You have to think how much time we will go through each of our flights, especially with long distances. These are for before the flight is not “ete to dest”. The way is by dividing your 500 distance. For example, your flight distance is 1000. So divide 1000 with 500. So it will go out “2” .2 it’s 2 hours.This is where you will pass 2 hours flight with 1000nm distance … Hopefully useful
Not sure how accurate this is. You are basically saying that you are flying at 500 kts the whole time, which is unrealistic. It helps to get you in the ballpark I guess.
Or… You could just use travelmath.com for real life flight times over distances.
If you go realistically (Speed, Flight Plan, ect) This will be 100% accurate!
That’s a really cool link!
Personally I divide my distance by 425kts to get a ROUGH estimate on my flight time. Works best for flights that are under 6hrs, over that less accurate but still close enough for early stages of planning before going to more in depth with full flight plan.
Wait, you mean descend below FL240 and slow down before 5 miles from intercept?
Surely you jest.
Am I the only one that decides to eyeball the descent phase? :)
I do the same thing 😅
Depends what you mean by ‘eye ball the descent phase’? Top of Descent is normally 100-130nm away from touch down from cruise in a typical jetliner, so if you can eyeball all that way in then you have super eyes! Personally I like to plan a bit ahead to avoid gaining any violations and have a stress free approach and landing.
I usually descend to one altitude first, and then gradually lower the altitude as I get lower and lower. It usually works fine.
Yes I do the same, wouldn’t call that ‘eyeball’ VFR though .that’s called planning or IFR ;-)
Normally I fly from Cruise down to FL120, then at 42nm to go ,descend to 6000 AGL at 24nm to go reduce further to 3000 AGL until on final approach.
I guess I’ll have to do it…
Descent calculation is all well and good. However, there are about 5000 other threads about it where it can be discussed.
I don’t think the math in the OP is even remotely precise [even if you travelled the same speed the whole way (You don’t), there can be 200 knots of difference between westbound and eastbound travel depending on wind, but anyway], but it’s still the topic of the thread; not descent calculation.
In physic, you would use the equation speed = Distance / Time
(Thanks AQA Physics)
Yes, but to get to his unknown of time, you have to do a little algebra to get Time=Distance/GS.
The problem is he assumes a constant for ground speed, when it’s variable over time.
There’s no single calculation that will work, because all of the variables involved change from moment to moment.
We all love abit of algebra to solve the issues in today’s society.
I use an average ground speed of 450kts to calculate my flight time. i.e. 1800nm= 450ktsx 4h, so if I had 1687nm FPL, I’d pack 3.75h +60-90 min reserve of fuel. Be sure to check windy.com to get a sense of the average speed and direction of the winds at your flight level across your entire flight path. Tailwinds will shorten flight time because your average ground speed will more than likely be above average, and headwinds will drop your ground speed below average, adding time.
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