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Re:Boeing 787 Suffers Rare Dual Engine Failure on Landing by AshleyGrant on Wednesday January 30, 2019 @02:21PM (#19038299)
>The cruising airspeed of an airplane is roughly speaking an order of magnitude faster than its landing speed.

No. No it is not. 787 approach speed is 145-153 knots. It does not cruise at 1400+ knots.

Re:Boeing 787 Suffers Rare Dual Engine Failure on Landing by gugagore on Wednesday January 30, 2019 @02:34PM (#19038483)
Thanks for bringing more precision to the conversation (really).

What would you like to call the factor? 3? Call me a weasel, but I was hoping "roughly speaking an order of magnitude" would go down to 3. I suspected it was comfortably above 2. Am I right about that?

Re:Boeing 787 Suffers Rare Dual Engine Failure on Landing by a1369209993 on Wednesday January 30, 2019 @03:13PM (#19038948)
> I was hoping "roughly speaking an order of magnitude" would go down to 3.

I'd call that half a order of magnitude, considering log₁₀(3) is around 0.477. So you're off by more than a factor of two.

Re:Boeing 787 Suffers Rare Dual Engine Failure on Landing by gugagore on Wednesday January 30, 2019 @03:40PM (#19039218)
You know, I considered saying that the "roughly" buys me a factor of two in log space. I didn't want to be that person, but I'm glad you were ;).
Re:Boeing 787 Suffers Rare Dual Engine Failure on Landing by a1369209993 on Wednesday January 30, 2019 @06:37PM (#19040803)
It's surprisingly non-trivial to pin down exactly what the 'correct' scale[0] for a given measurement is. I do agree about "roughly" generally being up to a factor of two in the appropriate scale[1], although I'm the sort who thinks a 19% increase (or 16% decrease) should be called a quarter of a factor of two.

0: Uniform, linear and logarithmic are obvious candidates, but depending on the domain you can end up with some really wierd scales (eg floating-point ULPs, which can look logarithmic or linear, but aren't either).

1: hence > So you're off by more than a factor of two.

Re:Boeing 787 Suffers Rare Dual Engine Failure on Landing by billforsternz on Wednesday January 30, 2019 @03:21PM (#19039018)
3 is half an order of magnitude (because it is a good approximation to 10^0.5)
Re:Boeing 787 Suffers Rare Dual Engine Failure on Landing by Tushon on Wednesday January 30, 2019 @03:34PM (#19039150)
re go down to 3: Use different words and see if you think it was reasonable

roughly 10x going down to 3x would also mean it would go up to 17x. That's a pretty wide range, so I don't think that order of magnitude is going to ever really be similar to 3x of something on the basis of what it means.

Re:Boeing 787 Suffers Rare Dual Engine Failure on Landing by gugagore on Wednesday January 30, 2019 @03:39PM (#19039207)
but what about a rough order of magnitude? There is definitely some qualifiers you can put on "order of magnitude" to make it include 3.
Re:Boeing 787 Suffers Rare Dual Engine Failure on Landing by abduhl on Wednesday January 30, 2019 @05:32PM (#19040305)
"within an order of magnitude"