Transportation Safety 3

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Message 1988750 - Posted: 4 Apr 2019, 17:03:08 UTC - in response to Message 1988712.  

That all depends on what is meant by "switched MCAS off".
There are two ways it can be "turned off"
- if the pilot takes over control by moving the control column more than a certain amount and for more than certain amount, or uses the control column trim toggle then MCAS stops acting for a time.
- if the pilot turns the two switches off then MCAS is isolated, and the servos between the trim wheels and the tail plane are cut out.

Obviously the latter is "properly turning it off", while the former is a "hold on a moment" , what is not clear in any of the news reports is exactly what mechanism the pilots used. But given that there didn't appear to be anything in their training or the checklists about the full action of the two isolation switches I would suspect they went for the trim toggle approach, and repeated it a few times, until the plane was heading to buy some real estate of its own.
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Message 1988849 - Posted: 5 Apr 2019, 4:06:00 UTC - in response to Message 1988750.  

Below is the relevant section taken from the WaPo Additional software problem detected in Boeing 737 Max flight control system, officials say
The preliminary report, which stops short of determining the cause of the crash, chronicles the chaotic last moments in the cockpit before the crash.
The report indicates that a minute after takeoff from Bole International Airport, one of the angle-of-attack sensors sent bad information to the aircraft’s computer system, activating the stick shaker — a vibration in the pilots’ controls that warns of an impending stall.
Reacting to the faulty data, MCAS kicked in to force the plane’s nose down. MCAS activated at least four separate times, and each time the pilots fought unsuccessfully to regain control of the plane.
Investigators think MCAS also contributed to the Oct. 29 crash of the Lion Air flight, where they say erroneous data from an angle-of-attack sensor caused the system to force the nose of that plane down repeatedly. Pilots were unable to regain control, and the Lion Air plane eventually plunged into the Java Sea, killing all 189 on board.
After the Indonesia crash, Boeing issued a bulletin outlining how to disable MCAS in case of a malfunction, and Thursday’s preliminary report indicated that the Ethio­pian pilots followed that procedure.
According to black-box data released by Ethio­pian investigators, the pilots struggled to regain control of the plane from the system, which repeatedly put the plane into a descent. The pilots tried to use a backup manual trim system in an attempt to raise the plane’s nose. The trim system is also used to stabilize a plane.
The captain called out “pull up” three times to tell the first officer to raise the nose, and in the last seconds of the flight, both pilots tried together to arrest the plane’s dive but still could not regain control, according to the report.
Experts say that the airplane was traveling too fast for the manual trim wheel to be operated.
“At higher speed, manual trim may not be available due [to] air load on the stabilizer,” said John Cox, a former pilot and an airline-safety consultant who has been privately briefed on the evidence by people familiar with the investigation. “Not enough force can be generated manually to move the trim.”
In the final struggle, as described in the report, the aircraft pitched downward, eventually diving at 40 degrees and crashing into the ground at 575 mph.
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Message 1988870 - Posted: 5 Apr 2019, 7:28:12 UTC - in response to Message 1988849.  

After the Indonesia crash, Boeing issued a bulletin outlining how to disable MCAS in case of a malfunction, and Thursday’s preliminary report indicated that the Ethio­pian pilots followed that procedure.

It would be nice to see the report in order to understand how they came to that determination, as the bulletin states clearly-
...ensuring that the STAB TRIM CUTOUT switches are set to CUTOUT and stay in the CUTOUT position for the remainder of the flight


It has been my experience that circuit breakers, once tripped or manually shut off, don't re-close themselves unless they are that specific type of breaker. Auto recloser breakers are used in high voltage distribution networks and they have a set number of re-tries before they stay tripped, i'm not aware of any such breakers for low voltage systems (which doesn't men they don't exist). Even so, I can't image such a breaker being used in this case. And for something to continue to function once it's official source of power has been cut would be highly unlikely.


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Message 1988883 - Posted: 5 Apr 2019, 10:18:37 UTC - in response to Message 1987431.  
Last modified: 5 Apr 2019, 10:19:53 UTC

Hmm...will it stop buses & trucks from hitting bridges?

Technology to the rescue

My car, new last year has the speed recognition camera (2 in the fig.) and shows the speed limit on the dashboard plus there are bleeps if you exceed by 10%. But it has a few limitations, you have to pass a speed limit sign, which if you live in a town or city, you might not do for several miles, and sometimes it goes off for no apparent reason, usually after you have had to stop before turning right (UK), probably does the same when turning left in US or remainder of Europe.
There are also sensors that warn of accident up to applying brakes full on if it detects crash is inevitable.
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Message 1988885 - Posted: 5 Apr 2019, 11:03:35 UTC - in response to Message 1988883.  

... you have to pass a speed limit sign, ...
I'm very worried about systems which rely on a single observation to register a change of state, which presumably remains in force until the next observation. You could get out of synch in either direction - either missing the speed reduction on entering a hazardous area, or remaining at restricted speed after you've left the restricted zone. There are plenty of reasons why a speed limit sign could be unreadable - dirt, mis-alignment, vegetation, parked vehicles...

My 2017 car doesn't have cameras, but has a limited amount of speed data associated with the SatNav maps: on major highways, the current limit is displayed constantly for me to refer to if needed. It isn't hooked up to the driving controls, it's sometimes out of date, and it doesn't know about temporary restrictions, but the concept of referring to an absolute location seems more robust than "blink and you've missed it".
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Message 1988933 - Posted: 5 Apr 2019, 18:35:18 UTC

My 1999 doesn't have any camera, though it could be added using some aftermarket tech, right now it's a moot point since I really don't want one. I discovered that the mechanic who is working on My car only works there 3 days a week. Right now the flywheel needs to be replaced and so the transmission has to be dropped to do the swap from the old engine to the "new" engine. It's been 2 months since I drove My car and about a month since the car started to be worked on, they said after this they don't want to do this again, it takes too long. All I can do now is wait, they said they'd call when it's done. Out here where I live at has no public transportation, the only bus route is between the 15 and 40 fwys, nothing to the south of the 40 and nothing to north of the 15, lovely, not even bus stop signs like in Barstow or bus stop shelters.
The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's
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Message 1988954 - Posted: 5 Apr 2019, 21:02:50 UTC - in response to Message 1988885.  

There are plenty of reasons why a speed limit sign could be unreadable - dirt, mis-alignment, vegetation, parked vehicles...

Bullet holes.
Here in more remote areas idiots like to use road signs for target practice.
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Message 1988959 - Posted: 5 Apr 2019, 21:59:05 UTC - in response to Message 1988870.  
Last modified: 5 Apr 2019, 22:00:31 UTC

It would be nice to see the report in order to understand how they came to that determination,

Here is a excerpt from the preliminary report, and a link to the report is at the bottom of the excerpt.

At 08:40:35, the First-Officer called out "stab trim cut-out" two times. Captain agreed and First-Officer confirmed stab trim cut-out.
At 08:40:41, approximately five seconds after the end of the ANU stabilizer motion, a third instance of AND automatic trim command occurred without any corresponding motion of the stabilizer, which is consistent with the stabilizer trim cutout switches were in the "cutout" position.


Further excerpts relating to trim-
From 08:40:42 to 08:43:11 (about two and a half minutes), the stabilizer position gradually moved in the AND direction from 2.3 units to 2.1 units. During this time, aft force was applied to the control columns which remained aft of neutral position.
At 08:41:46, the Captain asked the First-Officer if the trim is functional. The First-Officer has replied that the trim was not working and asked if he could try it manually. The Captain told him to try. At 08:41:54, the First-Officer replied that it is not working.
At 08:43:11, about 32 seconds before the end of the recording, at approximately 13,400 ft, two momentary manual electric trim inputs are recorded in the ANU direction. The stabilizer moved in the ANU direction from 2.1 units to 2.3 units.
At 08:43:20, approximately five seconds after the last manual electric trim input, an AND automatic trim command occurred and the stabilizer moved in the AND direction from 2.3 to 1.0 unit in approximately 5 seconds. The aircraft began pitching nose down. Additional simultaneous aft column force was applied, but the nose down pitch continues, eventually reaching 40° nose down. The stabilizer position varied between 1.1 and 0.8 units for the remainder of the recording.


Trim is set by adjusting the position of the horizontal stabiliser, positioned by a single electric motor and controlled by stab trim switches on the control wheel or the auto pilot.
There is also a Mach trim system that takes effect above Mach .615 by controlling the Elevators with respect to the stabiliser as speed increases.
Pitch is controlled by the Elevators which are positioned by the pilots control columns.


So far the indications are that the Lion air crash was a result of the MCAS system, and the pilots not disabling it.
But whatever caused this accident, it wasn't the MCAS system.
However the commonalities between the 2 accidents are erroneous inputs to the flight computer- AoA (Angle of Attack), IAS (Indicated Airspeed) and ALT (altitude) values- resulting in incorrect trim settings.
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Message 1988963 - Posted: 5 Apr 2019, 22:21:16 UTC - in response to Message 1988954.  

There are plenty of reasons why a speed limit sign could be unreadable - dirt, mis-alignment, vegetation, parked vehicles...
Bullet holes.
Here in more remote areas idiots like to use road signs for target practice.
LOL. Fortunately we don't have those. But we do have street-sign clutter. There are two speed-limit commencement signs in this Google streetview image: see if you can tell me where they are.

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Message 1988969 - Posted: 5 Apr 2019, 22:39:43 UTC - in response to Message 1988963.  

There are two speed-limit commencement signs in this Google streetview image: see if you can tell me where they are.

Maybe with a higher resolution image?
I can see street signs on the far RH side of the bridge, and on the far left is a small white sign (but can't see more than that). A sign (i'm guessing a stop sign?) on the far boom gate, and below that either a white part of the boom or another sign.
And the lights at each end of the bridge (speed painted on them that takes effect only when lights flashing?)
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Message 1988971 - Posted: 5 Apr 2019, 22:41:53 UTC - in response to Message 1988963.  
Last modified: 5 Apr 2019, 22:46:21 UTC

But we do have street-sign clutter. There are two speed-limit commencement signs in this Google streetview image: see if you can tell me where they are.
Morton Swing Bridge perhaps?. Carries the road from Crossflatts to East Morton over the Leeds and Liverpool Canal.
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Message 1988976 - Posted: 5 Apr 2019, 22:55:39 UTC - in response to Message 1988971.  

Yup. That's the location - on my outward route to the shops, and points south and east.

Here's the next street view image:



The left-hand speed limit sign was completely hidden by the warning-light mounting panel in the first image: the right-hand limit sign was beside the raised barrier. Both carry extra (non-standard) warnings that you are about to drive past a school entrance.
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Message 1988979 - Posted: 5 Apr 2019, 23:06:20 UTC
Last modified: 5 Apr 2019, 23:06:48 UTC

Try your luck here with a parking sign quiz.
I didn't even make 50%- luckily we've got nothing even approaching these made for confusion parking zones. If I ever came across an area with parking signs like those, i'd just treat it as a no parking area & go elsewhere.
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Message 1988981 - Posted: 5 Apr 2019, 23:15:09 UTC - in response to Message 1988979.  

Try your luck here with a parking sign quiz.
As soon as I saw the 1st pic I knew that they we're in the Sydney CBD area. LOL

Cheers.
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Message 1988987 - Posted: 5 Apr 2019, 23:26:13 UTC - in response to Message 1988976.  

Yup. That's the location - on my outward route to the shops, and points south and east.
Here's the next street view image:

The left-hand speed limit sign was completely hidden by the warning-light mounting panel in the first image: the right-hand limit sign was beside the raised barrier. Both carry extra (non-standard) warnings that you are about to drive past a school entrance.
LOL:) I love the sign on the road. "Keep Clear".
Doesn't it snow sometimes in the North West England?

Btw. There was an English pop-rock band here on tour in Sweden that was killed in a driving accident at Södertälje Bridge.
Lots of signs that warn you that the bridge is open sometimes...
https://sverigesradio.se/sida/artikel.aspx?programid=2054&artikel=6368161
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Message 1989061 - Posted: 7 Apr 2019, 5:38:05 UTC

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Message 1989062 - Posted: 7 Apr 2019, 5:52:42 UTC

This might be the best idea, if it works youtube - Driver Alcohol Detection System for Safety (DADSS)
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Message 1989882 - Posted: 13 Apr 2019, 5:39:49 UTC

ONLY IN FLORIDA....

Three Naked Women Stand Outside Rest Stop To 'Air Dry,' Trooper Shows Up, Then Things Get Really Out Of Control

What started off with three women's poor decision to "air dry" after taking a shower at a rest stop quickly escalated into a multi-phase car chase, threats against a trooper with a baseball bat, an attempt to run over an officer, all three women getting tased, and drug and alcohol charges.

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Message 1990038 - Posted: 14 Apr 2019, 16:47:20 UTC

https://www.bbc.com/news/world-asia-47926714
Three people have died in a plane crash in Nepal, at what is regarded as one of the world's most dangerous airports.

The plane veered off the runway and hit a stationary helicopter at Lukla Airport, the main gateway to the Everest region.

The runway is short and surrounded by mountains, making it extremely difficult for takeoff and landing.

Lukla Airport is located at an altitude of 2,845m (9,333ft).

Just looking at the photo, it looks like the wing flaps are at zero. Not normally the recommended setting for high altitude short field operations.
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Message 1990041 - Posted: 14 Apr 2019, 17:07:25 UTC - in response to Message 1990038.  

Wing flaps are at zero?
Does it matter when the pilot didn't stay on the runway?
CCTV Footage : Summit Air 9N-AMH Crash in Lukla Airport
https://www.youtube.com/watch?v=nYwqfNqy9GU
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