Night Flights: Newsletter Challenge (September 2019)

Probably would have to do with wind speed, at an altitude of 14.4k ft the weather is unpredictable and the average wind speed is like 30mph...at night the wind probably dies down a bit...

We usually referred to density altitude when planning departure time from high altitude airstrips, e.g., summertime at Bryce Canyon comes to mind <https://www.experimentalaircraft.info/flight-planning/aircraft-performance-3.php>.

Agreed, that has raised another point in my mind, are night time departures necessary to match day time landings, as some airports are only day time arrivals only?

But, I agree with the two points you raised, engine and wing performance, I think covers it. GA.

Given the elevation it is safe to assume that there is a bright white snow cover 24/7/365. Combined with the ultra-long runway snow blindness for the pilots is a constant daily concern.

Definitely not snow-covered 24/7/365
It is the last remaining habitat of the extremely rare Tibetan Echidna Platypus which as a nocturnal predatory carnivore only mates and sleeps during the daylight hours - hence the night time flight regime which goes some way to protecting the peasants from these fierce creatures.
The fact that the aircraft work better then is a wonderful side effect/benefit.

artistic rendition....

The Chinese military might see you during the day .

You're all wrong, I happen to know this is where all the vampires live, they can only travel at night...

Because they use Bejing time. (Air is densest early in the morning & all their arrivals/departures are between 7am & 11 am local time)

Corollary question: Does the size of the airplane affect the time of day the plane can take off? Can a smaller commercial jet -- like those that regional airlines use in the US -- take off during daylight when larger long-haul planes cannot?

I had to do some extra calculations flying a Piper Cherokee 180D out of Bryce Canyon airport one summer day--If I had just one other person on board (or more fuel) I'd have to delay takeoff until after sundown when it was cooler. As it was the takeoff roll seemed to go forever.

Good question.

"A runway of at least 6,000 ft (1,829 m) in length is usually adequate for aircraft weights below approximately 200,000 lb (90,718 kg). Larger aircraft including widebodies will usually require at least 8,000 ft (2,438 m) at sea level and somewhat more at higher altitude airports. International widebody flights, which carry substantial amounts of fuel and are therefore heavier, may also have landing requirements of 10,000 ft (3,048 m) or more and takeoff requirements of 13,000 ft (3,962 m). The Boeing 747 is considered to have the longest takeoff distance of the more common aircraft types and has set the standard for runway lengths of larger international airports."

https://en.wikipedia.org/wiki/Runway#Runway_length

The required runway length for an aircraft type is a factor of both density altitude and takeoff weight. (Airlines make more money if their planes are loaded.)

Here is a plot for the "infamous" 737-800

http://128.173.204.63/courses/cee4674/cee4674_pub/acft_run_length.pdf

There is no Qamdo Bamba Airport in Tibet...or anyplace else....

Correct -- fixed the spelling in the question.

Answer is posted.