Primarily for general aviation discussion, but other aviation topics are also welcome.
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By Josh
#1681091
Basically the problem is that as they’ve lengthened the aircraft and added larger diameter engines, the aircraft’s pitch stability has become an issue. At high angles of stack the engine nacelles themselves create lift forward of the CG, causing the aircraft to pitch up into a stall with no pilot input. This is obviously streng verboten in the certification requirements hence MCAS. Stability augmentation isn’t a new thing - the 737 already has a speed trim system and a Mach trim system from the early days, it’s just the new one is subject to some nasty falure modes, about which some duff assumptions were made, and nobody thought it was important to tell the crews flying it anything about it.

Boeing have been dumbing down their manuals for years now, which is a great frustration to more technically minded types who have to rely on getting hold of a copy of the maintenance manual to discover how things actually work! Airbus by contrast have system logic diagrams that make my head hurt.
#1681097
Josh wrote:Airbus by contrast have system logic diagrams that make my head hurt.

Does that not sort of support Boeing's position? :D

Boeing wrote:(Allegedly) …the Company had decided against disclosing more details to cockpit crews due to concerns about inundating average pilots with too much information - and significantly more technical data- than they needed or could digest
User avatar
By PaulB
#1681191
Singapore & Australia have gone further and banned 737 MAX8 from their airspace.
User avatar
By akg1486
#1681192
Boeing issued a press release saying that the MCAS will be updated and that they foresee an AD being issued in April. I've read it twice, but I don't understand exactly what the correction is and whether the correction would have prevented the accident.
#1681193
If nothing else, this comment (my bold) might go some way to answer much of the criticism I have (skim) read on pprune.
The enhanced flight control law incorporates angle of attack (AOA) inputs, limits stabilizer trim commands in response to an erroneous angle of attack reading
By KeithM
#1681224
Incidents of this nature are unlikely to accelerate a move towards pilotless passenger aircraft are they?

Perhaps the same could be said of driverless road vehicles?

Philosophically speaking, has there not always been a price to pay for progress?
#1681238
KeithM wrote:Incidents of this nature are unlikely to accelerate a move towards pilotless passenger aircraft are they?

Perhaps the same could be said of driverless road vehicles?

Philosophically speaking, has there not always been a price to pay for progress?


What is the logic in that statement?

Aircraft with pilots end up having accidents because there is a system failure (all alleged and assumed of course at this point) so pilotless aeroplanes will be less likely?

:scratch:
Rob P liked this
By KeithM
#1681265
Flyin'Dutch' wrote:
KeithM wrote:Incidents of this nature are unlikely to accelerate a move towards pilotless passenger aircraft are they?

Perhaps the same could be said of driverless road vehicles?

Philosophically speaking, has there not always been a price to pay for progress?


What is the logic in that statement?

Aircraft with pilots end up having accidents because there is a system failure (all alleged and assumed of course at this point) so pilotless aeroplanes will be less likely?

:scratch:


I have made no statement or statements, hence the question marks, therefore, questioning my logic has no relevance or basis.

I am merely addressing the limitations of both humans and technology and that progress has, and probably always will have, a price due to those unseen and/or untested limitations or “failure modes”.

Also addressing the fact that whilst, in many areas, we are comfortable to rely entirely on automation and technology (washing machines, for example!) that there are still areas where we are not, and with good reason.

Rightly or wrongly, seeing a human at the controls of an aircraft currently makes us feel more comfortable. Indeed, it seems that pilots, themselves, have similar concerns about automation.

I should, perhaps, have added a “smilie” to my first two questions. Apologies for that.

And, for clarity, my points are of a general nature, and not specific to the incident in question nor any other.
User avatar
By PaulB
#1681285
Just been announced on BBC News that CAA has banned 737 MAX 8s from UK airspace.

User avatar
By Iceman
#1681287
The list of countries issuing a temporary ban on the aircraft continues to grow. It will be interesting to see if any European countries (or EASA) follow suit and effectively force the FAA's hand.

Paul, we just crossed. There is the news that I expected (I think that only Tui and Norwegian are affected).

Mods, please move this to GA, it is far too Aviation-related for 'Non-aviation'.

Iceman 8)
Last edited by Iceman on Tue Mar 12, 2019 1:39 pm, edited 2 times in total.
User avatar
By PaulB
#1681288
Iceman wrote:The list of countries issuing a temporary ban on the aircraft continues to grow. It will be interesting to see if any European countries (or EASA) follow suit and effectively force the FAA's hand.

Paul, we just crossed. There is the news that I expected (I think that only Tui and Norwegian are affected).


Only TUI & Norwegian were mentioned on the news.
User avatar
By Iceman
#1681290
I would be surprised if other EASA members didn't follow suit.

If this had happened to an Airbus, the FAA would have been all over it. The FAA appears to me to be putting commercial considerations above safety.

Iceman 8)
JoeC liked this
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