Re: [SystemSafety] 737 tail strike caused by typo on a tablet

From: Klaus < >
Date: Wed, 18 Nov 2015 11:13:18 +0100

Well, hm...
I fly 747 since 1987. Copilot, Captain... Distractions have increased, procedure design hasnīt quite kept up with all the things going on during the last minutes before departure.

20 years back, the data for takeoff were calculated by hand, using tables, and everything was ready 15, 20 minutes before pushback.

Today, preliminary calculations are done 15, 20 minutes before pushback, but then updated with the latest info of + or - 5 passengers, a bit of cargo - whatever. THEN, with sheduled time of departure coming near, then things are recalculated and finally transferred, manually, into the airplane computers .

Distractions ? You better be immune to them - which no-one can really be.

About the 737: looks like a 10 ton error to me, maybe 15 % of takeoff-weight. May have been contributing, but I have doubts it was the main reason for the tail-strike.

747s , which are much larger than 737, have been known to scrape the runway, yes, but then the error was more than 25% of takeoff weight. 2xx tons instead of 3xx tons....

Solution: try to keep a calm working athmosphere in the cockpit and do as much preparation as can be done : every moment counts. And: do the checklists, the required crosschecks.

Hope that this was interesting,

Klaus Sievers

Am 18.11.2015 um 09:01 schrieb Peter Bernard Ladkin:
> Hash: SHA256
> Deja vu all over again.
> On 2015-11-18 06:57 , Heath Raftery wrote:
>> This news article is likely to be of interest to the list members. A jumbo's tail struck the
>> runway on take-off, and root cause was found to be an incorrect take-off weight entered in the
>> thrust parameter calculator. The fact the calculator is an app running on an iPad may or may
>> not be important to the story, but it does give it that everyday appeal.
>> The calculation is double checked using pen and paper, and so two dissimilar faults were
>> necessary to invoke the failure vector. Is there anything more that can reasonably be done to
>> avoid this safety issue?
> Prof. Peter Bernard Ladkin, Faculty of Technology, University of Bielefeld, 33594 Bielefeld, Germany
> Je suis Charlie
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systemsafety_at_xxxxxx Received on Wed Nov 18 2015 - 11:13:29 CET

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