Boeing 737 Max8 Aircraft Crashes and Investigations [Part 7] 16

[Sparweb]

This post is the continuation from this series of previous threads:

thread815-445840
thread815-450258
thread815-452000
thread815-454283
thread815-457125
thread815-461989

This topic is broken into multiple threads due to the length to be scrolled, and images to load, creating long load times for some users and devices.
If you are NEW to this discussion, please read the above threads prior to posting, to avoid rehashing old discussions.

Thank you everyone for your interest! I have learned a lot from the discussion, too.

Some key references:
Ethiopian CAA preliminary report (Link is now broken. See PDF download below, 3 MB)

Indonesian National Transportation Safety Committee preliminary report

A Boeing 737 Technical Site

Washington Post: When Will Boeing 737 Max Fly Again and More Questions

BBC: Boeing to temporarily halt 737 Max production in January

www.sparweb.ca

 

[waross]

Why Boeing might not need a bailout despite coronavirus, 737 Max crises
.....
Boeing isn’t mentioned by name in the 880-page bill. But the aerospace giant will qualify for as much as $17 billion in taxpayer relief through this language threaded into the fourth paragraph of page 513 of the CARES Act: “businesses critical to maintaining the national security.”
.....
After recently drawing a $13.8 billion bank loan, Boeing has about $24 billion in cash on hand, according to Debtwire estimates.

Link

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Alistair_Heaton]

I think one of the conditions of getting Government money is that the government take some % of ownership.

And there is no way Boeing board will want that and limit there ability to issues shares etc to board members.

And as for splitting well that's all very good if you have a cancerous limb. As far as I can see all the main sectors that Boeing is heavily involved in they have screwed up and have huge liabilities. So they need more of a chemotherapy treatment than an amputation.

 

[waross]

Boeing will work their way out of this with good old American ingenuity.
About 40 Billions worth.
They have just secured a bank loan for 13.8 billions.

After recently drawing a $13.8 billion bank loan, Boeing has about $24 billion in cash on hand, according to Debtwire estimates.

By the way, as far as I know, Boeing has not yet accepted any government money.
Despite that, one board member has resigned over the issue.

Critics of a bailout include former United States Ambassador to the United Nations and former South Carolina Gov. Nikki Haley, who resigned from Boeing's board in protest.

The bailout figure is 17 billions.
With the cash on hand, another 17 billion would but Boeing's available cash at over 40 billions.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[LittleInch]

Is that enough to buy back all the maxes and then rebuild them / strip them for a newly designed aircraft?

Now the market for aircraft is going to tank in the next 5 years stranger things have happened.

Someone somewhere in Boeing will be running the numbers....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Alistair_Heaton]

Biggest problem with that idea would be the production would be shut down for 5 years. They would find it next to impossible to get going again in any sort of volume. Most of the suppliers would have gone off to do something else or got rid of the workforce.

The MAX will fly again in its current Frankenstein state with modifications.

I don't think they will be stupid enough to entertain another iteration in the 737 family though.

They have that many areas that they need to develop products in.

 

[waross]

A certification flight required to clear the grounding on the 737 MAX is awaiting software validation, with Boeing CEO Dave Calhoun anticipating a third quarter return to service, according to the company’s Apr. 29 first quarter earnings call.

The certification flight awaits software validation for the 737 MAX flight control computer (FCC). Calhoun gave no timeline on when the software validation effort would be complete.
Link


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Sparweb]

Although not a step in Boeing's journey to restoring faith in their aircraft, nor toward certification of the 737, this is a very interesting event.
It is an asset to the Seattle Times and will mark Boeing for a very long time:

For groundbreaking stories that exposed design flaws in the Boeing 737 MAX that led to two deadly crashes and revealed failures in government oversight.

https://www.pulitzer.org/winners/do...etich-mike-baker-and-lewis-kamb-seattle-times

My sincere congratulations, esp. to Dominic Gates, whose articles I've come to rely on to understand many aviation issues (not just the 737 ones).

http://www.sparweb.ca

 

[Alistair_Heaton]

I will say as well that Seattle Times has been my go to first media outlet for aviation content for over a year now. To be honest mixing in with links from PhD mates about the virus stuff it seems to be more informed about that subject as well.

I if Dominic Gates picks this up I salute you Sir as a pilot and ex engineer. You are reporting in a truthful educated manner.

 

[btrueblood]

Hope you guys are paying for your access, though I cannot blame you if you don't (I don't pay for articles online very often either). I have been a subscriber to the ST for 20+ years, as it's my "local" paper. They have been pretty reliable reporters over the decades, on a variety of subjects. One of those subjects is the fairly rapid decline in local newspapers (and local reporters) due to buyouts from conglomerate enterprises, resulting in a lot of stories going un-reported or at least under-investigated.

 

[Alistair_Heaton]

Sorry but I don't, mainly due to its extremely hard internationally to pay for a subscription. The ST should actually think about making it easier. I am not alone being a none USA pilot using them for a primary source of info about Boeing.

BTW on the subjects of Aviation and IT I would consider it international.

 

[Alistair_Heaton]

This might be of interest to some.

The c series/A220 AoA setup.

It uses as the primary AoA static ports on the Pitot tubes to calculate AoA. It uses traditional AoA vanes as the standby/back up.

They are grouped in three's, So two static port sensors and 1 vane, there is comparison checks between the three in a group. The two groups are then compared for mismatch.

You have the ability to going into reversion swapping between groups and feeding one sensor to both groups.

So in total you have 6 AoA sensors. Error checking between 3 of them and then mismatch checking between the two groups. There are 3 independent flight control computers doing the checking, and they also do a sanity check referring to the IRS and Airdata computers if everything is inside a plausible envelope. If its not then the flight law changes and the pilot has to sort it out.

 

[waross]

Are the AoA sensors counterbalanced, or do they drop down when the aircraft is stationery?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Alistair_Heaton]

The main ones are not vanes. They have 2 static ports on the side of the pitot tubes. And the box of tricks works out the AoA from them.

The standby/backup vanes I really don't know what they do on the ground will take a look next time I am near one.

This pic seems to indicate they stay put.

The front line of 3 probes are top two pitot tubes and bottom one is a true air temperature sensor. the one under the window is the vane.. which looks straight to me.

here is a link to the pitot AoA system

http://www.goodrich.com/cap/systems...nd Systems/SmartProbe(R) Air Data Systems.pdf

 

[waross]

Thanks.
I was thinking; If the counterweight was trimmed so the vane pivoted down when at rest, They could have a three point check each takeoff.
1. At rest. Known check position vertical.
2. Takeoff run. Known check position horizontal.
3.Takeoff run. Transition from vertical to horizontal at known speed, freedom of movement, binding.
It looks as if the vane is 100% balanced by the counterweight so that idea goes out the window.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[IRstuff]

I recall looking into this earlier, and there is definitely a counterweight involved. The issue has never been the counterweight, per se; that's all processed internally, but the AoA sensor outputs will still give stupid answers, even on the ground, without the flight computer issuing a critical failure warning.

If you go back to the earlier parts of this specific thread, the FDRs show that the one, and only, AoA sensor being used for the stall indication was giving erroneous values even during taxiing, which one would think, should have caused an alert to the pilots to abort the the takeoff, since the AoA is such a critical part of the flight controls.

This shows that the whole issue isn't simply just the AoA sensor itself, but a failure to adequately detect anomalies in the sensor data, even on the ground, prior to takeoff. That is a serious problem that is hopefully resolved, but I'm a bit skeptical.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

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[waross]

I'm thinking, optical limit switches at the vertical and horizontal positions.
An independent circuit that takes inputs from both the limit switches and from the AoA indication from the flight computer.
That could prove the entire AoA system not just the mechanical function of the AoA vanes.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[IRstuff]

There's probably sufficient BIT in the instruments; Boeing just isn't using the BIT or the data to do validity tests.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

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[3DDave]

The local winds around the aircraft operated at low speeds, such as during taxiing, mean no meaningful information is gained from AoA sensors. There will be no stall warning with weight on wheels.

 

[IRstuff]

The problem was that the AoA was malfunctioning on the ground; that's a BIT problem which the flight computer should have been able to resolve and warn the pilots to abort takeoff

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[waross]

Thanks Dave.

Bill
--------------------
"Why not the best?"
Jimmy Carter