More woes at SFO - transposing runway numbers leaves little room for error
 

"A typical commercial airliner is traveling at 184 mph at liftoff,"

All I needed to read. Pretty hard to find a well written aviation story.

You mean that to most journalists, a knot is what you do with your shoelaces? :O

Pretty much. So frustrating to read a well meant article, so full of elementary mistakes.

Way back when, PanAm wasn't as lucky; they put the approach lights through the bottom of the fuselage while rotating. No real drama until they had to land with wing gear only (B747) on the subsequent return. However, when the aircraft came to a stop, it sat back on its tail and the evacuation went sideways when pax tried to exit the upper deck slide which was not close to the ground.

More on the Pan Am SFO mishap here:

https://en.wikipedia.org/wiki/Pan_Am_Flight_845

What's wrong with it? That's about 160 knots. It was nice of the journalist to convert to a unit of measurement that the general public can understand.

I regularly get airborne around 184. Griping about 400ft/1000ft is pretty petty too, compared to what actually happened.

V2 speed on just my narrow body will vary from about 120kts to 160kts depending on weight. Don't have a clue for anybody else, so saying "184" for a "typical" speed suggests a level of significance that is totally inappropriate.

General Innumeracy
 

I'm afraid this is just another case of innumeracy.
The reporter read "160kts" and maybe knew what that was and decided to convert it to 'reader familiar' units, or more likely didn't know what "160kts" was, converted it for their own edification. They put "160kts as mph" into Google's search box, and they were told "184.124712 miles per hour". They were numerate enough to put that as "184mph", but not numerate enough to ask themselves whether "160kts" is intended to be an exact measurement, and if not whether "185mph" or even "180mph" would be suitable.

You see the same sort of thing even in reputable industry magazines nowadays: for example an aircraft's range is quoted as "7,500nm (13890km)" which is arithmetically accurate but completely bonkers - anybody who thinks a long-range aircraft has its range estimated to +/- 10km shouldn't be reporting on aviation.

Folks, even "aviation journalists", don't understand numbers and trust Google far too much.

Who cares Hans? They took off on the "wrong" runway! Don't shoot the messenger.

Could this problem be compounded by the habit of saying, say, one left, instead of zero one left?

Curious that, if miss was as near as report suggests, it's surprising it seems to have only been reported via an anonymous report (US equivalent of CHIRPS?). Appreciate the report messes up explanation of how ASDA/V1 should work but on face consequence could have been serious.

It's similar to several incidents in UK (eg Sunwing at Belfast) where mistakes with temperature, weight or full length v intersection departure have lead to flex-thrust being wrongly set. Several examples in AAIB report/bulletins over the years.

That 01/10 confusion is possible is one thing and worrying; that initial mistake was not detected in cross/check is more so.

I appreciate that airborne systems need a degree of safety, development and security not applicable to domestic devices BUT my car knows:

• how heavy it is (and adjusts brake pressure accordingly)
• what the exterior temperature is
• where it is

It seems to be time that HAL caught up

Your car doesn't know what the temperature is. Your car knows what the temperature at the sensor is, but that's not the same thing at all, especially if it's been sitting in the sun on the same piece of tarmac for a while.

Fair point and perhaps I was being facile, but absolutely soluble at machine level. If it was important to my car then it would probably take the data from some 'nearest weather station'. METAR are already expressed in a form interpretable by a very simple machine. I am expressing lack of understanding as to why this ability is not used in performance calcs, as a check on human performance if nothing else.

No, they wouldn't know how to tie a knot. They have Velcro.

NAV display: check. ;)

What HAL could have known was that it was set up for runway 10 but it was lined up on runway 01. That kind of check could be useful as a second level of safety.