Ethiopian Airlines plane crashes on way to Nairobi

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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by heisan » Mon May 06, 2019 10:10 am

dollar wrote:
Sun May 05, 2019 9:27 pm
Mmmm, 747 fleet? I assume that they are all very similar? I read somewhere that the failure rate was much higher but can’t tell you where so the point is moot.

I don’t believe that they were designed and built as a super critical part anyway. Not like the big bolts that keep the wings attached. In fairness it would be a long stretch of the imagination (pre Max) that this thing would fail and create the chain of events that lead to the two crashes?

But we don’t even know this to be correct either? It could have been some other glitch. Power supply, connector, etc.
Correct. Was just addressing the posts here which basically say that the AoA sensor is a piece of crap, which could fail at any second. I doubt the 737 would use a lower quality sensor than the 747 - which basically means that the sensor typically outlasts the useful life of the airframe.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by StressMerchant » Mon May 06, 2019 10:18 am

The sensors are also part of the stall indication system, and hence are part of the required equipment. That means that the design must be compliant to FAR 25.1301, ie must be suitable for purpose. I have no idea how this was demonstrated, but the usual process is to qualify the sensor to appropriate requirements of standards such as DO-160. As a minimum, I would expect that an AoA sensor forming part of the stall indication system had at least passed testing for vibration, acceleration shock, vibration, salt spray, ice, humidity, and fluid susceptibility.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by richard C » Mon May 06, 2019 11:45 am

StressMerchant wrote:
Mon May 06, 2019 10:18 am
The sensors are also part of the stall indication system, and hence are part of the required equipment. That means that the design must be compliant to FAR 25.1301, ie must be suitable for purpose. I have no idea how this was demonstrated, but the usual process is to qualify the sensor to appropriate requirements of standards such as DO-160. As a minimum, I would expect that an AoA sensor forming part of the stall indication system had at least passed testing for vibration, acceleration shock, vibration, salt spray, ice, humidity, and fluid susceptibility.
...so not off the shelf from Builders' then, as some seem to imagine.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by Ugly Duckling » Mon May 06, 2019 11:51 am

Boeing knew of a issue
https://bbc.in/2Vj4GGS
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by heisan » Mon May 06, 2019 11:57 am

Ugly Duckling wrote:
Mon May 06, 2019 11:51 am
Boeing knew of a issue
https://bbc.in/2Vj4GGS
From the article:
But was that flaw a factor in that accident? Would a working "AOA Disagree" alert actually have made any difference?

It's highly unlikely.
At least this version of the story (unlike the CNN one), contains a clear and honest assessment of the fact that this is at best tangentially related to the accident. Many of the publication out there try to imply that it is a major safety issue.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by Ugly Duckling » Mon May 06, 2019 12:49 pm

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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by heisan » Mon May 06, 2019 1:55 pm

And then you get the Business Insider version (https://www.businessinsider.co.za/boein ... faa-2019-5):
Boeing reportedly knew of the software error on the 737 Max for a year before telling airlines and regulators
(my highlighting)
...
It's not clear if the correct functioning of the alert system would have changed the outcome of the fatal 737 Max crashes, however. Boeing called the system "supplemental" in a statement provided to Reuters. Still, the technology is linked to the Maneuvering Characteristics Augmentation System (MCAS), which the Federal Aviation Administration (FAA) has admitted was responsible for the crashes. The MCAS system appeared to misfire on both flights based on information from malfunctioning angle sensors. And while the alert system would not have prevented the malfunction, it would theoretically have alerted the pilots to the problem.
...
They are very clearly trying to leave the reader with the impression that it was the root cause, or at least a significant contributor, to the crashes.

This sort of 'journalism' should earn 'journalists' a ban - instead it earns them a bonus...
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by MadMacs » Mon May 06, 2019 6:26 pm

heisan wrote:
Mon May 06, 2019 10:10 am
dollar wrote:
Sun May 05, 2019 9:27 pm
Mmmm, 747 fleet? I assume that they are all very similar? I read somewhere that the failure rate was much higher but can’t tell you where so the point is moot.

I don’t believe that they were designed and built as a super critical part anyway. Not like the big bolts that keep the wings attached. In fairness it would be a long stretch of the imagination (pre Max) that this thing would fail and create the chain of events that lead to the two crashes?

But we don’t even know this to be correct either? It could have been some other glitch. Power supply, connector, etc.
Correct. Was just addressing the posts here which basically say that the AoA sensor is a piece of crap, which could fail at any second. I doubt the 737 would use a lower quality sensor than the 747 - which basically means that the sensor typically outlasts the useful life of the airframe.
Considering the fact that the 737 was designed maybe ten years before the 747, I'd say that the quality would be quite different.
When they use the loaded term "denier" that should be the first clue that we're not dealing with a rational opponent in a debate... but "religious" dogma.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by heisan » Mon May 06, 2019 7:43 pm

MadMacs wrote:
Mon May 06, 2019 6:26 pm
Considering the fact that the 737 was designed maybe ten years before the 747, I'd say that the quality would be quite different.
Huh? They were designed pretty much concurrently, with the first flights less than 2 years apart. They also shared key members of the design team. It is highly unlikely that they would not use the same, or very similar equipment.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by Romeo E.T. » Mon May 06, 2019 8:39 pm

60 Minutes in Aussie produced this video investigation

pity in the cockpit dramatization, they forgot to trigger and maintain the most annoying distraction of all, THE CONSTANT STICK SHAKER

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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by MadMacs » Mon May 06, 2019 11:24 pm

heisan wrote:
Mon May 06, 2019 7:43 pm
MadMacs wrote:
Mon May 06, 2019 6:26 pm
Considering the fact that the 737 was designed maybe ten years before the 747, I'd say that the quality would be quite different.
Huh? They were designed pretty much concurrently, with the first flights less than 2 years apart. They also shared key members of the design team. It is highly unlikely that they would not use the same, or very similar equipment.
The 737 was developed from the 707 sharing common cockpit and fuselage components.
When they use the loaded term "denier" that should be the first clue that we're not dealing with a rational opponent in a debate... but "religious" dogma.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by Deanw » Tue May 07, 2019 7:10 am

MadMacs wrote:
Mon May 06, 2019 11:24 pm
The 737 was developed from the 707 sharing common cockpit and fuselage components.
40/50 years ago maybe, but I very much doubt the NG and Max versions share any cockpit or instrument sensors with those early aircraft.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by dany » Tue May 07, 2019 10:45 am

Bean counter projects in almost 100% cases fail,yet the blame never even reach their table.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by StressMerchant » Tue May 07, 2019 11:00 am

dany wrote:
Tue May 07, 2019 10:45 am
Bean counter projects in almost 100% cases fail,yet the blame never even reach their table.
The bean counters are often smart enough to ensure that the blame stops elsewhere.

On the other hand, aircraft design is (usually) not a charity business. Someone has to pay the bills.
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Re: Ethiopian Airlines plane crashes on way to Nairobi

Unread post by rainier » Tue May 07, 2019 11:42 am

dany wrote:
Tue May 07, 2019 10:45 am
Bean counter projects in almost 100% cases fail,yet the blame never even reach their table.
This is a very true statement. This goes for any project - does not have to be related to anything technical at all.
Who said the sky is the limit ? I think not.

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