Longest flight in either total light or total darkness

[scudpilot]

Got to thinking at the weekend, long haul flights invariably have a mixture of dark or light, but what is the longest flight (in terms of time or distance) that you could have in either no darkness or total darkness.
I am assuming that the likes of the SR71 due to its high speed could probably hold some sort of record?
Any thoughts people?

[Invicta DC4]

Probably EWR - SIN in winter at a guess. 17 hours or thereabouts (total darkness)?

Generally, routing east - west; daylight, west - east; darkness.

[The Flying Pram]

Not quite what you're asking, but a society I'm a member of had a talk some years ago by a SR71 flight crew. They said that seeing two sunsets during one flight was quite possible....

[arem]

Two sunsets in one day - I seem to recall similar scenarios on the 744 on ULR LHR-SIN/HKG in the winter although. The reverse sectors again in the winter were of course total night.

Mind you doing NRT-LHR or even LHR-ANC could produce the unique sight of the sun rising in the west - well southwest to be strictly accurate!!

[MarkerInbound]

I've seen the moon "rise" in the west going KSEA-PANC. Was a little disorienting at first.

[praa]

I have a strange one coming up next week: Munich to Los Angeles. You leave about 3:30 in the afternoon giving you one sunset a couple of hours after take-off. Taking a very northerly route, the next few hours are in darkness and as you come down over western Canada it gets light again. As you travel through California you get your second sunset within 12 hours and land in darkness.
It's convenient timing as you can go to bed once you get in but it doesn't half muck up my body clock.

[beamender99]

...a SR71 flight crew. They said that seeing two sunsets during one flight was quite possible....


or a Concorde flight at this time of the year..
Sun set in UK, sun rise in the west and then sun set again in the US.

Just tried the BA CPT LHR day time flight. Very strange doing that length of sector in daylight and arriving with only two hour time change.

[Tim Zukas]

"Munich to Los Angeles. You leave about 3:30 in the afternoon giving you one sunset a couple of hours after take-off. Taking a very northerly route, the next few hours are in darkness and as you come down over western Canada it gets light again."

Why would it get light over Canada in November? Where would you have to be, at what time?

[bobleeds]

That's right, you effectively overtake the sunset for a period.

Done it on the BA269 from LHR to LAX in February. Took off a bit late about 1545 dark about an hour later over Scotland then we got a sunrise over greenland or the very north of Canada, then light for some time whilst we flew rougly westerly, didnt finally get dark until our path had turned back south and the darkness caught us up over north west of USA.

[philbky]

Why wouldn't it? As you head in a southerly direction you eventually come back into sunlight.

On flights I've taken from LHR to the west coast in December with a mid morning departure, "sunrise" tends to be somewhere well north of the 49th - how far north dependings on the date - at around 11.00 to 11.30 local time depending on the route that day. The disconcering thing is, again depending where you are, the sun appears to "rise" in the South or even Southwest a little later in the day.

[Wycombe]

Longest one I've done in total daylight is 13hrs HKG-LHR on the NZ038.

Leave Honkers at about 0900L, fly for 13hrs and arrive LHR at about 1400L - a very looooonnnngggg day!

[Sultan Ismail]

Similar experience awaits you on Singapore to Heathrow flights leaving SIN at 9am and 14 hours later arriving in LHR at 3pm! These flights do not get to the Northern latitudes where night or even dusk encroaches.
The Singapore flight to Newark does however get into those Northern latitudes and therefore it does not turn into "the Longest Day".

[African Wings]

Sorry if I am a bit off topic but maybe this is of interest:
In the mid 80's the SA gov (and US) supported the rebel forces in Angola.
During this time our Puma (SA 330) crews changed day with night.
Spare a thought for the guys who flew at 50-200 vt without NVG's or GPS's.
A map and fires ! This used to be 4-6 hours every night.
Sorry to disturb but I thought it will fit in nicely with the discussion.

[Tim Zukas]

"On flights I've taken from LHR to the [US] west coast in December with a mid morning departure, "sunrise" tends to be somewhere well north of the 49th [parallel]..."

Sure-- if you're arriving the west coast in daylight the sun has to come up sometime before you get there. But if you're leaving Europe late in the afternoon, going dark before Greenland, and arriving on the west coast after dark I don't offhand see how you can get daylight in Canada en route. (In the winter, that is.) I'm still scratching my head over the geometry, and not ruling it out yet, but...

[philbky]

OK, lets make the LHR departure 3 hours later - 13.30 local. It would be dark by the time you entered Icelandic airspace.

Eight hours after take off you would (depending on the route) be somewhere over the central time zone of Canada with a local time of 15.30 - so you would be in daylight. Three and a half hours later, arriving in LAX, it would be dark at 16.30.

If you left London at 15.30 local you would still have light from a very low sun with a Canadian local time of 17.30 and it would be dark landing at LAX at 19.00. Don't forget that there is always more light at altitude than on the ground as the sun is visible longer the higher you are.

This all assumes a winter track ovr Northern Canada and down over, say, Lake Athabasca/Uranium City or similar.

A more unusual track but one which is used would be over Greenland, where it would be dark, then across Hudson Bay and down over Winnipeg and Wyoming which would afford much more light, even with a 15.30 departure from LHR.

[Tim Zukas]

Okay, I finally got it. When you're far enough north that you're covering more than 15 degrees of longitude per hour then the sun will be climbing, relative to your horizon-- of course. So yes, if your flight's timing is right you can see two sunsets; as it happens the timing probably wouldn't be right on the MUC-LAX flight that the guy mentioned.

The LH flight is scheduled out of MUC at 1535; say the flight for 15 November follows the great-circle track to LAX at a constant ground speed of 440 knots, leaving MUC at 1445 GMT (which would put them overhead LAX in 11 hr 50 min, at 1835 local; scheduled arrival 1910).

At 1800 GMT, position 63-00-30 N 22-25-48 W, sun 98.6 degrees from zenith

1900, 64-52-19 38-33-05, sun 98.9

2000, 64-49-00 55-46-39, sun 98.0

2100, 62-51-16 71-46-43, sun 96.7

2200, 59-20-56 85-05-01, sun 95.8

2300, 54-45-26 95-34-20, sun 96.0 and continues to sink.

[WHBM]

I know it's only trivia compared to the technical discussion above, but I do smile at the approach of those pax who take the "Santa Claus" one-day flights to Rovamiemi, Finland, in December. Depart UK about 0800 local, 3 hour flight to Finland. Dark on arrival.

"It's dark. When does it get light ?".
"It doesn't".
"What, not at all ?".
"Well, now, what date is it ?".
"December 21. So ?".
"And whereabouts are you ?"
"On the Arctic Circle. So ?".
"Then it will be dark all day".
"But we've brought the children all this way ...."