Trains, Planes & Automobiles

[Padge]

11 hours ago, M j M said:

After a week in which there was lots of praise for the structural integrity of the a350 Boeing's beloved 737 Max decides to show the quality of under-regulated American workmanship.

This was a brand new (delivered October) plane. The piece missing is a plugged (unused and supposedly sealed on this plane) emergency exit door. Had the adjacent seat not been empty the person sitting there would have been lucky to survive.

 

We are not in the EU, we don't need all this regulation $h!t. Who cares if bits fall off planes mid air, its profits that matter.

[M j M]

 

[Futtocks]

Isn't it nice of the DLR to pretend they're only doing this for the children?

https://www.thelondoneconomic.com/lifestyle/dlr-to-introduce-fake-steering-wheels-to-allow-kids-to-drive-trains-366774/ 

[The Hallucinating Goose]

6 hours ago, Futtocks said:

Isn't it nice of the DLR to pretend they're only doing this for the children?

https://www.thelondoneconomic.com/lifestyle/dlr-to-introduce-fake-steering-wheels-to-allow-kids-to-drive-trains-366774/ 

Absolutely, there's a little kid in all of us! I mean, don't know about you Futtocks but I still sit at the front of the bus, upstairs, pretending to drive!

[Futtocks]

Samsung commissioned this alternative tube map, as part of a publicity drive for some product or other. Just for fun; it isn't supplanting the tradition layout.

[High Peak Rhino]

On 03/02/2024 at 12:11, Futtocks said:

Samsung commissioned this alternative tube map, as part of a publicity drive for some product or other. Just for fun; it isn't supplanting the tradition layout.

At least they kept the Thames in. When TFL went for a redesign approx 10 years ago they had the bright idea of removing it. That didn't last long. 

[The Hallucinating Goose]

https://www.hulldailymail.co.uk/news/history/gallery/lost-railway-lines-train-stations-9088048

An interesting article for any railway nerds like me on here. The lost lines and stations of Hull, then and now. 

[Futtocks]

6 hours ago, The Hallucinating Goose said:

https://www.hulldailymail.co.uk/news/history/gallery/lost-railway-lines-train-stations-9088048

An interesting article for any railway nerds like me on here. The lost lines and stations of Hull, then and now. 

There is more information here - http://www.disused-stations.org.uk - but the site isn't very navigable (to say the least).

[M j M]

United had to temporarily ground its five new a321neos because the illuminated No Smoking signs can't be switched off.

They've since resumed flying with a temporary exemption.

 

[M j M]

How is it possible Boeing are still having issues with the 737 rudder, this stuff was supposed to have been fixed years ago.

 

[Fly-By-TheWire]

15 hours ago, M j M said:

How is it possible Boeing are still having issues with the 737 rudder, this stuff was supposed to have been fixed years ago.

 

There are a few issues at play here, and they're not related to the rudder problem of the 'classic' 737s made infamous from the accidents in the 80s and 90s (although a phenomenon known as 'cold soaking' may be the root cause of both, I guess we'll see).   The original rudder problems of the 737 Classic were solved by a retrofitted redesigned rudder actuation system, and on newer 737s is a completely different system with redundancy that allows a sensed jammed actuator to be overridden.

Firstly, I should point out that this incident is not specifically related to the 737 MAX.   It has happened twice on the previous generation of 737s known as the 'Next Gen' or 'NG' variants (-600/700/800/900 series).   I don't want to go too technical, but when it's foggy the low visibility makes it to difficult to land the aeroplane manually by visual means.   For this reason, autopilots on most large modern jets can perform an automatic landing providing the wind is fairly calm (as it usually is in foggy conditions).   Some of these autopilots can only control two axes, the roll (bank) and pitch (nose up and down) of the aircraft during landing, but the pilot has to control the rudder himself/herself after touchdown (the 'rollout').   However, there are also some autopilots that can control the 'rollout' using a 3rd 'yaw' axis through the rudder after landing.   Having this capability means that you can perform an automatic landing at even lower visibility than the 2-channel auto land (75m vs 200m).   This 3rd axis is controlled by the 'rollout guidance servo' mentioned in the tweet.

The 737 traditionally has a 2-axis autoland system, but there is an option to have the 3-axis one installed.   The airline in question here took delivery of an aircraft with a 3-axis autoland, but with the 3rd axis 'rollout guidance servo' deactivated.   I'm not sure what the deactivation involved, but crucially the servo was still mechanically linked to one of the torque tubes that is connected to all three rudder Power Control Units (PCUs).   It appears that the servo became jammed when exposed to long period of low temperatures, and actuated the linkage to make an input to the two active main PCUs.  

I'm still not sure why or how a deactivated servo could somehow influence the rudder system, but then I'm not that familiar with the rollout option on 737s (not many have it fitted, as it's quite rare to get visibility below 200m).  An input on the flight controls by the pilot should trigger a disconnect of the servos from the system under normal circumstances, so it's a bit disconcerting that this didn't seem to do the trick.   However, the NTSB didn't rush to ground the fleet, which leads me to think they're not too concerned about the ability to override the system.   Maybe the pilots just didn't feel the need to apply that much pressure on the rudder pedals at the later stages on the rollout, so elected to use the nosewheel steering tiller instead until they were clear of the active runway, then applied a bigger input to finally cause the disconnect.

Whatever the case, it's just another chink of bad publicity for Boeing.   I'm not aware of any rollout guidance issues occurring on the Airbus family, which are all fitted with 3-axis autoland systems as standard.

 

Edited March 8 by Fly-By-TheWire

[Fly-By-TheWire]

https://avherald.com/h?article=515e3618&opt=0

Not really the fault of the 737, but more negative publicity yesterday.

 

[Futtocks]