A random thread for small things that don't really warrant a thread of their own

[ScumOfTheRoad]

ps. Regarding shore power, I fly frequently.  At some airports such as Gatwick there are fixed cabinets for the shore power. At smaller airports like Eindhoven the ground staff bring up a generator trolley, which connects up the aircraft. That is why you sometimes see the lights on an aircraft flicker - I think this is when the shore power is being connected.

I know that cruise liners are much bigger, but one would imagine an international standard could be agreed.

As another aside, many years ago I used to know a couple who were interpreters at the UN. quite a demanding job. One thing the UN does is standardise road signs around the world. SO if anyone ever complains that international organisations do preciou slittle, remind them that you can drive your car off the train into France and not immediately come a cropper because the road signs are meaningless squiggles.

[Jakob W]

It's a popular spot. With visitors from teh FORRINS.

Might be linked to the plans for a cruise liner terminal at Enderby's Wharf (just a few hundred yards along the river from the foot tunnel), which was granted planning permission without imposing any sort of requirement for the docked liners to use shore-based electric hookups to power onboard services (lights, aircon etc etc). Running onboard generators - with mucky marine fuel, albeit probably a (slightly) lower-sulphur variant - has been estimated by protestors to be the equivalent of about 700 trucks passing by ...

Ta - that sounds plausible; I mean, I understand grumbling about tourists, but annoying though the language exchange schools can be, calling them a menace to HEALTH and ENVIRONMENT seemed a little excessive...

[Kim]

ps. Regarding shore power, I fly frequently.  At some airports such as Gatwick there are fixed cabinets for the shore power. At smaller airports like Eindhoven the ground staff bring up a generator trolley, which connects up the aircraft. That is why you sometimes see the lights on an aircraft flicker - I think this is when the shore power is being connected.

Thanks to the usual combination of wiksand and the RISKS Digest, I can tell you that commercial jets have delightfully complicated electrical systems.  Typically a generator on each engine, an APU at the rear, sufficient battery to start the APU (and keep the flight instruments going if all the generators fail - some emergency systems will have independent batteries, too) and provision for external power.  Provision for switching all of these onto multiple redundant busses, and converters for different AC and DC voltages as needed.  And, like with all complex systems, potential for unintuitive edge-cases^[1] where things can go wrong.

Flickering lights would likely happen as a result of switching power between various sources, as well as startup/shutdown of the APU and engines.


_{[1] Eg. the system getting horribly confused and needing the full turn-it-off-and-on-again treatment if it sees external power without a weight-on-wheels signal.  Fortunately that only tends to happen while fettling landing gear in a hanger.}

[citoyen]

Might be linked to the plans for a cruise liner terminal at Enderby's Wharf...

I just realised that I used to live directly across the river from Enderby's Wharf. Kind of glad I'm not there any more if this goes ahead.

[Jurek]

This morning, at the entrance to the foot tunnel lift in Greenwich, two laminated A4 signs, printed in red:
"YOUR HOLIDAY IS COSTING US OUR HEALTH AND OUR ENVIRONMENT! LISTEN TO THE F****** PEOPLE"
That'll be the traditional South London welcome, then.

That was at 06:30 this morning.
Needless to say, at 17:30 this evening, all trace of it had vanished.

[Wowbagger]

I am delighted to say that I have booked accommodation at the Agnes Blackadder Hall.

[Chris S]

Flickering lights would likely happen as a result of switching power between various sources, as well as startup/shutdown of the APU and engines.

Capt Chesley Sullenberger's decision to start the APU out of checklist sequence after the double engine failure of Flight 1549, was a major contributor to at least making putting down on the Hudson an option.

#aviationnerd

[ScumOfTheRoad]

Indeed. This shows the value of experience above blind following of procedure.

Not really procedure, but I watched a documentary on Apollo 13 recently. Mission Control had the option of attempting a quick turn around and direct return to Earth, rather than continuing with a trajectory around the Moon. they chose to continue the tried and tested trajectory, to give them time rather than rushing into unknowns.

[ian]

I can't find the thread where I complained about an airline (I think it was American) censoring not just the rude language but also naked statues in Blade Runner 2049.

Anyway, I was very shocked to find Norwegian had done much the same (is there some centralised source?). Fudgepackers. I expected better of the Scandinavians! Or at least some adult-orientated naked frolicking to a splendidly 70s soundtrack.

[spesh]

I can't find the thread where I complained about an airline (I think it was American) censoring not just the rude language but also naked statues in Blade Runner 2049.

You did that in the thread on gun control - or rather, the lack thereof - in P&OBI.

Link for those logged and opted-in: https://yacf.co.uk/forum/index.php?topic=90786.msg2284980#msg2284980

[Tim Hall]

Flickering lights would likely happen as a result of switching power between various sources, as well as startup/shutdown of the APU and engines.

Capt Chesley Sullenberger's decision to start the APU out of checklist sequence after the double engine failure of Flight 1549, was a major contributor to at least making putting down on the Hudson an option.

#aviationnerd

An episode of Cabin Pressure,  by that nice John Finnemore, features the non-restartableness of the APU in G-ERTI. Arthur Shappey saves the day with a snowman and a hat.

#finnemore_fan

[citoyen]

An episode of Cabin Pressure,  by that nice John Finnemore, features the non-restartableness of the APU in G-ERTI. Arthur Shappey saves the day with a snowman and a hat.

That was a good episode. I remember thinking while I was listening to it that I bet John Finnemore had looked it up to make sure he got all the details absolutely correct.

ISTR there's a self-mocking sketch on his Souvenir Programme that takes the piss out of his attention to detail.

[Wowbagger]

How much for one night in Cologne? (No, I don't mean bathing in the stuff...)

What is there in Cologne that makes a typical double room for one night cost over £500?

Edit: have booked an AirBnB for just over £60, very close to the station.

[Beardy]

Marine shore hookups are notoriously difficult because of the earth bonding issues. Electricity and water famously don’t play nicely together and if you add in galvanic erroision issues you’ve got major problem areas that need to be addressed. The complexity and thus expense of these issues is probably why they are avoided where at all possible.

[ElyDave]

Marine shore hookups are notoriously difficult because of the earth bonding issues. Electricity and water famously don’t play nicely together and if you add in galvanic erroision issues you’ve got major problem areas that need to be addressed. The complexity and thus expense of these issues is probably why they are avoided where at all possible.

Good point, I've asked that question on an FPSO when talking about earthing from a process safety point of view. Essentially the structure itself was the reference point for earthing.  I could imagine that if you then earth that back to a true earth you could set up all sorts of galvanic nastiness.

[T42]

In one computer room (remember computer rooms?) I worked in we had two machines on different circuits, with a 100v difference between earths. This was discovered by a customer who completed the circuit.

[mrcharly-YHT]

Marine shore hookups are notoriously difficult because of the earth bonding issues. Electricity and water famously don’t play nicely together and if you add in galvanic erroision issues you’ve got major problem areas that need to be addressed. The complexity and thus expense of these issues is probably why they are avoided where at all possible.

No, this really isn't a major problem. It is a solved problem.

Many people live aboard boats with this problem solved. You just use an appropriate isolating transformer. For a cruise ship, it is going to be a large transformer, but it is still a solved problem.
The cruise ship/port simply doesn't want to pay the cost of the system.

Think of it like this; when the ship is running on ship power, the ship's generators are the power source, you 'earth' to the ship's hull and the 'neutral' return path is to the generators.
With an isolating transformer, the shorepower is supplied to the ship's distribution board system in the same way, it is the same return to the distribution board. Earth is the same. There is no earth connection between ship and shore.

[hellymedic]

BBC quiz today...
https://www.bbc.co.uk/news/uk-england-44290942

[Legs]

10/10

[T42]

5/10 - not entirely surprising.

[ElyDave]

8/10

[Mr Larrington]

9/10.  Failed over Salford.

[SteveC]

10/10 

[Butterfly]

10/10 

[hellymedic]

I got 10/10.