[SystemSafety] "FAA chief '100% confident' of 737 MAX safety as flights to resume"

[Littlewood, Bev]

Michael

I don’t know about US speakers of our (apparently) common language. But I think English English speakers - and readers - would regard “100% confident” to mean “certain”. It does not seem to me to be a “quantification of confidence”, as you put it, but a declaration of absence of doubt.

The substantive issue seems to me to be not what this man said, but rather how safe is the tweaked Max. Tom Ferrell puts the technical issues well, and Olwen’s characterisation of the problem is admirably and wittily succinct:

If I want computer-moderated aerodynamic instability, I'll fly in an Su-35. What the 737 MAX needs isn't revamped systems but a new airframe design.

I find it hard to believe that any honest and competent engineer could tell the public that he was certain a software solution to the problem of such a flawed design was sufficiently safe. What do you think, Michael? I know you don’t like numbers, but tell us, qualitatively at least, how safe you think it is likely to be.

All the best

Bev



On 20 Nov 2020, at 14:41, Michael Holloway <cmh at alumni.virginia.edu<mailto:cmh at alumni.virginia.edu>> wrote:

Only have the energy and interest to reply to one bit of PBL's response ...

> So you are suggesting that he is at least as confident that he won't die, flying in a MAX, as he is
> that 2+2=4 ? Or should that confidence be relativised somehow?

I am saying that to the best of my knowledge, the most common intended meaning of the phrase "100% confident" when used by a typical speaker in the US is much closer to, "confident enough to stake my reputation and life  on it," than it is to "certain beyond any and all doubt," or even to "certain beyond a reasonable doubt." Personally, I abhor the use of any phrase that appears to quantify confidence, but I see no benefit, and some harm, in harping on such a usage, when the meaning is as generally well understood as it is here.

--
Michael

mercy > judgment
love > faith & hope
grace > law



On Fri, Nov 20, 2020 at 8:44 AM Peter Bernard Ladkin <ladkin at causalis.com<mailto:ladkin at causalis.com>> wrote:
On 2020-11-20 14:26 , Michael Holloway wrote:
>  the criticism here is ridiculous.

Thanks, Mike. Might you have a technical, rather than an emotional, reaction to share?

> First, it is pedantry of an extreme sort to think that "100% confident" means anything more
> than "as
> confident as it is possible for me to be."

So you are suggesting that he is at least as confident that he won't die, flying in a MAX, as he is
that 2+2=4 ? Or should that confidence be relativised somehow?

> Third, everything Tom wrote about the level of scrutiny the plane has undergone is correct.

Yes. And that the defined procedures are not enough has been pointed out twice in reports.

After Ermenonville, the DC-10 became "the most scrutinized [sic] aircraft in the history of the
commercial transport fleet." Then came Sioux City. Along with nobody noticing that you could lose
structural integrity if you lost pressure in one half of the PV (which led to Ermenonville through a
couple of other occurrences), nobody apparently noticed that they had routed all the control system
hydraulics through one spot in the tail, which was duly sliced through by a shed blade. Many put
that down to the overall design process of the airplane and worried about other oversights. Which
ended up being, some say, why the DC-10 fleet converted to freighters, followed quite quickly by the
MD-11.

PBL

Prof. Peter Bernard Ladkin, Bielefeld, Germany
ClaireTheWhiteRabbit RIP
Tel+msg +49 (0)521 880 7319  www.rvs-bi.de<http://www.rvs-bi.de/>





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