Cirrus Lands via Parachute in Nantucket

As I argued earlier today, a plausible guess for the number of VFR-
into-IMC crashes in 2006 is 7 or 8 (with a possible range from 0 to
49).

Oops, small correction: 7 or 8 was the guess for PTS-proficient VFR-
into-simple-IMC crashes. The guess for ALL VFR-into-IMC crashes was
30, with a possible range from 25 to 49.

On Sat, 18 Aug 2007 16:52:04 -0400, Owen Rogers
wrote:

Looks like another save for BRS and Cirrus.

Apparently a Cirrus was attempting to land ACK VFR last night when they
ran into weather (fog and low visibility after sunset on the island are
common in the summer). They pulled the Ballistic Recovery System
parachute about 5 miles northeast of ACK.

The two aboard had minor injuries but will be ok. Nobody was injured on
the ground.

Here is a news link:
http://www.capecodonline.com/apps/pb...180319/-1/NEWS

Other reports said that it was a Cirrus, although the make/model hasn't
been confirmed yet.



And finally, the NTSB preliminary report:

http://www.ntsb.gov/ntsb/brief.asp?e...21X01216&key=1

If the report is accurate, we have a non-instrument rated pilot who, when
ACK suddenly "went IFR", "informed the controller that he was capable of
executing the ILS approach". Five minutes later, Cape Approach informed
the tower controller that the pilot had deployed the parachute.

--ron

On Aug 22, 12:38 pm, wrote:
On Aug 22, 10:53 am, "Neil Gould" wrote:

I am unaware of any data that documents the number of occurances of pilots
inadvertently venturing into IMC,

Come to think of it, we can make a reasonable estimate about this.

Suppose the average pilot wanders accidentally into IMC about once
every ten years. There are about 600,000 active pilots in the US. So
that would mean about 60,000 VFR-into-IMC events each year.

As I argued earlier today, a plausible guess for the number of VFR-
into-IMC crashes in 2006 is 7 or 8 (with a possible range from 0 to
49).

So unless the ten-years estimate is low by ORDERS OF MAGNITUDE, we
find that there is a very low fatality rate for VFR-into-IMC events.

Not stating anything for or against your argument, because I think it
is slightly flawed. You are assuming that all flights by all pilots
are initiated in VMC or under VFR.

I think a more correct estimate would be to take only the non
instrument rated pilots. Unless someone has done any study about
instrument rated pilots flying VFR and wandering into IMC. That would
significantly decrease the numbers of incursions per anum.

Well, come to think of it, I don't know. Now I'm thinking "what about
currency?"

The whole problem is that we don't know the number of:
total number of VFR into IMC (by non rated pilots)
total number of VFR into IMC (by rated pilots)
successful CONTINUED VFR in IMC (by non rated pilots)
successful CONTINUED VFR into IMC (by rated pilots).

All we have are total failed VFR into IMC (by rated/non-rated) pilots.

On Aug 22, 2:12 pm, Doug Semler wrote:
Not stating anything for or against your argument, because I think it
is slightly flawed. You are assuming that all flights by all pilots
are initiated in VMC or under VFR.

No, I'm making no such assumption. I'm just assuming what I stated:
that an average pilot accidentally flies VFR into IMC at least once
every ten years or so. I think that's a pretty conservative guess.

I think a more correct estimate would be to take only the non
instrument rated pilots.

IFR pilots accidentally fly VFR into IMC too, and sometimes get killed
doing it. But even if we exclude instrument-rated pilots from the
analysis I gave, that could at most double the fatality rate I
calculated--which would still be very small.

Ron Rosenfeld wrote:


And finally, the NTSB preliminary report:

http://www.ntsb.gov/ntsb/brief.asp?e...21X01216&key=1

If the report is accurate, we have a non-instrument rated pilot who,
when ACK suddenly "went IFR", "informed the controller that he was
capable of executing the ILS approach". Five minutes later, Cape
Approach informed the tower controller that the pilot had deployed
the parachute.



That sort of revives the stupid pilot theory.

On Aug 22, 10:30 am, Thomas Borchert
wrote:
In addition, many (perhaps the large majority) of the VFR-into-IMC
crashes result because the pilot did NOT maintain basic instrument
competence, or because the accidentally-encountered instrument
conditions were NOT uncomplicated.

So the majority of pilots is not competent? Hmm.

No, that doesn't follow at all! Surely nonproficient pilots will be
OVERREPRESENTED in the sample that consists of fatal crashes! So your
extrapolation to the general pilot population is completely spurious.



[Sorry if this post is a duplicate; something got lost.]

Recently, posted:

On Aug 22, 10:53 am, "Neil Gould" wrote:
Are you implying that VFR-only pilots regularly fly into IMC, and as
a result the odds are that they will eventually crash? If so, please
support that notion with some data. If you are implying that there
are "many" occurances of competent VFR-only pilots flying into IMC
and that the "small chance" that applies to the group-at-large
affects the likelihood that there will be "some crashes", please
supply a reference to some supporting data.

I am unaware of any data that documents the number of occurances of
pilots inadvertently venturing into IMC, and without that number, it
would seem difficult to support any notions of probability bases
solely on the number of crashes. OTOH, the data on the survivability
of non-IFR pilots in IMC has been presented numerous times in this
ng, and it appears to refute either of your notions of probability,
so if you have information to the contrary, I, for one, would like
to see it.

Which data about non-IFR pilots in IMC are you referring to? If it's
the ancient "158 seconds" study (or whatever the number was), that
involved pilots who did not have (present-day) PTS proficiency at
instrument flight, so it doesn't address my claim. If you mean the
Nall Report, then (see my post about that a few minutes ago) the data
there don't tell us whether there are more than a few (or even more
than zero) crashes each year when a PTS-proficient pilot inadvertently
enters simple IMC.

You're right that we also don't know the baseline number of VFR-into-
IMC occurrences that DON"T result in a crash. So my claim is NOT that
the available data show us that the probability is large that a PTS-
competent pilot can safely return from simple IMC. Rather, my claim is
that the available data (as far as anyone has shown here) do not
(contrary to Thomas's claim) REFUTE the assertion that a PTS-competent
pilot can (very probably) safely return from simple IMC.

What I'm having difficulty with is the notion that *any* predictions of
the probability of crashes involving the VFR pilot into IMC can be made
based on the available data. It would be just as possible that the crashes
represent a small fraction of such excursions as it representing the vast
majority of them. The only information that I've seen (ancient or
otherwise) suggests that the probability of surviving such an occurance is
fairly low, and that practice didn't have much of an impact on the
result -- the difference was measured in seconds, not success. However,
the missing baseline information makes it impossible to use this as more
than a caution, albeit rather compelling.

Also, I did read your post on the Nall report, but I saw nothing that
excludes the possibility that *all* of the pilots involved in those fatal
accidents were "proficient" (which may be a reason they felt confident
enough to proceed). While I understand the face validity of your notion
that practice improves one's chances of survival, I just don't see the
supporting data to back it up. IMO, one risk of proceding into unkown IMC
is the lack of an answer to "...and then what?" Bottom line, I agree with
Tom's perspective that the truly proficient pilots won't find themselves
in that situation to begin with.

Neil

Recently, posted:

On Aug 22, 10:53 am, "Neil Gould" wrote:
I am unaware of any data that documents the number of occurances of
pilots inadvertently venturing into IMC,

Come to think of it, we can make a reasonable estimate about this.

Suppose the average pilot wanders accidentally into IMC about once
every ten years.

Based on...?

I'm not so sure that VFR into IMC is unintentional. "...and then what?"

Neil

On Aug 22, 4:51 pm, "Neil Gould" wrote:
Recently, posted:

On Aug 22, 10:53 am, "Neil Gould" wrote:
I am unaware of any data that documents the number of occurances of
pilots inadvertently venturing into IMC,

Come to think of it, we can make a reasonable estimate about this.

Suppose the average pilot wanders accidentally into IMC about once
every ten years.

Based on...?

Based on anecdotal evidence. Ask several pilots you know about their
own experience. The point of my analysis is that the guess doesn't
have to be very accurate. Suppose (implausibly) that the average time
between VFR-into-IMC events is 100 years (rather than ten) for the
average pilot. EVEN THEN, the analysis I gave shows that well over 99%
of VFR-into-IMC events are survived. (If the time is ten years, or
less, then the survival rate is well over 99.9%, by the analysis I
gave.)

It's reasonable to use anecdotal evidence if it only needs to be
accurate to within an order of magnitude or two to support a
particular conclusion, as is the case here.

Also, I did read your post on the Nall report, but I saw nothing that
excludes the possibility that *all* of the pilots involved in those fatal
accidents were "proficient"

Correct. But even if (implausibly) it's only the proficient pilots who
crash, that still gives a survival rate of well nover 99% for VFR-into-
IMC events.

Bottom line, I agree with
Tom's perspective that the truly proficient pilots won't find themselves
in that situation to begin with.

But if THAT were true, then all of the VFR-into-IMC crashes would
involve NONproficient pilots! Therefore, the +99% survival rate for
VFR-into-IMC events would be the rate for NONproficient pilots in that
situation. Proficient pilots presumably would be able to fare even
better in IMC than nonproficient pilots do.

Jim Stewart wrote:
wrote:
On Aug 22, 11:30 am, Thomas Borchert
wrote:

Rather, my claim is
that the available data (as far as anyone has shown here) do not
(contrary to Thomas's claim) REFUTE the assertion that a PTS-competent
pilot can (very probably) safely return from simple IMC.

Well, maybe, but wouldn't one of the first things that the
oh-so-"competent" pilot of your scenario would do is adhere to the
rules? And that would certainly preclude him from flying VFR into IMC,
wouldn't it, let alone having to get out of it?


No. Once again, you're confusing competence with perfection. A
competent pilot will seldom if ever enter IMC inadvertently, but it's
not IMPOSSIBLE for him to so.

It's worth noting that Lindberg baled twice
in his career as a mail pilot, both times
because he flew into weather and couldn't
find his way out.

And what instruments did he have in the panel of his airplane?

Matt