Hacker News Reader

Hacker News

Comment by ethbr1 | Hacker News Reader

Parent Full thread

ethbr1

> nobody is flying an airplane that only 'works' 99.99% of the time

Might I introduce you to the Tupolev Tu-134?

https://en.m.wikipedia.org/wiki/List_of_accidents_and_incide...

View on HN

> Might I introduce you to the Tupolev Tu-134?

Also perhaps the 737-MAX. :)

* https://en.wikipedia.org/wiki/Maneuvering_Characteristics_Au...

Given how much the max family and 8 are flown, I don't think this holds up.

Some searching says...

1. >1000 flights per day for the family

2. 2 US carriers accounting for more than 200 Max 8 per day

So one would have to get to 20,000 flights after two crashes to get 2 nines. We're well past that threshold

From inception to the second crash, numbers were abysmal. The 737 Max was crashing at a rate of about one per hundred thousand flights, two order of magnitude worse that the 737 NG (one fatal crash per 10 million flights).

Said differently, the Max 8 was working safely 99.999% of the time, while the 737 NG was working safely 99.99999% of the time. An order of magnitude better than 99.99%, but two orders of magnitude worse than expected...

It is certainly a lot safer now. Hopefully even better than the 737 NG.

The probability of not having a crash after 20,000 flights, with 99.99% chance per flight, assuming no serial correlation, is 13%.

Yes, there is a better, more accurate method than my napkin math, which was only to provide a baseline most could understand to see we are well beyond the two nines

I disagree that it's possible to estimate how dangerous an aircraft is based on its incidents/flight ratio. There's lots of other factors: Russian weather, inadequate training, inadequate maintenance, and far more landings on poorly maintained and even totally unpaved runways:

> Capable of operating from unpaved and gravel airfields with only basic facilities, it was widely used in the extreme Arctic conditions of Russia's northern/eastern regions, where other airliners were unable to operate.

Russian weather? Is this an euphemism for Russian air defense?

not to mention the Tu-144, aka the "Concordski":

https://en.wikipedia.org/wiki/Tupolev_Tu-144

though that one was so defective that even the Soviets didn't want to risk flying it. it could barely get into the air, and that'd be with several major faults and alarms blaring.

Kinda scary how many times I flew with those in 80s.

I was thinking about that... but even with a relatively abysmal safety record... on average it's still an incredibly safe way to travel.

Air safety seems the quintessential "discounting the horror of extremely rare accidents from the actual total safety rate" mental trap.

When it's years between incidents, and that widely used? Yeah, I'd still fly on one if I needed to.

But I swim in the pool during thunderstorms too, so not really a zero risk type person.

Reply on news.ycombinator.com