Re: Airbus Safer?

Date:         19 Aug 98 16:01:37 
From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
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>In terms of flight operation the A320 tended to stand hand and
>shoulders above the rest (as in a high accident rate). There have been
>numerous accidents with A320's on approach and landing. D10's don't
>fare all that well either.

At one point, I remember reading that the A320 had passed even the DC-10
as having the worst safety record.  Unfortunately, I don't know what the
exact metric was and haven't been able to find the reference again.  For
most any metric, the statistics were distorted by a small sample and a
lot of crashes relatively early on.  If you looked again (and included
the A319 and A321), I suspect the A320 family would fare reasonably well
since there have been only two hull losses and no fatalities in nearly
five years, despite a tremendous buildup in the number of aircraft in
service.

>On this basis, my recollection is the 727 turns out to be safest
>aircraft in the sky.

Perhaps, though there were a series of troubling crashes in the early
days which gave the 727 a really bad safety record at the time.  One
might argue that the early A320 crashes were analogous, but the early
727 crashes were due to a dissonance between pilot psychology and the
unprecedented (for an airliner) performance of the 727.  The return
for those painful lessons was a quantum leap in efficiency.  The A320,
in contrast, paid a similar price for comparatively minor advances.
(This is really Robert Dorsett's argument -- hopefully he'll correct
me or elaborate if I've bobbled it up.)

Actually, the safest types by flight operations (and flight hours)
include Concorde, the Mercure, and the 777, all of which have zero
crashes adn zero fatalities.  Maybe that means they're really safe,
or maybe that just means the sample is too small.

Of the planes which have had at least one fatal event and/or hull
loss, I thought the 737 was the safest by flight operations, ahead of
the 727.  Yes, there have been a substantial number of 737 crashes, but
there are a hell of a lot of 737s out there and they each have been
racking up flights at a tremendous rate.

>If you measure in terms of flight hours, I think the 747 wins.

Not surprising since it probably flies the most hours per flight and
most accidents are during to takeoff or landing, not cruise.

All of this illustrates the problem of figuring out what's a useful
metric.  For example, I've noted before that http://www.airsafe.com/
has an interesting and useful collection of data, but to me the metric
is a bit screwy -- events in which at least one passenger was killed.
As a result, the 747 is dinged for an Aerolineas Argentinas flight
during which a passenger died of food poisoning, but the 737 is *not*
dinged for the Aloha "convertible" since the only fatality was a crew
member.  Obviously there's a lot more context, but looking at those
two alone, which would you pick on a safety standpoint?  For better or
worse, here are a few of his rates including best and worst, taken from
http://www.airsafe.com/events/models/rate_mod.htm.

Model                   Rate  Events  Flights
-----                   ----  ------  -------
Fokker F28              2.63    20      7.6M
Douglas DC10/MD11       1.92    15      7.8M
Boeing 747              1.85    22     11.9M
Airbus A310             1.25     3      2.4M
Airbus A300             1.01     7      6.9M
Lockheed L1011          0.93     5      5.4M
Airbus A320             0.77     4      5.2M
Fokker F70/F100         0.75     3      4.0M
Boeing 737-100/200      0.72    34     47.1M
Boeing 727              0.66    46     69.5M
Boeing 757              0.59     4      6.8M
Boeing 737-300/400/500  0.47    11     23.5M
Boeing 767              0.34     2      5.9M
Douglas MD80            0.32     6     19.0M
Saab 340                0.16     1      6.3M

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Karl Swartz	|Home	kls@chicago.com
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"The average dog is a nicer person than the average person." - Andrew A. Rooney