Ethiopian airliner down in Africa

[phylosocopter]

https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/768x561/img_0098_9132c0f7e3266475d70c305a8dff22f11c3623b5.jpg
Good article: What is the MCAS? (https://theaircurrent.com/aviation-safety/what-is-the-boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/)

Simple answer if jet behaves unexpectedly: disconnect and fly it manually!


EEEEEEEEKKKKKK this diagram is fatally WRONG! it states that DEACTIVATES when "Pilots override with manual trim" IT DOES NOT! it pauses but REMAINS ACTIVE! which is a completely different thing! If i was looking for a smoking gun this is it! If this diagram came from Boeing then they are F*****kd

[HalfMoonRising]

I’d be interested to know of the QA plan, most obviously failure modes, and how it was executed and signed off.
Likewise, great comment. Pax/Ex-IT QA engr here. With all the discussion around MCAS being somewhat of a kludge to overcome an unbalanced design introduced by the heavier more forward mounted engines on the MAX, I have thought since start of this thread about necessity for a robust test script with particular emphasis on wringing out all possible failure types. Big no-no if this is engineer driven, they are notoriously focused on making stuff WORK. Proper test plan would of course pass/fail all feature/functionality stuff, but should primarily focus on making things BREAK, anticipating every possible adverse situation engineers might deem next to impossible, or so minor or rare as to be "insignificant". Testing impact of bad control inputs to MCAS seems rather a no-brainer, no?

[mini]

The key phrase is "along the lines of" , as apparently Boeing preferred not to admit to the possibility, let alone produce a procedure for it. In the absence of any guidance, what would be the quickest way to inhibit the MCAS system under pressure ? I suspect it would be to reproduce a configuration where it is inactive ?

Unfortunately it would appear that if the MCAS system has intervened due to a fault somewhere, you may be somewhat inhibited in configuring to inhibit. So to speak...

Dodgy airspeed - no AP
Flaps? not at 300Knts
High AOA? its pointing at the ground...

It seems flicking the switches is the only real option, easier said than done when you're hauling back 50Kgs amidst the disco and wondering WTF?

[Chesty Morgan]

To be clear, which switches are you talking about? The stab cutouts? The overhead?
The overhead. I think it was the Lufthansa with the sweep up - on. Ansett was the more traditional forward - on.

[JamesT73J]

I think the intent behind the system is not unusual, but with one AOA sensor? I can't quite get my head around that.

Why not have it read from both, if they disagree, go INOP and warn via ECAM? I don't know about the feasability of retrofitting the proper solution - triplex - but it seems that this is a pretty reckless implementation.

[Vessbot]

The overhead. I think it was the Lufthansa with the sweep up - on. Ansett was the more traditional forward - on.

Thanks for the clarification -- first I thought you meant the stab cutouts, which would have been bonkers crazy stupid (in addition to making me eat my words for the second time on one page!)

[JumpJumpJump]

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/720x1280/img_20190311_wa0016_591d779a46743a810b2dd4474215e3cc4faa7bf4 .jpg
737 max fleet grounded by Gol in Brazil.

They use their Max fleet for direct flights from Brazil to Florida.... Routes suspended, though imagine that they will be frantically working out how to honour current schedule with a fuel stop added in either the north of Brazil or the Caribbean

[First_Principal]

I see a number of comments relating to crew hours. In particular it has been said that the FO had '200 hours'. IF this is is total time, and it's correct, then by normal training methodology the FO could, at most, be a newly-minted CPL and have next to no time as a 'released to fly solo' pilot on this aircraft.

The source or veracity of this information appears to be a little hazy, however if it were correct then it would suggest to me that Ethiopian could have been operating outside of their own SOP's as outlined in s1.17.1.7 "Procedure for Flight Crew Pairing" on page 50 of the report into the ET409 accident dated 17th Jan 2012:

ET provided their procedure for crew pairing; the procedure is inserted as Appendix H of this
report. It stipulates under “Inexperience flight crews” that “Captain who has less than 300 hours
and F/O who has less than 100 hours on type should not be scheduled together.”

I offer this as information only and make no personal conclusion nor suggestion that crew experience could have contributed to this accident at this stage, particularly as, to the best of my knowledge, the source of the data is unverified.

Thus this detail from the accident report may simply call into question the veracity of the information regarding pilot hours, the training regime (FO especially), whether '100 hours on type' includes pre-CPL training or 'released to fly solo', relevance to current SOP's for the airline, or failure to follow their own procedure amongst various other possibilities.

FP.

[RoyHudd]

Firstly, I disagree about opposite switch direction. Having flown the same type with some switches ON/UP and on a different reg the same functions OFF/UP, I can tell you that many colleagues, and myself, made mistakes. Unlike the perfect people who insist on posting here.

Secondly, a question. Why did the Ethiopian B737 in this case keep accelerating? At 1000 ft AGL, in VMC, it is simple to see that the a/c is accelerating, without reference to instruments. (Maybe not for the FO, drastically inexperienced as he/she was).

I believe the training, regulatory and operating standards vary widely around our world. Just because every country has a CAA or equivalent, does not mean they are all able to adhere to the same standards. Most of us know that they do not. Most of us are just worried about the usual easily-voiced criticisms of nationalism, racism and the like, so we do not express our opinions.

Smaller, and less developed countries are unable to produce sufficient nationals to train or to operate complex jets to the same standards as the bigger, more developed countries. The accident stats bear this out.

[DaveReidUK]

Just released.

"we have not been provided data to draw any conclusions or take any actions"

[Chesty Morgan]

Firstly, I disagree about opposite switch direction. Having flown the same type with some switches ON/UP and on a different reg the same functions OFF/UP, I can tell you that many colleagues, and myself, made mistakes. Unlike the perfect people who insist on posting here.
Actually what I said was it didn't take much getting used to not that mistakes weren't made.

[joema]

I don't know if it's behind a paywall but NYT has a chart showing which 737 MAX operators have grounded them as of today.

https://www.nytimes.com/interactive/2019/03/11/world/boeing-737-max-which-airlines.html

Grounded - # of 737 MAX in operator's fleet
=================================
China Southern Airlines - 22
Air China - 15
SpiceJet - 13
Hainan Airlines - 11
Shanghai Airlines - 11
Xiamen Airlines - 10
Lion Air - 10
Jet Airways - 9
Shandong Airlines - 7
Shenzhen Airlines - 6
SilkAir - 6
Ethiopian Airlines - 4
China Eastern Airlines - 4
Lucky Air - 3
Cayman Airways - 2
Eastar Jet - 2
Fiji Airways - 2
Fuzhou Airlines - 2
Kunming Airlines - 2
Okay Airways - 2
9 Air - 1
Garuda Indonesia - 1
Comair - 1

Not Grounded (partial list)
====================
Southwestern Airlines - 34
Air Canada - 24
American Airlines - 24
Norwegian Air - 18
TUI fly - 15
WestJet - 13
FlyDubai - 11
Turkish Airlines - 11
Smartwings - 7
GOL Airlines - 7
Aeromexico - 6
Aerolineas Argentinas - 5
Oman air - 5
(remainder omitted for brevity)

[LiamNCL]

I don't know if it's behind a paywall but NYT has a chart showing which 737 MAX operators have grounded them as of today.

https://www.nytimes.com/interactive/2019/03/11/world/boeing-737-max-which-airlines.html

Grounded - # of 737 MAX in operator's fleet
=================================
China Southern Airlines - 22
Air China - 15
SpiceJet - 13
Hainan Airlines - 11
Shanghai Airlines - 11
Xiamen Airlines - 10
Lion Air - 10
Jet Airways - 9
Shandong Airlines - 7
Shenzhen Airlines - 6
SilkAir - 6
Ethiopian Airlines - 4
China Eastern Airlines - 4
Lucky Air - 3
Cayman Airways - 2
Eastar Jet - 2
Fiji Airways - 2
Fuzhou Airlines - 2
Kunming Airlines - 2
Okay Airways - 2
9 Air - 1
Garuda Indonesia - 1
Comair - 1

Not Grounded (partial list)
====================
Southwestern Airlines - 34
Air Canada - 24
American Airlines - 24
Norwegian Air - 18
TUI fly - 15
WestJet - 13
FlyDubai - 11
Turkish Airlines - 11
Smartwings - 7
GOL Airlines - 7
Aeromexico - 6
Aerolineas Argentinas - 5
Oman air - 5
(remainder omitted for brevity)

I believe GOL can go on 'Grounded' list now.

[HEMS driver]

If it's Boeing, I'm not going.

[henra]

Fuel contamination, engine problems, flight control problems, terrorism, instrument problems, birdstrike, suicide, runaway trim ? Nothing can be excluded, but ony one issue is discussed.
MCAS.

Have you looked at least to the most crude bits of information on this crash before climbing up the sope box?
Fuel contamination, engine problems => 383kts, Ultra high energy impact. Scrap it.
instrument problems: 383kts (read: no stall) and sunny, nice weather => WTF instrument should cause this??? I don't see a reasonable scenario for this.
bird strike: => why spearing along at 1000ft at ridiculous speeds after being hit by a bird??? That would be exactly opposite of what you would want to do: Higher altitude and low speed. IMHO not really supported from what we know so far.

I would accept flight control problems ( would be extremely worrying though on a just 5 month old aircraft of a new type!), suicide (but why would someone fly for so long at low altitude and high and increasing speed when he wants to commit suicide?), runaway trim (here we go -that is what has been mostly discussed and wehre there is a precedence).

So if I draw a line below your objection I still end up mostly with what is being discussed here (although I agree it is much to early to be sure it was MCAS).
Would I happily board a MAX tomorrow? Not if I could avoid it.

[Callsign Kilo]

Someone mentioned that the MCAS provides 10 secs of trim input when activated. Can that be correct/verified? 10 secs of trim input is massive on the 737. The stabiliser is a powerful secondary flight control and has known limitations - for example Boeing are explicit about overuse of stabiliser trim
during the approach to stall recovery. Positioning the stabiliser in such a sense can severely reduce elevator authority - was this not the contributing factor in the FlyDubai 738 crash in Rostov? Two separate variants, one without MCAS, but with the same concerns relating to pitch authority?

[SMYDSTS]

Big well done to Southwest Airlines Safety Department for retrofitting their Max’s with the optional head down AoA display after the Lion Air accident! I wonder how many other Safety Managers would have liked to get the budget for that too?
I read that the head down display option was an extra $60K on top of the purchase price of a new Max? Small price to pay for the extra info, although I’m not sure that more extra info is needed - the PFD is starting to look like an F1 steering wheel. Can anyone confirm if the AoA disagree warning light is also an option and was it installed on the ET fleet?

[Thomas coupling]

Phylosocopter.
Correct, the statement is incorrect - one cannot overide manually, the system stays in and you have to motor the trim fwd electronically using the system.

Happened with Lion Air.

Wouldn't like to be the CEO Boeing tonight!

Many airlines have trained their pilots to resolve this issue properly....unfortunately, others .....have not.

[oldoberon]

Can someone clear up something for me please.

I know from reading the whole thread the MCAS has a single AoA input, but some post refer to xchecking against the 2nd AoA ( which is not connected to MCAS)

However post 188 says this

post 188

At least Southwest took it's own initiative by adding an extra AOA indicator into 737 MAX for crew to cross-check erroneous data, but, shouldn't that be a Boeing responsibility and hence fitted to the worldwide fleet? I doubt Ethiopian purchased or insisted on these upgrades.

Is this extra a 3rd AoA or is there only 1 AoA and this IS the 2nd "comparison only" one.

Just to add I was horrified to read the certification is basically a grandfather one, when major changes to airframe, engine or flying controls are made it should be a new certification, loved the analogy " like putting a new dash and a 300bhp engine in a model T and saying it is safe to use!

ta

Oldoberon

[ManaAdaSystem]

Have you looked at least to the most crude bits of information on this crash before climbing up the sope box?
Fuel contamination, engine problems => 383kts, Ultra high energy impact. Scrap it.
instrument problems: 383kts (read: no stall) and sunny, nice weather => WTF instrument should cause this??? I don't see a reasonable scenario for this.
bird strike: => why spearing along at 1000ft at ridiculous speeds after being hit by a bird??? That would be exactly opposite of what you would want to do: Higher altitude and low speed. IMHO not really supported from what we know so far.

I would accept flight control problems ( would be extremely worrying though on a just 5 month old aircraft of a new type!), suicide (but why would someone fly for so long at low altitude and high and increasing speed when he wants to commit suicide?), runaway trim (here we go -that is what has been mostly discussed and wehre there is a precedence).

So if I draw a line below your objection I still end up mostly with what is being discussed here (although I agree it is much to early to be sure it was MCAS).
Would I happily board a MAX tomorrow? Not if I could avoid it.

Have you read what FAA says? They can’t draw any conclusions.
You obviously know better.

[savall]

Can someone clear up something for me please.

I know from reading the whole thread the MCAS has a single AoA input, but some post refer to xchecking against the 2nd AoA ( which is not connected to MCAS)

However post 188 says this

post 188

At least Southwest took it's own initiative by adding an extra AOA indicator into 737 MAX for crew to cross-check erroneous data, but, shouldn't that be a Boeing responsibility and hence fitted to the worldwide fleet? I doubt Ethiopian purchased or insisted on these upgrades.

Is this extra a 3rd AoA or is there only 1 AoA and this IS the 2nd "comparison only" one.

ta

Oldoberon
They opted to have an additional sensor added as backup verification. A feature which I believe should have been installed as standard.

[downunderupover]

According to math an unlikely indecent is more likely to happen the next day than on "the average" time.

Perhaps I can help. Some "indecents," while unlikely, may be welcome. Others are unwelcome and one hopes they remain unlikely.

[LandASAP]

I don't know if it's behind a paywall but NYT has a chart showing which 737 MAX operators have grounded them as of today.

https://www.nytimes.com/interactive/2019/03/11/world/boeing-737-max-which-airlines.html

Grounded - # of 737 MAX in operator's fleet
=================================
China Southern Airlines - 22
Air China - 15
SpiceJet - 13
Hainan Airlines - 11
Shanghai Airlines - 11
Xiamen Airlines - 10
Lion Air - 10
Jet Airways - 9
Shandong Airlines - 7
Shenzhen Airlines - 6
SilkAir - 6
Ethiopian Airlines - 4
China Eastern Airlines - 4
Lucky Air - 3
Cayman Airways - 2
Eastar Jet - 2
Fiji Airways - 2
Fuzhou Airlines - 2
Kunming Airlines - 2
Okay Airways - 2
9 Air - 1
Garuda Indonesia - 1
Comair - 1

Not Grounded (partial list)
====================
Southwestern Airlines - 34
Air Canada - 24
American Airlines - 24
Norwegian Air - 18
TUI fly - 15
WestJet - 13
FlyDubai - 11
Turkish Airlines - 11
Smartwings - 7
GOL Airlines - 7
Aeromexico - 6
Aerolineas Argentinas - 5
Oman air - 5
(remainder omitted for brevity)
I see at least Lion Air and Spice Jet sill flying max on FR24 ...

[lucille]

I have difficulty in believing that this is a similar failure to the Lion Air one.

After the LionAir accident, any 737 Max pilot worth his salt would have read up on it, understood the new system and would be clear in his mind on how to deal with it. This is what all of us would do without exception.

[Organfreak]

You'd do well to stay home, then. It's not whether or not mistakes are made - they're always being made. The question is whether or not they're recognized and corrected before things go pear-shaped.

Well, quite. I didn't intend to say that "mistakes can never be made," but rather that we not mention them so casually as if they don't matter. Sometimes they do. I'll sit down and be quiet now.

[WHBM]

I don't know if it's behind a paywall but NYT has a chart showing which 737 MAX operators have grounded them as of today.
You would normally expect that the FAA/EASA, as principal safety regulators, would be making the running here, but they are getting left behind by the operators, the ones who get the financial hit from such action - and who are headed up by decidedly practical and knowledgeable aviation professionals.

I wonder what, if any, compensation to the operators Boeing will be offering.

[YukonHusky]

The procedures that were rushed out after Lionair and didnt appear to help either pilot in the cockpit in this case ?Nobody knows what caused this crash, and nobody knows what actions they did.Not only does nobody know what caused this crash nor the exact actions or inactions of the pilot and FO, it's woefully premature to speculate whether the pilot and FO even knew about Boeing's post-Lionair crash new procedures let alone whether they read the procedures, followed the procedures nor whether such procedures were even related to the cause of Ethiopian air crash. Premature much rmac?

[bluesideoops]

The graph has striking resemblances to Lion Air crash...

[extreme P]

Someone mentioned that the MCAS provides 10 secs of trim input when activated. Can that be correct/verified? 10 secs of trim input is massive on the 737. The stabiliser is a powerful secondary flight control and has known limitations - for example Boeing are explicit about overuse of stabiliser trim
during the approach to stall recovery. Positioning the stabiliser in such a sense can severely reduce elevator authority - was this not the contributing factor in the FlyDubai 738 crash in Rostov? Two separate variants, one without MCAS, but with the same concerns relating to pitch authority?

MCAS trims 0.27 units per second - up to 2.5 units in 10 second cycle

[tarkay01]

They opted to have an additional sensor added as backup verification. A feature which I believe should have been installed as standard.

i believe SWA simply added an AOA display. The standard 737 does not display AOA readings nor does it directly indicate an AOA disagree status.

[oldoberon]

Savall

yes I k now that but is this additional one 2nd or 3rd AoA, some posts ask why they didn't look at the other AoA read out ie there are 2 others appear to say there is only 1.

If only 1 adding another very wise , if there are already 2 why add a 3rd

oldoberon

[hans brinker]

Can someone clear up something for me please.

I know from reading the whole thread the MCAS has a single AoA input, but some post refer to xchecking against the 2nd AoA ( which is not connected to MCAS)

However post 188 says this

post 188

At least Southwest took it's own initiative by adding an extra AOA indicator into 737 MAX for crew to cross-check erroneous data, but, shouldn't that be a Boeing responsibility and hence fitted to the worldwide fleet? I doubt Ethiopian purchased or insisted on these upgrades.

Is this extra a 3rd AoA or is there only 1 AoA and this IS the 2nd "comparison only" one.

Just to add I was horrified to read the certification is basically a grandfather one, when major changes to airframe, engine or flying controls are made it should be a new certification, loved the analogy " like putting a new dash and a 300bhp engine in a model T and saying it is safe to use!

ta

Oldoberon


AFAIK there are 2 AOA-s on the 737, the MCAS uses only AOA-1, Southwest elected the option of having AOA-1 on the PIC EFIS & AOA-2 on FO EFIS. please correct me if I am wrong.
Also if you want to see "grandfathered", compare the DC-9 cockpit with the B717. Same type rating, one day differences class is all that is required to go from one to the other.....

[hans brinker]

They opted to have an additional sensor added as backup verification. A feature which I believe should have been installed as standard.

I don't think so. There is 2 AOAs installed on every MAX, SWA bought the option to have the AOA info displayed to the pilots on their respective instruments, not just the AOA disagree light.

[savall]

I don't think so. There is 2 AOAs installed on every MAX, SWA bought the option to have the AOA info displayed to the pilots on their respective instruments, not just the AOA disagree light.
Thanks for the correction. I am not familiar with the type, I misinterpreted an earlier post. I still believe having two readouts would have been a sound decision from the beginning.

[GroundGeek]

I'm a (non-aero) engineer who has done User Interface work in the past. All of the discussions of MCAS seem to suggest you'll only know it's active when the nose pitches down (et al.) without being commanded.

Is there no definitive visual or auditory signal that MCAS is active?

[oldoberon]

Hans

"AFAIK there are 2 AOA-s on the 737, the MCAS uses only AOA-1, Southwest elected the option of having AOA-1 on the PIC EFIS & AOA-2 on FO EFIS."

I am ex ground crew don't know all your abbreviations but you seem to be saying there were always 2 they just reconfigured their functionality.NOT added another as post 188 stated, what is the resulting effect of their change

oldoberon

[Speed of Sound]

FAA says Boeing 737 Max 8 is airworthy http://www.bbc.co.uk/news/world-africa-47533052

This may well come back to bite them!

[Winemaker]

Have you looked at least to the most crude bits of information on this crash before climbing up the sope box?
Fuel contamination, engine problems => 383kts, Ultra high energy impact. Scrap it.
instrument problems: 383kts (read: no stall) and sunny, nice weather => WTF instrument should cause this??? I don't see a reasonable scenario for this.
bird strike: => why spearing along at 1000ft at ridiculous speeds after being hit by a bird??? That would be exactly opposite of what you would want to do: Higher altitude and low speed. IMHO not really supported from what we know so far.

I would accept flight control problems ( would be extremely worrying though on a just 5 month old aircraft of a new type!), suicide (but why would someone fly for so long at low altitude and high and increasing speed when he wants to commit suicide?), runaway trim (here we go -that is what has been mostly discussed and wehre there is a precedence).

So if I draw a line below your objection I still end up mostly with what is being discussed here (although I agree it is much to early to be sure it was MCAS).
Would I happily board a MAX tomorrow? Not if I could avoid it.

Okay, I can add one: Pilot disabled for some reason, FO unable to fly the plane.

[hans brinker]

Hans

"AFAIK there are 2 AOA-s on the 737, the MCAS uses only AOA-1, Southwest elected the option of having AOA-1 on the PIC EFIS & AOA-2 on FO EFIS."

I am ex ground crew don't know all your abbreviations but you seem to be saying there were always 2 they just reconfigured their functionality.NOT added another as post 188 stated, what is the resulting effect of their change

oldoberon

Sorry, after 30 years it is hard not to speak in allcaps three letter words, here is the English version:
Every 737 has 2 Angle Of Attack indicators, and an OPTIONAL warning light for a difference in value between the two. SW have paid extra to display the actual AOA value displayed on the respective pilots instruments. The left pilot seas AOA one, the right pilot sees AOA 2 values. These should be the same, and if they are not seeing the value could help in deciding who is right.

[MemberBerry]

Sorry, after 30 years it is hard not to speak in allcaps three letter words, here is the English version:
Every 737 has 2 Angle Of Attack indicators, and a warning light for a difference in value between the two. SW have paid extra to display the actual AOA value displayed on the respective pilots instruments. The left pilot seas AOA one, the right pilot sees AOA 2 values. These should be the same, and if they are not seeing the value could help in deciding who is right.

Correct, except the AOA disagree warning light is an optional extra on the 737 MAX, so not every 737 has it.

For example the Lion Air 737 MAX didn't have either of those options installed, so it would have been difficult for the crew to determine they had an AOA disagree situation or not.

[oldoberon]

Several more airlines pull the 737 Max after the 2nd crash in Ethiopia.

Royal Air Maroc RAM, and now BA RSA franchise Comair.

whio would make he Comair decision

Oldoberon

[lancs]

AFAIK there are 2 AOA-s on the 737, the MCAS uses only AOA-1
From the Lion Air thread, I believe MCAS cycles between the 2 AOAs between each flight....

[b1lanc]

Sorry, after 30 years it is hard not to speak in allcaps three letter words, here is the English version:
Every 737 has 2 Angle Of Attack indicators, and a warning light for a difference in value between the two. SW have paid extra to display the actual AOA value displayed on the respective pilots instruments. The left pilot seas AOA one, the right pilot sees AOA 2 values. These should be the same, and if they are not seeing the value could help in deciding who is right.

Decent write-up here. Also says American had opted for the display feature from the get go.

https://theaircurrent.com/aviation-safety/southwest-airlines-is-adding-new-angle-of-attack-indicators-to-its-737-max-fleet/

[thcrozier]

I haven’t flown a plane as PIC since 1994, but I’m pretty systems automation and computer savvy. Reading the above posts I get the feeling that hardly anyone understands how MCAS really works, not even its designers. It reminds me of the financial crisis a decade ago when the so-called professionals ultimately didn’t understand what they created.

Pages of debate on both this and the Lion Air threads about how the thing actually behaves should be a big red flag, regardless of the actual cause of these accidents.

[WillowRun 6-3]

Phylosocopter, the diagram is marked with Ostrower's trademark. It's 98.9 percent clear that it is something Jon created to explain somewhat arcane and technical flight control systems to an essentially layman readership (for his publication "The Air Current"). Not carrying water for Jon here but -- Boeing has enough of headaches at the moment, without even a "rumour" that gives forum folks the "EEEKs."

WillowRun 6-3

[CONSO]

re post 52111th Mar 2019, 15:33
#521 (https://www.pprune.org/showpost.php?p=10414332&postcount=521) (permalink (https://www.pprune.org/showthread.php?p=10414332))

phylosocopter



. . .


Ask the author where he got the data and MIS info on MCAS- re override by pilot
https://theaircurrent.com/author/jonostrower/

[OldnGrounded]

Pages of debate on both this and the Lion Air threads about how the thing [MCAS] actually behaves should be a big red flag, regardless of the actual cause of these accidents.

Yes. In the discussions of both crashes, it has been striking that there has been so much confusion and disagreement about the operation of MCAS, much of it on the part of transport-experienced professional aviators. And no matter how much relevant material I've read, or how often I've re-read it, some things still aren't clear. For instance, some descriptions of the "system" (software patch) suggest that it is necessary for the MAX to be in a high bank for it to be activated. That doesn't make sense and it doesn't seem to have been the case in the Lion Air or the ET crashes (if the ET incident was MCAS-related), but it pops up repeatedly in lists and graphics.

Common sense and basic principles of human engineering dictate that a system or application that creates this much uncertainty and confusion, even among experts in a discipline, is begging for redesign.

[cooperplace]

I get the feeling that hardly anyone understands how MCAS really works,

yep, I sure as hell don't and I'd love to see it explained in a way so that a dimwit like me (LSA pilot) can understand.

[WillowRun 6-3]

". . . begging for redesign" [OldnGrounded]

Seems a prudent conclusion - based on present state of actual information and reasonable inferences.
But there's another design redo flopping onto agendas, isn't there? The certification process itself. Maybe the lithium-ion batteries were a vague straw in the wind, albeit not stretching out an older type design as such. Clearly the MCAS situation - even if this accident doesn't turn out to be rooted in MCAS - is a strong indicator. As others have stated here and on Lion Air 610 thread, the process being set-up and administered so that mods can be added, to a basic type that is decades old, with this result, should not be allowed to persist. I won't even try to sketch a new and improved architecture for the FARs and the industry-regulator collaboration arrangement, even if I could, but isn't this work coming into necessity?

WillowRun 6-3

[Dee Vee]

Boeing to upgrade software in 737 MAX 8 fleet in 'weeks'

https://www.reuters.com/article/ethiopia-airplane-boeing/boeing-to-upgrade-software-in-737-max-8-fleet-in-weeks-idUSL1N20Z01K

Just wow... Begs the question, how long have they known about the issues???
Was the aircraft pushed out too early to "meet schedule" and increase profit?

[Raptor Systems TT]

How?

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/650x488/2019_03_10t135005z_2006177136_rc18e19c5000_rtrmadp_3_ethiopi a_airplane_e1552227042286_46c7d5480e66a6e7f69c4e0cb9bad4f7b5 ac8faf.jpg

[CONSO]

The FAA Has No Current Plans to Ground Boeing’s 737 MAX After Deadly Crash

Agency to mandate software fix by end of April :mad:


from WSJ behind paywall
ByRobert Wall,Andrew Tangel andAndy Pasztor

Updated March 11, 2019 8:35 p.m. ET

The Federal Aviation Administration said Monday it doesn’t plan to ground Boeing (https://quotes.wsj.com/BA) Co.’s BA -5.33% (https://quotes.wsj.com/BA?mod=chiclets) 737 MAX planes, despite concerns by other countries, passengers and airline employees after the model’s second crash in less than five months.


But yet they grounded 787 worldwide for two battery fires with no deatchs or injuries ..

Now that A covers are in place - we ill follow SOP and carefully avoid pointing fingers at ???

:ugh:

[oldoberon]

lancs said " From the Lion Air thread, I believe MCAS cycles between the 2 AOAs between each flight..""..

If the system uses 1 &2 on alternate flights both are wired in, I would think it is relatively simple to put a 1-2 switch in the cockpit but it is only active when the red light / HUD shows there is a difference, that could possibly immediately allow crew to rectify problem

Oldoberon

[AerocatS2A]

I recently transitioned to an Airbus from an old British machine. It wasn’t until some months into flying the bus that I realised the switch directions were opposite to what I was supposedly used to. You see, what I’d been doing is this, if I knew something was off and I wanted to turn it on, I would locate the appropriate switch and move it to its other position. I would then check that what was once off was now on and I would carry on. I do something similar with light switches in a room, if the lights are off, I locate a light switch and move it to its opposite position, I then check that the lights have come on. If they haven’t, I look for another light switch and repeat the procedure ;).

I find it very hard to believe that someone could be confused by switch direction. If the trims need to be cutout, you lift the guard and move the switch. Right? You don’t lift the guard, observe the switch in a particular position, mistake that position for OFF, and then assume that somehow the switch was already off! Talk about overthinking.

[Amelia_Flashtart]

Fiji Airways have not grounded their two - I am about to board one

[sdelarminat]

Aerolíneas Argentinas has suspended their MAX operations, currently 5 in the fleet.

[PJ2]

lancs said " From the Lion Air thread, I believe MCAS cycles between the 2 AOAs between each flight..""..

If the system uses 1 &2 on alternate flights both are wired in, I would think it is relatively simple to put a 1-2 switch in the cockpit but it is only active when the red light / HUD shows there is a difference, that could possibly immediately allow crew to rectify problem

Oldoberon
There is no information in the current B738M AOM that tells crews that the "MCAS cycles between the left AoA and the right AoA sensor". What is the source for the above statement?

[jolihokistix]

In Boeing's Nov 6 2018 (FAA as of that date unapproved) bulletin, p. 25, Skyjob's post#496, no mention is made anywhere by Boeing of MCAS.

In Post #511, the clear graphic from Air Current states that MCAS activates when 'steeply turning'.

[GordonR_Cape]

lancs said " From the Lion Air thread, I believe MCAS cycles between the 2 AOAs between each flight..""..

If the system uses 1 &2 on alternate flights both are wired in, I would think it is relatively simple to put a 1-2 switch in the cockpit but it is only active when the red light / HUD shows there is a difference, that could possibly immediately allow crew to rectify problem

Boeing's software update for the 737 MAX should address the AOA-1 vs -2 inconsistency (assuming that is its scope), obviating the need for physical switches. That also seems a good stage to include reasonability checks on AOA data before triggering MCAS.

[CONSO]

In Boeing's Nov 6 2018 (FAA as of that date unapproved) bulletin, p. 25, Skyjob's post#496, no mention is made anywhere by Boeing of MCAS.

In Post #511, the clear graphic from Air Current states that MCAS activates when 'steeply turning'.

But there is more for example post 427 also applies and AirCurrent does a lot of interpretation



MCAS activates automatically when all of the following conditions are met:
http://cdn.jsdelivr.net/emojione/assets/3.1/png/64/1f449.png High angle of attack ( could be high bank angle for example )
http://cdn.jsdelivr.net/emojione/assets/3.1/png/64/1f449.png Autopilot disengaged
http://cdn.jsdelivr.net/emojione/assets/3.1/png/64/1f449.png Flaps are up

[hans brinker]

Correct, except the AOA disagree warning light is an optional extra on the 737 MAX, so not every 737 has it.

For example the Lion Air 737 MAX didn't have either of those options installed, so it would have been difficult for the crew to determine they had an AOA disagree situation or not.

Thanks, edited my post accordingly

[juice]

Straits Times says SAL will ground.

https://www.straitstimes.com/singapore/transport/singapore-to-ground-all-boeing-737-max-8-planes-after-ethiopian-airlines-crash

[MemberBerry]

There is no information in the current B738M AOM that tells crews that the "MCAS cycles between the left AoA and the right AoA sensor". What is the source for the above statement?

I'm not the person you replied to but I tried to find some sources for it, I could only find an article titled "737 FCC Pitch Axis Augmentation - Command Integrity Mandate for Dual Channel, Fail-Safe" on satcom guru.

They assume that's the case because that's how the similar speed trim and mach trim functions work, the functions are controlled by the active FCC, and the active FCC changes when the plane lands, and reverts to one the left side after a power cycle.

[hans brinker]

Yes. In the discussions of both crashes, it has been striking that there has been so much confusion and disagreement about the operation of MCAS, much of it on the part of transport-experienced professional aviators. And no matter how much relevant material I've read, or how often I've re-read it, some things still aren't clear. For instance, some descriptions of the "system" (software patch) suggest that it is necessary for the MAX to be in a high bank for it to be activated. That doesn't make sense and it doesn't seem to have been the case in the Lion Air or the ET crashes (if the ET incident was MCAS-related), but it pops up repeatedly in lists and graphics.

Common sense and basic principles of human engineering dictate that a system or application that creates this much uncertainty and confusion, even among experts in a discipline, is begging for redesign.

The Lion Air crash happened presumably because of a faulty AOA indicator. I guess the Boeing statement about needing high bank is related to needing a high AOA (so low speed and high bank) to activate MCAS as opposed to a separate AOB input into MCAS. This further proves you are totally right about the confusion and disagreement.

[gums]

AoA sensor switch for MCAS
_________________________
Salute PJ2 !!

The alternating AoA sensor scheme was fully eplained in the 610 thread and apparently was defeated for the 610 flight leg due to disconnecting things and putting in new things. Don't have time now to give you a specific post, but it is all there or on the tech log companion.

Gums sends...

[RatherBeFlying]

We are all keenly interested in what the FDR and CVR will show from this second accident.

Either they will show:

a similar scenario as Lion or
something different.

Barring something out of control by the crew and manufacturer, neither outcome will reflect well on the MAX.

The 37 has enjoyed an extraordinary run of success since its inauguration, but the latest engineering efforts seem to have pushed an initially robust and exemplary design into fragile behavior .

[jimtx]

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/720x1280/img_20190311_wa0016_591d779a46743a810b2dd4474215e3cc4faa7bf4 .jpg
737 max fleet grounded by Gol in Brazil.

They use their Max fleet for direct flights from Brazil to Florida.... Routes suspended, though imagine that they will be frantically working out how to honour current schedule with a fuel stop added in either the north of Brazil or the Caribbean
That's surprising since Brazil's certifying authority differed with others and required training on the MCAS system. What that training was and whether it was a pencil whip might explain their grounding.

[RetiredTooEarly]

Gotta agree!

In great VMC conditions - as reported - even the very worst of pilots should surely be able to maintain some semblance of the old Straight and Level.

Seems inconceivable to me that even if this Max had the same airspeed/attitude problems as the last one that crashed, the pilots couldn't have controlled it?

Something else going gone here I suspect!

A bad start to 2019!

[thcrozier]

Clearly the MCAS situation - even if this accident doesn't turn out to be rooted in MCAS - is a strong indicator.

Agreed. Aerodynamic problems have been buffered by computerized controls at least since OXCART, which experienced lopsided flameouts at close to Mach 3 because the pilots were unable to manually adjust the intake cones with adequate precision. It was a fight to get the test pilots to agree to the automation at that time, even though a couple had been lost.

Now, 60 years later, we seem to have turned 180 degrees in our thinking. As little as I understand MCAS, it is clear, at least to me, that it is a computer controlled solution to aerodynamic instability inherent in the design.

While computerized aerodynamic stabilization of inherently unstable new designs may be the trajectory of future, to apply it as a fix as we push 50 year old designs to new limits may prove to be a mistake.

[gear lever]

Easily the most sensible and correct post I have read so far.
Speculation is just that. All will be revealed in good time.

And how long will that take and possibly how many more MAX's will crash (or nearly do so)? I would guess 2 or 3 years for the publication of an Ethipian Accident Report, so should we just sit on our hands and wait patiently? Of course not. Humans are curious by their nature and this thread proves that. The quicker the CVR and DFDR are downloaded and we know more, the better.

Without reading 500 odd posts, do we know who was PF? The experienced Captain or the inexperienced Co-PIlot? Steep expereince difference don't you think?

[CONSO]

Interesting details/analysis by a control guru which **may** help explanation of which sensor does what and how

https://www.satcom.guru/2018/11/737-fcc-pitch-axis-augmentation-command.html

Obviously put together after LionAir . .

Peter was Boeing avionics supervisor for 767 and 747-400 data link recording, data link reporting, and satellite communications. He was an FAA designated engineering representative (DER) for ACARS, satellite communications, DFDAU, DFDR, ACMS and printers. Peter was lead engineer for Thrust Management System (757, 767, 747-400), also supervisor for satellite communications for 777, and was manager of terminal-area projects (GLS, MLS, enhanced vision).

[etudiant]

The crew reported problems with air speed indications. Does that invalidate the reported 383kt speed?
It does seem a high speed for less than 6 minutes after takeoff and at low altitude. Is it even credible?

[Airbubba]

Interesting details/analysis by a control guru which **may** help explanation of which sensor does what and how

Peter made a few posts here a couple of years ago but I think someone didn't like his ADS-B analysis.

[ChicoG]

Interesting piece from Slate:

"Boeing’s either going to have to come up with a very convincing fix for whatever caused these two crashes, or think about starting over with a fresh sheet of paper.".

https://slate.com/technology/2019/03/ethiopian-air-crash-where-did-boeing-go-wrong-with-the-737-max.html

[jolihokistix]

Interesting yes, but if they can write this with a straight face... "Malaysia Airlines, which the public viewed with misgivings after it lost two 777s in less than five months in 2014. Though it bore no obvious responsibility for either incident—one was shot down by Russia, the second was hijacked..." how deep will the rest of it be?

[MD80767 Driver]

Captain was Pilot Flying. Addis is a "Capt only" Airport

[FCeng84]

737 MAX stabilizer cutout switches are guarded. With the guards in their normal, closed positions the switches are forced into the position that provides normal operation of the stabilizer. To cutout the stabilizer motor (i.e., disable electric trim from any source) the guards must be raised and the switches moved to the position that is only possible with the guards raised. Guarded switches of this sort provide two very strong levels of safety. First they make it very difficult/impossible to toggle the switch inadvertently as the guard must be raised before the switch can be toggled. Second they make the polarity of the switch very clear as normal operation position is the only one possible with the guard closed.

[Capn Bloggs]

The crew reported problems with air speed indications. Does that invalidate the reported 383kt speed?
It does seem a high speed for less than 6 minutes after takeoff and at low altitude. Is it even credible?
If you stayed at low level and didn't pull the power WAY back (eg if you didn't know what speed you were doing) you'd very quickly (less than 6 minutes) be going VERY VERY fast.

Done a low-level level-off recently?

[Icelanta]

Captain was Pilot Flying. Addis is a "Capt only" Airport

are you ET. Crew?
ADD is certainly NOT Cat C or Captain Only in most companies.

[PJ2]

lancs said " From the Lion Air thread, I believe MCAS cycles between the 2 AOAs between each flight..""..

If the system uses 1 &2 on alternate flights both are wired in, I would think it is relatively simple to put a 1-2 switch in the cockpit but it is only active when the red light / HUD shows there is a difference, that could possibly immediately allow crew to rectify problem

Oldoberon

Is this correct? Can someone cite the source?

[CONSO]

What is the source for the above statement? There is no information in the current B738M AOM that tells crews that the "MCAS cycles between the left AoA and the right AoA sensor".




I **suspect** ther confusion comes from a much earlier post- probably re lion/maintenance comments that as I ***vaguely *** recall - there is an automatic change/switch of right side to left side computer systems/ TO displays every flight cycle or similar.

[etrang]

Some rough working assumptions (probably overly optimistic):

350 aircraft
In service for 2 years, each aircraft available 340 days/yr, 5 sectors/day.
Total number of departures: approx 1.2m giving a fatal accident rate of 1.67 per million flights.

In comparison using figures up to 2017:

Banderantie - 3.07. (Ouch!)
Concorde - 11.36 (indicative of very low numbers in service and utilisation)
F28 - 1.65
A310 - 1.34
B747 (early models) 1.02
B747 (-400 onwards) - 0.06
B737 (all models) - 0.28
A320 series - 0.11


First 737 max was delivered in May 2017 so none have been in operation for 2 years. Most have been in operation for less than 1 year. 5 sectors per day is also a very high estimate.

[Old King Coal]

Captain was Pilot Flying. Addis is a "Capt only" Airport

Not necessarily. In FlyDubai I seem to recall that it was, but in other airlines that I've been in it was not. It depends upon the airline and how they choose to categorise it.

[Chris2303]

https://pbs.twimg.com/media/D1Zt2ktX4AAChBX.jpg

I profoundly hope and pray this doesn't come back to bite them

[c53204]

https://www.reuters.com/article/ethiopia-airplane-boeing/boeing-to-upgrade-software-in-737-max-8-fleet-in-weeks-idUSL1N20Z01K

Just wow... Begs the question, how long have they known about the issues???
Was the aircraft pushed out too early to "meet schedule" and increase profit?

Sick of hearing the “safety come first” quote. How many accidents have been caused by trying to save money? Do they think people are stupid?

[FCeng84]

Is this correct? Can someone cite the source?

This is correct. MCAS is implemented within the two Flight Control Computers (FCCs). The Left FCC uses the Left AOA sensor for MCAS and the Right FCC uses the Right AOA sensor for MCAS. Only one FCC operates at a time to provide MCAS commands. With electrical power to the FCCs maintained, the unit that provides MCAS changes between flights. In this manner, the AOA sensor that is used for MCAS changes with each flight.

[PJ2]

Thanks very kindly, FCeng84.

The switching from left to right to left etc., would likely be handled by the air-ground condition, I suspect?

[Dark Knight]

This still will not prevent an urgent or quick movement of the switches to the OFF position if necessary.
From B707's, B727 & B747 all the same where in the event of a runaway stabilizer (or serious Nose Up\Down Stab trimming) the procedure was/is to switch the Stab Trim off and revert to Manual trim.
Instilled into me when flying these types and exercises practiced in simulator form time to time.

Would have thought this would have summed all up and provided operations Departments and Pilots with fairly clear instructions?
https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/1994x1639/boeing_737_max_service_bulletin_aoa_jpeg_074af6c932ab8f49b23 3dbe4dc22cfd1db0c2fc9_405e31058d86fdb8b0aed477b5c5de0bb6b77b 28.jpg

[greenfields]

Sick of hearing the “safety come first” quote. How many accidents have been caused by trying to save money? Do they think people are stupid?





Well aren't they? They'll go with the dodgiest of airlines to save $50! So the answer is, yes, people are stupid so maybe they are thinking exactly that.

We are all keenly interested in what the FDR and CVR will show from this second accident.

Either they will show:
a similar scenario as Lion or
something different.
Barring something out of control by the crew and manufacturer, neither outcome will reflect well on the MAX.



Really? Do we not understand that had the crew in the Lionair accident performed the Runaway Stabiliser NNC then the jet will have in all likelihood have landed safely, as it did when the previous crew followed procedure? The Boeing bulletin is emphasising a procedure that already exists and all 737 crew should be aware of.

IF it has occurred again, AND the crew haven't done the checklist, then we really should be looking at pilot training. However, despite conclusions that many are jumping to here, we should be awaiting the CVR and FDR outcome because this has the potential to be one of many scenarios.

[jolihokistix]

(Top right above) Quote: "Pilots are reminded that an erroneous AOA can cause some or all of the following indications and effects."

How calm would you need to be, and long would you need to sort out all of those?

So, not only erroneous AOA sensors can set off MCAS.

[FlightlessParrot]

Really? I'll admit to being wrong, but can you give some examples? I've done a small bit of traveling around Western and Eastern Europe (France, England, Bulgaria), and I don't remember anything about the light switches, and I feel like it would stick out in my memory as a shocking adjustment had they been down=on.
FIL's house in Australia, where down = on. Light switches baffling, because house first built for Finnish sea-captain: Finland, up=on. But not ALWAYS baffling. Anyway, as already pointed out, this is an arbitrary convention: the point is to implement a convention consistently.

[gravityf1ghter]

737 pilot here.

What concerns me, is that many people are saying “I’d just set Power and Pitch, I’d notice if the aircraft was trimming against me, and move the STAB TRIM CUTOUT switches” Which, following the Lion Air accident, was exactly what I was thinking.

However, if this accident also turns out to be MCAS related, do we need to explore the possibility that the MCAS operation in flight, combined with the possibility of Airspeed Unreliable, Stall Warning, Possible Windshear alerts, is much more violent and hard to control than we initially thought?

Two sets of pilots can’t deal with it- is my aircraft actually flyable under these conditions 1000ft above the ground?

[Cows getting bigger]

Put another way, if you’ve got a problem why would you choose to stay so low? As someone else said, set power, pick an attitude, get away from the ground and take things from there.

The first question must be - why didn’t/couldn’t the crew do that? Sort of sums-up 600+ Forum posts.

[DaveReidUK]

So? That is outrageously fast 5 minutes into the flight. Even at a “high” airport. You need some serious trimming (either by yourself or by the MCAS) to achieive that.

That may be so. Looking at the GS vs time profile shows a gradual, steady acceleration with no spikes. It doesn't look like UAS, particularly given that it's GNSS-derived and not dependent on air data,

[KRUSTY 34]

https://pbs.twimg.com/media/D1Zt2ktX4AAChBX.jpg

Perhaps they should have done so after the first prang. Oh that’s right, they’re the ones who certified the aircraft (and it’s MCAS) in the first place.

The FAA shouldn’t be anywhere near the investigation.

[KRUSTY 34]

I profoundly hope and pray this doesn't come back to bite them

How does the old saying go Chris?

Better to remain mute and let people think you are...... Than to open your mouth and remove all doubt!

I honestly can’t see a spin that will extricate certain authorities from this.

[BEagle]

Boeing is allegedly to 'deploy a software upgrade' which will 'make an already safe airplane safer'.

In April.

So that's OK then....

Surely the 737 Max8 should be grounded immediately until the cause of the accidents has been established and appropriate modifications incorporated? Boeing has said that the software enhancements include "limiting stabiliser trim commands in response to erroneous readings, pilot displays, operation manuals and crew training". Which sounds rather more than a software upgrade to me....

[Cows getting bigger]

Krusty 34, agreed. As we’ve found in the UK (Shoreham Hunter crash), sometimes the regulator is a little too close to the action. One trusts that the NTSB keep their excellent reputation.

[Berealgetreal]

One poster summed it up so well.

”imagine you’re the crew walking down the aerobridge to fly one of these things”.

[Jeps]

I don’t drive the MAX but I think I understand what MCAS does and doesn’t do (maybe). Is it possible that two things could be true and that whilst Boeing have stuffed up on a few different levels as I see it could it also be the case that if training were appropriate neither of these incidents would’ve been fatal?

[juice]

Australia has suspended operations of all Boeing 737 Max aircraft

https://www.rte.ie/news/world/2019/0312/1035823-ethiopian-airlines-crash/

[lederhosen]

In fifteen years on the 737 I cannot remember using the stab trim cutout switches apart from in the sim and even then only very occasionally. If the pilot flying was confronted with a similar scenario to the Lion accident then the combination of startle, unfamiliarity with the aircraft and a very new co-pilot could plausibly lead to this kind of end result.

The statements from Ethiopian about ‚senior captains‘ with a couple of months experience on the airplane and first officers with 200 hours are not terribly reassuring. There is no ‚single size fits all‘ solution to minimum experience levels for pairing new pilots. But it would be surprising if this did not play a role.

Finally Boeing‘s experience with electronic systems and stabilizers has not been uniformly happy. The MD11 which they inherited from Douglas had well reported issues in this area. This looks to be quite unrelated. But if I was a Boeing lawyer, aside from leafing through new sailboat catalogues in anticipation of massive billable hours, I would be looking into who was responsible for the MCAS development and implementation.

[silverstrata]

For clarity it was an option on Boeings (might be 737 only) to have it either way.
I've flown ex Lufthansa 737s one day and ex Ansett the next where switches operated in the opposite sense. Didn't take much getting used to.

I don’t think switch direction was a Boeing option. Ansett demanded the switches all be reversed, so that all their fleets had the switches operating in the same direction - to prevent the very confusions we are talking about. But I thought there were some hard negotiations about this - it was never a Boeing option.

Silver

[RetiredBA/BY]

Its a long time since I flew. a 737, ( 200 and 300) but is it the case that the Max system is capable of driving the stab. to FULL deflection .
Time dims the memory but IIRC. The 73 75 and 76 and other types I have flown, that was not the case, in fact stick pushers only moved the elevators, stabs were not moved.

Surely switch direction of the stab trim cutout switches is irrelevant, if something is ON. to switch OFF. Simply move the switch(es) away from that position !

[Old King Coal]

In fifteen years on the 737 I cannot remember using the stab trim cutout switches apart from in the sim and even then only very occasionally. If the pilot flying was confronted with a similar scenario to the Lion accident then the combination of startle, unfamiliarity with the aircraft and a very new co-pilot could plausibly lead to this kind of end result. The statements from Ethiopian about ‚senior captains‘ with a couple of months experience on the airplane and first officers with 200 hours are not terribly reassuring. There is no ‚single size fits all‘ solution to minimum experience levels for pairing new pilots. But it would be surprising if this did not play a role.Ditto that. With more than two decades on the B737 I too have never had recourse to have to move the Stabiliser switches to CutOff. And total hours are not a measure of competence; e.g. thousands of hours poling about in a normally highly-reliable-where-nothing-ever-goes-wrong aeronautical chariot does not necessarily turn someone into a latter day Chuck Yeager,

[Aihkio]

A few things noticed: MCAS seems to be a fast_put_together SW solution to a certification problem (stick force/g). Not a stall preventer directly. It also looks like B forgot to include data validity checks and "reasonables" checks that would return any trimming actions done after AoA returns to safe range.

A thought I had when reading what STS does, that sounds like SW augmented longitudinal stability. Meybe B thought that when that was acceptable other similar patching would be ok too.

Maybe they really should retire the 737 base and have a new one (yes, that does cost a lot), design methods have advanced a lot since the first flight of 737, which I understand was a good airliner in its first versions.

[silverstrata]

.Someone mentioned that the MCAS provides 10 secs of trim input when activated. Can that be correct/verified? 10 secs of trim input is massive on the 737.

Was this not the contributing factor in the FlyDubai 738 crash in Rostov?




Yes, that is correct - 10 seconds, or 2 degrees forward, for each operation of MCAS. And after 5 seconds, you get another 2 degrees of trim, until you end up with full forward trim. It was designed for slow speed, but if it happens inadvertently at high speed, you could be in the sh1t. Imagine this happening up in coffin corner, and you suddenly get 10 seconds of pitch - even the quickest of crews disconnecting the stab-trim would still result in an overspeed incident. And I can tell you the aircraft shakes a lot - we had an autopilot failure which pitched the aircraft down by 5 degrees. The recovery was smooth, but the high spoeed buffet was considerable.

But I still cannot imagine why or how this MCAS system was ever certified by the FAA. Even if MCAS operated at the right time, in a stall condition, who on earth would want full trim forward when pulling out of the subsequent dive? We tried it in the sim, and concluded it was impossible to recover from the dive. So the system that is supposed to save you, saves you and then kills you.

Rostov.

I have been wondering about Rostov. Is it possible that the Fly Dubai was fitted with a Max speed-trim computer? I bet they are compatible, because that is cheaper, and Boeing does everything on the cheap. So did an engineer not have the right spare unit, so fitted one from a Max instead? - Not realising that there was a fundamental software difference between the two units?

I wonder because the report said that the Fly Dubai pilots trimmed forward for 10 seconds. And everyone was aghast by that news, because no pilot would ever trim forward for 10 seconds. We were thinking in terms of a health issue, with someone freezing on the controlls. But as it happens, this is exactly what MCAS does - it trims forward for 10 seconds. So was the Fly Dubai fitted with a Max speed-trim computer?

Silver

P.S. If Boeing had fitted a stick-pusher, none of this would have happened. A stick push operates on the elevator, not the stab, and is more easily overcome with stick force. More importantly, when a stick-push relents (by either a stall recovery or a cutout), the aircraft is instsantly in trim. But with a trim-pusher you are way out of trim, and it will take you 30 seconds to trim back to the normal position. You may not have 30 seconds left. (But if course a stick-pusher would have cost money, and lots of certification time...)

[etrang]

Interesting yes, but if they can write this with a straight face... "Malaysia Airlines, which the public viewed with misgivings after it lost two 777s in less than five months in 2014. Though it bore no obvious responsibility for either incident—one was shot down by Russia, the second was hijacked..." how deep will the rest of it be?

Pretty accurate. One was shot down by a Russian missile and the other was (almost certainly) hijacked by its captain .......

[First_Principal]

yep, I sure as hell don't and I'd love to see it explained in a way so that a dimwit like me (LSA pilot) can understand.

In reference what people are discussing here it's fundamentally straightforward, albeit perhaps not easily explained without a piece of paper - let me see if I can provide a suitable analogy:

If you were to push a small (non power-steer) car somewhere near the middle of its boot (you're in Oz so I don't need to say 'trunk' :-) it would travel in a relatively straight line along a flat road without much input from the driver.

If you then moved that push/thrust off-centre (let's say to the right) and started pushing, the vehicle would want to drift gradually to the left if it weren't corrected by the driver via the steering wheel.

If you pushed harder, and/or you moved to the right-hand extremity of the boot then the vehicle would have a significantly greater left-hand drift which could require considerable correction by the driver, and even catch them unawares.

MCAS on the 73-MAX is a little as if you installed automatic centering power steer to this car so that an off-centre push wouldn't cause it to drift off-line significantly and wouldn't require much, if any, effort/correction by the driver.

To move from the analogy to the reality; as the MAX has significantly more thrust (push) than earlier 73 models, and that thrust is further out (down) from the centre of the aircraft (in elevation) it will want to pitch up significantly when power is applied. This is not a good thing and so without major re-design of the control surfaces or airframe MCAS is a system that takes data from an Angle-Of-Attack (AOA) sensor and corrects for this undesirable pitch up by trimming down, should it 'see' the aircraft deviating from its true path. It does this without specific input from the pilot.

There's clearly somewhat more detail around the actual operation/methodology of MCAS as we understand Boeing's implementation, but I think this gives the essence of it?

FP.

[Mark in CA]

U.S. to mandate design changes on Boeing 737 MAX 8 after crashes (https://www.reuters.com/article/us-ethiopia-airplane-usa/u-s-to-mandate-design-changes-on-boeing-737-max-8-after-crashes-idUSKBN1QS2CL?feedType=RSS&feedName=topNews&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+reuters%2FtopNews+%28News+%2F+US+%2F+To p+News%29)


WASHINGTON (Reuters) - The United States will mandate that Boeing Co implement design changes by April that have been in the works for months for the 737 MAX 8 fleet after a fatal crash in October but said the plane was airworthy and did not need to be grounded after a second crash on Sunday.

Boeing confirmed the Federal Aviation Administration’s announcement late Monday that it will deploy a software upgrade across the 737 MAX 8 fleet “in the coming weeks” as pressure mounted. Two U.S. senators called the fleet’s immediate grounding and a rising number of airlines said they would voluntarily ground their fleets.

The company confirmed it had for several months “been developing a flight control software enhancement for the 737 MAX, designed to make an already safe aircraft even safer.”

The FAA said the changes will “provide reduced reliance on procedures associated with required pilot memory items.”

The FAA also said Boeing will “update training requirements and flight crew manuals to go with the design change” to an automated protection system called the Maneuvering Characteristics Augmentation System or MCAS. The changes also include MCAS activation and angle of attack signal enhancements.

[Skillsy]

Australia has suspended operations of all Boeing 737 Max aircraft

https://www.rte.ie/news/world/2019/0312/1035823-ethiopian-airlines-crash/

This affects only two Fiji Airways aircraft after Silk grounded their six 737 MAX 8 aircraft that fly into Darwin and Cairns although it's really hard for Fiji Airways with 2 out their dozen aircraft grounded.

[silverstrata]

In great VMC conditions - as reported - even the very worst of pilots should surely be able to maintain some semblance of the old Straight and Level.

Seems inconceivable to me that even if this Max had the same airspeed/attitude problems as the last one that crashed, the pilots couldn't have controlled it.

I don’t agree at all.

If the f/o was flying, he only had 200 hours. After flaps up, the stick shaker goes off, which is mighty disconcerning, and MCAS bungs in a load of trim. The captain cannot see why the trim is trimming, and the low-hours f/o has no clue (seen that many times). The captian thinks he has an airspeed problem and is stalling, and tells the f/o to lower the nose - which the f/o does rather easily, because he is holding a load of back pressure. MCAS then bungs in another load of trim, and the f/o is now really struggling with the controls - never having felt an aircraft behave like this (at this stage, you need about 30 kg of force to hold the aircraft level).

The captain is still convinced the airspeed is wrong and they may be stalling (stick shaker still going), and shouts “I have control”, but does not realise so much pitch force is necessary, so the aircraft instantly pitches forward into a steep dive. Captain is mighty startled by this - is this pitch down the result of a stall? He has forgotten all about the previous trim episodes, and just hauls back on the stick. But MCAS now gives another load of forward trim, which makes the aircraft completely unflyable (60 kg of force necessary on the stick). And here comes terra firma....

Silver

[Non-Driver]

I have been wondering about Rostov. Is it possible that the Fly Dubai was fitted with a Max speed-trim computer? I bet they are compatible, because that is cheaper, and Boeing does everything on the cheap. So did an engineer not have the right spare unit, so fitted one from a Max instead? - Not realising that there was a fundamental software difference between the two units?

I wonder because the report said that the Fly Dubai pilots trimmed forward for 10 seconds. And everyone was aghast by that news, because no pilot would ever trim forward for 10 seconds. We were thinking in terms of a health issue, with someone freezing on the controlls. But as it happens, this is exactly what MCAS does - it trims forward for 10 seconds. So was the Fly Dubai fitted with a Max speed-trim computer?

Silver


Given that accident was in Dec 2016 to an aircraft built in 2010 and the Max didn't enter service until Aug 2017 I think that's a pretty fanciful hypothesis.

[excrab]

Rostov.

I have been wondering about Rostov. Is it possible that the Fly Dubai was fitted with a Max speed-trim computer? I bet they are compatible, because that is cheaper, and Boeing does everything on the cheap. So did an engineer not have the right spare unit, so fitted one from a Max instead? - Not realising that there was a fundamental software difference between the two units?

I wonder because the report said that the Fly Dubai pilots trimmed forward for 10 seconds. And everyone was aghast by that news, because no pilot would ever trim forward for 10 seconds. We were thinking in terms of a health issue, with someone freezing on the controlls. But as it happens, this is exactly what MCAS does - it trims forward for 10 seconds. So was the Fly Dubai fitted with a Max speed-trim computer?

Silver


The issue with your theory is that the Rostov accident happened only two months after the Max first flew and at least a year before FZ took delivery of their first MAX, so it is pretty unlikely that a flydubai engineer happened to find a spare MAX component kicking around in a parts bin and then randomly fit it into an 800.

[Chesty Morgan]

Something else to ponder is that the 737 is controllable with the trim at either the forward or rear extreme. However, it's a two hands on the column job.

[Eutychus]

Australia joins the list:

https://www.bbc.com/news/world-asia-47536502

[oxide]

I don’t agree at all.

If the f/o was flying, he only had 200 hours. After flaps up, the stick shaker goes off, which is mighty disconcerning, and MCAS bungs in a load of trim. The captain cannot see why the trim is trimming, and the low-hours f/o has no clue (seen that many times). The captian thinks he has an airspeed problem and is stalling, and tells the f/o to lower the nose - which the f/o does rather easily, because he is holding a load of back pressure. MCAS then bungs in another load of trim, and the f/o is now really struggling with the controls - never having felt an aircraft behave like this (at this stage, you need about 30 kg of force to hold the aircraft level).

The captain is still convinced the airspeed is wrong and they may be stalling (stick shaker still going), and shouts “I have control”, but does not realise so much pitch force is necessary, so the aircraft instantly pitches forward into a steep dive. Captain is mighty startled by this - is this pitch down the result of a stall? He has forgotten all about the previous trim episodes, and just hauls back on the stick. But MCAS now gives another load of forward trim, which makes the aircraft completely unflyable (60 kg of force necessary on the stick). And here comes terra firma....

Silver

Woah!! They should hire you for the inevitable National Geographic over-dramatization.

[RickNRoll]

I don’t drive the MAX but I think I understand what MCAS does and doesn’t do (maybe). Is it possible that two things could be true and that whilst Boeing have stuffed up on a few different levels as I see it could it also be the case that if training were appropriate neither of these incidents would’ve been fatal?

It is also possible this flight discovered a new failure mode for the software logic.

[KRUSTY 34]

Australia has suspended operations of all Boeing 737 Max aircraft

https://www.rte.ie/news/world/2019/0312/1035823-ethiopian-airlines-crash/

Well that’s easy. Considering there are none operating in Australia.

Cheaply bought spine CASA!

[quentinc]

Something else to ponder is that the 737 is controllable with the trim at either the forward or rear extreme. However, it's a two hands on the column job.

and whilst you have two hands on the yoke, the FAA directive to follow the trim runaway memory checklist, requires you to operate the guarded stabilizer trim cut out switches. Maybe the FO can do this. Once done, you still have the aircraft out of trim but now your trim switches on the yoke wont work. You need to shout at the copilot, to operate the trim wheels manually. If way out of trim, he's got plenty of spinning to do. Too much speed? Will reducing thrust result in more pitch down or give more time for the copilot to save the aircraft?

[Drjojo]

Well that’s easy. Considering there are none operating in Australia.

Cheaply bought spine CASA!




The Australian suspension affects Singapore's SilkAir (which has already grounded its fleet) as well as Fiji Airways that will have to substitute their two 737 Maxs on routes to Australia for other aircraft. So they have bought a spine within some, albeit limited impact.

[SMYDSTS]

Is this a good summary of what the crew may have experienced:

normal rotation to takeoff attitude and within a few seconds;

GEAR RETRACTION
IAS DISAGREE WARNING
ALT DISAGREE WARNING
STICK SHAKER ACTIVATION
STAB OUT OF TRIM WARNING (?)
MASTER CAUTION FLIGHT CONTROLS
TROUBLESHOOTING AND MEMORY ITEMS
DISCONNECT AUTOTHRUST
TURN OFF BOTH FLIGHT DIRECTORS
SET 10 DEGREES PITCH UP
SET 80%N1
CHECK PROBE HEAT ON
SPEED TRIM SYSTEM ACTIVATION (in background) - PUSHING THE NOSE DOWN
FLAP RETRACTION AT 1000ft OR AS SPEED INCREASES, OR OVERSPEED OF FLAPS
MCAS ROLLING IN NOSE DOWN STAB TRIM INCREMENTLY (NOT A RUNAWAY)
PM GETS OUT THE QRH TO READ CHECKLIST
PF IS ON THE RADIO AND STARTING TO FIGHT AGAINST THE NOSE DOWN BIAS
VARIOUS ALERTS SOUNDING:
”TOO LOW GEAR”
”CAUTION TERRAIN”
”TERRAIN TERRAIN”
“DONT SINK”
”PULL UP”

At this stage either the PF remembers the Bulletin and goes for the MCAS cutout switches - AKA STAB TRIM CUTOUT SWITCHES or he doesn’t.

The difference between an excellent pilot and an average pilot at this point is minuscule due to information overload and serious anxiety - a bad result is highly possible.

PLEASE sit in a quiet space, close your eyes and imagine its you sitting in that flightdeck. Just like the Air France and Perpignan accidents the AoA played a part - so its not just a Boeing problem.

[wheels_down]

There is a Fiji MAX inbound to Sydney right now a few hundred miles to go but no obvious diversion point at this late stage.

I wonder if they will let it leave?

[rog747]

Several more airlines pull the 737 Max after the 2nd crash in Ethiopia.

Royal Air Maroc RAM, and now the BA RSA franchise Comair.

Who would make that Comair decision?

Oldoberon

That is a very good point old chap - I wonder if BA Waterside called JNB?

Meanwhile over on TUI's Facebook and Twitter pages they are Inundated with their 1000's of their customers who are really not happy to be going on their holidays on a TUI or a Norwegian MAX right now...
(Even Enter Air who flies for some UK Greek tour operators is getting flack for not grounding their Max for now)

The bog standard tweeted reply continually coming from TUI has a slight smack of arrogance about it which, if that has come from the TUI PR department is rather disconcerting.
Although I doubt some little social media customer agent would be allowed to pass off a message like that...

However,
I would like to think that (as has been mentioned here in other posts) that all well respected TUI or DI MAX pilots would have burnt the midnight oil late into the night reading up on the MACS systems and how to deal with that - plus any spurious data that may occur. (and how to switch it all off)

[jantar99]

Rostov.

I wonder because the report said that the Fly Dubai pilots trimmed forward for 10 seconds. And everyone was aghast by that news, because no pilot would ever trim forward for 10 seconds. We were thinking in terms of a health issue, with someone freezing on the controlls. But as it happens, this is exactly what MCAS does - it trims forward for 10 seconds. So was the Fly Dubai fitted with a Max speed-trim computer?
Avherald explicitly says "lasted for 12 seconds"

[MD80767 Driver]

Capt was flying. Or should be. As he had only a few months on the MAX, and - Addis is a 'Capt only" airport. At least in Ethiopian it is

[Chesty Morgan]

and whilst you have two hands on the yoke, the FAA directive to follow the trim runaway memory checklist, requires you to operate the guarded stabilizer trim cut out switches. Maybe the FO can do this. Once done, you still have the aircraft out of trim but now your trim switches on the yoke wont work. You need to shout at the copilot, to operate the trim wheels manually. If way out of trim, he's got plenty of spinning to do. Too much speed? Will reducing thrust result in more pitch down or give more time for the copilot to save the aircraft?
If it gets to the forward stop there's no rush to get to the stab trim cut outs cos it ain't going any further. Fly it away from the ground, might take both of you, then distribute work load accordingly. It'll take something like 30 odd turns to get it back to somewhere more manageable.

[MD80767 Driver]

I don’t agree at all.

If the f/o was flying, he only had 200 hours. After flaps up, the stick shaker goes off, which is mighty disconcerning, and MCAS bungs in a load of trim. The captain cannot see why the trim is trimming, and the low-hours f/o has no clue (seen that many times). The captian thinks he has an airspeed problem and is stalling, and tells the f/o to lower the nose - which the f/o does rather easily, because he is holding a load of back pressure. MCAS then bungs in another load of trim, and the f/o is now really struggling with the controls - never having felt an aircraft behave like this (at this stage, you need about 30 kg of force to hold the aircraft level).

The captain is still convinced the airspeed is wrong and they may be stalling (stick shaker still going), and shouts “I have control”, but does not realise so much pitch force is necessary, so the aircraft instantly pitches forward into a steep dive. Captain is mighty startled by this - is this pitch down the result of a stall? He has forgotten all about the previous trim episodes, and just hauls back on the stick. But MCAS now gives another load of forward trim, which makes the aircraft completely unflyable (60 kg of force necessary on the stick). And here comes terra firma....

Silver
Capt was flying. Or at least he should be. He was a few months into his 737 carreer. And Addis is a "Capt Only" airport

[wheels_down]

The Fiji MAX will be grounded in Sydney. Thankfully they didn’t send the other to Melbourne otherwise they would be screwed. The Brisbane flight just got out in time.

[Rated De]

and whilst you have two hands on the yoke, the FAA directive to follow the trim runaway memory checklist, requires you to operate the guarded stabilizer trim cut out switches. Maybe the FO can do this. Once done, you still have the aircraft out of trim but now your trim switches on the yoke wont work. You need to shout at the copilot, to operate the trim wheels manually. If way out of trim, he's got plenty of spinning to do. Too much speed? Will reducing thrust result in more pitch down or give more time for the copilot to save the aircraft?

Yes and the poor souls at Lion Air were likely focused on another memory item checklist, ultimately one that didn't rectify the issue.
The FAA Boeing Bulletin might seem simple in hindsight, but with a cacophony of noise and spurious alerts and call outs, it is not too hard to imagine a sense of overwhelm.

Have Boeing unknowingly introduced a single point of failure into the aircraft?

That the SWA 737MAX fleet was 'fitted' with a Boeing factory option displaying AOA on both PFD, not just the Captain's HUD is suggestive that at least some airlines consider that indications need cross checking.
The sense one gets is that the pilots with the AOA displayed can cross-check and likely the display would assist a rapid diagnosis of the issue.

Indeed the early QF orders of the 738, were destined for another customer and had the option already 'fitted' , all additional aircraft have the same indication.
Perhaps it is time Boeing 'fitted' it to all 737 MAX? Or are their lawyers suggesting to do so implies a problem?

https://theaircurrent.com/aviation-safety/southwest-airlines-is-adding-new-angle-of-attack-indicators-to-its-737-max-fleet/

The FAA look the odd one out as increasingly a risk aversion mindset takes hold.
Regulatory capture it may well be, but other aircraft have been grounded for a lot less, all in the name of safety.
How much short open interest in BA (NYSE) ? How much of an eye has the regulator on the economics?

That this event occurred in the same phase of flight is the concern. Until they categorically rule out that the MCAS system was at play here, the aircraft ought be sitting idle on the ground.

[KRUSTY 34]

If it gets to the forward stop there's no rush to get to the stab trim cut outs cos it ain't going any further. Fly it away from the ground, might take both of you, then distribute work load accordingly. It'll take something like 30 odd turns to get it back to somewhere more manageable.

Didn’t work with Lion Chesty. Perhaps it is easier said than done?

[Interflug]

Engineer here - trying to look at MCAS out of the box...

So they say, one AoA sensor outputting wrong data alone can activate the MCAS erroneously.
If that is so, which engineering workgroup at Boeing could in their sane minds design such a system, that is supposed to save you from a stall but instead:

decisively flies you into the ground
on a calm sunny cloudless day
with a (except from the AoA sensor) perfectly functioning airplane and engines
with the same system getting indications for:

positive vertical (upward) speed within normal margins
positive horizontal (forward) speed and acceleration within normal margins
secondary parameters like radar AGL data, GPS groundspeed

last but not least two pilots, able to look out of the window and able to assess AoA visually

Why would an engineer think it is a good idea to implement such a system that ignores all other available data (which indicates nothing like a stall)? Even if you want to take the pilot/human out of the equation, assuming he put the airplane into an attitude that will result in a stall in the first place, you still have lots of other available data the system can read, that tells it that you are in fact not stalling and that most likely the AoA sensor is telling you nonsense.

Probably the MCAS subsystem will enter the course books of engineering schools, as a textbook example of AS, artificial stupidity, a system designed to be stupid, when you actually need a smart system.

Or are these engineers disciples of the Church of the AoA sensor, since they believe the one and only AoA sensor never fails?

Someone can enlighten me? What did I overlook?

[jetopa]

On May 24th 2011 a Dassault Falcon 7X experienced a pitch anomaly resulting in a sudden and rapid pitch up in Malaysian airspace. This was recovered by some quick and good thinking on the part of the flying pilot.

2 days later, the manufacturer asked EASA to ground the entire fleet. One day later, the FAA followed.

A key Dassault employee acknowledged that ‘our design was not perfect’. Pretty honorable thing to do for a (rightfully) proud French engineer.

Shouldn’t Boeing do the honorable thing, too?

(see article below)

[Chesty Morgan]

Didn’t work with Lion Chesty. Perhaps it is easier said than done?
Most definitely is. I haven't seen the Lion Air data so I don't know if it ran full forward and stayed there or something else. Obviously startle factor might play a part as well but I'm not sure how startling the trim running slowly forward would be but maybe combined with the stall warning going off wouldn't encourage you to haul back as hard as you can.

I'm only saying that it is controllable at either extreme. Just.

[olster]

Engineer here - trying to look at MCAS out of the box...

So they say, one AoA sensor outputting wrong data alone can activate the MCAS erroneously.
If that is so, which engineering workgroup at Boeing could in their sane minds design such a system, that is supposed to save you from a stall but instead:
-decisively flies you into the ground
-on a sunny cloudless day
-with a (except from the AoA sensor) perfectly functioning airplane and engines
-with the same system getting indications for:positive vertical (upward) speed within normal margins
positive horizontal (forward) speed and acceleration within normal margins-secondary parameters like radar AGL data, GPS groundspeed-last but not least two pilots, able to look out of the window and able to assess AoA visually

Why would an engineer think it is a good idea to implement such a system that ignores all other available data (which indicates nothing like a stall)? Even if you want to take the pilot/human out of the equation, assuming he put the airplane into an attitude that will result in a stall, you still have lots of other available data the system can read, that tells it that you are in fact not stalling and that most likely the AoA sensor is telling you nonsense.

Probably the MCAS subsystem will enter the course books of engineering schools, as a textbook example of AS, artificial stupidity, a system designed to be stupid, when you actually need a smart system.

Or are these engineers disciples of the Church of the AoA sensor, since they believe the one and only AoA sensor never fails?

Someone can enlighten me? What did I overlook?


Yes Interflug, very difficult to disagree with you. Quite amazing, not in a good way. I have been flying the 737 off and on since the late 70s then the -200 through to latterly, the NG. I have continually said that the 737 is an old aircraft with bits bolted on over the decades. The ergonomics of the flightdeck are out of date for 2019 with the stab trim cut out switches hid away to the right of the start levers among many counter intuitive switches / system. I thought that the NG was a step too far, let alone the max. I am not going to join in the speculation but it does not look good. Tragic.

[ManaAdaSystem]

If it gets to the forward stop there's no rush to get to the stab trim cut outs cos it ain't going any further. Fly it away from the ground, might take both of you, then distribute work load accordingly. It'll take something like 30 odd turns to get it back to somewhere more manageable.

From full AND to about 5 units it takes 60 - 70 turns. Manually trimming on ground is easy. In the air it’s a different story. Add 300 kts+ and it gets even worse. Not impossible, of course, but much harder.
If any of you would like to try manual trim on your next flight, remember to place the stabilizer cut out switches to OFF. That trim wheel can be very nasty if it starts to trim when you hold the handle.

[12A]

The Fiji MAX will be grounded in Sydney. Thankfully they didn’t send the other to Melbourne otherwise they would be screwed. The Brisbane flight just got out in time.
Could the authorities give effected airlines a quick 'heads up' to remove or divert their aircraft before any bar comes into force?

[KRUSTY 34]

Most definitely is. I haven't seen the Lion Air data so I don't know if it ran full forward and stayed there or something else. Obviously startle factor might play a part as well but I'm not sure how startling the trim running slowly forward would be but maybe combined with the stall warning going off wouldn't encourage you to haul back as hard as you can.

I'm only saying that it is controllable at either extreme. Just.

Believe me Chesty I’m not attempting to downplay your expertise, nor the basic nuts and bolts required to save this situation. Unfortunately it appears that two professional airline crews have been unable to prevent their aircraft from flying them into the ground/sea. That sort of ticks the easier said than done box for me.

There are many more moving parts to this story, and I’m afraid we’re not just referring to the trim wheel.

[Chesty Morgan]

Believe me Chesty I’m not attempting to downplay your expertise, nor the basic nuts and bolts required to save this situation. Unfortunately it appears that two professional airline crews have been unable to prevent their aircraft from flying them into the ground/sea.

There are many more moving parts to this story, and I’m afraid we’re not just referring to the trim wheel.
Of course, and I agree with your second paragraph. The trim is just a part of the big puzzle.

[ifylofd]

It has been reported that crew in the following aircraft at holding point (tower frequency) heard the crew advise ATC of 'an airspeed issue' and 'controllability problems' whilst declaring their intention to turn back.
This is not something that appears to be reported at present, which seems odd. (media)

Where is the manufacturer in all this? Funny how the party line always refers to safety, however those in the industry know and understand all too well the commercial prerogative will normally (covertly) take precedence.

Condolences to those people who have been directly affected by this tragic event.

[rzw30]

Not a pilot, but an engineer.
Reading this stuff, no doubt in my mind that all these aircraft need to be grounded until comprehensive answer and solution is found.

[AndyJS]

Not a pilot, but an engineer.
Reading this stuff, no doubt in my mind that all these aircraft need to be grounded until comprehensive answer and solution is found.

I'm pretty surprised that these aircraft are still flying in a lot of countries, like here in the United Kingdom for instance. There needs to be a worldwide ban while the investigation takes place.

[Capn Bloggs]

If it gets to the forward stop there's no rush to get to the stab trim cut outs cos it ain't going any further. Fly it away from the ground, might take both of you
Controllable? At say 340KIAS (380 GS)? I very much doubt it.

[blind pew]

Obvious that many of you do not understand the different forces involved with the stabiliser and elevator. The elevator only generates a small fraction of the force that the stabiliser generates.
On second and third generation aircraft I flew we had a huge wheel with a white mark, a claxon and a by heart emergency drill to stop a runaway.
You cannot override the stab with the elevator on most aircraft.

[Drjojo]

Where is the manufacturer in all this? Funny how the party line always refers to safety, however those in the industry know and understand all too well the commercial prerogative will normally (covertly) take precedence.

Indeed, with Max sales trailing the NEO by 2900 to 4400 I would be suspicious that Boeing will do everything they can to avoid any suggestion that there is a problem with the MAX.

Boeing enjoyed dominance of this market sector for decades, and the MAX being reduced from dominance to a 40% market share will have the suits worried.

[jolihokistix]

Pinch of salt warning.
Interesting observation by one witness, for further consideration: "Tamrat Abera, a witness who saw the plane go down, told The Associated Press smoke was coming out of the rear and the aircraft rotated twice before hitting the ground."
https://www.aljazeera.com/news/2019/03/regulator-demands-boeing-modify-737-max-ethiopia-crash-190312020507489.html

[Chesty Morgan]

Controllable? At say 340KIAS (380 GS)? I very much doubt it.
Well they didn't start at 340kts but they let it get there.

[jan99]

Maybe it would be good to remind people that aerodynamic forces increase with the square of airspeed. When mis-trimmed airspeed is not your friend.

[bud leon]

Controllable? At say 340KIAS (380 GS)? I very much doubt it.

I'm not sure people fully appreciate that the crew only had three minutes to sort this out, that is not a lot of time to process the situation and troubleshoot in any circumstances, but especially so close to the ground at that speed just after take off, no matter what the cause.

[Air Snoop]

Pinch of salt warning.
Interesting observation by one witness, for further consideration: "Tamrat Abera, a witness who saw the plane go down, told The Associated Press smoke was coming out of the rear and the aircraft rotated twice before hitting the ground."
https://www.aljazeera.com/news/2019/03/regulator-demands-boeing-modify-737-max-ethiopia-crash-190312020507489.html

Having interviewed many folk who have witnessed aircraft accidents, it is not unusual to get the sequence of events in the wrong order or to misinterpret what they are seeing. It is a very traumatic experience for them.

[Luc Lion]

Maybe it would be good to remind people that aerodynamic forces increase with the square of airspeed. When mis-trimmed airspeed is not your friend.
And if AOA sensor reports a stall, pitch up force on the elevator is multiplied by 4 by EFS.
(I don't imply that this is what happened for the ET accident, but it did happen with the Lion Air accident)

[bud leon]

Having interviewed many folk who have witnessed aircraft accidents, it is not unusual to get the sequence of events in the wrong order or to misinterpret what they are seeing. It is a very traumatic experience for them.

And that is often used in court cases to discredit witnesses. It is notable when multiple witnesses describe similar experiences though.

[SLFinAZ]

Having interviewed many folk who have witnessed aircraft accidents, it is not unusual to get the sequence of events in the wrong order or to misinterpret what they are seeing. It is a very traumatic experience for them.

I agree completely, the most relevant aspect of the eyewitness accounts is the consistency in believe that the engines sounded wrong. Aural memory is much stronger and more consistently correct then visual memory. That doesn't mean in anyway that anything was actually wrong with the engines just that the sound was different. The airplane was significantly lower than normal and moving at significantly higher speed so the acoustic signature for lack of a better term would be much much different then they would expect and is what they noticed before even acquiring the aircraft visually I'd wager....

[infrequentflyer789]

Something else to ponder is that the 737 is controllable with the trim at either the forward or rear extreme. However, it's a two hands on the column job.

Surely the more pertinent question (at least for Lion Air) is: is it controllable with full forward trim and EFS activated. If it is, is it a two hands on the column job or a four hands on both columns job (and if the latter, which appendage should be used for the trim cut outs / wheels).

[RAD_ALT_ALIVE]

The difference between the QF72 incident and the Max8 accidents is that in QF72’s case, it was that its ADR AoA input data was corrupted. As a result they then sent misleading pitch orders.

It was intermittent thus causing even more confusion for the pilots and complicating their ability to identify the root cause.
They also were blessed with a great deal more altitude than the two Max accident crew. In fact one of the QF72 pilots was quoted as saying that his biggest concern during the whole event was what might happen if it occurred again while they were at low altitude.

Nor do I think that there was any trim or HST misbehavior.

Their calm, methodical and disciplined approach to the problem they faced also helped achieve a safe resolution (not that I’m in even the slightest way insinuating the contrary about either of the Max crews). Airbus subsequently issued a bulletin advising pilots how to deal with a similar event.

[PiggyBack]

It is early to be making assumptions about the cause of this crash but it seems there is already good evidence of failures in the design/regulatory/certification process and that these need proper investigation.

I am not a pilot and although I design systems with safety aspects I am not in the aerospace areas. Despite this a key question is why a design change intended as a risk control measure seems to have introduced significant new risks.

On the face of it both the design/development/change control process seems to have failed but also the certification process in considering the impact of a change.

Given what MCAS does the risks of it failing to operate correctly do not need to have been properly consideer and controlled and although there is an element of hindsight it seems quite a stretch to have it vulnerable to a single point failure and with the assumptions that the pilots could control the risk of it failing under all reasonable circumstances and conditiosn without specific training.

There will be a focus on the specific cause of the accident but I would argue more worrying is what looks like a breakdown in the safety/regulatory process with respect to design modifications. Certainly for medical devices (my expertise) statistics suggest that modification of software is one of the largest causes of safety incidents and is therefore an area of focus for regulators.

[netstruggler]

Is MCAS the sort of system that would previously have been tested with flight trials on a prototype aircraft, but which is now tested using computer modelling?

[Halfnut]

If the weather was 60-65 degrees with the field elevation at 7625 then the density altitude was around 9000-9500 at take off.

If they lost an engine then it would be rather sporty.

For bonus points, was it the 200 hr TT F/O's leg?

[shackson]

Is it known how many times the MCAS system has activated erroneously on the MAX and been successfully dealt with?

[gmx]

Most definitely is. I haven't seen the Lion Air data so I don't know if it ran full forward and stayed there or something else. Obviously startle factor might play a part as well but I'm not sure how startling the trim running slowly forward would be but maybe combined with the stall warning going off wouldn't encourage you to haul back as hard as you can.


I'm only saying that it is controllable at either extreme. Just.


I think its important to remember that the Lion crew kept the aircraft reasonably steady for 6 minutes after MCAS issues presented, continuously and manually counteracting the MCAS nose down events that occurred during that whole time. The crew knew they had a stabilizer runaway b/c they kept using the electric trim to correct it. They kept the aircraft basically level at 5000 feet for that 6 minute duration, until, for the last four MCAS nose down commands, the crew's manual trim responses occur but are just "blipped" (not sufficient to counteract the MCAS input), and assumedly resulted in the stabilizer being full forward.


No one knows why the crew were able to successfully counteract MCAS with manual trim operation for 6 minutes, and then fail to do so for the final 4 MCAS inputs. That is the mystery that we are hoping the CVR will explain.


Lastly, as I understand it, MCAS only dials in *ONE* nose-down increment (2 degrees or whatever it is) and then deactivates itself, until something happens to reactivate MCAS allowing it to dial in another increment. I can't recall all of the crew activities that result in MCAS being reactivated, but I believe one is operation of the manual trim. This is why the last four "blipped" manual trim inputs in the Lion flight result in four unmitigated MCAS nose-down events, because any manual trim input resets MCAS and allows it to reasses the AoA / speed picture and dial in another MCAS trim input.

[gravityf1ghter]

No one knows why the crew were able to successfully counteract MCAS with manual trim operation for 6 minutes, and then fail to do so for the final 4 MCAS inputs. That is the mystery that we are hoping the CVR will explain.




Lets just hope the Stab Trim Cutout switches aren’t found to disconnect all Trim (pilot electric trim included) but not MCAS Trim!

[oldoberon]

There is no information in the current B738M AOM that tells crews that the "MCAS cycles between the left AoA and the right AoA sensor". What is the source for the above statement?

my quote tells you LANCS THINKS it is in the Lion Air thread, which is why I started my post off with IF IT IS TRUE..

As the crew cannot do anything about it ie cannot select which one, why bother giving them that info, Ground crew need to know IF it switches because if there is a fault reported not being able to tell which one was in use means they HAVE to check both, personally I don't believe this to be correct info.. However if it is true my suggestion would IMHO improve the system.

Oldeberon

[jagema]

Lastly, as I understand it, MCAS only dials in *ONE* nose-down increment (2 degrees or whatever it is) and then deactivates itself, until something happens to reactivate MCAS allowing it to dial in another increment. I can't recall all of the crew activities that result in MCAS being reactivated, but I believe one is operation of the manual trim. This is why the last four "blipped" manual trim inputs in the Lion flight result in four unmitigated MCAS nose-down events, because any manual trim input resets MCAS and allows it to reasses the AoA / speed picture and dial in another MCAS trim input.

MCAS is perpetually active so as long as ONE AoA sensor relays: high angle of attack, flaps up and autopilot disengaged. Simply, it will trim the Stabilizer down for 10 seconds (2.5 degrees nose down) and pause for 5 seconds before doing it all over again if it deems conditions remain the same (which often does with faulty sensor data; in the case of MCAS it's engaged on single channel FCC). You could have an aircraft ~4 degrees nose down from level flight as early as 45 seconds.

Application of electric trim pauses MCAS (5 seconds). Selecting TRIM CUTOUT to OFF deactivates MCAS (much like Speed Trim, Mach Trim and Column switch electric trim)

So if they were manually trimming the stab wheel as you say, one would assume they'd have tried either of those two options which begs the question why wouldn't they have been able to control the aircraft in the pitch axis thereafter? Time will tell.

[AndyJS]

On the reliability of witnesses: I was once watching through binoculars a Starfighter display. It was flying erratically. My interest and concentration were at a peak. The pilot ejected and the aircraft exploded in the air. Or maybe it was the other way round. And since then I have not really trusted anyone's account of things they have seen.

(Frankfurt Airport/Rhein-Main AFB, about 1990)

About 5 years ago the BBC here in the UK did a very interesting TV show on the reliability of witnesses. They set up a situation (with actors) in a bar where a young woman started a fight by punching a man, and they asked people what they thought happened. Most of the older men said that a man had started the fight, not a woman. The explanation was that when they were young the idea of a woman starting a fight was so unlikely that they discounted it, even though that was what actually happened in front of their eyes. In other words, in the 1950s or 1960s it was unheard of for a woman to do something like that in public, so they just assumed that the man had started it. It just shows how unreliable eyewitnesses can be, because things like people's basic assumptions about life can get in the way of giving a true account of what happened. That's just one example, but it applies to lots of situations. People often see what they expect to see instead of what has actually taken place.

[The Dominican]

The famous eye witness accounts!

Lately I've been flying a 1948 Grumman Mallard with a good friend of mine, We landed and docked by a nice hotel and went inside for lunch, the military showed up asking if we were OK! When we asked why, they said that people have called reporting an airplane that crashed in the ocean and was on fire!

[silverstrata]

Lastly, as I understand it, MCAS only dials in *ONE* nose-down increment (2 degrees or whatever it is) and then deactivates itself, until something happens to reactivate MCAS allowing it to dial in another increment. .

Not my understanding. The logic of the system was posted in the extensive Indonesian thread, and if I recall correctly the MCAS system will continue operating as long as it thinks the aircraft is in a stall situation. So it gives 10 secs of trim, 5 secs waiting, and then another 10 secs of trim. That is why the Indonesian aircraft got multiple trim events (about 12 or so) in quick succession.

The system was obiously never designed to recognise that the aircraft was not stalled - it took the word of one AoA sensor as being gospel. Never mind that the airspeed and attitude were correct, the system reacted solely, and incorrectly, to the erroneous AoA sensor.

It did not even bother checking with the other AoA sensor. All you need is one line of code that says: “if AoA1 not equal to AoA2, deactivate system”. I mean, how hard was that? Ok, it would be nice to have three sensors, but even two can resolve that there is an error somewhere, so the system should not start trimming.

And while we are at it, why was there not a line of code that says: “if ASI greater than 210 kts, deactivate system”. I mean, how hard was that? Please don’t say that high speed stalls are a real problem with the Max, because I will not buy that one.

Silver

[spiros737]

may I ask something did the pilots of the Ethiopian air engage the autopilot after the takeoff ? because if they did then the MCAS is not taking any action.

[Escape Velocity]

Okay, after perusing through this multi-page thread of, frankly, mostly useless and uninformed speculation and, in some cases, pure garbage, I have a few items to contribute:

Background: my first Boeing was the 737-200 and 300, left seat on the 757 and 767, currently flying the 737NG, never been closer to a Max than across the ramp. I have never operated MS Flight Sim. Multiple carriers, all overseas for the last 12 years. I spent a year flying the NG at ET a few years ago. Total flying career 32 years and counting.

First: ET pilots. I entered ET right at the introduction of the MPL program for FOs. As far as I know their new pilots are still graduating under the MPL: program. For those who don't know what that is, it's Multicrew Pilot License. It consists of 70 hours of actual airplane flight time and 130 hours of simulator. The pilot does not have a CPL. So the 200 hour copilot is plausible, though unless the Captain was an instructor the FO probably had a little more time than 200. I sometimes got a fresh FO with a grand total of 230 hours, having been signed off as meeting the standards. Here's the truth - none of them could fly an airplane. Plain and simple. No exaggeration, just the plain truth. There were multiple times I flew with an FO who, after almost a year on type still couldn't fly worth a darn. I'm not talking the finer points, I'm talking basic airmanship. Next, local captains. Most are competent but ET had (probably still has) difficulties with new upgrade captains. they move up the ranks strictly by seniority. After a year or so on the Q400 or 737 they go to junior FO on the widebody, then senior FO on the widebody, then back to the Q400 or 737 for upgrade. Big culture shock, big step backwards on technology, big change in route structure. Their upgrade line training program typically took 4 or 5 times as long as a current & qualified captain. There's a big difference between logging time droning along for 12 hours vs. short-haul. Not throwing rocks but I usually see a large quality gap between FOs who came from short-haul vs. long-haul. As was said previously, Addis is a captain only airport and almost certainly the captain was PF. Lastly on the pilot side, CRM is mostly non-existent there, it is very much a top down cockpit culture, though that probably was not a factor here.

Next, the FAA: I'm certainly glad that PPRUNE has, in three days, solved the crash! Hallelujah! The NTSB and local crash investigators need not even show up. The big uproar that the FAA has not grounded the Max is a good thing. It means they are doing their jobs, not acting rashly and on pure emotion, rather basing any decision on facts when they come. I notice that EASA has not issued a grounding order (which they certainly can). Considering that the bulk of the Max fleet is operating in the US and Europe, what on earth are they waiting for? (that's sarcasm, by the way). Maybe they are waiting for some actual data to come forth before condemning the aircraft. Maybe they know something we don't. Hmmmm....

Next, MCAS: I'm not weighing in on this as I have exactly zero more facts than anyone else. I do have a few questions though concerning the final few moments of both the ET crash and the Lion crash. Both times the aircraft was in day VMC conditions, both seemingly experienced speeds much higher than what could and should be considered normal for level flight at low altitude, so what gives? I can certainly tell my airspeed by looking out the window, regardless of how many alarms at whatever obscene volume are blaring any time. If the data is to be believed, 330+ knots at around 1000AGL to me means someone forgot the cardinal rule: fly the airplane. Pitch, power, and if possible (it was) look out the damn window!

Next, basic airmanship: If I have, simultaneously, an A/S and/or ALT disagree, stick shaker, and an increasing need for backpressure on the yoke, my first action is to fix the flight control issue and that means assuming a trim problem. I can handle the airplane all day long without an altimeter or airspeed indicator (in VMC conditions) but aircraft control is first, second and third on the to-do list. Maybe airmanship is not taught anymore (it's not but that's another story) but basic airmanship teaches us that even in an airplane without a trimmable HS, a mistrimmed airplane will be harder to control at higher speeds. So grab the thrust levers and use them. Set pitch and power. The 737 can be flown, albeit with a lot of force required, with the pitch trim at either stop, but at full nose down the control forces will be massive at high speeds. Couple that with the elevator force diminishing with higher airspeeds and it may reach a point where at speeds above barber pole you may run out of elevator. I was taught this years ago, though I know it is not taught anymore. Moral: fly the damn airplane.

I could chime in on lots more but frankly, why bother? Based on most of what I've read (and could stomach) the PP needs to be removed from PPRUNE.

[SeenItAll]

The captain of this flight has been reported to have 8000 flight hours -- and was 28 years old. Does this seem anomalous to anyone. That is a lot of hours for someone so young. And has there been any information as to how many hours he had on either the MAX 8 or his previous types?

[oldoberon]

Interesting details/analysis by a control guru which **may** help explanation of which sensor does what and how

https://www.satcom.guru/2018/11/737-fcc-pitch-axis-augmentation-command.html

Obviously put together after LionAir . .

Thanks Conso

The link is to an article by someone worthy of the title "expert" in system design. very interesting and detailed analysis of the system, how it should function, what could go wrong, and what should be done going forward.

[Capt Scribble]

Has Boeing issued any Maintenance or Crew notices since the Ethiopian accident? If not, what has prompted some countries to ground the Max. Although there is speculation on this site about a similar cause to that of Lion Air crash, I have not seen anything from official sources to confirm the idea.

[737only]

Boeing seems to think differently, judging from the Runaway Stabilizer checklist, which includes the following additional step after switching off the cutout switches: "If the runaway continues: stabilizer trim wheel - grasp and hold".

This ist meant as last resort and was always included, nothing to do with MCAS! Airloads could drive the elevator, etc..

[SigWit]

Has Boeing issued any Maintenance or Crew notices since the Ethiopian accident? If not, what has prompted some countries to ground the Max. Although there is speculation on this site about a similar cause to that of Lion Air crash, I have not seen anything from official sources to confirm the idea.


You haven't seen official sources confirm it, but you also haven't seen them deny it.

Seeing two brand new planes crash in a relatively likely manner, within such a short time of each other and within two years of the plane's release. They are probably not taking any chances until it is clear that this is not the same issue.

[Schnowzer]

Hi EV,

Let me start by offering my condolences to all involved in two horrific crashes.

No idea about the technical merits of the aircraft but I wholeheartedly agree. With attitude information available and control of pitch and power it is surprising these types of crashes happen. Looking out the window and seeing if the ground is getting closer or further away and where the aircraft is pointing seems to be a lost art.

Like you I worry about true experience, I have quite a lot of hours but in the last 10,000 or so gained less true experience (dealing with new/different issues) than in some 1 hour long flights a couple of decades ago. My experience is now measured by hours and the industry even considers me to be gaining experience (competence?) when asleep in a bunk:confused: The standards set in regulation allow for an if you don’t succeed try, try again and you will eventually be successful.

That is jumping ahead, we don’t have the reason for these crashes but if simple procedures and aviation skill in handling a malfunction were contributory, the industry as a whole needs to wake up and realize that the training being given and more importantly the regulatory standards being applied were causal and cost these crews and several hundred passengers their lives.

[Chesty Morgan]

Re: captain had 8000 flt hours@ 28 years of age:

That sounds hardly believable.
18 out of high school
20 out of flight school with 200 hours
that means 1000 hours per year for every 8 years.
I dont buy it. Must be false.
How about finishing flight school with a CPL at 18. Straight into first job at ET. Average of 800 hours a year for 10 years.

Not common but plausible.

[Richard C]

Not my understanding. The logic of the system was posted in the extensive Indonesian thread, and if I recall correctly the MCAS system will continue operating as long as it thinks the aircraft is in a stall situation. So it gives 10 secs of trim, 5 secs waiting, and then another 10 secs of trim. That is why the Indonesian aircraft got multiple trim events (about 12 or so) in quick succession.

The system was obiously never designed to recognise that the aircraft was not stalled - it took the word of one AoA sensor as being gospel. Never mind that the airspeed and attitude were correct, the system reacted solely, and incorrectly, to the erroneous AoA sensor.

It did not even bother checking with the other AoA sensor. All you need is one line of code that says: “if AoA1 not equal to AoA2, deactivate system”. I mean, how hard was that? Ok, it would be nice to have three sensors, but even two can resolve that there is an error somewhere, so the system should not start trimming.

And while we are at it, why was there not a line of code that says: “if ASI greater than 210 kts, deactivate system”. I mean, how hard was that? Please don’t say that high speed stalls are a real problem with the Max, because I will not buy that one.

Silver



The Australian Civil Aviation Safety Authority (CASA) has taken action. The article's vague about what's actually suspended but I think it must be temporary suspension of the type C of A. That's noteworthy as CASA usually take the lead from the FAA on US manufactured equipment.

It won't directly affect many flights as there are no Max 8s in service with Australian carriers yet (Virgin Australia have over 30 on order). Only Fijian among the operators flying Max 8s to Australia hadn't already stopped operations.

https://www.abc.net.au/news/2019-03-12/boeing-737-max-8-suspended-operations-australia/10894426

[EIFFS]

Lets just hope the Stab Trim Cutout switches aren’t found to disconnect all Trim (pilot electric trim included) but not MCAS Trim!


the Trim switch cutout removes all electric power to the trim system including the MCAS, it does mean that you need to manually trim the aircraft.

[Intrance]

Re: captain had 8000 flt hours@ 28 years of age:

That sounds hardly believable.
18 out of high school
20 out of flight school with 200 hours
that means 1000 hours per year for every 8 years.
I dont buy it. Must be false.

Apparently you can be through the school system at age 17 in Ethiopia. An integrated ATPL(A) course can be done in 12-18 months if all runs smooth. Let's say 19 when he started flying. At 900hrs a year it would be possible. Just saying, the math can work out. So let's not jump to conclusions.

[StopStart]

Banned from UK airspace now....

[wheels_down]

I think after the Australian decision you are going to see a very swift and immediate response from everyone else. Malaysia and Oman just in.

Canada will be next I’d imagine.

[22/04]

UK CAA ban now. Probably no choice given unease of TUI pax. Social media drives the world!

[EIFFS]

Unreliable airspeed is a memory item on the 737

[Mad (Flt) Scientist]

Boeing seems to think differently, judging from the Runaway Stabilizer checklist, which includes the following additional step after switching off the cutout switches: "If the runaway continues: stabilizer trim wheel - grasp and hold".

That statement isn't there for "erroneous MCAS". If the MCAS has "gone crazy" due to either faulty inputs and/or internal fault in whatever box drives it, then you can assume that the stab drive itself is healthy and just getting nonsense commands. So the cut-out switches will work.

the "if it still moves" is to cover something like a fault downstream of the cutout switches - maybe a short in the motor driving it regardless of command. In such a failure case, the motor will run regardless of the cutouts, so hanging on to the wheel is the last resort.

The chances of having a simultaneous MCAS (or other command system) fault AND an internal stab motor fault are insanely remote.

The procedure isn't just for MCAS, it has to cover all the various uncommanded stab scenarios.

[cessna729]

From the CAA website: www.caa.co.uk/News/Boeing-737-MAX-Aircraft
A spokesperson for the UK Civil Aviation Authority said: "Our thoughts go out to everyone affected by the tragic incident in Ethiopia on Sunday."The UK Civil Aviation Authority has been closely monitoring the situation, however, as we do not currently have sufficient information from the flight data recorder we have, as a precautionary measure, issued instructions to stop any commercial passenger flights from any operator arriving, departing or overflying UK airspace."The UK Civil Aviation Authority's safety directive will be in place until further notice.

"We remain in close contact with the European Aviation Safety Agency (EASA) and industry regulators globally."

-ENDS-There are currently five 737 MAX aircraft registered and operational in the United Kingdom. A sixth is planned to commence operations later this week.

[rightstuffer]

[QUOTE=_pudknocker_;10415002]MAX to be stopped flying in UK airspace according to skyWho foots the bill for this decision? (Just asking)

[22/04]

The wide range of views on here is something I applaud - rather I am concerned by some people who do not live in the real world - this one here.

MPLs are a fact of life- I fly EasyJet and Ryanair and the FOs often look like they should still be at school. Same on SpiceJet and Go-Air in India. I don't see them going away. The US seems to be out of step if anything by still insisting on more experience- I am surprised commercial pressure hasn't led to the same there.

Aeroplanes must be built such that they can be flown by these crews - safely operated all over the world. As I said yesterday, I am not sure certification bodies are doing their duty here.

[Toruk Macto]

Is it as simple as flicking a switch ? The crews that have survived a MACS event got the switch off in time the one(s) who did not could not for some reason identify or react quickly enough to disable the system and perished ?

[SigWit]

Norwegian also suspended their 737 MAX operations: https://media.en.norwegian.com/pressreleases/norwegian-temporarily-suspends-flights-with-the-boeing-737-max-following-recommendations-by-european-aviation-authorities-2846615 (https://media.en.norwegian.com/pressreleases/norwegian-temporarily-suspends-flights-with-the-boeing-737-max-following-recommendations-by-european-aviation-authorities-2846615?utm_source=TWITTER&utm_medium=TBA&utm_campaign=Proactive+Posts%2620190312%2620190312135800&Placement=N%2FA)

[cooperplace]

Re: captain had 8000 flt hours@ 28 years of age:

That sounds hardly believable.
18 out of high school
20 out of flight school with 200 hours
that means 1000 hours per year for every 8 years.
I dont buy it. Must be false.



quite an accusation; maybe he finished high school at 17, maybe he flew a lot in his teens, so maybe 7000 hrs in 9 years, say 15 hrs/week. Obviously not common, but impossible?

[Sucram]

​Here's the truth - none of them could fly an airplane. Plain and simple. No exaggeration, just the plain truth. ​​​​​​
Thats a pretty unfair and sweeping statement

[Intrance]

"With electrical power to the FCCs maintained, the unit that provides MCAS changes between flights"

I am assuming by flights you mean airborne not one continuous flight number with multiple stops I e multiple take off/landing. I believe a flight from A to B stopping at C,D and E keeps the same flight number right through all legs. To meet your conditions of continuous power, on landing either the engines are kept running, APU is started or ground power applied, so how does the system know when next flight starts, Is there a weight on switch on the UC, or does it monitor engine power/aircraft speed to determine next flight has started.. What happens if all power is turned off how does it know which FCC to use.next time.

Why would the system do this switch over? On landing crew report any defects to ground crew for rectification, you land a perfectly serviceable a/c but the not in use AoA sensor had developed a fault , you don't know that ( unless you have the red light upgrade), next crew takes off and oops they have problems because the now in use AoA is faulty, Confusion reigns cant be AoA problem none were reported or even more likely it is the same crew on a multi hop flight so they know it was working. I would expect that system to at least tell them which FCC/AoA was supplying power to controls.

It is quite common for all kinds of systems to switch like that between flights. Usually by weight on wheels. If power is lost, it simply starts with a predetermined default source. If you'd always be using the same input, you'd never notice if the other one went INOP. Suddenly the always used source goes unserviceable and the backup has been unserviceable for ages but was never used so not noticed. As long as this behavior is documented in the FCOM it is absolutely not an issue. And no one simply dismisses a possible source of problems just because the previous crew didn't have any issues.

[John R81]

UK CAA now issued SD-2019-001
SD-2019-001: Boeing 737-8 "MAX" and Boeing 737-9 "MAX" Limitation of Operations due to a Fatal Accident in Ethiopia on 10 March 2019This SD is made in the interests of safety of operation and to protect the public following the accident of an Ethiopian Airlines Boeing Model 737-8 "MAX" aircraft on 10 March 2019. External reports are drawing similarities between this accident and Lion Air flight 610 (x-apple-data-detectors://4) on 29 October 2018 involving the same type of aircraft. Given the similarity of the two accidents, it has been decided that as a precautionary measure that all Boeing 737-8 "MAX" and Boeing 737-9 "MAX" operations in the United Kingdom, whether by UK AOC holders or foreign AOC holders and carriers, should stop until appropriate safeguards are in place.

[derjodel]

UK CAA Statement and associated OSD http://publicapps.caa.co.uk/docs/33/SD2019001.pdf

They are mostly doing it to shield TUI, but nice to see someone had the balls. Specially due to the importance of the future US-UK relations.

[lpfflyer]

TK595 IST - NKC looks like it's turning around and returning to base so guessing Turkey is next with the grounding

EDIT: all outbound TK flights on the MAX look like they're turned around.

[El Bunto]

They are mostly doing it to shield TUI, but nice to see someone had the balls. Specially due to the importance of the future US-UK relations.

It's a complete inversion of the DC-10 grounding in 1979, when the FAA withdrew its cert but the CAA protested that it was an over-reaction.

Just realised that was nearly 40 years ago, 6 June 1979. Where did the time go?!

[Ian W]

It's looking like we are witnessing the first aircraft to be killed by social media since the Hindenburg.

My thoughts entirely.

There is also similarity to the Osprey - now the safest rotary flown by the US Military.

[Cows getting bigger]

My view is that the UK CAA haven’t jumped-the-gun. They have clearly tried to get as much information as possible and either don’t have that information or are troubled by some of the responses.

One thing I admire about the UK CAA is that they almost always play with a straight bat; it seems so here.

[quentinc]

but G-TUMB is still flying on. Clearly TUI know what they are doing, but to a casual reader, the CAA directive looks pretty clear.

[meleagertoo]

And what qualification for you is enough for someone to have privilege to step in b737 cockpit?
When I did my 737 type rating some years ago the vastly experienced CFI told us that Boeing's original design philosophy on the type was that it could be safely and efficiently operated by an experienced Captain and a third-world PPL. I think they pretty much succeeded. Of course the P2's experience counts but if he's been properly trained he's more than capable of backing up an experienced Captain who was always assumed to take the controls immediately an emergency occurred, though not necessarily to keep them if the situation warranted that course of action. Captain fly, boy do. It works.

I find it very surprising that anyone on this variant wouldn't have MCAS malfunctions so close to the front of his mind that the slightest extra clank of the trim didn't shock him alert in an instant, grabbing the trim wheel and reaching (or calling) for either Flap1 or the Stab Trim Cutout switches. How anyone on-type could fly 6 long minutes with trim problems and not tumble to the nature of the malfunction simply beggars belief.

For that reason alone I wouldn't be at all surprised if this particular duck turns out to be a goose.

[SLFinAZ]

Thats a pretty unfair and sweeping statement

Actually it's a factual statement in the sense that the vast majority of newer commercial pilots have very little hand flying experience in a line environment. SOP for just about every airline globally involves positive rate, gear up, AP on as quickly as possible. As a general rule AP disconnect on landing also occurs very late in the process. The result is that most pilots with no experience prior to the "glass cockpit" era have significantly underdeveloped intuitive capabilities.

Ebbatson (2009) found that pilots who had significant experience flying traditional, non-glass cockpit aircraft, developed robust mental models of performance characteristics during different phases of flight. These heuristics allowed experienced pilots to quickly and accurately predict and anticipate exactly how the aircraft would perform, thus reducing the high processing demands imposed by closed-loop processing. These pilots developed their own schema for the operation of the aircraft based upon experience with power settings, descent profiles, and rules of thumb. They no longer had to perform 14 complex mathematical calculations to determine when to begin a descent; rather they could simply apply the heuristic model for that situation. Less experienced pilots, lack these heuristics and quickly become saturated, resulting in poor aircraft control and planning. Over-dependence on automated systems exacerbates this issue and further inhibits the ability to develop the required mental models for manual flight.

https://scholarworks.sjsu.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=5108&context=etd_theses (https://scholarworks.sjsu.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=5108&context=etd_theses)



The simple truth is that while the planes themselves are infinitely safer the pilots are not. Obviously that is a harsh blanket statement but the truth is that if you can't practice your craft you won't maintain proficiency.

[Airmann]

When I did my 737 type rating some years ago the vastly experienced CFI told us that Boeing's original design philosophy on the type was that it could be safely and efficiently operated by an experienced Captain and a third-world PPL.

Sure, but the experienced Captains have long since retired and the third world PPLs have upgraded to the left seat. And for that matter the first world PPLs are not much better.

[diclemeg]

Not a pilot, but an engineer here.
That the MCAS system was relying solely on one sensor and not cascade to backup sensors or other checkpoint data, too.... well, it almost sounds to me that Boeing went rouge from their philosophy and instead errantly took a page from Airbus' philosophy, trying to fully automate the plane, and half-assed the entire logic and failed miserably. Otherwise, this MCAS system seems criminally designed, not to mention the lack of instruction in their Flight Manual.

[Dont Hang Up]

but G-TUMB is still flying on. Clearly TUI know what they are doing, but to a casual reader, the CAA directive looks pretty clear.
Landing will not be denied to aircraft already inbound.
Only those not UK based will turn around as they would not be able to depart again.

[Interflug]

Next, basic airmanship: ...I can handle the airplane all day long without an altimeter or airspeed indicator (in VMC conditions)
Really?
Have you tried?

[SLFinAZ]

I've got a basic question on the level of training for an MPL. Does the simulator work include/require a demonstrated ability to fly and land on raw data only? Same thing for Captain upgrade for ET?

[Smythe]

Looks like the Aussies joined the ban

[Tetsuo]

Landing will not be denied to aircraft already inbound.
Only those not UK based will turn around as they would not be able to depart again.
TK-LCG has turned back several hours into the flight and it's on it's way back to Istanbul.

[Phenom 300]

Looks like the Aussies joined the ban

Germany as well!

[hum]

AoA is a fundamental parameter in aerodynamic lift generation, it should be displayed to flight crew in airlines.

The AoA/G awareness training mandated for all EASA pilots that start training from the end of 2019 as part of the new mandatory UPRT package for professional licence issue is long overdue.

AoA/G awareness training cannot be done in a Simulator. Anyone who does not understand this needs to do a UPRT course.

[Scuffers]

The V-22 took 18 years to reach IOC from date of first flight. If airliners followed a similar length of development I reckon they'd be pretty well debugged, too...

In contrast the 737 Max was certificated and entered service within 16 *months*.

after the 787 farce, you would think they would have learned not to rush this stuff?

I'm not sure who to blame here, FAA seem all too keen to pass Boeing's stuff without enough scrutiny..

[adr]

CAA (http://publicapps.caa.co.uk/docs/33/SD2019001.pdf): "[...]after 1300 hrs on 12 March 2019 [...] [the affected models of] aircraft registered in the UK are not to be flown anywhere."
G-TUMB departed ALC at 1307.

"Oops. Sorry,er, the captain's watch was slow."

[FanControl]

Yesterday about 24 hours ago I checked how many 737 Max 8 were in flight - there was 145 around the world. Today there are currently 102.

[Less Hair]

France and Ireland have joined the ban.
Are there any news from first recorder readouts available? Must be something going on?

[SLFinAZ]

Going back to the statement about the Co Pilot having 200 hours exerience. Was this total, or on type?
I was under the impression you needed minimum 400 hours for a commercial licence and 1500 for ATPL
How are you allowef to fly a passenger jet with below the minimum required, or is Ethiopian licencing somewhat more lax regarding hours/experience.

The FO had an MPL not an ATPL, The program provides for 70 hours of actual flight time and 130 hours of simulator training. From an earlier post of a pilot who actually flew with ET he stated that most MPL holders had roughly 230 total hours before they were released to Line (vs. Training) captains.

[loob]

RE: Comments that the pilots don't know how to fly. If this was true the issue would not be concentrated on this aircraft.

RE: Comments that flights should continue until the problem is identified. This is backwards and people who believe this obviously don't understand basic risk management. The fact that you may be a pilot is irrelevant, pilots are not trained in data analysis and risk and a lot of you seem to be allowing your personal politics and biases come into your opinions.

The correct approach is to ground the craft until faults are identified, the idea that the craft should continue flying until we discover the fault is backwards and seems to be a common line of thought nowadays amongst people who like to think that they are scientific but do not understand data analysis.

[virginblue]

I find it mildly irritating that folks here warn about putting the blame on MCAS prematurely while at the same time it seems to be perfectly legit to point the finger at this poor FO without the slightest hint that he has done anything wrong or could have stopped the aircraft from falling out of the blue sunny sky with more hours under his belt (which, btw, begs the question: how many more hours?)

[A0283]

What surprises me most, since the Lion Air crash, is how very very very far Boeing and the FAA are behind in this. Historically Boeing has often been ahead of events (having the benefit of validated information of course). Viewed from the outside this is a watershed in Boeing culture. In the coming years we will find out if this has anything to do with the move to Chicago, or that they have just been surprised and startled by social media speed.

[kyden]

Boeing just delivered a 737 Max 8 (C-FAXD) yesterday from Seattle to Toronto (Sunwing with PH livery), so it doesn't look like they have grounded anything from their end for now.

[A0283]

UK CAA as I read it:
"as we do not currently have sufficient information from the flight data recorder,
we have, as a precautionary measure, issued instructions to stop any commercial passenger flights from any operator arriving, departing or overflying UK airspace."

Which sounds logical because they are not in the direct line of the investigation. The recorder(s) are probably under way to either NTSB or BEA or ... And the UK AAIB/CAA will not be present at the first readout(s) (hoping that they can be read).

You would think that when FDR information comes available they would compare that with the Lion Air case and investigation and design discussions associated with that. And based on that comparison every party informed will decide on lifting a ban or making it less temporary.

Next to this you would at least expect a press release by EASA stating they are following events ... that individual countries can make a decision ... and list the status of the decision by individual EU countries.

[22/04]

So, is the CAA taking action on the basis of objective evidence, or is it being driven by social media and apparent public opinion?

Probably a bit of both- sooner or later TUI pax were probably not going to get on a Max. Just being prudent until more is known.

while at the same time it seems to be perfectly legit to point the finger at this poor FO without the slightest hint that he has done anything wrong

Just for the record my posts are not criticising the FO or the system - just letting folks know how it is - some in the USA do not seem to realise.

[fox niner]

Netherlands airspace is closed for the MAX.

[ChicoG]

OSLO (Reuters) - Norwegian Air will temporarily ground its Boeing 737 MAX 8 passenger jets at the advice of European regulators, it said on Tuesday.

“Following the decision by the relevant aviation regulatory bodies to temporarily suspend operations of Boeing 737 MAX, Norwegian will not operate any flights with this aircraft type until further notice,” the company said in a statement.

https://www.reuters.com/article/us-ethiopia-airplane-norweg-air-shut-sus/norwegian-air-grounds-its-boeing-737-max-8-jets-idUSKBN1QT1U5

[Speed of Sound]

THOUGHTS ON A POSSIBLE FIX

On the subject of a 'software fix', as well as possibly feeding data from both AoA sensors to the microprocessor concurrently rather than consecutively, would adding another precondition to MCAS operation affect certification?

What I am suggesting is a >minimum altitude to be achieved before operation of the system.

The stabiliser is a very powerful control surface and having a system which can repeatedly trim the nose down at an altitude where time to recover is limited has the potential to cause more harm than it can prevent. A system which can require both pilots to simultaneously apply greater than normal elevator control added to the need for either the system to be disabled (one hand off the control column to operate two guarded switches or selection of flaps), opposing the MCAS trim by repeated manual trim control, or all three is quite frankly an ergonomic mess!

Despite the 'it wouldn't happen in a Western/white airline' nonsense we keep hearing, as many people on here have said, MCAS operates normally most of the time and even the best forewarned crew would (and should) not immediately respond to every upset as though it was an MCAS problem. Even a very quick and efficient diagnosis of the problem could still take the same length of time as it takes for the automatics to put your aircraft in a potentially fatal nose down trim. This is not primarily a training issue, it is a systems issue which Boeing now seems to be accepting despite the 'making a very safe aircraft even safer' statement.

This is a general observation, regardless of the cause of this particular incident. As mentioned above, the best time to have an AoA sensor failure is just after take off (even at night) when there are still some visual references to help you decide whether to believe either what your instruments are telling you or what you are seeing outside the cockpit.

So if we don't get a rethink of the whole system, would putting a minimum altitude requirement for its operation pass existing certification or is MCAS protection required for all phases of clean flight? As MCAS is intended to provide protection in low energy situations a great deal of thought would need to be given to how the minimum operating altitude would be determined.

[diclemeg]

What surprises me most, since the Lion Air crash, is how very very very far Boeing and the FAA are behind in this. Historically Boeing has often been ahead of events (having the benefit of validated information of course). Viewed from the outside this is a watershed in Boeing culture. In the coming years we will find out if this has anything to do with the move to Chicago, or that they have just been surprised and startled by social media speed.

This MCAS system was half-assed designed... behested on only one AOA sensor, which is simply criminal. They did not think it fully through, by any means. Nor were they weren't true to their philosophy, and took a poke at Airbus' philosophy, and it is gonna bite them.

[22/04]

Posting a bit too much but

If it were the AAIB they would put out a preliminary as soon as possible I think to try to clarify - as we saw with the recent heli crash in Leicester, with an almost concurrent AD. Can we expect the same from an Ethiopian inquiry?

[derjodel]

The correct approach is to ground the craft until faults are identified, the idea that the craft should continue flying until we discover the fault is backwards and seems to be a common line of thought nowadays amongst people who like to think that they are scientific but do not understand data analysis.

That is, if we want to place lives and people before profits :O
If profits come first, continuation of operation might be the only option. E.g.: we continue, ET crash was not mcas related -> best possible profit outcome. All others are just loss minimisation.

Just saying.

[threemiles]

Be it MCAS in this case or not, the MCAS certification of the MAX series smells. To certify a system that directly controls primary flight surfaces AND that is reliant on a single sensor (AOA), is against written and unwritten rules in aircraft design, engineering and certification. If we were not living in times of massive commercial global rivalry (US, Europe, China) I would have expected the FAA and subsequently EASA coming under enormous public and political pressure how they ever had accepted the MCAS certification proposal by Boeing. But it had become a political and commercial case where no country wants to damage its industry and protects its agencies. This is too sad as it damages the culture of aviation safety in lieu of local interests.

[Less Hair]

It's really strange that the relevant certifying authorities like FAA and EASA are so far behind the operators and many nations this time and seem to come to different conclusions. Has this ever happened before on this level?

[jantar99]

THOUGHTS ON A POSSIBLE FIX

On the subject of a 'software fix', as well as possibly feeding data from both AoA sensors to the microprocessor concurrently rather than consecutively, would adding another precondition to MCAS operation affect certification?

What I am suggesting is a >minimum altitude to be achieved before operation of the system.

The stabiliser is a very powerful control surface and having a system which can repeatedly trim the nose down at an altitude where time to recover is limited has the potential to cause more harm than it can prevent. A system which can require both pilots to simultaneously apply greater than normal elevator control added to the need for either the system to be disabled (one hand off the control column to operate two guarded switches or selection of flaps), opposing the MCAS trim by repeated manual trim control, or all three is quite frankly an ergonomic mess!

Despite the 'it wouldn't happen in a Western/white airline' nonsense we keep hearing, as many people on here have said, MCAS operates normally most of the time and even the best forewarned crew would (and should) not immediately respond to every upset as though it was an MCAS problem. Even a very quick and efficient diagnosis of the problem could still take the same length of time as it takes for the automatics to put your aircraft in a potentially fatal nose down trim. This is not primarily a training issue, it is a systems issue which Boeing now seems to be accepting despite the 'making a very safe aircraft even safer' statement.

This is a general observation, regardless of the cause of this particular incident. As mentioned above, the best time to have an AoA sensor failure is just after take off (even at night) when there are still some visual references to help you decide whether to believe either what your instruments are telling you or what you are seeing outside the cockpit.

So if we don't get a rethink of the whole system, would putting a minimum altitude requirement for its operation pass existing certification or is MCAS protection required for all phases of clean flight? As MCAS is intended to provide protection in low energy situations a great deal of thought would need to be given to how the minimum operating altitude would be determined.

Well, you wouldn't want to stall low as well. And MCAS is there bc MAX couldn't be certifed w/o it. To put it harshly, with MCAS one* dives, w/o it one* stalls.
*Applicable to some, not all pilots.

[PaxBritannica]

I’m not sure they’ll be with Boeing!
According to the BBC news site:What happens next?The investigation will be led by Ethiopian authorities in co-ordination with teams of experts from Boeing and the US National Transportation Safety Board.

Does this mean the boxes are being processed in the US?

[derjodel]

Lion Air FDR has been found on Nov 2nd and read on Nov 4h - 2 days. ET recorders were found yesterday, but LOTS of parties are VERY interested in what data they have. Is it technically possible they have been read?

[A0283]

@22/04 ... Question is if Ethiopia will take the lead or delegate the whole or part of the investigation. There was a photo with Ethiopian CAA and other investigators going aboard a plane to the location. But their labs and technical backup will probably not be sufficient to lead this one (with all due respect).

[Non-Driver]

It's looking like we are witnessing the first aircraft to be killed by social media since the Hindenburg.

Not quite - the EC225 suffered that fate, albeit one with the offshore industry lobby factor. Similar parallels with the UKCAA (and Norwegians) acting fairly promptly and EASA dragging its heels. The Eurocopter/Airbus strategy on dealing with that one would be a salutary lesson for Boeing.

[Lonewolf_50]

Does this mean the boxes are being processed in the US?
Why don't you ask the Ethiopians?
It's their investigation.
They'll either want to do it in house, or somewhere else, based on their view on what gets the best results.

[MLHeliwrench]

According to the BBC news site:[h2]

Does this mean the boxes are being processed in the US?

i read in an article yesterday that a lab in Israel may me used. Sorry I can’t recall where I read that.

[ORAC]

https://twitter.com/independent/status/1105499842737029123?s=21

[ChicoG]

Holland has joined in.

https://www.rtlnieuws.nl/nieuws/buitenland/artikel/4639901/boeing-737-max-flightradar-omdraaien

Is the European regulator doing this? There is also news that Turkish Airlines are grounding them (not yet confirmed).

Now confirmed: https://www.apnews.com/94c19abef66d4a0e977a1286d779ba22

[SLFinAZ]

RE: Comments that the pilots don't know how to fly. If this was true the issue would not be concentrated on this aircraft.

RE: Comments that flights should continue until the problem is identified. This is backwards and people who believe this obviously don't understand basic risk management. The fact that you may be a pilot is irrelevant, pilots are not trained in data analysis and risk and a lot of you seem to be allowing your personal politics and biases come into your opinions.

The correct approach is to ground the craft until faults are identified, the idea that the craft should continue flying until we discover the fault is backwards and seems to be a common line of thought nowadays amongst people who like to think that they are scientific but do not understand data analysis.

Your actually outlining the real issue at hand here perfectly. The "issue" is not specific to one aircraft or one aircraft type...not even one manufacturer. It's a systemic issue based on the ever increasing demand for air travel globally and the real cost involved in properly training pilots. The current reality is that the focus is on increasingly complex automation instead of pilot training. The primary fault lies in the cockpit not in the plane itself. I've seen multiple comments on defending the FO, that's nonsensical. The issue isn't the FO it's the system that allowed him in the cockpit that is at fault.

[Lonewolf_50]

The CAA's statement is perfectly clear. It only fails to make sense if a poster arbitrarily removes part of it:

"however, as we do not currently have sufficient information from the flight data recorder we have, as a precautionary measure, issued instructions to stop any commercial passenger flights from any operator arriving, departing or overflying UK airspace." I could be cynical and observe that a problem that seems to manifest during the take off phase with the flaps up is now deemed to pose a risk in the landing phase with the flaps down but that is not necessarily a clear distinction in terms of do operators know what does and doesn't lead to odd inputs?
I thus appreciate that their remit has to do with public due care, etc. and thus the abundance of caution approach is understood.

(Plus, it has to take off again, doesn't it?)

[fmgc]

“However, the Civil Aviation Authority of the United Kingdom announced in the afternoon of March 12, 2019, that as they “do not currently have sufficient information from the flight data recorder”, a precautionary ban of the aircraft within the UK’s airspace was ordered.”

https://www.aerotime.aero/clement.charpentreau/22455-more-countries-ban-boeing-737-max-amid-safety-concerns?utm_source=newsletter&utm_medium=email

So why isn’t every aircraft type banned after an accident until there is any idea of cause?

[RoyHudd]

Absolutely right SLFinAZ. (3 entries above) Pilot experience levels and standards are rock bottom in so many places.The poor saps simply are not trained adequately on today's complex jets. Blame the accountants, the airline management, and even the operational and training management.

It was always about making bucks. But safety used to be of paramount importance. No longer.

[11K-AVML]

Holland has joined in.

https://www.rtlnieuws.nl/nieuws/buitenland/artikel/4639901/boeing-737-max-flightradar-omdraaien

Is the European regulator doing this? There is also news that Turkish Airlines are grounding them (not yet confirmed).
Doubt EASA will move until the curve is well ahead of them.

[dirk85]

Also Italy banning the Max as of 2100 local today.

[hans brinker]

I think its important to remember that the Lion crew kept the aircraft reasonably steady for 6 minutes after MCAS issues presented, continuously and manually counteracting the MCAS nose down events that occurred during that whole time. The crew knew they had a stabilizer runaway b/c they kept using the electric trim to correct it. They kept the aircraft basically level at 5000 feet for that 6 minute duration, until, for the last four MCAS nose down commands, the crew's manual trim responses occur but are just "blipped" (not sufficient to counteract the MCAS input), and assumedly resulted in the stabilizer being full forward.


No one knows why the crew were able to successfully counteract MCAS with manual trim operation for 6 minutes, and then fail to do so for the final 4 MCAS inputs. That is the mystery that we are hoping the CVR will explain.


Lastly, as I understand it, MCAS only dials in *ONE* nose-down increment (2 degrees or whatever it is) and then deactivates itself, until something happens to reactivate MCAS allowing it to dial in another increment. I can't recall all of the crew activities that result in MCAS being reactivated, but I believe one is operation of the manual trim. This is why the last four "blipped" manual trim inputs in the Lion flight result in four unmitigated MCAS nose-down events, because any manual trim input resets MCAS and allows it to reasses the AoA / speed picture and dial in another MCAS trim input.

I remember reading that the captain transferred control after 6 minutes. He had been making large trim inputs successfully counteracting MCAS. The FO made much smaller trim inputs, so they ended up with full AND trim.

Also I think if MCAS still senses high AOA after the 5sec pause, it will make another up to 10 second trim input.

Some people say this would confuse the pilot because it is intermittent and not continuous runaway trim. I feel 10sec trim should definitely be seen by the pilot as way too long, and acted upon as runaway trim, especially if it keeps doing it repeatedly.

[Organfreak]

The US seems to be out of step if anything by still insisting on more experience- I am surprised commercial pressure hasn't led to the same there.
Aeroplanes must be built such that they can be flown by these crews - safely operated all over the world. As I said yesterday, I am not sure certification bodies are doing their duty here.

Standards were raised (required hours) here in the U.S. after the Colgan crash in response to a huge public outcry.

[threemiles]

Because this is an accident that strikes close resemblance to another very recent accident -with brand new airplanes- where a faulty system was the root cause, and that system is still not fixed.

FAA says when then new MCAS software is certified and out it shall be implemented by an AD Note. I am not sure this is the right sequence if FAA feels something is very critical. Because the interim AD had nothing in it but hot air it reads like the MCAS problem is minor. Now they say it deserves implementation of the fix by AD note not by Service Bulletin. Again, this smells and the FAA does not seem to act logical and independantly but rather as the long arm of Boeing and US commercial interests. A logical step would be a grounding order by FAA until the fix can be implemented.

[dougydog]

Shame these guys didn`t monitor their speed a little better...MCAS was the result. And `rushed` in perhaps? The law of unintended consequences. Bit like the locking of flight deck door...

https://www.gov.uk/aaib-reports/aar-3-2009-boeing-737-3q8-g-thof-23-september-2007

As I understand it, some at Boeing couldn`t understand how, with 82 knots seen during the recovery, the aeroplane didn`t crash. It was literally hanging on the engines at full power.

[Icarus2001]

To certify a system that directly controls primary flight surfaces AND that is reliant on a single..

MCAS controls the stab trim.

Stab trim is not a primary flight control.

[rog747]

Korea and Turkey ground all their Max fleets, The TK a/c en-route to UK and EU have all turned back.

Norwegian have said we have more than 110 Boeing 737–800 aircraft in its fleet, which is not affected by this temporary suspension of our MAX fleet.
This evening's transatlantic's back to Europe on their MAX are all cancelled.
But tomorrow's EDI - NYC is still showing as operating with a MAX, so this will be canx or pax put on a 738.

Meanwhile - over on the Atlas 767 down thread
NTSB gets FDR readout shows full forward control column input - and full thrust applied on both engines.

Gosh what a week.

[threemiles]

MCAS controls the stab trim.

Stab trim is not a primary flight control.

This is the pilot's view. The aerodynamic view is that it directly affects attitude, drag and lift, so it is primary. Trim systems are treated as such during certification.