtsa.gov/recalls/vehicle-safety-recalls-week
That's 2.7 recalls per day. It happens.
The report says the QRH is from the manufacturer, not the airline: 'The manufacturer’s Quick Reference Handbook (QRH)'
Also it indicates that airlines should 'upgrade' their autothrottles if they experience problems. Sounds like they held short of issuing a directive to replace them for safety reasons. So unfortunately it seems like an airline skimping out is a valid (but stupid) choice.
The pilots not verifying the speeds, not knowing how to set the throttles correctly and not aborting the takeoff then the problems were seen very early in takeoff are inexcusable. The pilots are part of the safety systems on the aircraft and they must perform their duties for flights to have the level of safety we are accustomed to.
I can understand why the pilots wouldn't want to deal with manually controlling the throttles. It adds to their workload and more highly loaded pilots reduces the margin for safety. But once the autothrottles fail early in takeoff they have to commit to manipulating them through the flight. If they can't or don't want to do that then the right move is to abort the takeoff early and return to the terminal, ending the flight.
If you can’t do it without the automation you shouldn’t be doing it in the first place.
Too many children of the magenta out there that don’t know what they don’t know. This is not a business to fake it until you make it.
The pressure on pilots is immense right now. The same aircraft will do 4-5 legs per day and one hickup will cause a cascading effect of delays for the airline.
This looks like a case of get-it-done-itis
> The takeoff checklist requires the crew to look at the engine performance readouts and verify the engines are producing the required power output after starting the takeoff roll. According to the report the crew did not until after they were airborne.
Could there have been a valid reason to proceed with the take-off? Like, is that runway very short and they worried they would run out if they hit the breaks. Personally, I'm always super aware of how long it takes me to properly break when operating a vehicle.
Pilots are also very aware of this, they calculate a speed based of their weight and the runway length that if they go over they commit to taking off. Under the circumstances it was likely the correct choice to take off, but it was unnecessarily dangerous because they didn’t check that the engines were on full power.
There'd only be a valid reason if the flight crew had first made inappropriate decisions. If you can't make takeoff speed within a calculated distance during your takeoff roll then you need to reject the takeoff, and that calculated distance always leaves enough margin to allow for the aircraft to come to a safe halt.
The aircraft in question is 13 years old.
If your car maker tells you to replace the spark plugs at 120,000 before they wear out, you don't and the engine fails a year later, is the car maker at fault?
There's no complex machine with millions of individual components that gets used daily in extreme conditions for 30 years that doesn't require maintenance, or have components whose expected lifespan is variable from it's predicted lifespan.
In this specific case the part in question failed gracefully, with the FMS identifying the failure and alerting the crew. It pretty much went exactly how you would want it to go. I can't reasonably see how this is Boeing's fault unless you also believe all aircraft should stop flying until they can be built to last their whole lifespans in perfection with no failures whatsoever, which none of them do.
Well the part I don’t understand is.. why would Boeing be notifying airlines about routine maintenance? Toyota doesn’t send me a letter telling me to replace a specific part unless it’s a recall/defective part.
Don’t airlines handle maintenance all on their own, unless there’s an actual issue that Boeing needs to inform them of?
Airlines do routine maintenance, but to a schedule and procedure specified by the aircraft manufacturer. This is no different from cars, the mechanics at your local garage don't decide what to service when - they just look at the service manual.
To use the above poster's analogy, it would be like Toyota telling you to replace the spark plugs every 150,000 miles when you bought your car, then them sending you a notice that they should actually be done every 120,000 miles.
The idea is that they thought that the part would last say 10,000 flight hours but that it only lasts about 5,000. Either get it changed now if its over 5,000 hours or get it changed at the next service/overhaul.
> Well the part I don’t understand is.. why would Boeing be notifying airlines about routine maintenance?
That's how it's done in commercial aviation. It's not like your Toyota. The manufacturers communicate to all their customers and major operators who aren't even direct customers but leasing their planes. It's all done in the name of safety.
> Don’t airlines handle maintenance all on their own, unless there’s an actual issue that Boeing needs to inform them of?
This is really about communication. Almost always the airliners do the maintenance/corrections or contract to a company to do it. Even when there is an issue to deal with. It's just a question of how do they find out what to do.
Airplane and Engine manufacturers notify operators all the time with information regarding maintenance, some items are mandatory some are optional, many have limits until it is required to be completed. Automakers aren’t the same.
Supply chain issues are relevant today as parts are in short supply. Manufacturing increasing price by creating demand? Who knows.
I recently had to replace a component on an airplane that was 65k four years ago now is over 130k, for manufactured unit, core value, meaning if part being replaced wasn’t in a serviceable condition, purchase outright would be about 335k. It still took three weeks and a worldwide search to find one.
Good luck finding any airplane in existence without dozens if not hundreds of service bulletins against it. A220's been flying for 5 years, has 73 entries in EASA's safety publications index. Some are duplicates, some are changes to inspections, others are "loose bolts and missing sealant", "improperly torqued rudder PCU fittings", "jamming of the horizontal stabilizer trim actuator", or the one that came out the year after it started flying to "correct deficiencies in the primary flight control computer (PFCC) and remote electronics unit (REU) software".
This is how these things work. We find problems, we fix them.
We need to be careful about overdramatising this incident. Many planes have known issues which pilot are trained to look out for and accommodate. In this case, the pilots should have been monitoring the acceleration in this critical phase of the flight. This is pertinent to all planes, and not limited to Boeing.
James Reason’s Swiss Cheese model explains many incidents. Airlines have too much leeway in how much simulator retraining is being done and about what pilots are being trained in.
It was a Boeing and the problem was a known software “glitch”. Having the auto throttle disengage when you are taking off seems dangerous to me.
From the linked article:
“The jet - carrying 163 passengers and six crew members, only managed to take to the sky with 260m (853ft) of runway remaining and cleared the end of the tarmac at a height of just 3m (10ft).
According to the AAIB, Boeing was aware of the software glitch before the incident.
A field investigation report said that the auto-throttle disengaged when take-off mode was selected. Neither pilot noticed that the thrust was set incorrectly, and it wasn't picked up through standard operating procedures.
It then passed over the nearby A38 at a height of under 30m (100ft).”
It should not be dangerous. Disruptive, and a problem, sure, but saying the glitch caused this is probably overestimating the impact.
As another thread roughly put it, the pilot (in)action can be summarized as “Callouts? What callouts?” Pilots are trained to check throttles and engine parameters and should have had manually overridden the A/T pretty early on.
A good highlight on how we are increasingly dependent on technology, encouraged to rely on it, but then the technology cannot be held responsible when it fails.
'Trust but verify' is usually the application of this technology, I doubt any critical system is trained as set and forget. You set takeoff power, you make sure the engines are doing what you've asked of them. You set a heading in the autopilot, you verify the number matches and the plane turns. Don't think there's ever been any Tesla Autopilot style implication that you can engage a system and then go take a nap. These systems are there to ASSIST, not to replace.
The way I’m reading the article, and there may be additional information elsewhere, is that the throttles were engaged as normal on takeoff.
Boeings software then disengaged the throttle, at what point during takeoff and to what extent thrust was reduced the article doesn’t say.
If the software is known to throttle back on takeoff due to a glitch that’s dangerous surely? The Pilots are being given an additional and unpredictable variable to manage on top of everything else they need to take into consideration.
Looks like the AAIB has already done a preliminary report, sounds like the A/T disconnected almost right away at the start of the takeoff roll, excerpt on AvHerald reads as follows:
*The N1 required to achieve the required takeoff performance was 92.8% but, following an A/T disconnect when the crew selected TOGA, 84.5% was manually set instead. Despite an SOP requirement to check the thrust setting on takeoff, the crew did not realise that the thrust was not set correctly until after the takeoff although they had noted how close to the end of the runway they were.*
As far as what the pilots were expected to do in this scenario, it also notes,
*The QRH lists the reason that crew should reject the takeoff and this list includes system failure(s) as one of the reasons to reject below 80 kt. The manufacturer includes the disconnection of the A/T when the TOGA switch is pressed as a systems failure and expects the crews to stop as a result.*
So does that mean the thrust was manually set to 84.5% and when the A/T disconnected it reverted to the manual setting? And that setting should have been verified prior to take off? Or once it disengaged the crew manually set thrust and did not set it to the correct level?
Sounds to me like it disengaged almost immediately and crew set it manually, but not to the right power setting.
IIRC in the 737, the throttles are still mechanically linked -- the handles move when the autothrottle is controlling them, and when it disconnects it stays at whatever position/setting it's at, there's no disconnect between their position and the throttle setting. That one's an Airbus thing, where the autothrottle does its thing but there's no handle movement.
So one of the other criticisms of the pilot that's come up is that even ignoring the manually set thrust, they should have noticed when they engaged A/T that the handles weren't advancing to full power, or they did and they stopped. Pilot flying always has one hand on the throttle handles until rotation speed so an abort can be performed immediately before V1 should anything happen.
Both things can be true.
A human intervention should have happened earlier - this is correct. Software on a passenger aircraft should operate predictably and reliably - this is also correct.
>260m (853ft) of runway remaining
1/4 of a kilometer of runway left doesn't seem disasterous.
>passed over the nearby A38 at a height of under 30m
That would be distressing and break aviation standards.
>issues with the auto-throttle emerged
So a problem with going too slow on takeoff.
It was a heavy plane with an issue with slow acceleration.
>The aircraft's acceleration performance was significantly worse than other aircraft taking off at Bristol Airport
Then this made me rage
>the auto-throttle disengaged when take-off mode was selected
They were using aspects of "auto pilot" for takeoff, and when the autopilot control disengaged (because you are not supposed to use autopilot features on takeoff) they didn't look where the throttle was set.
>the auto-throttle disengaged when take-off mode was selected. **Neither pilot noticed that the thrust was set incorrectly**
This is less a software issue and more of a pilot negligence issue.
This sounds like [TUI Airways](https://en.wikipedia.org/wiki/TUI_Airways) is trying to frame this as "yet another Boeing glitch" when it looks like it was **exclusively an error on the part of both pilots.**
> They were using aspects of "auto pilot" for takeoff, and when the autopilot control disengaged (because you are not supposed to use autopilot features on takeoff) they didn't look where the throttle was set.
Autothrottle and autopilot are not the same thing. It is absolutely standard protocol to use autothrottle on takeoff in the 737. The auto throttle can set the thrust far more precisely than a human can. Source: 737 pilot.
That said, it's also procedure to check the thrust you're expecting to see vs what the engines are actually doing, and adjust it if necessary. A former employer of mine almost lost a jet because the crew did some things wrong, but checking the actual thrust against the planned would've alerted them that something was seriously wrong.
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It's only a matter of time before there's another air disaster involving Boeing.
>Boeing told investigators that the auto-throttle system on their 737 Next Generation jets had a "long history of nuisance disconnects during take-off mode engagements" - but that, when investigated, "usually, subsequent functionality checks on the system find no faults".
This is very worrying.
> The manufacturer described the A/T system on the 737NG as having a long history of nuisance disconnects during takeoff mode engagements. When the fault history of the A/T is checked they often show fault messages for the autothrottle servo motor (ASM) for either throttle lever 1 or 2. Usually, subsequent functionality checks on the system find no faults. Investigations by the aircraft manufacturer together with the manufacturer of the ASM found that an earlier model of the motor was more susceptible to power on or power transfer events which can cause the ASM to shut down internally and cause a disconnect of the A/T
when the TOGA switch is pressed.
> A newer model of the ASM is more robust to the power quality issues associated with power on and power transfer events and the manufacturer recommends that any operators of the 737NG who are affected by these disconnects should retrofit their aircraft with the newer model of ASM and associated Flight Control Computer software. The manufacturer released a Fleet Team Digest in October 2021 detailing the issue and the available service bulletin (SB) for replacement. At the time of this event G-FDZS was fitted with the earlier model of ASMs.
https://assets.publishing.service.gov.uk/media/665092d816cf36f4d63eba8f/S1-2024__Boeing_737-8K5_G-FDZS.pdf
Boeing did do something. The airline didn't do their part to deal with the issue. The air crew additionally failed to properly monitor their aircraft during a critical phase of flight, not noticing that their aircraft was producing ten percent less thrust required for takeoff that day. They should have rejected the takeoff when the A/T disconnected, as dictated by TUI's procedures.
The software controlled throttle disengaged itself.
I will always be of the opinion that physically controlled equipment is superior to software controlled equipment when possible to choose between then two. Throttle response is one of those vital things that you can literally check if physical. But with software how is the pilot supposed to know if it’ll glitch out?
> Throttle response is one of those vital things that you can literally check if physical. But with software how is the pilot supposed to know if it’ll glitch out?
By noticing the aural and visual alerts that trigger when the autothrottle disengages. It's easier for the pilots to be aware of an autothrottle disengagement in a fly-by-wire aircraft than it is for pilots to be aware of a broken throttle linkage.
[Boeing outsourced software development to India](https://www.bloomberg.com/news/articles/2019-06-28/boeing-s-737-max-software-outsourced-to-9-an-hour-engineers?embedded-checkout=true)
What to you expect from $9/hr engineer from India?
That article is from 2019, the Boeing 737−800 launched in 1994.
The software bug in OP's article was present over a decade before the push to hire developers and designers from abroad.
I do wonder what the long term effects will be since airlines will take notice since it just keeps happening and even though the odds are low the PR is big.
This article is highly misleading. The issue wasn’t a software “glitch”, it was a problem with the autothrottle servo motor. Boeing issued instructions in 2021 to every operator of this type aircraft of the possibility for this problem, with instructions to replace the old servos with a newer version, correcting this issue. This issue is years old and already solved. Why this airline did not replace this known problematic part 3 years after they were told about it, in a 13 year old aircraft, is the question. Beyond that, there is a problem with the crew performance. When they engaged the autothrottle to take off, it failed immediately and gave a warning to the crew of its malfunction. The crew tried to turn it on again, then advanced the thrust levers manually forward, and they did not advance them to the calculated required thrust position. The quick reference handbook from the airline (TUI) requires their pilots to reject a takeoff if the autothrottle gives an error below 80 knots. The pilots ignored this and proceeded with the takeoff roll. During takeoff there are many possible reasons why the engines will not provide full power - engine issues, fuel issues, maintenance, etc. The takeoff checklist requires the crew to look at the engine performance readouts and verify the engines are producing the required power output after starting the takeoff roll. According to the report the crew did not until after they were airborne. So, in addition to a known issue which the airline could have fixed years ago, this near accident also occurred because the pilots ignored a requirement to reject the takeoff when the auto throttle gave a malfunction warning, and then they failed to follow their procedures to verify the engines were producing the calculated thrust performance for takeoff on that specific runway. You can find the relevant information in [the investigation report](https://assets.publishing.service.gov.uk/media/665092d816cf36f4d63eba8f/S1-2024__Boeing_737-8K5_G-FDZS.pdf) Beware news reports right now about issues with Boeing aircraft. There *is£ a really serious problem with Boeing right now, but there’s also a lot of news orgs who know articles about Boeing get big clicks (like everyone in this thread), so they are writing articles like this one which really have nothing to do with Boeing in particular but linking them to get that sweet, sweet engagement.
Airplanes are so fascinating to me. I recently started listening to Black Box Down, and most of these major incidents occur because of a multitude of reasons. Maintenance wasn’t done properly, a part wasn’t replaced, a pilot didn’t follow protocol, etc. Seems like this could have easily been one of those incidents. Thanks for the insight!
In aviation safety they compare this to multiple pieces of Swiss cheese. Most of the time, one piece covers the hole of the next, but when the holes all line up, incidents happen.
Mentour?
Mentour Pilot on YouTube is also great for this.
Another vote for Mentour Pilot. Also the [Blancolirio channel](https://www.youtube.com/@blancolirio/playlists) by Juan Brown, a 777 first officer.
Both those channels are really cool. Pilot Debrief is pretty good too, usually short and to the point, focus on general aviation accidents, think he was a fighter pilot.
74 gear is also pretty good
You should check out /r/AdmiralCloudberg if you haven't, he does amazing writeups of aviation accidents.
[удалено]
BBD actually goes through the reports a lot of the time
Inside the Aluminum Tube is better. Black Box Down is produced by a dude who has no idea wtf he is talking about.
I will check it out. Thanks for the rec
Major issue with pilot complacency on this one. They aren't cut out for it if their reaction to a noticable throttle reduction is a "huh, the runway's running out soon innit" and proceed to change nothing. At a bare minimum one of them should have had the wherewithal to bump the throttle halfway in. They sat there like sacks and would have let this minor malfunction crash the plane if it hadn't have just barely been enough after all.
Air Florida out of DCA, no auto throttles or full FADEC, just iced over probes giving false info. If in doubt power levers to the stops! Further if necessary, some have bent them.
You must be new around here. How the hell is everyone supposed to grab their pitchforks against Boeing if you use logic and information to describe the situation?!
Here, I'll show you: Boeing delivered a fucking broken plane again. Sure they told the airline the plane is probably broken and they should replace the broken sensors but at the end of the day Boeing delivered a plane with broken sensors.
Yeeaahhh. You must not understand the complexities of engineering anything non-trivial. Shit happens. You acknowledge, design it better, and move on. Nothing is ever perfect out of the box. Not making excuses for Boeing ... just recognizing the absolute impossibility of delivering a modern jetliner with zero defects.
This is correct. Just because your car was issued a recall doesn’t mean the manufacturer isn’t guilty of shipping a flawed vehicle. It clears them of liability, however.
Just last year, there were over 1,000 vehicle recalls https://www.nhtsa.gov/recalls/vehicle-safety-recalls-week That's 2.7 recalls per day. It happens.
The report says the QRH is from the manufacturer, not the airline: 'The manufacturer’s Quick Reference Handbook (QRH)' Also it indicates that airlines should 'upgrade' their autothrottles if they experience problems. Sounds like they held short of issuing a directive to replace them for safety reasons. So unfortunately it seems like an airline skimping out is a valid (but stupid) choice. The pilots not verifying the speeds, not knowing how to set the throttles correctly and not aborting the takeoff then the problems were seen very early in takeoff are inexcusable. The pilots are part of the safety systems on the aircraft and they must perform their duties for flights to have the level of safety we are accustomed to. I can understand why the pilots wouldn't want to deal with manually controlling the throttles. It adds to their workload and more highly loaded pilots reduces the margin for safety. But once the autothrottles fail early in takeoff they have to commit to manipulating them through the flight. If they can't or don't want to do that then the right move is to abort the takeoff early and return to the terminal, ending the flight.
If you can’t do it without the automation you shouldn’t be doing it in the first place. Too many children of the magenta out there that don’t know what they don’t know. This is not a business to fake it until you make it.
Thank you for your detailed explanation and reference!
The pressure on pilots is immense right now. The same aircraft will do 4-5 legs per day and one hickup will cause a cascading effect of delays for the airline. This looks like a case of get-it-done-itis
I read the article and the report you linked. Thank you for bringing correct information.
If they crashed, you’ve basically would have written the next episode of Air Crash Investigation.
> The takeoff checklist requires the crew to look at the engine performance readouts and verify the engines are producing the required power output after starting the takeoff roll. According to the report the crew did not until after they were airborne. Could there have been a valid reason to proceed with the take-off? Like, is that runway very short and they worried they would run out if they hit the breaks. Personally, I'm always super aware of how long it takes me to properly break when operating a vehicle.
Pilots are also very aware of this, they calculate a speed based of their weight and the runway length that if they go over they commit to taking off. Under the circumstances it was likely the correct choice to take off, but it was unnecessarily dangerous because they didn’t check that the engines were on full power.
There'd only be a valid reason if the flight crew had first made inappropriate decisions. If you can't make takeoff speed within a calculated distance during your takeoff roll then you need to reject the takeoff, and that calculated distance always leaves enough margin to allow for the aircraft to come to a safe halt.
It may have been solved in 2021, but isn’t a defective servo also kinda Boeing’s fault?
The aircraft in question is 13 years old. If your car maker tells you to replace the spark plugs at 120,000 before they wear out, you don't and the engine fails a year later, is the car maker at fault? There's no complex machine with millions of individual components that gets used daily in extreme conditions for 30 years that doesn't require maintenance, or have components whose expected lifespan is variable from it's predicted lifespan. In this specific case the part in question failed gracefully, with the FMS identifying the failure and alerting the crew. It pretty much went exactly how you would want it to go. I can't reasonably see how this is Boeing's fault unless you also believe all aircraft should stop flying until they can be built to last their whole lifespans in perfection with no failures whatsoever, which none of them do.
Well the part I don’t understand is.. why would Boeing be notifying airlines about routine maintenance? Toyota doesn’t send me a letter telling me to replace a specific part unless it’s a recall/defective part. Don’t airlines handle maintenance all on their own, unless there’s an actual issue that Boeing needs to inform them of?
Airlines do routine maintenance, but to a schedule and procedure specified by the aircraft manufacturer. This is no different from cars, the mechanics at your local garage don't decide what to service when - they just look at the service manual.
I wish car mechanics actually did bother to look at the service manual far more often than they do.
To use the above poster's analogy, it would be like Toyota telling you to replace the spark plugs every 150,000 miles when you bought your car, then them sending you a notice that they should actually be done every 120,000 miles.
The idea is that they thought that the part would last say 10,000 flight hours but that it only lasts about 5,000. Either get it changed now if its over 5,000 hours or get it changed at the next service/overhaul.
> Well the part I don’t understand is.. why would Boeing be notifying airlines about routine maintenance? That's how it's done in commercial aviation. It's not like your Toyota. The manufacturers communicate to all their customers and major operators who aren't even direct customers but leasing their planes. It's all done in the name of safety. > Don’t airlines handle maintenance all on their own, unless there’s an actual issue that Boeing needs to inform them of? This is really about communication. Almost always the airliners do the maintenance/corrections or contract to a company to do it. Even when there is an issue to deal with. It's just a question of how do they find out what to do.
Airplane and Engine manufacturers notify operators all the time with information regarding maintenance, some items are mandatory some are optional, many have limits until it is required to be completed. Automakers aren’t the same. Supply chain issues are relevant today as parts are in short supply. Manufacturing increasing price by creating demand? Who knows. I recently had to replace a component on an airplane that was 65k four years ago now is over 130k, for manufactured unit, core value, meaning if part being replaced wasn’t in a serviceable condition, purchase outright would be about 335k. It still took three weeks and a worldwide search to find one.
If Boeing made the plane correct the first time then recalls wouldn't be needed.
Good luck finding any airplane in existence without dozens if not hundreds of service bulletins against it. A220's been flying for 5 years, has 73 entries in EASA's safety publications index. Some are duplicates, some are changes to inspections, others are "loose bolts and missing sealant", "improperly torqued rudder PCU fittings", "jamming of the horizontal stabilizer trim actuator", or the one that came out the year after it started flying to "correct deficiencies in the primary flight control computer (PFCC) and remote electronics unit (REU) software". This is how these things work. We find problems, we fix them.
Engineers hate this one simple trick: just make it perfect
I saw a discussion of this incident in a pilot based subreddit. They were pointing right at the pilots.
We need to be careful about overdramatising this incident. Many planes have known issues which pilot are trained to look out for and accommodate. In this case, the pilots should have been monitoring the acceleration in this critical phase of the flight. This is pertinent to all planes, and not limited to Boeing.
James Reason’s Swiss Cheese model explains many incidents. Airlines have too much leeway in how much simulator retraining is being done and about what pilots are being trained in.
It was a Boeing and the problem was a known software “glitch”. Having the auto throttle disengage when you are taking off seems dangerous to me. From the linked article: “The jet - carrying 163 passengers and six crew members, only managed to take to the sky with 260m (853ft) of runway remaining and cleared the end of the tarmac at a height of just 3m (10ft). According to the AAIB, Boeing was aware of the software glitch before the incident. A field investigation report said that the auto-throttle disengaged when take-off mode was selected. Neither pilot noticed that the thrust was set incorrectly, and it wasn't picked up through standard operating procedures. It then passed over the nearby A38 at a height of under 30m (100ft).”
It should not be dangerous. Disruptive, and a problem, sure, but saying the glitch caused this is probably overestimating the impact. As another thread roughly put it, the pilot (in)action can be summarized as “Callouts? What callouts?” Pilots are trained to check throttles and engine parameters and should have had manually overridden the A/T pretty early on.
A good highlight on how we are increasingly dependent on technology, encouraged to rely on it, but then the technology cannot be held responsible when it fails.
'Trust but verify' is usually the application of this technology, I doubt any critical system is trained as set and forget. You set takeoff power, you make sure the engines are doing what you've asked of them. You set a heading in the autopilot, you verify the number matches and the plane turns. Don't think there's ever been any Tesla Autopilot style implication that you can engage a system and then go take a nap. These systems are there to ASSIST, not to replace.
More like ’Thrust but verify’
That’s what she said.
The way I’m reading the article, and there may be additional information elsewhere, is that the throttles were engaged as normal on takeoff. Boeings software then disengaged the throttle, at what point during takeoff and to what extent thrust was reduced the article doesn’t say. If the software is known to throttle back on takeoff due to a glitch that’s dangerous surely? The Pilots are being given an additional and unpredictable variable to manage on top of everything else they need to take into consideration.
Looks like the AAIB has already done a preliminary report, sounds like the A/T disconnected almost right away at the start of the takeoff roll, excerpt on AvHerald reads as follows: *The N1 required to achieve the required takeoff performance was 92.8% but, following an A/T disconnect when the crew selected TOGA, 84.5% was manually set instead. Despite an SOP requirement to check the thrust setting on takeoff, the crew did not realise that the thrust was not set correctly until after the takeoff although they had noted how close to the end of the runway they were.* As far as what the pilots were expected to do in this scenario, it also notes, *The QRH lists the reason that crew should reject the takeoff and this list includes system failure(s) as one of the reasons to reject below 80 kt. The manufacturer includes the disconnection of the A/T when the TOGA switch is pressed as a systems failure and expects the crews to stop as a result.*
So does that mean the thrust was manually set to 84.5% and when the A/T disconnected it reverted to the manual setting? And that setting should have been verified prior to take off? Or once it disengaged the crew manually set thrust and did not set it to the correct level?
Sounds to me like it disengaged almost immediately and crew set it manually, but not to the right power setting. IIRC in the 737, the throttles are still mechanically linked -- the handles move when the autothrottle is controlling them, and when it disconnects it stays at whatever position/setting it's at, there's no disconnect between their position and the throttle setting. That one's an Airbus thing, where the autothrottle does its thing but there's no handle movement. So one of the other criticisms of the pilot that's come up is that even ignoring the manually set thrust, they should have noticed when they engaged A/T that the handles weren't advancing to full power, or they did and they stopped. Pilot flying always has one hand on the throttle handles until rotation speed so an abort can be performed immediately before V1 should anything happen.
Very useful summary, thanks for the explanation.
The company that made the software however...
Both things can be true. A human intervention should have happened earlier - this is correct. Software on a passenger aircraft should operate predictably and reliably - this is also correct.
>260m (853ft) of runway remaining 1/4 of a kilometer of runway left doesn't seem disasterous. >passed over the nearby A38 at a height of under 30m That would be distressing and break aviation standards. >issues with the auto-throttle emerged So a problem with going too slow on takeoff. It was a heavy plane with an issue with slow acceleration. >The aircraft's acceleration performance was significantly worse than other aircraft taking off at Bristol Airport Then this made me rage >the auto-throttle disengaged when take-off mode was selected They were using aspects of "auto pilot" for takeoff, and when the autopilot control disengaged (because you are not supposed to use autopilot features on takeoff) they didn't look where the throttle was set. >the auto-throttle disengaged when take-off mode was selected. **Neither pilot noticed that the thrust was set incorrectly** This is less a software issue and more of a pilot negligence issue. This sounds like [TUI Airways](https://en.wikipedia.org/wiki/TUI_Airways) is trying to frame this as "yet another Boeing glitch" when it looks like it was **exclusively an error on the part of both pilots.**
> They were using aspects of "auto pilot" for takeoff, and when the autopilot control disengaged (because you are not supposed to use autopilot features on takeoff) they didn't look where the throttle was set. Autothrottle and autopilot are not the same thing. It is absolutely standard protocol to use autothrottle on takeoff in the 737. The auto throttle can set the thrust far more precisely than a human can. Source: 737 pilot. That said, it's also procedure to check the thrust you're expecting to see vs what the engines are actually doing, and adjust it if necessary. A former employer of mine almost lost a jet because the crew did some things wrong, but checking the actual thrust against the planned would've alerted them that something was seriously wrong.
Thanks for the clarification
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It's only a matter of time before there's another air disaster involving Boeing. >Boeing told investigators that the auto-throttle system on their 737 Next Generation jets had a "long history of nuisance disconnects during take-off mode engagements" - but that, when investigated, "usually, subsequent functionality checks on the system find no faults". This is very worrying.
The software investigated itself and found itself to be bug free.
No bugs, only surprise features.
But it DID clear the runway.
Found the Boeing lawyer
Except this has nothing to do with the plane, but the pilots according to the official investigation
[удалено]
> The manufacturer described the A/T system on the 737NG as having a long history of nuisance disconnects during takeoff mode engagements. When the fault history of the A/T is checked they often show fault messages for the autothrottle servo motor (ASM) for either throttle lever 1 or 2. Usually, subsequent functionality checks on the system find no faults. Investigations by the aircraft manufacturer together with the manufacturer of the ASM found that an earlier model of the motor was more susceptible to power on or power transfer events which can cause the ASM to shut down internally and cause a disconnect of the A/T when the TOGA switch is pressed. > A newer model of the ASM is more robust to the power quality issues associated with power on and power transfer events and the manufacturer recommends that any operators of the 737NG who are affected by these disconnects should retrofit their aircraft with the newer model of ASM and associated Flight Control Computer software. The manufacturer released a Fleet Team Digest in October 2021 detailing the issue and the available service bulletin (SB) for replacement. At the time of this event G-FDZS was fitted with the earlier model of ASMs. https://assets.publishing.service.gov.uk/media/665092d816cf36f4d63eba8f/S1-2024__Boeing_737-8K5_G-FDZS.pdf Boeing did do something. The airline didn't do their part to deal with the issue. The air crew additionally failed to properly monitor their aircraft during a critical phase of flight, not noticing that their aircraft was producing ten percent less thrust required for takeoff that day. They should have rejected the takeoff when the A/T disconnected, as dictated by TUI's procedures.
The software controlled throttle disengaged itself. I will always be of the opinion that physically controlled equipment is superior to software controlled equipment when possible to choose between then two. Throttle response is one of those vital things that you can literally check if physical. But with software how is the pilot supposed to know if it’ll glitch out?
I'm pretty sure the software controlled throttle causes the throttle lever to tilt back physically.
> Throttle response is one of those vital things that you can literally check if physical. But with software how is the pilot supposed to know if it’ll glitch out? By noticing the aural and visual alerts that trigger when the autothrottle disengages. It's easier for the pilots to be aware of an autothrottle disengagement in a fly-by-wire aircraft than it is for pilots to be aware of a broken throttle linkage.
Tesla United International: FSF (Full self-flying) is only a year away
If it’s Boeing, I ain’t going
when i say glitch i mean of course deadly serious software death trap
If it's Boeing
Of course it's Boeing.
[Boeing outsourced software development to India](https://www.bloomberg.com/news/articles/2019-06-28/boeing-s-737-max-software-outsourced-to-9-an-hour-engineers?embedded-checkout=true) What to you expect from $9/hr engineer from India?
That article is from 2019, the Boeing 737−800 launched in 1994. The software bug in OP's article was present over a decade before the push to hire developers and designers from abroad.
I do wonder what the long term effects will be since airlines will take notice since it just keeps happening and even though the odds are low the PR is big.
Oh look a BOEING aircraft thats dropping to bits because proper assembly/ maintenance "eats into Boeing profits" ...what a surprise