Critique of: Crash Risk in General Aviation

For what it is worth, my feedback on your proposed response:

Larry Dighera wrote:
For pilots without instrument training, flying from visual flight
rules into instrument meteorological conditions is a perilous
scenario.

[There are a miniscule number of airmen who hold FAA certificates,
that have not received any instrument training; instrument training is
not required to obtain a Glider certificate. The phrase the
researchers probably meant to use was 'instrument rating' not
'instrument training.'

Regardless, it is true that the average life expectancy of a pilot who
is not instrument rated and qualified (recent experience) is a bit
over a minute when unintentionally finding himself in a cloud that
totally obscures his outside reference.]

I think a more appropriate rebuttal here is that other sources, such as
the annual Nall Report, find that in 2005 weather related accidents
accounted for only about 11% of all fatal GA accidents. By comparison,
Nall claims 27% of fatal GA accidents in 2005 are due to pilot control
errors during what it calls "maneuvering flight." Therefore the emphasis
on VFR into VMC and lack of mention of "maneuvering flight" by the
researchers as a causal factor is an improper inversion of priorities.

In 1990, the FAA amended regulations regarding background checks
on pilots for alcohol-related motor vehicle convictions, requiring
pilots to provide a written report of each alcohol-related traffic
offense within 60 days of the conviction. Flying privileges can be
suspended or revoked if a pilot has had 2 or more convictions for
driving under the influence in the past 3 years. A recent cohort
study indicated that a history of driving while intoxicated is a
valid risk marker for general aviation pilots. After adjusting for
age, sex, and flight experience, the study showed that a history
of driving while intoxicated was associated with a 43% increased
risk of aviation crash involvement.12 Following intensive research
and interventions, the proportion of alcohol involvement in fatal
general aviation crashes has decreased progressively from more
than 30% in the early 1960s to about 8% today.13

I think a rebuttal may be approprihere might be:
[The 2006 Nall Report found that alcohol and drugs account for only about
1.1% of all accidents in the past few years. This is again an inversion
of causal priorities and places an improper emphasis on a minor causative
factor. Further efforts and analysis on reducing alcohol and drug related
aviation accidents is misguided effort that is better spent elsewhere.]

[A pilot who flies without the use of shoulder restraint belts is a
fool.

It is curious that the researchers failed to mention ballistic
parachute recovery systems like those currently mandated for the
recently FAA certified Cirrus aircraft.]

I don't think you can properly claim the FAA mandated the Cirrus BRS.


The general aviation crash fatality rate has remained at about 19%
for the past 20 years while the overall airline crash fatality
rate has declined from 16% from 1986 through 1995 to 6% from 1996
through 2005.4,24

[Due to the reduction in airline operations due to the September 11,
2001 terrorist attacks, increased airport security, and general
decline in airline ticket sales, that statistic may be misleading.]

Their statistics look okay to me, though I'm not sure where they get the
6%. From their two NTSB references, out of 34 accidents listed for CFR
121 carriers, 3 had fatalities (~9%) and out of 1669 GA accidents, 321
had fatalities (~19%). Averaging over the last several N years may yield
~6%. Maybe they did that.

The higher fatality rate for general aviation crashes may be
because such aircraft are not as able to withstand impact forces
and protect occupants from death and severe injury as commercial
aircraft are.

[A more robust airframe requires increased weight. There is a
tradeoff of safety for performance.]

Another objection would be that the difference in rates may be due to the
nature of the accidents the two classes of flights encounter. Having two
experienced pilots on board would almost certainly skew where and when
accidents take place such that the impacts on the airframes are not
comparable.


In recent decades, while major airlines have improved seat
strength, revised exit row configurations, and used more fire
retardant materials, few improvements have been made in general
aviation aircraft, in part, because federal regulations only
require safety improvements for entirely new aircraft models. A
corresponding policy for automobiles would have meant that
Volkswagen Beetles could have been sold without seatbelts for
decades after federal regulation required them in all new cars.

[The Volkswagen analogy is flawed. The ubiquitous Cessna 172 aircraft
have had should restraints for decades despite their first being FAA
certified in the 1950s.]

Typo: "shoulder restraints" not "should restraints".

To improve the safety of general aviation, interventions are
needed to improve fuel system integrity and restraint systems,
enhance general crashworthiness of small aircraft,

Those are only viable measures if their added weight and cost do not
so negatively impact aircraft performance and affordability so as to
render General Aviation operations impractical.]

Furthermore, restraints systems in many small aircraft are already
superior to those found on airlines.

On Sat, 14 Apr 2007 01:14:57 +0200, Mxsmanic
wrote in :

Do you have a source for the report itself?


On Wed, 11 Apr 2007 20:09:27 -0500, "Dan Luke"
wrote in
:

Wait 'til Scary Mary gets on TV with this:

http://www.alertnet.org/thenews/newsdesk/N10403256.htm

On Fri, 13 Apr 2007 17:11:41 -0700, Sylvain wrote in
:

Jim Logajan wrote:

will read it to its end) I think you'll need to focus in on the one or two
aspect of their article you think are most in need of rebuttal and discard
the other criticisms.

As much as I appreciate the effort made by Larry, I'll have to agree; two
points that could be worth focusing on is that (a) they do not understand
what General Aviation is; (b) they have no undestanding of what IFR (and
VFR and IMC and VMC) mean; both points which they could have clarified
by spending two minutes on Internet and/or talking to some pilots (and/or
association of same such as AOPA); These two points alone discredite the
whole argument.


Agreed. But it's worse than that. One of the Johns Hopkins
University researchers who authored the report has apparently authored
several other aviation oriented reports that are mentioned in the
bibliography! It makes you wonder what those reports are like.

Larry Dighera writes:

On Sat, 14 Apr 2007 01:14:57 +0200, Mxsmanic
wrote in :

Do you have a source for the report itself?


On Wed, 11 Apr 2007 20:09:27 -0500, "Dan Luke"
wrote in
:

Wait 'til Scary Mary gets on TV with this:

http://www.alertnet.org/thenews/newsdesk/N10403256.htm


That's just a review of the report, not the report itself.

I don't much like what I read even in the review, but I'd still like to see
the report. Apparently you must be a JAMA member to see it, which is a bit
odd, since it was apparently produced with public funds.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Larry,
not exactly sure what you are trying to say here, but if you are going
to rebut this article you should have some references. Your opinion is
nice, but facts would be better. For example you state that the author
implies that GA is more inherently dangerous than the airlines. This
is actually true and the statistics bear this out. Another example is
where you state that the reason for more GA crashes as opossed to the
airlines is because there is more GA planes. This doesnt take into
account the fact that airliners fly more. There are nearly 26000
airline flights a day (This is actually up from 9/11 by a couple
grand), how many GA operations are there? Does the typical GA plane
spend over 300 hours a month in the air? I dont want to beleger this
and I hope you get the idea.
There is no doubt that this report contains some errors, but I would
sugest that you rebut the report on the basis of survivability of GA
crashes and not the comparison of ailines and GA fatality rates. Good
luck and let us know what you come up with.

Larry Dighera wrote:

Agreed. But it's worse than that. One of the Johns Hopkins
University researchers who authored the report has apparently authored
several other aviation oriented reports that are mentioned in the
bibliography! It makes you wonder what those reports are like.

write/email the author and ask for copies; academics are
vain enough that they'll bend over backward to satisfy someone
who admits having read their papers :-) THEN, send them the
critique :-)

--Sylvain

Are these aeromedical people at John Hopkins? I fail to see the
connection between a medical school and aviation safety.

Andrew Sarangan writes:

Are these aeromedical people at John Hopkins? I fail to see the
connection between a medical school and aviation safety.

Aviation medicine.

--
Transpose mxsmanic and gmail to reach me by e-mail.

On Fri, 13 Apr 2007 20:03:07 -0700, Sylvain wrote in
:

Larry Dighera wrote:

Agreed. But it's worse than that. One of the Johns Hopkins
University researchers who authored the report has apparently authored
several other aviation oriented reports that are mentioned in the
bibliography! It makes you wonder what those reports are like.

write/email the author and ask for copies; academics are
vain enough that they'll bend over backward to satisfy someone
who admits having read their papers :-) THEN, send them the
critique :-)

--Sylvain


Great suggestion!

What would it take to get you to shoulder that task?

On 13 Apr 2007 19:38:25 -0700, "K Baum" wrote in
.com:

Larry,
not exactly sure what you are trying to say here, but if you are going
to rebut this article you should have some references. Your opinion is
nice, but facts would be better.

Thank you for the suggestion. I'll see what sort of supporting
citations I can find.

For example you state that the author
implies that GA is more inherently dangerous than the airlines. This
is actually true and the statistics bear this out.

I don't refute that contention.

I just don't believe the comparison of fatality rates between
different types of aircraft operation is useful or valid. Consider
the hazards involved in crop=dusting vs airline transport operations.
If you strengthen the airframe, and develop fuel bladders capable of
withstanding impact into a granite mountain face until you can only
fill the hopper half full and still be within the weight and balance
envelope, the fatality rate will always remain higher for duster
operations than for airline transport operations.

Another example is
where you state that the reason for more GA crashes as opossed to the
airlines is because there is more GA planes. This doesnt take into
account the fact that airliners fly more.

Huh? More? More hours? More miles? More passenger miles?

There are nearly 26000
airline flights a day (This is actually up from 9/11 by a couple
grand), how many GA operations are there? Does the typical GA plane
spend over 300 hours a month in the air? I dont want to beleger this
and I hope you get the idea.

You seem to be overlooking the fact that there are over ten times as
many GA aircraft as airliners:

There is no doubt that this report contains some errors, but I would
sugest that you rebut the report on the basis of survivability of GA
crashes and not the comparison of ailines and GA fatality rates.

And I would prefer the Johns Hopkins University researchers not
publicly make invalid and misleading comparisons also.

Thanks for the suggestion. I'll try to incorporate more of that into
my rhetoric.

Good luck and let us know what you come up with.
..
Thank you for your input. I know I have a narrow point of view just
as the researchers do. It's good to see others reactions.