Ethiopian Airlines Crash/ B737MAX grounding

murphaph · 27-03-2019 01:32PM

Gaoth Laidir wrote: »

There's nothing inherently unsafe about this aircraft if flown by properly-trained personnel. No problem with repositioning flights like that.

Too early to say this IMO. The MCAS issue is one (very bad) issue that got through (self) certification far too easily it seems. What else got through that shouldn't have?

It's not just that Boeing downplayed the effect of MCAS to avoid pilot training costs, they designed this system with just one sensor input and no warning light if the AoA sensors even disagreed.

Where else have they made similar decisions with this aircraft, which have not yet surfaced? There are not many of them in service yet.

kmart6 · 27-03-2019 01:58PM

Tenzor07 wrote: »

Confidence in Boeing Aircraft expressed by airlines:

https://www.ethiopianairlines.com/corporate/media/media-relations/press-release/detail/1106

Qatar also:

https://www.euronews.com/2019/03/25/qatar-airways-ceo-has-confidence-in-boeing-airplanes-after-max-crash

That Ethiopian statement reads like a political message to me about the bounds between the nation and the US.

Shedite27 · 27-03-2019 01:59PM

Realistically is turning their back on Boeing an option for airlines?

Would Airbus have the capacity to churn out more planes if people wanted them?
Is there any other supplier that could get involved?
If Boeing did fall off in demand, would it not just create a monopoly?

L1011 · 27-03-2019 02:07PM

It would take years if not decades for Airbus and their suppliers to spin up production enough to replace Boeing. The Russians and Chinese are both in theory working on new aircraft of suitable sizes... but really, do you trust them either?

Trust in Boeing needs to be rebuilt. If it somehow seems utterly gone the logical thing to do would be to either sell the commercial aircraft division to another US manufacturer, e.g. Lockheed; but that's really really unlikely.

Also extremely unlikely, but with their new deal with Embraer, a 737 class replacement could be sold as an Embraer potentially. But also really not going to happen!

Henry Ford III · 27-03-2019 02:14PM

smurfjed wrote:

Did the AF330 crash stop you from flying on that aircraft type?

Wasn't the issue pilot error there?

vicwatson · 27-03-2019 02:23PM

Shedite27 wrote: »

Realistically is turning their back on Boeing an option for airlines?

Would Airbus have the capacity to churn out more planes if people wanted them?
Is there any other supplier that could get involved?
If Boeing did fall off in demand, would it not just create a monopoly?

L1011 wrote: »

It would take years if not decades for Airbus and their suppliers to spin up production enough to replace Boeing. The Russians and Chinese are both in theory working on new aircraft of suitable sizes... but really, do you trust them either?

Trust in Boeing needs to be rebuilt. If it somehow seems utterly gone the logical thing to do would be to either sell the commercial aircraft division to another US manufacturer, e.g. Lockheed; but that's really really unlikely.

Also extremely unlikely, but with their new deal with Embraer, a 737 class replacement could be sold as an Embraer potentially. But also really not going to happen!

Airbus wins China order for 300 jets in US$34b blow to Boeing

https://www.channelnewsasia.com/news/business/airbus-wins-china-order-jets-boeing-aviation-11380616

L1011 · 27-03-2019 02:27PM

Chinese orders are made for political reasons tbh.

murphaph · 27-03-2019 02:36PM

It would be bad for airlines and as a result passengers if Boeing vanished. A monopoly would be no good. Far better for the FAA & EASA (and the Chinese) to "cross inspect" each other's regimes more carefully than in the past. Boeing is the biggest exporter in the US. It is too big to fail and won't let be either. Root and branch reform of the processes and culture is required however.

Nijmegen · 27-03-2019 02:58PM

Boeing isn't going to vanish. But the regulatory heat on them is going to be turned up for a few years and the 797 is likely going to attract a lot more attention. Might we see a baby 797 I wonder.

serfboard · 27-03-2019 03:08PM

From RTE:

RTE wrote:

A Senate Commerce Committee panel will hold a hearing later today to question FAA Acting Administration Daniel Elwell and Transportation Department Inspector General Calvin Scovel.

The officials are expected to face questions on the FAA's certification of the 737 MAX and whether regulators have become too cozy with the company and fast-tracked some approvals.

Bob24 · 27-03-2019 07:36PM

L1011 wrote: »

The Russians and Chinese are both in theory working on new aircraft of suitable sizes... but really, do you trust them either?

They’re clearly not ready yet, but in a decade or so China will very likely have credible options and gain trust from airlines. The FAA and some other regulators will do everything they can to slow down adoption in some territories - but it will flourish in others.

Will be a serious challenge for Airbus and Boeing which while competitors are in a semi-monopolistic situation as airlines have no interest in a complete monopolistic situation and have to support both manufacturers.

billy few mates · 27-03-2019 07:52PM

vicwatson wrote: »

Airbus wins China order for 300 jets in US$34b blow to Boeing

https://www.channelnewsasia.com/news/business/airbus-wins-china-order-jets-boeing-aviation-11380616

That's more to do with Trump and his current trade war over tariffs on Chinese imports and the ban on Huawei devices and the arrest of thier CFO...

billy few mates · 27-03-2019 08:05PM

Bob24 wrote: »

Regardless of the root cause of the issue and how severe it is, at this stage I think it is madness for any airline to fly a 737 Max, even without passengers.

Any incident - serious or not - means instant and widespread bad PR.

And IMO it’s also in Boeing’s interest to recommend not to fly then under any circumstances for now besides test flights supervised by the manufacturer, as they also get badly affected by any potential incident.

That's pretty much how these flights are carried out. The manufacturer has to give approval, the airworthiness authorities issue the necessary permits and paperwork, the aircraft are flown by the most highly qualified and senior pilots on type.
I would have no problem flying on a 737max today or at any time in the future. There can't be too many pilots who aren't now fully aware of how the system works and fully prepared to hit the override switches the moment those trim wheels move if the aircraft is in manual flight.
I wouldn't surprised if it became a procedural response for one of the crew members to place their hand on or near the switch guard the moment MCAS light comes or the stab any time the trim wheels move
in MCAS conditions so in case of any doubt they can simply hit the switch and isolate the electric motor that drives it.

billy few mates · 27-03-2019 08:22PM

http://www.boeing.com/commercial/737max/737-max-software-updates.page

Damien360 · 27-03-2019 09:06PM

billy few mates wrote: »

http://www.boeing.com/commercial/737max/737-max-software-updates.page

So there were 2 sensors all along. But before this "fix", one sensor could cause errors or was it ever the sensor at all ?

Deaf student · 27-03-2019 09:52PM

The problem of 'trust' with Boeing as regards to MAX 737 that i have right up to now no matter their PR exercise. This is a damage limitation exercise for them as they try to limit the losses of sales.

coastwatch · 27-03-2019 10:00PM

Damien360 wrote: »

So there were 2 sensors all along. But before this "fix", one sensor could cause errors or was it ever the sensor at all ?

My understanding is the MCAS system uses just 1 of the 2 AOA sensors, so a fault with that sensor, could cause the MCAS to continually adjust the horizontal stabilisers. Apparently there is an alarm system that checks for differences between the two sensors (disagree alert) and alerts the crew by warning light, but this alarm was available as an "optional extra", ie. extra cost for airlines.

From reading that Boeing software update, the updated MCAS will not activate (or will de-activate) if the sensors disagree, and the warning
alarm will now be included on all new aircraft. I presume all the existing fleet will be upgraded too.

swampgas · 27-03-2019 10:09PM

Is there a possibility that the MCAS could engage legitimately, to prevent a stall (as I understand it), and the crew, paranoid about the MCAS issue, could disable the MCAS inappropriately? And that the issue the MCAS was designed to address becomes a real risk again?

Bebop · 27-03-2019 10:25PM

the bit about the original 737 fuselage design being narrow, is simply not true..Boeing used the original 707 fuselage section, they had developed a modular design which they also used for the 727/737/757 with the same 3x3 seating

billy few mates · 27-03-2019 11:10PM

Damien360 wrote: »

So there were 2 sensors all along. But before this "fix", one sensor could cause errors or was it ever the sensor at all ?

There has always been two sensors (alpha vanes), MCAS currently only uses one of them, from what I recall the system used to alternate between sensors on alternate legs but I'm not 100% certain of that.

L1011 · 27-03-2019 11:11PM

coastwatch wrote: »

My understanding is the MCAS system uses just 1 of the 2 AOA sensors, so a fault with that sensor, could cause the MCAS to continually adjust the horizontal stabilisers. Apparently there is an alarm system that checks for differences between the two sensors (disagree alert) and alerts the crew by warning light, but this alarm was available as an "optional extra", ie. extra cost for airlines.

From reading that Boeing software update, the updated MCAS will not activate (or will de-activate) if the sensors disagree, and the warning
alarm will now be included on all new aircraft. I presume all the existing fleet will be upgraded too.

Safer again would be 3+ AoA sensors and voting to exclude info from a faulty one, as is done on Airbus aircraft.

Irish Steve · 27-03-2019 11:22PM

And infinitely safer, but they were not ready to bite the bullet, would have been a new design that didn't need to be tweaked by MCAS to make it work like the previous versions did.

What's not been made clear yet is if the underlying issue is a fault with the AOA sensors, are they failing or somehow being damaged so that they don't work correctly, the MCAS inappropriate response to the wrong information from the active sensor is a massive fail by Boeing, but if the real issue is that there is some sort of design or manufacturing problem with the AOA sensor, or they are somehow being damaged in service, that's a very different issue that needs to be clearly addressed and clarified.

Turbulent Bill · 27-03-2019 11:30PM

L1011 wrote: »

Safer again would be 3+ AoA sensors and voting to exclude info from a faulty one, as is done on Airbus aircraft.

For voting to work, though, you need confidence that the 3 inputs are truly independent. This basically implies that the sensor processing systems aren't shared between sensors, otherwise common-mode failures in these are masked.

Given it looks like Boeing made a bags of the MCAS system design, it's probably safer for them to just to switch it off when an anomaly happens, and let the pilot interpret what's actually happening.

Bob24 · 27-03-2019 11:51PM

Turbulent Bill wrote: »

Given it looks like Boeing made a bags of the MCAS system design, it's probably safer for them to just to switch it off when an anomaly happens, and let the pilot interpret what's actually happening.

Isn’t the purpose of the system to make the flying characteristics the same as the previous generation?

And if it isn’t redundant and can disengage automatically and unexpectedly when it sense something is wrong with sensor data, can Boeing still argue the flying characteristic are the same?

Bob24 · 27-03-2019 11:52PM

Turbulent Bill wrote: »

Given it looks like Boeing made a bags of the MCAS system design, it's probably safer for them to just to switch it off when an anomaly happens, and let the pilot interpret what's actually happening.

Isn’t the purpose of the system to make the flying characteristics the same as the previous generation?

And if it isn’t redundant and can disengage automatically and unexpectedly when it senses something is wrong with sensor data, can Boeing still argue the flying characteristic are the same?

troyzer · 28-03-2019 10:00AM

OSI wrote: »

So apparently they've replicated the Lion Air flight in a sim and found the pilots effectively had 40 seconds to discover the root cause of their issue and fix it.

Is that a lot? I have no idea.

murphaph · 28-03-2019 10:59AM

troyzer wrote: »

Is that a lot? I have no idea.

I would say it is not a lot at all. As I posted previously, Boeing gave the flight crews of that flight no chance. It's 40 seconds while desperately trying to pull the stick back in a doomed effort to fight against the MCAS trimming the stab. It's disgraceful this whole business.

odyssey06 · 28-03-2019 11:00AM

murphaph wrote: »

I would say it is not a lot at all. As I posted previously, Boeing gave the flight crews of that flight no chance. It's 40 seconds while desperately trying to pull the stick back in a doomed effort to fight against the MCAS trimming the stab. It's disgraceful this whole business.

It might have been enough if they'd put it into the flight manual.

Nijmegen · 28-03-2019 12:02PM

I go back to an earlier point I made re US 1549 - Some (but not all) post-accident sims got the aircraft back to the field when they turned immediately after the simulated bird strike. But when they introduced a 35 second delay for real world figuring out status and options, they ended up dead. 40 seconds is not a lot of time to go from normal takeoff to -> unknown deadly things happening -> resolving the problem while you're fighting with the stick and trying to interpret alarms.

Raging_Ninja · 28-03-2019 12:03PM

OSI wrote: »

So apparently they've replicated the Lion Air flight in a sim and found the pilots effectively had 40 seconds to discover the root cause of their issue and fix it.

https://www.nytimes.com/2019/03/25/business/boeing-simulation-error.html

Well that's not necessarily accurate. The "40 seconds" was only reproduced if the pilots didn't press the electric stabilizer trim thumbswitch on the control yoke to override MCAS. The Lion Air pilots pressed it 24+ times, buying themselves a few-second reprieve each time before MCAS kicked in again.

Ethiopian Airlines Crash/ B737MAX grounding

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