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Search: Posts Made By: GordonR_Cape
Showing results 1 to 35 of 57
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Forum: Rumours & News
16th Dec 2019, 10:20
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Short answer: The autopilot and MCAS are...

Short answer: The autopilot and MCAS are different sub-systems running on each FCC.

The autopilot is a 3-axis system, and demands high integrity data from muliple sensors to operate safely.
...
Forum: Rumours & News
15th Dec 2019, 05:54
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

The recent comments about MCAS reinforce the...

The recent comments about MCAS reinforce the point that it is very difficult to design a complex system that is safe, effective and reliable, and operates within the limitations of the human-machine...
Forum: Rumours & News
26th Nov 2019, 23:19
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

I agree to some extent, I noted dozens of...

I agree to some extent, I noted dozens of nit-picks in the article. Many new facts have emerged since Apr 2019, but fundamental issues remain unanswered. Neither Boeing nor the FAA have clarified...
Forum: Rumours & News
26th Nov 2019, 22:15
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Thanks for the link, which I had not seen before....

Thanks for the link, which I had not seen before. It included a description of an issue that I raised recently (which elicited some skepticism):


My bold added.

Edit: I understand that it is...
Forum: Rumours & News
25th Nov 2019, 04:20
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Under MCAS 1.0 the linearity would be preserved,...

Under MCAS 1.0 the linearity would be preserved, because the system could fire a second time if the pilot continued to pull up. With MCAS 2.0 this repeated triggering can no longer happen during a...
Forum: Rumours & News
24th Nov 2019, 17:00
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

That is also an excellent link on FBW pitch...

That is also an excellent link on FBW pitch augmentation, relevant to the above discussion, and the opposite of what MCAS does.
Forum: Rumours & News
24th Nov 2019, 16:54
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

I think fdr nailed it earlier with this chart of...

I think fdr nailed it earlier with this chart of the unsatisfactory control forces (trim-speed as a proxy for AOA).
...
Forum: Rumours & News
24th Nov 2019, 16:10
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Allowing MCAS to move the horizontal stabiliser...

Allowing MCAS to move the horizontal stabiliser into a nose down position does not solve the non-linear elevator feel curve. It simply forces the aircraft away from that part of the flight envelope....
Forum: Rumours & News
24th Nov 2019, 15:21
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

AFAIK the B737 elevator feel computer is a...

AFAIK the B737 elevator feel computer is a hydraulic mechanism, not an electronic system. Reverse engineering it would create many more certification obstacles than it would solve. It would also be...
Forum: Rumours & News
10th Nov 2019, 06:24
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

I did hint a few months ago that Dominic Gates...

I did hint a few months ago that Dominic Gates should be nominated for a Pulitzer Prize. His work is certainly merit-worthy, and the clarity of the writing is excellent. It may not be under the same...
Forum: Rumours & News
9th Nov 2019, 06:40
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

The Boeing 737 Classic (-300 onwards) was...

The Boeing 737 Classic (-300 onwards) was introduced in 1984. That is the benchmark for the FCCs, not the -200 model.
Forum: Rumours & News
8th Nov 2019, 17:34
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

We knew about the change to MCAS to use both AOA...

We knew about the change to MCAS to use both AOA sensors, but that was only the tip of the iceberg.

More thorough simulator testing uncovered the potential for runaway trim on the MAX, caused by...
Forum: Rumours & News
8th Nov 2019, 13:21
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

"Good, cheap, fast. Pick any two." This one is...

"Good, cheap, fast. Pick any two." This one is attributed to Red Adair, the famous oil and gas fire suppressing expert.

P.S. I tried to click on the 'like' button, but had to leave a comment...
Forum: Rumours & News
5th Nov 2019, 03:51
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

IMO the real question is not whether there is a...

IMO the real question is not whether there is a lightening of the controls (which seems certain), but whether the MAX ever reaches a point in the flight envelope at which the aircraft pitches up,...
Forum: Rumours & News
1st Nov 2019, 10:50
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

No technical news, but provides a broad context...

No technical news, but provides a broad context to the MAX story. Worth reading: https://www.forbes.com/sites/hershshefrin/2019/10/31/broad-lessons-from-boeings-737-max-greek-tragedy/
Forum: Rumours & News
30th Oct 2019, 15:59
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Don't get too excited. House Transportation and...

Don't get too excited. House Transportation and Infrastructure Committee:
https://www.c-span.org/video/?465775-1/boeing-ceo-dennis-muilenburg-testifies-737-max-safety&live&vod
Forum: Rumours & News
30th Oct 2019, 09:11
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

One of the highlights, but barely noticed points...

One of the highlights, but barely noticed points in the testimony, was when Senator Duckworth asked that Peter Lemme's article be read into the record, and this was accepted with no comments!? This...
Forum: Rumours & News
29th Oct 2019, 04:58
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

This is an extremely long article, but weaves...

This is an extremely long article, but weaves together important points from both the JATR report and the Lion Air crash report, along with FAA regulations. It offers some new insights which were not...
Forum: Rumours & News
25th Oct 2019, 23:22
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Interesting addendum (p286 of the report) on the...

Interesting addendum (p286 of the report) on the original intermittent AOA sensor failure that triggered this whole cascade:
Forum: Rumours & News
18th Oct 2019, 19:26
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

NY Times version (may be paywalled). See:...

NY Times version (may be paywalled). See: https://www.nytimes.com/2019/10/18/business/boeing-flight-simulator-text-message.html
Forum: Rumours & News
6th Oct 2019, 16:33
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

A few random thoughts (not a coherent argument). ...

A few random thoughts (not a coherent argument).
1. EICAS on its own (on an unaltered airframe) might not make a difference to runaway trim.
2. Implementing EICAS would require detailed fault-tree...
Forum: Rumours & News
5th Oct 2019, 05:09
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

I could have a lengthy argument about your...

I could have a lengthy argument about your statement, but that would take us off topic. Regulators clearly think that pilot workload played a role in the crashes, and the MAX will remain grounded...
Forum: Rumours & News
30th Sep 2019, 13:47
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Off topic: The Mentour video is an attempt to...

Off topic: The Mentour video is an attempt to emulate a runaway trim, since the B737 NG simulator is not programmed to do that! The crew inputs do not match a real world situation, but the idea is to...
Forum: Rumours & News
29th Sep 2019, 17:14
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

The KC-46 version of MCAS was mentioned many...

The KC-46 version of MCAS was mentioned many months ago. The WSJ link was posted in a parallel thread. I did not learn much new from the article, though it does cover material that may be unfamiliar...
Forum: Rumours & News
26th Sep 2019, 17:58
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Worth reading some of the detailed NTSB safety...

Worth reading some of the detailed NTSB safety analysis, as part of the recommendations to the FAA: https://www.ntsb.gov/investigations/AccidentReports/Reports/ASR1901.pdf

I found the following...
Forum: Rumours & News
23rd Sep 2019, 16:59
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

I raised this point a long time ago, and it was...

I raised this point a long time ago, and it was (politely) ignored. It seems that there is no indication of the stabiliser trim position on any of the primary flight displays, only on the pedestal...
Forum: Rumours & News
23rd Sep 2019, 14:33
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

https://www.skybrary.aero/index.php/Standby_Flight...

https://www.skybrary.aero/index.php/Standby_Flight_Instruments


Presumably standby instruments are not affected by AOA failure, and things like unreliable airspeed, and false stall warning are...
Forum: Rumours & News
22nd Sep 2019, 08:34
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

My comment is not a full fault-tree analysis, and...

My comment is not a full fault-tree analysis, and there are several sub-cases of AOA failure on the MAX. In particular nose down or 'small' disagree value would not trigger MCAS. Since AOA disagree...
Forum: Rumours & News
22nd Sep 2019, 06:45
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

This issue was discussed some time ago. The main...

This issue was discussed some time ago. The main points are that:
1. AOA sensor failure are relatively rare, but do occasionally occur.
2. A number of AOA failures have been recorded on other...
Forum: Rumours & News
21st Sep 2019, 08:45
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Touche! Have to type extra characters...

Touche!

Have to type extra characters...
Forum: Rumours & News
17th Sep 2019, 06:47
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

This WSJ article indicates that the Joint...

This WSJ article indicates that the Joint Technical Review Panel report is expected to be critical of FAA approval, and the B737 MAX certification process. Link may be paywalled:...
Forum: Rumours & News
7th Sep 2019, 09:13
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

Story just came to my attention. Link may be...

Story just came to my attention. Link may be paywalled:...
Forum: Rumours & News
4th Sep 2019, 18:04
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

This point has been raised before, but your...

This point has been raised before, but your comment highlights the reality that the original MCAS design was not thought through from beginning to end result, in terms of a flow-chart or...
Forum: Rumours & News
17th Aug 2019, 08:00
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

[/left] A number of interesting topics in that...

[/left]
A number of interesting topics in that article.

One which seems to have been half-forgotten recently amid the safety oriented discussions (it was discussed in the prior threads), is what...
Forum: Rumours & News
6th Aug 2019, 18:14
Replies: 4,656
Views: 4,778,855
Posted By GordonR_Cape

IMO the fundamental issue with the MAX (and this...

IMO the fundamental issue with the MAX (and this is not a problem with the NG) is that for MCAS to operate, the FCC must have a relay that inhibits the pilots column trim cutout switches. Previously...
Showing results 1 to 35 of 57
 
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