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Search: Posts Made By: ST Dog
Showing results 1 to 35 of 74
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Forum: Rumours & News
4th Nov 2019, 21:12
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

That was done with the first, high Mach, limited...

That was done with the first, high Mach, limited authority, version of MCAS. It was not rushed. It was found in wind tunnel testing. Multiple options were tested before MCAS was developed.

The...
Forum: Rumours & News
4th Nov 2019, 16:00
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

One of the recent articles linked discussed it a...

One of the recent articles linked discussed it a bit.

As I recall, the FHA was reviewed and determined the new function did not increase the hazard, so the SSA wasn't updated.
The new...
Forum: Rumours & News
1st Nov 2019, 14:49
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

The column cutout stops trim opposing the stick....

The column cutout stops trim opposing the stick. If pulling up the cutout does not prevent ANU trim.
MCAS trims opposite the column (to make it harder to continue pulling up) which is why it had to...
Forum: Rumours & News
31st Oct 2019, 17:54
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

That all aligns with my experiences in any...

That all aligns with my experiences in any company. In general managers frown on people speaking up and even worse going over there heads.
The worst was active duty military.

I've heard the lip...
Forum: Rumours & News
31st Oct 2019, 17:36
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

That appears to be the norm for most of the...

That appears to be the norm for most of the systems I've worked on. The same seems true for most of the "design" documents.
Forum: Rumours & News
30th Oct 2019, 17:49
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Wasn't trying to be snarky. Just wondering. My...

Wasn't trying to be snarky. Just wondering. My experience with safety analyses for aircraft systems and ARP4761 and ARP4754A colors my comments.
I've seen a lot of comments here that lead me to...
Forum: Rumours & News
29th Oct 2019, 16:52
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Just curious. How many safety analysis have you...

Just curious. How many safety analysis have you been involved with, with writing or reviewing?
FHA, FMEA, FTA, etc.

Having been involved with several and what has been published about the process...
Forum: Rumours & News
25th Oct 2019, 22:05
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

And as the NTSB report stated, it ignored the...

And as the NTSB report stated, it ignored the rest of the flight deck effects.

A human factors failure in large part, but also an inherent problem with how FHAs and FMEAs are done (not just at...
Forum: Rumours & News
25th Oct 2019, 22:00
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

If the airspeed checklist was followed then you'd...

If the airspeed checklist was followed then you'd be in a better position to maintain control, especially before flaps-up.

Once past that, or if not done at all, executing the runaway stab check...
Forum: Rumours & News
25th Oct 2019, 21:51
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

I recall that the airline procedures were for the...

I recall that the airline procedures were for the PM (FO here) to do the memory items/checklists while the PF flies the plane.


There was also commentary about the Captain not controlling the...
Forum: Rumours & News
25th Oct 2019, 18:41
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Some interesting takes on the report... I...

Some interesting takes on the report...
I haven't finished it, but what I've read so far doesn't really correlate with many of the comments so far.

I do appreciate the more in-depth report of the...
Forum: Rumours & News
23rd Oct 2019, 19:48
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Seems to happen more in smaller companies,...

Seems to happen more in smaller companies, particularly when lead by engineers (like the semiconductor company I was once with).
As they grow, business (MBA) type and marketing get more and more...
Forum: Rumours & News
23rd Oct 2019, 18:03
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

I'd have to research the history of that...

I'd have to research the history of that regulation, but I suspect it predates the NG.
More likely the NG (or even the Classic) was designed to stay under the limit.
Forum: Rumours & News
23rd Oct 2019, 17:59
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Engineers seldom get free reign on design. They...

Engineers seldom get free reign on design. They deal with design constraints set by company policies and marketing.

That's just life as an engineer, especially at a large company.
Forum: Rumours & News
23rd Oct 2019, 17:56
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

If that's really in the report, and not just a...

If that's really in the report, and not just a bad reporting job, then it contradicts what has been stated about MCAS.

Other repeated inaccuracies too, but that bit caught my attention.
Forum: Rumours & News
23rd Oct 2019, 17:44
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Maybe. I don't think it was explored in the...

Maybe. I don't think it was explored in the design because doing so would have negated constraints of the prospective buyers.
Given the design constraints, taller gear wasn't an option to even...
Forum: Rumours & News
22nd Oct 2019, 16:29
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

But the reason for MCAS is a separate discussion...

But the reason for MCAS is a separate discussion from what MCAS was intended to do.
It appears to work fine on the tanker, the difference being the implementation.
And it's not much different...
Forum: Rumours & News
21st Oct 2019, 23:01
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

I think they meant the concept of what MCAS was...

I think they meant the concept of what MCAS was supposed to do. Poorly implemented but sound concept.
Forum: Rumours & News
21st Oct 2019, 21:23
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

As an EE I'd hope I'd do the same too. But just...

As an EE I'd hope I'd do the same too.
But just how far one would actually go is hard to say until in that situation.

It's one thing to bring something up and have higher management overrule you....
Forum: Rumours & News
18th Oct 2019, 17:04
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Anyone have more info on what those messages...

Anyone have more info on what those messages supposedly contain?
All I see is
"suggest that employees misled the FAA about a key safety system on the 737 Max"
Forum: Rumours & News
18th Oct 2019, 17:02
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

It does say that the SIM tests are to help...

It does say that the SIM tests are to help determine required training updates.
https://www.cnn.com/2019/10/17/politics/737-max-boeing-flight-simulator/index.html
3rd paragraph:



They also...
Forum: Rumours & News
17th Oct 2019, 16:20
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Keeping quiet and not making statements about...

Keeping quiet and not making statements about every little thing that happens.

Have you ever reviewed certification artifacts like FHAs or SSAs?
It's a long, tedious process normally. With the...
Forum: Rumours & News
10th Oct 2019, 23:35
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

This. The basic change to MCAS was simple and...

This. The basic change to MCAS was simple and quick. Boeing had been working on it since Lion Air and it was probably ready in May or June.

Then changes with the FCC, based on the injected faults...
Forum: Rumours & News
10th Oct 2019, 22:19
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Ah, but the answer is safest practical, not...

Ah, but the answer is safest practical, not possible.

Deciding what's practical is the hard part in light of diminishing returns.
The first million dollars reduces risk a lot. The next million...
Forum: Rumours & News
7th Oct 2019, 18:57
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Sure, but those assumptions were acceptable in...

Sure, but those assumptions were acceptable in the past.
The time for certain conditions to be recognized and acted on was well established and used for certification of many aircraft. This wasn't a...
Forum: Rumours & News
7th Oct 2019, 18:52
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Then no airplane will fly. Every one of them has...

Then no airplane will fly. Every one of them has a risk of catastrophic failure and only flies because the likelihood of such failures is low.
The whole point of safety processes is to identify,...
Forum: Rumours & News
4th Oct 2019, 20:10
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Well for a major criticality they only needed...

Well for a major criticality they only needed 10E-5 for uncommanded trim AND.
Recalling that even full AND stab trim can be overcome by the elevator normally, then uncommanded trim is not...
Forum: Rumours & News
4th Oct 2019, 19:18
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

I can't find it now. But it was the results of...

I can't find it now. But it was the results of the line pilots testing the new software.
I recall an AA pilot being quoted.
Forum: Rumours & News
3rd Oct 2019, 20:30
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Well, you have that with Boeing's estimates. But...

Well, you have that with Boeing's estimates. But I've never seen much of a detailed timeline for certification efforts.

You don't see things like the SRS for subsystem X on date Y, or status for...
Forum: Rumours & News
3rd Oct 2019, 19:16
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

What exactly do you think would be said/shown? ...

What exactly do you think would be said/shown?

We have reports from the SIM tests of the MCAS changes by airline pilots.

Beyond that there's never really a timeline. Certification doesn't...
Forum: Rumours & News
3rd Oct 2019, 19:08
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Hazard criticality is determined first. Then...

Hazard criticality is determined first. Then based on that you design at the appropriate assurance level.
But DALs don't have failure rates.

And the criticality probabilities are per flight hour,...
Forum: Rumours & News
3rd Oct 2019, 16:32
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Last year I saw a paper presented at an avionics...

Last year I saw a paper presented at an avionics conference that talked about how in the future regulators were going to have to rely more on the OEs for compliance. Trust relationships with...
Forum: Rumours & News
3rd Oct 2019, 15:46
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

While implementing MCAS as FDAL A would be good...

While implementing MCAS as FDAL A would be good solution, I'm not certain that it's the only solution.

I'd have to go back through the rules. Multiple systems at various DALs combining together...
Forum: Rumours & News
3rd Oct 2019, 14:56
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

But the hazard analysis said it was a major...

But the hazard analysis said it was a major hazard, not catastrophic, and a single input is acceptable for a major hazard.
The analysis was wrong/incomplete, as the NTSB noted. But that's what the...
Forum: Rumours & News
3rd Oct 2019, 14:45
Replies: 4,656
Views: 4,786,251
Posted By ST Dog

Right. So if extensive retraining was required...

Right. So if extensive retraining was required they just would have went with the existing A320 instead of waiting to for whatever Boeing ended up building.
W/o the limited training the MAX didn't...
Showing results 1 to 35 of 74
 
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