[zlhglp]

Presumably the issue now is that some types are cleared for night flight.

Aside from the 2.5 degree discrepancy, are marine lights required to be visible to vessels approaching from 30 degrees above or below the horizon?

[Grumpy One]

Marine lights - The vertical sectors must show at all angles from least 5deg above and 5deg below the horizontal.
Also at least 60% of the required minimum light intensity is to be shown from 7.5deg above & 7.5deg below the horizontal.

Sailing vessels are the same for the except for the 60% bit.
They have to show at least 50% of the minimum intensity from 25deg above and 25deg below the horizontal - This to accommodate the heeling over aspect.

And in case you're still awake.... The minimum intensity is calculated by a very strange formula, one with loads of lux's , luminosity & atmospheric transmissivity - You'll forgive me please, if I can't recall it!!
But roughly - at 5 nautical mile range an intensity of light would be about 50 candelas - or so I'm told!!!
Have fun

[Miscellaneous]

Grumpy, does that mean the marine version os more visible than the aviation variant?

[Grumpy One]

As has already been expounded ad nauseum - The marine light has a wider arc (112.5 deg) than the aeronautical side light (110.0 deg) thus more of it to see!)
Other than that - I have no idea

[Miscellaneous]

Yip, got the angles, I thought you may have been suggesting the luminosity was significantly different.

So, if the marine variant is 'better' can I ask again why you 'would go for the throat'?

viewtopic.php?p=1520156#p1520156

[Grumpy One]

So, if the marine variant is 'better' can I ask again why you 'would go for the throat'?

T'was an aggressive euphemism to indicate that, in the event of them having a mid air with one of my family, friends, or even Forum acquaintances , I would be actively trying to show that the poor misguided soul, who even dared to fit illegal equipment, should be keel hauled, stripped naked and put in a cage with a hairy bosun I once knew!!
Does that help?

[cockney steve]

I cannot visualise any situation where a collision could take place and all lights remain unseen by both parties , if both were acting properly.... of course, if one was heads- down texting on their I- phone, all bets are off......and that may well be the "legally" equipped machine.

All the hairy seamen I've heard of, have been stokers......damned declining standards everywhere.

[Miscellaneous]

Does that help?

Absolutely, although it's a bit of a convoluted way of describing grumpiness!

[zlhglp]

Reading CS23 I would be more concerned about meeting vertical luminosity criteria than the small difference in the horizontal plane.

[Nick]

Well...for Kirk the flying vet.

Could you recommend which NAV lights he should use when he has his floats on his Cub?

[Waveflyer]

Grumpy One
Your posts and your encyclopaedic knowledge of the subject of lighting means the question is bound to be asked, which set of lights would be needed for a Flying Boat or would you need both?

[patowalker]

No fuss with riding lights.. You just get the lanterns out and put a match to their wicks.

CS 23.1399 Riding light
(a) Each riding (anchor) light required for a seaplane or amphibian, must be installed so that it can –
(1) Show a white light for at least 3·2 km (2 miles) at night under clear atmospheric conditions; and
(2) Show the maximum unbroken light practicable when the aeroplane is moored or drifting on the water.
(b) Externally hung lights may be used.

[Grumpy One]

Absolutely, although it's a bit of a convoluted way of describing grumpiness!

I'm a grumpy convoluted sort of bloke ...... As Waveflyer can attest.

[kanga]

This predates EASA by a very long time. CS 23.1387 is CFR 25.1387 word for word, so we can blame the Americans.

As I was taught these angles as part of PPL ground school in Canada and then again in UK, I'm guessing it is an ICAO standard. In which case it may go back to Chicago Convention, or even earlier.

This, of course, does not tell us why ICAO, collectively, chose different angles from IMO collectively.

[nkt2000]

As a Master Mariner like Grumpy, I tend to agree with his sentiments. I have been on the wrong end of a DTI/BOT/MCA surveyor often enough with him measuring angles, vertical separation and and chock sizes. I also think that the angles for ships navigation lights may pre-date the IMO by several decades, if not centuries.