While not affecting, or caused by, Boeing this new story is a fine example of what can happen when software updates aren't properly tested:
https://www.bbc.co.uk/news/technology-56690529

And yet three flights took off with the incorrect weights...

Ok, so the pilots coped with that and raised the Incident Reports after the event... However...

What happened to the procedures that are supposedly in place and that are supposedly all about aviation safety to catch such (potentially deadly) silliness before an aircraft leaves the ground?...


Too much greed cutting a deadly corner?...

Fly safe folks!
Martin

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Brief Boeing update for some Boeing 737 bits in the news at the moment...


All my personal opinion and personal view as always:

• A batch of something like 60 new Boeing 737 MAX aircraft are terrafirma grounded due to a manufacturing change that installed an electrical power control unit using "fastenings" rather than metal rivets and noone had considered that there might then be problems with the units not being safely electrically grounded (bad pun)... Serious consequences if that was to go wrong in flight...
  
  
• And the wing mounted fuel load computers on the Boeing 737 have been found to be faulty/inaccurate and do not operate safely as designed and can allow a fuel overload that then can spill to become a fire hazard...
  
  
• What yet else?!
  

Fly safe folks!
Martin

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to err is human, to really f' it up requires a computer

to err is human, to really f' it up requires a computer

I'd rephrase that to:

... requires deadly no-morals blindly selfish blind greed.


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Martin

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to err is human, to really f' it up requires a computer

I'd rephrase that to:

... requires deadly no-morals blindly selfish blind greed.

But they do have morals and ethics. They know their FIRST (and only) duty is to the shareholder, to make as much profit as possible.
The legal ethic of fiduciary duty. The moral; Of the Profit, by the Profit, for the Profit!
A corporation is nothing except legal ethics. A piece of paper does not have morals.
They do not owe the customer or the public any duty unless it is imposed by a statute.
"Airplane Corp expressly disclaims any implied warranty of merchantability or fitness for a particular purpose. Airplane Corp expressly disclaims and liability for incidental or consequential damages arising from the use or misuse of its products."

Brief Boeing update for some Boeing 737 bits in the news at the moment...


All my personal opinion and personal view as always:

• A batch of something like 60 new Boeing 737 MAX aircraft are terrafirma grounded due to a manufacturing change that installed an electrical power control unit using "fastenings" rather than metal rivets and noone had considered that there might then be problems with the units not being safely electrically grounded (bad pun)... Serious consequences if that was to go wrong in flight...
  

Blancolirio clearly explains the first fault with his usual good clear explanation:

737 Max UPDATE 16 April 2021 Electrical Issues


Noting the further details for that one, my personal (most humbly ignorantly opinionated) take is:

What the ....!

So that looks like an out-of-sequence assembly in the rush and hustle to push aircraft off the production line, with unapproved use of bolts likely due to physical access restrictions due to the out-of-sequence muck-up, with no cares about what goes where or how or with what consequences.

The consequences here are that the electrical grounding for a safety critical controller wasn't grounded, due to it now being bolted onto (insulating) primed and painted fixings. Also, were those bolts fixed such that they are vibration proof so that the unit doesn't go flying away in mid flight?...

And failure could cause the loss of aircraft deicing systems and the Auxiliary Power Unit, just for what was mentioned... Very much "not good".

And really, the production monkeys and production management really do not know about aircraft to not notice at the get-go to not do such unapproved potentially dangerous shoddiness?!


I hope there is additionally an on the ground automated check made for electrical connections before flight?

We've had "self test" designed systems for decades. Do Boeing (and others) implement and use that?


Fly safe folks!
Martin

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Here is a good succinct summary of the 'game of play' at Boeing to date:


Why Boeing's Downfall...
wrote:

... Boeing has a variety of fundamental issues that have made the situation much worse for Boeing than any other aircraft manufacturer. This includes years of negligence, poor management, and a monopolistic position within the aircraft market. The culmination of these shortfalls is the primary reason for the initial failure of the Boeing 737 max. Though the 737 max was the first failure that caught the public's eye, Boeing has had a history of poor quality control and lack of timely action. This video explains the various reasons Boeing is on a downfall today and why their downfall is well deserved.

To my most humble personal view: Eye-watering deadly stuff.

Yet how do the Boeing Board members still walk away with their $Millions? How do they sleep at night??...


All in our deadly greedy world,
Martin

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For my most humble personal ignorant view:

This one must rate as totally an example of "Boeing Profits First" and all other concerns and consequences be damned:


Latest Starliner Delays (and excuses) - How can Boeing get any worse? Find out, and Get Angry!!


How much? For how long?? And for dubiously how long yet for so many fixes?

And what of the fixes to the fixes??

And can those fixes be trusted???


Ronald Regan made grand use of a reworked Russian phase of "Trust. But Verify."

Can such greedy profits and damaging 'short cuts' be overcome?

Or should the USA just cut the ongoing losses?


Fly safe!
Martin

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... All my personal opinion and personal view as always:

• A batch of something like 60 new Boeing 737 MAX aircraft are terrafirma grounded due to a manufacturing change that installed an electrical power control unit using "fastenings" rather than metal rivets and noone had considered that there might then be problems with the units not being safely electrically grounded (bad pun)... Serious consequences if that was to go wrong in flight...
  

... Noting the further details for that one, my personal (most humbly ignorantly opinionated) take is:

What the ....!

... The consequences here are that the electrical grounding for a safety critical controller wasn't grounded...

And failure could cause the loss of aircraft deicing systems and the Auxiliary Power Unit, just for what was mentioned... Very much "not good".

And really, the production monkeys and production management really do not know about aircraft to not notice at the get-go to not do such unapproved potentially dangerous shoddiness?!

I hope there is additionally an on the ground automated check made for electrical connections before flight?

We've had "self test" designed systems for decades. Do Boeing (and others) implement and use that?

This has taken a long time to hit the mainstream news:

Boeing's 737 Max aircraft under scrutiny again
wrote:

... The discovery of a potential electrical problem last month led to the renewed grounding of more than 100 aeroplanes, belonging to 24 airlines around the world.

Deliveries of many more new aircraft have been suspended. Boeing and the US regulator, the Federal Aviation Administration say they are working closely to address the issue.

But the affair has given new energy to critics who claim the 737 Max was allowed back into service prematurely...

... According to Boeing and the FAA, the problem first became apparent during testing of a newly manufactured 737 Max 8, which had yet to be delivered to its owner. It was found that electrical power systems on the aircraft were not working correctly.

The fault was traced to poor electrical ['earthing'] bonding... This meant that some components on the plane, including the pilots' main instrument panel and a standby power control unit, were improperly grounded, or earthed.

According to the FAA, this could potentially "affect the operation of certain systems, including engine ice protection, and result in loss of critical functions and/or multiple simultaneous flight deck effects, which may prevent continued safe flight and landing".

The flaw, then, was a dangerous one. The FAA was worried that over time other aircraft, which were already in service, could develop the same condition. It issued an Airworthiness Directive on 30 April stipulating that affected aircraft should be modified before being permitted to fly again...

So... I read that as deadly dangerous.

Note also that the two fatal crashes for the Boeing 737 Max involving the MCAS failure included "loss of critical functions and/or multiple simultaneous flight deck effects" that overwhelmed the pilots to soon kill everyone onboard. 'Critical' usually means "can't survive without"...

Gobsmacking!

And note how that was only found by chance after a real-world failure rather than being found by QA-and-test during production, and only after over a hundred other aircraft had been similarly shoddily built...

Reset my no-fly counter for Boeing for many months yet... (To forever no-fly for their present operations?)


Fly safe folks!
Martin

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Which connects with a lower electrical resistance? (Assume all are made of the same metal, physical diameter, and properly installed and torqued.)
Screw, nut and lock washer? Pop rivet? Blind rivet? Snap rivet?

Can you explain why?

Which connects with a lower electrical resistance? (Assume all are made of the same metal, physical diameter, and properly installed and torqued.)
Screw, nut and lock washer? Pop rivet? Blind rivet? Snap rivet?

Can you explain why?

With or without primer paint and top coat paint?...

I'd go with the screw, nut, and serrated lock washers under BOTH the screw head and the nut.

(Edit: Note that the serrations cut through any surface oxide to make a good metal-metal connection. And aluminium/aluminum is best avoided!)


However, far far better and safer and far more obvious is to have a dedicated electrical lug with deliberately sized and marked cabling to visibly and obviously connect to, that can also be deliberately isolated and tested to ensure correct operation.

... Randomly relying on fixings for chassis earthing/bonding is lazy and haphazard. Dangerously so when there is no way to test what the correct electrical path is or should be...


Do I pass the electrical safety test?

Fly safe!
Martin

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Are you absolutely certain that the chassis at location 'A' is at the same potential as the chassis at location 'B' or any other location.

I've come across earthing problems when the earth at the top of a hill wasn't, as is above an insulating rock layer
And another problem in a vehicle with two battery packs where the second set, used for comms equipment, wasn't charging correctly because the negative connection was the vehicle chassis and as you guessed there were paint layers between parts of the chassis.

And the world of cypher equipment incorrect earthing can cause unwanted radiation of signals.

Which connects with a lower electrical resistance? (Assume all are made of the same metal, physical diameter, and properly installed and torqued.)
Screw, nut and lock washer? Pop rivet? Blind rivet? Snap rivet?

Can you explain why?

With or without primer paint and top coat paint?...

I'd go with the screw, nut, and serrated lock washers under BOTH the screw head and the nut.

(Edit: Note that the serrations cut through any surface oxide to make a good metal-metal connection. And aluminium/aluminum is best avoided!)


However, far far better and safer and far more obvious is to have a dedicated electrical lug with deliberately sized and marked cabling to visibly and obviously connect to, that can also be deliberately isolated and tested to ensure correct operation.

... Randomly relying on fixings for chassis earthing/bonding is lazy and haphazard. Dangerously so when there is no way to test what the correct electrical path is or should be...


Do I pass the electrical safety test?

Fly safe!
Martin

Well, here is the thing, the screw/nut combo is the bad one on the Boeing and the rivet is the good one.

I'm going to take a guess that the parts are painted. I'm also going to guess that the inside of the holes is not painted. So when the rivet is set the walls expand in the hole and make contact. Not a way I'd say is good practice, but apparently it is how the aircraft was certified.

I'm much rather see a screw and pem nut where the panel under the screw is never painted.
Of course a bonding strap is the ideal method.

Which connects with a lower electrical resistance?...

With or without primer paint and top coat paint?...

I'd go with the screw, nut, and serrated lock washers under BOTH the screw head and the nut.

(Edit: Note that the serrations cut through any surface oxide to make a good metal-metal connection. And aluminium/aluminum is best avoided!)


However, far far better and safer and far more obvious is to have a dedicated electrical lug with deliberately sized and marked cabling to visibly and obviously connect to, that can also be deliberately isolated and tested to ensure correct operation...

Do I pass the electrical safety test?

Fly safe!

Well, here is the thing, the screw/nut combo is the bad one on the Boeing and the rivet is the good one.

I'm going to take a guess that the parts are painted. I'm also going to guess that the inside of the holes is not painted. So when the rivet is set the walls expand in the hole and make contact. Not a way I'd say is good practice, but apparently it is how the aircraft was certified.

I'm much rather see a screw and pem nut where the panel under the screw is never painted.
Of course a bonding strap is the ideal method.

Message 2075503 wrote:

... And another problem in a vehicle with two battery packs where the second set, used for comms equipment, wasn't charging correctly because the negative connection was the vehicle chassis and as you guessed there were paint layers between parts of the chassis...

Yes...

Ouch!

By 'eck! Even on such as equipment racks in datacentres and telephone exchanges here on terra-firma, there are dedicated clearly marked earth bonding straps very deliberately connecting all the metalwork together and also connecting to a dedicated earth point, usually multiple times over. Good for electrical safety but also very good for reliable operation and additionally good for helping to form a Faraday cage to protect against... LIGHTNING STRIKES and other 'electrical surges'...

Note that aircraft are all too often hit by electrostatic charging and discharging and especially the biggie of actual lightning strikes...

So... How have Boeing been able to cut production corners (and design corners?) and dodged the good and safe requirement of ensuring there is a secure and visible and testable earthing system throughout the entire cockpit and all the electrical racks?...

That has deadly consequences...


Fly safe!
Martin

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If I recall correctly, when I worked at the fire truck factory, they used 'single point grounding'.
The trucks had multiple batteries, which were connected in parallel. Then a single large ground cable was run to a large dedicated ground stud mounted in the frame.
Anything requiring a good or high current ground connection was then in turn run to this ground stud, not grounded to the frame or the body, ensuring that they all had the same ground point.
Some things, like compartment lights in the body, were grounded to the body. But then the body had it's own ground cable which was then connected to that main ground point in the frame.

---

"Freedom is just Chaos, with better lighting." Alan Dean Foster

Well, here is the thing, the screw/nut combo is the bad one on the Boeing and the rivet is the good one.

I'm going to take a guess that the parts are painted. I'm also going to guess that the inside of the holes is not painted. So when the rivet is set the walls expand in the hole and make contact. Not a way I'd say is good practice, but apparently it is how the aircraft was certified.

I'm much rather see a screw and pem nut where the panel under the screw is never painted.
Of course a bonding strap is the ideal method.

I'd guess your unpainted rivet guess is the 'hidden secret' that Boeing were relying upon to keep the aircraft flying.


Which leads to: What other invisible (undocumented?) 'critical secrets' are there in that design that are required to keep the plane flying?...

Have we moved from winging some prayers and hanging on by a thread to instead now be flying dependent upon the oxide layer skin of a rivet?


Fly safe folks!
Martin

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Yep, thanks for that.

Add fire trucks to the list of vehicles/equipment that have very deliberately designed bonded earthing cabling.

So for the painted and rivets vs bolts example, why not for Boeing aircraft?...


Fly safe folks!
Martin

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Yes, and the grounding strategy now used in fire trucks was not used in the very early years. It was adopted later on in response to a nightmare of grounding problems encountered when relying on the body and cab as ground points, which was common practice in standard automotive manufacturing decades ago.
Many of these problems became apparent only after the vehicles were in service for a period of months to years, and rust or corrosion or simple oxidation started to occur in places that initially had provided the grounding paths.
So they then went to the use of hard grounding cables that always provided a positive path to the known good dedicated grounding point.

---

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Well, here is the thing, the screw/nut combo is the bad one on the Boeing and the rivet is the good one.

I'm going to take a guess that the parts are painted. I'm also going to guess that the inside of the holes is not painted. So when the rivet is set the walls expand in the hole and make contact. Not a way I'd say is good practice, but apparently it is how the aircraft was certified.

I'm much rather see a screw and pem nut where the panel under the screw is never painted.
Of course a bonding strap is the ideal method.

I'd guess your unpainted rivet guess is the 'hidden secret' that Boeing were relying upon to keep the aircraft flying.

Doubt it is a secret. I'm sure there is an FAA standards document from the '50s that indicates that is the method to use. And you know that the Boeing lawyers made sure that their design followed those standards to the letter. Remember this is an aircraft of the '50s. It has to be made to 1950's standards or it would need a new type certificate.

But, I have two words to say on the earthing discussion: "Ground Loop"

But, I have two words to say on the earthing discussion: "Ground Loop"

Did you really 'have to'.

The rules are followed to the letter on electrical grounding, and then the electronics people follow the rules on fitting connectors on shielded cables and what do you get?