Today's Message Index:
----------------------
1. 05:13 AM - Re: Jabiru USA 3300 engine mount NOT to Specs (KARL POLIFKA)
2. 06:53 AM - Flying Times (BobbyPaulk@comcast.net)
3. 08:28 AM - Re: Flying Times (KARL POLIFKA)
4. 08:45 AM - Re: Flying Times (John Davis)
5. 08:55 AM - Re: Flying Times (mhubel)
6. 08:59 AM - Re: Flying Times (DaveG601XL)
7. 09:08 AM - Re: Flying Times (Bryan Martin)
8. 09:37 AM - Re: Re: Flying Times (Doug - SportAviation)
9. 11:12 AM - Flying times (roger lambert)
10. 11:48 AM - Re: Flying times (Paul Mulwitz)
11. 11:51 AM - Re: Flying Times ()
12. 12:08 PM - Re: Flying times (KARL POLIFKA)
13. 01:11 PM - How many of you have grounded... (Gig Giacona)
14. 01:28 PM - Re: How many of you have grounded... (Jim Belcher)
15. 02:39 PM - Re: Flying times (Doug - SportAviation)
16. 02:44 PM - Re: Flying times (Doug - SportAviation)
17. 02:58 PM - Re: Flying times (Terry Turnquist)
18. 03:51 PM - Re: Flying times (Jim Belcher)
19. 04:54 PM - Re: Flying Times (Randy)
20. 05:14 PM - How Many of You Have Grounded... (Rosalie)
21. 05:32 PM - Re: Flying Times (Tonyplane)
22. 06:11 PM - Re: Jabiru USA 3300 engine mount NOT to Specs (601RX)
23. 08:10 PM - Re: Flying Times (Randy L. Thwing)
24. 08:35 PM - Re: Nose wheel fork failure (Thruster87)
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| Subject: | Re: Jabiru USA 3300 engine mount NOT to Specs |
I think they may have been through more than one welder. We went
through three engine mounts before they got it right in 2006. Wrong
angle -- not the wrong material.
Karl
----- Original Message -----
From: Thruster87
To: zenith601-list@matronics.com
Sent: Tuesday, October 27, 2009 10:50 PM
Subject: Zenith601-List: Jabiru USA 3300 engine mount NOT to Specs
<alania@optusnet.com.au>
Started the repair on the bent/cracked engine mount and during the
straightening process it broke off at the lower mid point at the
intersection of tubes 7 & 6.On measuring the wall thickness it came to
0.035" and the drawings called for 0.058" [6-JE-1] This is now the
second engine mount supplied with the use of incorrect thickness
tubing/plates.What is happening to quality control?????? Jab USA has to
get rid of the person welding these mounts.Lucky or unlucky as the case
may be, if it wasn't for the nose wheel collapse the bloody engine might
have fallen off.Cheers T87
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=269775#269775
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Guys
can we get a show of hands on who is flying and how much. i would have done much
more except for weather and runway construction. went to a fly-in 100 miles
away. good time, good food. indicated 125 mph at 5500' with a 155 mph ground speed
hopefully we are getting better weather.
N131BP
601 XL E-AB
14hrs since June
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| Subject: | Re: Flying Times |
N156WT (Williamsburg, VA with 4 owners) does about 140 hours per year.
----- Original Message -----
From: BobbyPaulk@comcast.net
To: zenith601-list-digest@matronics.com
Sent: Wednesday, October 28, 2009 9:50 AM
Subject: Zenith601-List: Flying Times
Guys
can we get a show of hands on who is flying and how much. i would have
done much more except for weather and runway construction. went to a
fly-in 100 miles away. good time, good food. indicated 125 mph at 5500'
with a 155 mph ground speed
hopefully we are getting better weather.
N131BP
601 XL E-AB
14hrs since June
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| Subject: | Re: Flying Times |
N601JD in Spruce Pine, NC, I've gotten 32 hours since my first flight in
Jan. Would have had more but the wx has been crummy this year...
John Davis
BobbyPaulk@comcast.net wrote:
> Guys
> can we get a show of hands on who is flying and how much. i would have
> done much more except for weather and runway construction. went to a
> fly-in 100 miles away. good time, good food. indicated 125 mph at
> 5500' with a 155 mph ground speed
> hopefully we are getting better weather.
>
> N131BP
> 601 XL E-AB
> 14hrs since June
> *
>
>
> *
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| Subject: | Re: Flying Times |
N708HU FIT, MA have 32 hours since first flight. Like others, weather and fighting
with Bing have reduced the total.
--------
Mark Hubelbank
N708HU
CH601XL
Jabiru 3300
Rotec TBI 40 carb
Sensenich ground adj prop.
28 hr TAF
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=269841#269841
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| Subject: | Re: Flying Times |
I flew about 70 hours this year and have 115 total hours now. Made x-country trips
to Oshkosh once and to Illinois three times. Hit about 15 fly-ins and pancake
breakfasts. This week I flew at night for the first time and got enough
takeoff's and landings to become night current. I have no qualms about flying
the 601XL, even at night.
p.s. since we have had recent discussions about nose gear, my experience with a
light engine (Jabiru) and the gear turned around (flat face forward), is that
I can typically hold the nose gear off for about 5 seconds before it eases down.
It required some technique refining, but not a lot.
Footloose and flutter free,
--------
David Gallagher
601 XL/Jabiru 3300
First flight 7/24/08
115 hours and climbing!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=269842#269842
Attachments:
http://forums.matronics.com//files/sworfi09_35_910.jpg
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| Subject: | Re: Flying Times |
52 hours over the past twelve months out of Ray, MI.
BobbyPaulk@comcast.net wrote:
> Guys
> can we get a show of hands on who is flying and how much. i would
> have done much more except for weather and runway construction. went
> to a fly-in 100 miles away. good time, good food. indicated 125 mph
> at 5500' with a 155 mph ground speed
> hopefully we are getting better weather.
>
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
do not archive.
Message 8
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| Subject: | Re: Flying Times |
172 hrs personal flying so far this year on the Zodiac; 468 total. No
Stephen Smith trips, but regularly back and forth between north Georgia and
Clearwater, FL. And often back and forth between Clearwater and Boca Raton,
FL (visiting kids). Only issue (since taking it off the rental line - whole
other story there) was an oil leak in a valve cover (Continental O-200); and
a cracked canopy from having it slam down onto a headset from a gust of wind
- take note folks. Nothing with the airframe.
Doug Norman, CFI, AGI
N601DN
-----Original Message-----
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of DaveG601XL
Sent: Wednesday, October 28, 2009 12:00 PM
Subject: Zenith601-List: Re: Flying Times
<david.m.gallagher@ge.com>
I flew about 70 hours this year and have 115 total hours now. Made
x-country trips to Oshkosh once and to Illinois three times. Hit about 15
fly-ins and pancake breakfasts. This week I flew at night for the first
time and got enough takeoff's and landings to become night current. I have
no qualms about flying the 601XL, even at night.
p.s. since we have had recent discussions about nose gear, my experience
with a light engine (Jabiru) and the gear turned around (flat face forward),
is that I can typically hold the nose gear off for about 5 seconds before it
eases down. It required some technique refining, but not a lot.
Footloose and flutter free,
--------
David Gallagher
601 XL/Jabiru 3300
First flight 7/24/08
115 hours and climbing!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=269842#269842
Attachments:
http://forums.matronics.com//files/sworfi09_35_910.jpg
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Approximately 90 hrs/year. 220 in total on this airframe. The real question
is: how many of you have stopped flying the airplane because of this
"flutter" mess. The nay-sayers are of the opinion that only a few people are
flying, and they're in the majority with their decision not to fly. I don't
see anyone on ZenithAero having made that decision, and no, I don't include
those don't have a finished airplane and spend their days wringing their
hands and looking for another reason not to complete.
Message 10
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| Subject: | Re: Flying times |
Hi Roger,
I hope you are not including me in the "nay-sayers of the opinion
that only a few people are flying" but I suspect this is indeed your
interpretation. I also object to your characterization of the
problems with the Zodiac XL as "Flutter" mess. Let me try to clear
up my own position.
Flutter never was a serious likelihood to explain the XL
problems. Indeed, the problems are a considerable number of fatal
in-flight structural failures in the last few years. I don't know
the exact number of these events but I think it is somewhere between
5 and 10 worldwide.
As to the number of grounded XLs, my belief is that nobody knows the
answer to this question. There is no official registry of flights
world-wide to give a definitive answer. We all know that several
countries in Europe have grounded the XL and that one of them, the
UK, has released a long list of changes that will enable owners in
that country to resume flights. As far as I know the other countries
still have the XLs grounded.
I appreciate the idea of having list members announce their own
recent flight records. This is a haphazard way to determine how many
planes are flying vs. grounded, but it is the best one I have heard of yet.
So far I have counted around 8 owners who replied that they are still
flying their XLs. For reference, the 2008 Kitplanes lists the number
of completed and flying XLs as 950. I don't know how to interpret
these related numbers, but it does seem only a few are still
flying. Of course the number of responses is only a small percentage
of the number actually in use. This is a limited, but large, email
list of Zodiac builders and owners, and I am sure there are a number
of owners flying that have not responded. Several list members have
made it clear they are flying and have not responded to this query.
If only 10 percent of the flying Zodiac XL owners have responded and
the Kitplanes number is reasonably accurate that would suggest 90
percent of the fleet is grounded. This doesn't surprise me since the
NTSB asked for this result and indeed several countries (not
including the USA) have responded with regulatory force on the subject.
Still, I am not sure of the real numbers, and I don't even think this
really matters. My position always has been that we don't need a
consensus on this issue. It is a decision each owner should make
according to his own judgement and situation. It is only a few very
vocal folks still flying their Zodiac XLs that seem to want a
justification for their choice by citing numbers of people who agree
with them.
My own position since the NTSB letter has been, and remains, my plane
is grounded until we get a formal release of engineering changes from
Chris Heintz or one of his related companies to resolve this
problem. That change has been promised to me by Sebastian Heintz as
coming "Soon". I have no idea when his promise will be filled, but I
will wait for it. I don't know why it seems to annoy some people so
much that I have chosen this path, but apparently it does.
Paul
XL awaiting engineering changes
At 11:06 AM 10/28/2009, you wrote:
>Approximately 90 hrs/year. 220 in total on this airframe. The real
>question is: how many of you have stopped flying the airplane
>because of this "flutter" mess. The nay-sayers are of the opinion
>that only a few people are flying, and they're in the majority with
>their decision not to fly. I don't see anyone on ZenithAero having
>made that decision, and no, I don't include those don't have a
>finished airplane and spend their days wringing their hands and
>looking for another reason not to complete.
>
Message 11
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| Subject: | Re: Flying Times |
Add my 2 cents worth..672 hrs total..CH601HDS.NSI subaru
Jackie Johnson N5JZ
--- bryanmmartin@comcast.net wrote:
From: Bryan Martin <bryanmmartin@comcast.net>
Subject: Re: Zenith601-List: Flying Times
52 hours over the past twelve months out of Ray, MI.
BobbyPaulk@comcast.net wrote:
> Guys
> can we get a show of hands on who is flying and how much. i would
> have done much more except for weather and runway construction. went
> to a fly-in 100 miles away. good time, good food. indicated 125 mph
> at 5500' with a 155 mph ground speed
> hopefully we are getting better weather.
>
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
do not archive.
Message 12
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| Subject: | Re: Flying times |
Rubbish.
Karl
----- Original Message -----
From: Paul Mulwitz
To: zenith601-list@matronics.com
Sent: Wednesday, October 28, 2009 2:44 PM
Subject: Re: Zenith601-List: Flying times
Hi Roger,
I hope you are not including me in the "nay-sayers of the opinion that
only a few people are flying" but I suspect this is indeed your
interpretation. I also object to your characterization of the problems
with the Zodiac XL as "Flutter" mess. Let me try to clear up my own
position.
Flutter never was a serious likelihood to explain the XL problems.
Indeed, the problems are a considerable number of fatal in-flight
structural failures in the last few years. I don't know the exact
number of these events but I think it is somewhere between 5 and 10
worldwide.
As to the number of grounded XLs, my belief is that nobody knows the
answer to this question. There is no official registry of flights
world-wide to give a definitive answer. We all know that several
countries in Europe have grounded the XL and that one of them, the UK,
has released a long list of changes that will enable owners in that
country to resume flights. As far as I know the other countries still
have the XLs grounded.
I appreciate the idea of having list members announce their own recent
flight records. This is a haphazard way to determine how many planes
are flying vs. grounded, but it is the best one I have heard of yet.
So far I have counted around 8 owners who replied that they are still
flying their XLs. For reference, the 2008 Kitplanes lists the number of
completed and flying XLs as 950. I don't know how to interpret these
related numbers, but it does seem only a few are still flying. Of
course the number of responses is only a small percentage of the number
actually in use. This is a limited, but large, email list of Zodiac
builders and owners, and I am sure there are a number of owners flying
that have not responded. Several list members have made it clear they
are flying and have not responded to this query.
If only 10 percent of the flying Zodiac XL owners have responded and
the Kitplanes number is reasonably accurate that would suggest 90
percent of the fleet is grounded. This doesn't surprise me since the
NTSB asked for this result and indeed several countries (not including
the USA) have responded with regulatory force on the subject.
Still, I am not sure of the real numbers, and I don't even think this
really matters. My position always has been that we don't need a
consensus on this issue. It is a decision each owner should make
according to his own judgement and situation. It is only a few very
vocal folks still flying their Zodiac XLs that seem to want a
justification for their choice by citing numbers of people who agree
with them.
My own position since the NTSB letter has been, and remains, my plane
is grounded until we get a formal release of engineering changes from
Chris Heintz or one of his related companies to resolve this problem.
That change has been promised to me by Sebastian Heintz as coming
"Soon". I have no idea when his promise will be filled, but I will wait
for it. I don't know why it seems to annoy some people so much that I
have chosen this path, but apparently it does.
Paul
XL awaiting engineering changes
At 11:06 AM 10/28/2009, you wrote:
Approximately 90 hrs/year. 220 in total on this airframe. The real
question is: how many of you have stopped flying the airplane because of
this "flutter" mess. The nay-sayers are of the opinion that only a few
people are flying, and they're in the majority with their decision not
to fly. I don't see anyone on ZenithAero having made that decision, and
no, I don't include those don't have a finished airplane and spend their
days wringing their hands and looking for another reason not to
complete.
Message 13
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| Subject: | How many of you have grounded... |
...your plane because of the NTSB letter or the issues surrounding it?
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=269885#269885
Message 14
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| Subject: | Re: How many of you have grounded... |
Now THERE is the question. Nothing in this country really formally grounds an
amateur built experimental, except on a plane by plane basis.
In my view, the NTSB is too prone to respond to political pressure, and not
prone enough to find the real problems, especially with light aircraft. I
cannot accept the validity of the NTSB position (I can't call it an
analysis), and therefore went right on building. When I get done, unless
something new, and a whole lot more revealing happens, I have every intention
of flying the airplane.
I have refused to fly in aircraft with whose design/construction I had
involvement, because I thought they were unsafe. I don't have a death wish.
But I don't see anything like that in the XL.
On Wednesday 28 October 2009 15:11, Gig Giacona wrote:
>
> ...your plane because of the NTSB letter or the issues surrounding it?
>
> --------
> W.R. "Gig" Giacona
> 601XL Under Construction
> See my progress at www.peoamerica.net/N601WR
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=269885#269885
>
>
--
============================================
Do not archive.
============================================
Jim B Belcher
BS, MS Physics, Math, Computer Science
A&P/IA
Retired aerospace technical manager
Mathematics and alcohol do not mix.
Do not drink and derive.
============================================
Message 15
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Paul's right that nobody knows the actual number of "grounded" 601s, or
those "still flying." And there are some weak arguments offered which claim
some statistical backup for what one might conclude. He's also correct that
this isn't a consensus activity.
If one could gather data on a reasonable sample of people who have XLs, and
mine their experiences, then one could apply simple non-parametric
statistics and get a handle on what the likely status is.
So. I took a couple of hours and went on the Zenith.Aero site to gather what
data there might be. I went and pulled the member data from the site for all
the 601 XLs which are flying in the US. I then divided them into four
categories:
1) Those who list themselves as "flying," but there's not enough data
to put them clearly into flying or not flying (as determined by there being
no activity on the site. They registered, described themselves, but no other
data is there to conclude whether they are actually flying or not).
2) Those who are clearly flying as determined by pictures, discussions
with others, etc.
3) Those who list themselves as flying, but are explicit about keeping
themselves on the ground, or where one can reasonably infer that they are
not flying
4) Those who register as "other" and who might have changed their
listing from "flying" based on them grounding themselves.
Remember, these are only for those people who have registered on the site.
The details are below for those who want to check my math.
The results are clear: people, as a rule, are not grounding themselves. The
explanation for the continuing belief that they are grounding themselves
must be due to those who are asserting this without any data to support
their contention. In fact I wasn't able to find a single example of someone
who had voluntarily grounded themselves on the site. But we know they exist.
Paul is one. Therefore, they must represent a small slice of the
owners/operators of Xls. Essentially, statistically insignificant (yet loud
with assertions).
This invalidates a number of assertions I've seen which suggest that the
reason there are few additional episodes is probably due to the lack of
flight hours. Sorry, that suggestion is not supportable.
The most likely explanation is that people are flying within the limits of
the airplane in a reasonable, responsible manner. And, isn't that what
everyone should do at all times? Fly your airplanes and enjoy them.
----------------------------------------------------------
Here are the results:
- Total 601 XLs Flying in the US: 92
- "Flying" but indeterminate: 32
- "Flying" and flying: 60
- "Flying" but grounded: 0
- "Other" and grounded: 0
We now have sufficient data to test a number of hypotheses
---------------------------------------------------
Hypothesis 1: "90% of the fleet are voluntarily grounded"
To allow the best possibility of this, we'll assign all "Flying but
indeterminate" to the "voluntarily grounded" category.
Now we'll perform a Chi Square in the following way:
Flying:
Observed: 60 Expected: 9 (10% of 92)
Grounded:
Observed: 32 Expected: 83 (90% of
92)
Chi Square = 0.0001 Thus, this hypothesis is exceedingly unlikely,
and we reject it.
-------------------------------------------------------
Hypothesis 2: "50% of the fleet are voluntarily grounded"
Again, to allow for the reading of the data which would most support this
possibility we assign all "Flying but indeterminate" to the "voluntarily
grounded category"
Flying:
Observed: 60 Expected: 46
Grounded:
Observed: 32 Expected: 46
Chi Square = 0.0035 Thus, as before, we reject the hypothesis
-----------------------------------------------------------------
Hypothesis 3: "Everybody is flying"
Flying:
Observed: 60 Expected: 91
Grounded:
Observed: 32 Expected: 1
Chi Square = 0.0001 Thus this must be rejected too. Thus, because we
can't assign the indeterminate category, we can't make this statement
either.
It turns out the largest supportable global distribution of voluntarily
grounded aircraft turns out to be about 20% IF you assume ALL
indeterminates are voluntary groundings. This is probably not correct; thus,
one might conclude that, among the Zenith.Aero community, there are few
voluntary groundings.
I suspect that, since there were NO explicit statements of voluntary
grounding, they probably are pretty rare.
Thus, fleet-hours are being accumulated at a rate consistent with what one
would expect absent this unfortunate set of issues.
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of KARL POLIFKA
Sent: Wednesday, October 28, 2009 3:08 PM
Subject: Re: Zenith601-List: Flying times
Rubbish.
Karl
----- Original Message -----
From: Paul Mulwitz <mailto:psm@att.net>
Sent: Wednesday, October 28, 2009 2:44 PM
Subject: Re: Zenith601-List: Flying times
Hi Roger,
I hope you are not including me in the "nay-sayers of the opinion that only
a few people are flying" but I suspect this is indeed your interpretation.
I also object to your characterization of the problems with the Zodiac XL as
"Flutter" mess. Let me try to clear up my own position.
Flutter never was a serious likelihood to explain the XL problems. Indeed,
the problems are a considerable number of fatal in-flight structural
failures in the last few years. I don't know the exact number of these
events but I think it is somewhere between 5 and 10 worldwide.
As to the number of grounded XLs, my belief is that nobody knows the answer
to this question. There is no official registry of flights world-wide to
give a definitive answer. We all know that several countries in Europe have
grounded the XL and that one of them, the UK, has released a long list of
changes that will enable owners in that country to resume flights. As far
as I know the other countries still have the XLs grounded.
I appreciate the idea of having list members announce their own recent
flight records. This is a haphazard way to determine how many planes are
flying vs. grounded, but it is the best one I have heard of yet.
So far I have counted around 8 owners who replied that they are still flying
their XLs. For reference, the 2008 Kitplanes lists the number of completed
and flying XLs as 950. I don't know how to interpret these related numbers,
but it does seem only a few are still flying. Of course the number of
responses is only a small percentage of the number actually in use. This is
a limited, but large, email list of Zodiac builders and owners, and I am
sure there are a number of owners flying that have not responded. Several
list members have made it clear they are flying and have not responded to
this query.
If only 10 percent of the flying Zodiac XL owners have responded and the
Kitplanes number is reasonably accurate that would suggest 90 percent of the
fleet is grounded. This doesn't surprise me since the NTSB asked for this
result and indeed several countries (not including the USA) have responded
with regulatory force on the subject.
Still, I am not sure of the real numbers, and I don't even think this really
matters. My position always has been that we don't need a consensus on this
issue. It is a decision each owner should make according to his own
judgement and situation. It is only a few very vocal folks still flying
their Zodiac XLs that seem to want a justification for their choice by
citing numbers of people who agree with them.
My own position since the NTSB letter has been, and remains, my plane is
grounded until we get a formal release of engineering changes from Chris
Heintz or one of his related companies to resolve this problem. That change
has been promised to me by Sebastian Heintz as coming "Soon". I have no
idea when his promise will be filled, but I will wait for it. I don't know
why it seems to annoy some people so much that I have chosen this path, but
apparently it does.
Paul
XL awaiting engineering changes
At 11:06 AM 10/28/2009, you wrote:
Approximately 90 hrs/year. 220 in total on this airframe. The real question
is: how many of you have stopped flying the airplane because of this
"flutter" mess. The nay-sayers are of the opinion that only a few people are
flying, and they're in the majority with their decision not to fly. I don't
see anyone on ZenithAero having made that decision, and no, I don't include
those don't have a finished airplane and spend their days wringing their
hands and looking for another reason not to complete.
href="http://www.matronics.com/Navigator?Zenith601-List">http://www.matronic
s.com/Navigator?Zenith601-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
Message 16
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Paul's right that nobody knows the actual number of "grounded" 601s, or
those "still flying." And there are some weak arguments offered which claim
some statistical backup for what one might conclude. He's also correct that
this isn't a consensus activity.
If one could gather data on a reasonable sample of people who have XLs, and
mine their experiences, then one could apply simple non-parametric
statistics and get a handle on what the likely status is.
So. I took a couple of hours and went on the Zenith.Aero site to gather what
data there might be. I went and pulled the member data from the site for all
the 601 XLs which are flying in the US. I then divided them into four
categories:
1) Those who list themselves as "flying," but there's not enough data
to put them clearly into flying or not flying (as determined by there being
no activity on the site. They registered, described themselves, but no other
data is there to conclude whether they are actually flying or not).
2) Those who are clearly flying as determined by pictures, discussions
with others, etc.
3) Those who list themselves as flying, but are explicit about keeping
themselves on the ground, or where one can reasonably infer that they are
not flying
4) Those who register as "other" and who might have changed their
listing from "flying" based on them grounding themselves.
Remember, these are only for those people who have registered on the site.
The details are below for those who want to check my math.
The results are clear: people, as a rule, are not grounding themselves. The
explanation for the continuing belief that they are grounding themselves
must be due to those who are asserting this without any data to support
their contention. In fact I wasn't able to find a single example of someone
who had voluntarily grounded themselves on the site. But we know they exist.
Paul is one. Therefore, they must represent a small slice of the
owners/operators of Xls. Essentially, statistically insignificant (yet loud
with assertions).
This invalidates a number of assertions I've seen which suggest that the
reason there are few additional episodes is probably due to the lack of
flight hours. Sorry, that suggestion is not supportable.
The most likely explanation is that people are flying within the limits of
the airplane in a reasonable, responsible manner. And, isn't that what
everyone should do at all times? Fly your airplanes and enjoy them.
----------------------------------------------------------
Here are the results:
- Total 601 XLs Flying in the US: 92
- "Flying" but indeterminate: 32
- "Flying" and flying: 60
- "Flying" but grounded: 0
- "Other" and grounded: 0
We now have sufficient data to test a number of hypotheses
---------------------------------------------------
Hypothesis 1: "90% of the fleet are voluntarily grounded"
To allow the best possibility of this, we'll assign all "Flying but
indeterminate" to the "voluntarily grounded" category.
Now we'll perform a Chi Square in the following way:
Flying:
Observed: 60 Expected: 9 (10% of 92)
Grounded:
Observed: 32 Expected: 83 (90% of
92)
Chi Square = 0.0001 Thus, this hypothesis is exceedingly unlikely,
and we reject it.
-------------------------------------------------------
Hypothesis 2: "50% of the fleet are voluntarily grounded"
Again, to allow for the reading of the data which would most support this
possibility we assign all "Flying but indeterminate" to the "voluntarily
grounded category"
Flying:
Observed: 60 Expected: 46
Grounded:
Observed: 32 Expected: 46
Chi Square = 0.0035 Thus, as before, we reject the hypothesis
-----------------------------------------------------------------
Hypothesis 3: "Everybody is flying"
Flying:
Observed: 60 Expected: 91
Grounded:
Observed: 32 Expected: 1
Chi Square = 0.0001 Thus this must be rejected too. Thus, because we
can't assign the indeterminate category, we can't make this statement
either.
It turns out the largest supportable global distribution of voluntarily
grounded aircraft turns out to be about 20% IF you assume ALL
indeterminates are voluntary groundings. This is probably not correct; thus,
one might conclude that, among the Zenith.Aero community, there are few
voluntary groundings.
I suspect that, since there were NO explicit statements of voluntary
grounding, they probably are pretty rare.
Thus, fleet-hours are being accumulated at a rate consistent with what one
would expect absent this unfortunate set of issues.
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of KARL POLIFKA
Sent: Wednesday, October 28, 2009 3:08 PM
Subject: Re: Zenith601-List: Flying times
Rubbish.
Karl
----- Original Message -----
From: Paul Mulwitz <mailto:psm@att.net>
Sent: Wednesday, October 28, 2009 2:44 PM
Subject: Re: Zenith601-List: Flying times
Hi Roger,
I hope you are not including me in the "nay-sayers of the opinion that only
a few people are flying" but I suspect this is indeed your interpretation.
I also object to your characterization of the problems with the Zodiac XL as
"Flutter" mess. Let me try to clear up my own position.
Flutter never was a serious likelihood to explain the XL problems. Indeed,
the problems are a considerable number of fatal in-flight structural
failures in the last few years. I don't know the exact number of these
events but I think it is somewhere between 5 and 10 worldwide.
As to the number of grounded XLs, my belief is that nobody knows the answer
to this question. There is no official registry of flights world-wide to
give a definitive answer. We all know that several countries in Europe have
grounded the XL and that one of them, the UK, has released a long list of
changes that will enable owners in that country to resume flights. As far
as I know the other countries still have the XLs grounded.
I appreciate the idea of having list members announce their own recent
flight records. This is a haphazard way to determine how many planes are
flying vs. grounded, but it is the best one I have heard of yet.
So far I have counted around 8 owners who replied that they are still flying
their XLs. For reference, the 2008 Kitplanes lists the number of completed
and flying XLs as 950. I don't know how to interpret these related numbers,
but it does seem only a few are still flying. Of course the number of
responses is only a small percentage of the number actually in use. This is
a limited, but large, email list of Zodiac builders and owners, and I am
sure there are a number of owners flying that have not responded. Several
list members have made it clear they are flying and have not responded to
this query.
If only 10 percent of the flying Zodiac XL owners have responded and the
Kitplanes number is reasonably accurate that would suggest 90 percent of the
fleet is grounded. This doesn't surprise me since the NTSB asked for this
result and indeed several countries (not including the USA) have responded
with regulatory force on the subject.
Still, I am not sure of the real numbers, and I don't even think this really
matters. My position always has been that we don't need a consensus on this
issue. It is a decision each owner should make according to his own
judgement and situation. It is only a few very vocal folks still flying
their Zodiac XLs that seem to want a justification for their choice by
citing numbers of people who agree with them.
My own position since the NTSB letter has been, and remains, my plane is
grounded until we get a formal release of engineering changes from Chris
Heintz or one of his related companies to resolve this problem. That change
has been promised to me by Sebastian Heintz as coming "Soon". I have no
idea when his promise will be filled, but I will wait for it. I don't know
why it seems to annoy some people so much that I have chosen this path, but
apparently it does.
Paul
XL awaiting engineering changes
At 11:06 AM 10/28/2009, you wrote:
Approximately 90 hrs/year. 220 in total on this airframe. The real question
is: how many of you have stopped flying the airplane because of this
"flutter" mess. The nay-sayers are of the opinion that only a few people are
flying, and they're in the majority with their decision not to fly. I don't
see anyone on ZenithAero having made that decision, and no, I don't include
those don't have a finished airplane and spend their days wringing their
hands and looking for another reason not to complete.
href="http://www.matronics.com/Navigator?Zenith601-List">http://www.matronic
s.com/Navigator?Zenith601-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
Message 17
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| Subject: | Re: Flying times |
Ouch Doug, you've hurt my brain! Thanks anyway.=0ATerry=0A=0A=0A=0A=0A____
____________________________=0AFrom: Doug - SportAviation <Doug.Norman@spor
taviation.aero>=0ATo: zenith601-list@matronics.com=0ASent: Wed, October 28,
2009 4:36:05 PM=0ASubject: RE: Zenith601-List: Flying times=0A=0A =0APaul
=99s right that nobody knows the actual number of =9Cgrounded
=9D=0A601s, or those =9Cstill flying.=9D And there are so
me weak arguments=0Aoffered which claim some statistical backup for what on
e might conclude. He=99s=0Aalso correct that this isn=99t a con
sensus activity. =0A =0AIf one could gather data on a reasonable sample of
people who have=0AXLs, and mine their experiences, then one could apply sim
ple non-parametric statistics=0Aand get a handle on what the likely status
is.=0A =0ASo I took a couple of hours and went on the Zenith.Aero
=0Asite to gather what data there might be. I went and pulled the member da
ta from=0Athe site for all the 601 XLs which are flying in the US. I then d
ivided them=0Ainto four categories: =0A1) Those who list themselves as
=9Cflying,=9D but there=99s=0Anot enough data to put the
m clearly into flying or not flying (as determined by=0Athere being no acti
vity on the site. They registered, described themselves, but=0Ano other dat
a is there to conclude whether they are actually flying or not).=0A2)
Those who are clearly flying as determined by pictures,=0Adiscussions with
others, etc.=0A3) Those who list themselves as flying, but are explici
t about=0Akeeping themselves on the ground, or where one can reasonably inf
er that they=0Aare not flying=0A4) Those who register as =9Cothe
r=9D and who might have=0Achanged their listing from =9Cflying
=9D based on them grounding=0Athemselves.=0A =0ARemember, these are o
nly for those people who have registered on=0Athe site. The details are bel
ow for those who want to check my math.=0A =0AThe results are clear: people
, as a rule, are not grounding=0Athemselves. The explanation for the contin
uing belief that they are grounding=0Athemselves must be due to those who a
re asserting this without any data to=0Asupport their contention. In fact I
wasn=99t able to find a single example=0Aof someone who had voluntar
ily grounded themselves on the site. But we know=0Athey exist. Paul is one.
Therefore, they must represent a small slice of the=0Aowners/operators of
Xls. Essentially, statistically insignificant (yet loud=0Awith assertions).
=0A =0AThis invalidates a number of assertions I=99ve seen which=0Asu
ggest that the reason there are few additional episodes is probably due to
=0Athe lack of flight hours. Sorry, that suggestion is not supportable.=0A
=0AThe most likely explanation is that people are flying within the=0Alimit
s of the airplane in a reasonable, responsible manner. And, isn=99t
=0Athat what everyone should do at all times? Fly your airplanes and enjoy
them.=0A =0A----------------------------------------------------------=0AHe
re are the results:=0A =0A- Total 601 XLs Flying in the US: 92
=0A- =9CFlying=9D but indeterminate: 32=0A-
=9CFlying=9D and flying: 60=0A-
=9CFlying=9D but grounded: =0A0=0A-
=9COther=9D and grounded: 0=0A =0AWe
now have sufficient data to test a number of hypotheses=0A-----------------
----------------------------------=0AHypothesis 1: =9C90% of the flee
t are voluntarily grounded=9D=0A =0ATo allow the best possibility of
this, we=99ll assign all =9CFlying=0Abut indeterminate=9D
to the =9Cvoluntarily grounded=9D category.=0ANow we=99l
l perform a Chi Square in the following way:=0A Flying: =0AO
bserved:=0A60 Expected: 9 (10%=0Aof 92)=0A Ground
ed:=0A Observed:=0A32 Expected: 83 (
90% of 92)=0A =0AChi Square = 0.0001 Thus,=0Athis hypothesis is e
xceedingly unlikely, and we reject it.=0A----------------------------------
---------------------=0A =0AHypothesis 2: =9C50% of the fleet are vol
untarily grounded=9D=0A =0AAgain, to allow for the reading of the dat
a which would most=0Asupport this possibility we assign all =9CFlying
but indeterminate=9D=0Ato the =9Cvoluntarily grounded category
=9D=0A =0A Flying:=0A O
bserved:=0A60 Expected: 46=0A Grounded:=0A
Observed:=0A32 Expected: 46=0A =0AChi Square = 0.00
35 Thus,=0Aas before, we reject the hypothesis=0A------------------
-----------------------------------------------=0A =0AHypothesis 3:
=9CEverybody is flying=9D=0A =0A Flying:=0A
Observed:=0A60 Expected: 91=0A Grou
nded:=0A Observed:=0A32 Expected: 1=0A
=0AChi Square = 0.0001 Thus=0Athis must be rejected too. Thus, be
cause we can=99t assign the indeterminate=0Acategory, we can=99
t make this statement either.=0A =0AIt turns out the largest
supportable global distribution of voluntarily=0Agrounded aircraft turns
out to be about 20% IF you assume ALL=0Aindeterminates are voluntary ground
ings. This is probably not correct; thus,=0Aone might conclude that, among
the Zenith.Aero community, there are few=0Avoluntary groundings. =0A =0AI s
uspect that, since there were NO explicit statements of=0Avoluntary groundi
ng, they probably are pretty rare.=0A =0AThus, fleet-hours are being accumu
lated at a rate consistent=0Awith what one would expect absent this unfortu
nate set of issues. =0A =0AFrom:owner-zenith601-list-server@matronics.com
=0A[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of KARL=0AP
OLIFKA=0ASent: Wednesday, October 28, 2009 3:08 PM=0ATo: zenith601-list@mat
ronics.com=0ASubject: Re: Zenith601-List: Flying times=0A =0ARubbish.=0A
=0AKarl=0A>=0A>>=0A>-----=0A>Original Message ----- =0A>>=0A>From:Paul Mulw
itz =0A>>=0A>To:zenith601-list@matronics.com =0A>>=0A>Sent:Wednesday, Octob
er=0A>28, 2009 2:44 PM=0A>>=0A>Subject:Re: Zenith601-List:=0A>Flying times
=0A>>=0A> =0A>Hi Roger,=0A>=0A>>I hope you are not including me in the "nay
-sayers of the opinion that=0A>only a few people are flying" but I suspect
this is indeed your=0A>interpretation. I also object to your characterizat
ion of the problems=0A>with the Zodiac XL as "Flutter" mess. Let me try to
clear up my=0A>own position.=0A>=0A>>Flutter never was a serious likelihoo
d to explain the XL problems. =0A>Indeed, the problems are a considerable n
umber of fatal in-flight structural=0A>failures in the last few years. I d
on't know the exact number of these=0A>events but I think it is somewhere b
etween 5 and 10 worldwide.=0A>=0A>>As to the number of grounded XLs, my bel
ief is that nobody knows the answer to=0A>this question. There is no offic
ial registry of flights world-wide to=0A>give a definitive answer. We all
know that several countries in Europe=0A>have grounded the XL and that one
of them, the UK, has released a long list of=0A>changes that will enable ow
ners in that country to resume flights. As far=0A>as I know the other coun
tries still have the XLs grounded.=0A>=0A>>I appreciate the idea of having
list members announce their own recent flight=0A>records. This is a haphaz
ard way to determine how many planes are flying=0A>vs. grounded, but it is
the best one I have heard of yet.=0A>=0A>>So far I have counted around 8 ow
ners who replied that they are still flying=0A>their XLs. For reference, t
he 2008 Kitplanes lists the number of=0A>completed and flying XLs as 950.
I don't know how to interpret these=0A>related numbers, but it does seem on
ly a few are still flying. Of course=0A>the number of responses is only a
small percentage of the number actually in=0A>use. This is a limited, but
large, email list of Zodiac builders and=0A>owners, and I am sure there are
a number of owners flying that have not=0A>responded. Several list member
s have made it clear they are flying and=0A>have not responded to this quer
y.=0A>=0A>>If only 10 percent of the flying Zodiac XL owners have responded
and the=0A>Kitplanes number is reasonably accurate that would suggest 90 p
ercent of the=0A>fleet is grounded. This doesn't surprise me since the NTS
B asked for this=0A>result and indeed several countries (not including the
USA) have responded with=0A>regulatory force on the subject. =0A>=0A>>Stil
l, I am not sure of the real numbers, and I don't even think this really=0A
>matters. My position always has been that we don't need a consensus on=0A
>this issue. It is a decision each owner should make according to his own
=0A>judgement and situation. It is only a few very vocal folks still flyin
g=0A>their Zodiac XLs that seem to want a justification for their choice by
citing=0A>numbers of people who agree with them. =0A>=0A>>My own position
since the NTSB letter has been, and remains, my plane is=0A>grounded until
we get a formal release of engineering changes from Chris Heintz=0A>or one
of his related companies to resolve this problem. That change has=0A>been
promised to me by Sebastian Heintz as coming "Soon". I=0A>have no idea wh
en his promise will be filled, but I will wait for it. I=0A>don't know why
it seems to annoy some people so much that I have chosen this=0A>path, but
apparently it does.=0A>=0A>>Paul=0A>>XL awaiting engineering changes=0A>
=0A>=0A>>At 11:06 AM 10/28/2009, you wrote:=0A>=0A>=0A>=0A>Approximately 90
hrs/year. 220 in total on this airframe.=0A>The real question is: how many
of you have stopped flying the airplane because=0A>of this "flutter" mess.
The nay-sayers are of the opinion that only a=0A>few people are flying, an
d they're in the majority with their decision not to=0A>fly. I don't see a
nyone on ZenithAero having made that decision, and no,=0A>I don't include t
hose don't have a finished airplane and spend their days=0A>wringing their
hands and looking for another reason not to complete. =0A> =0A> =0A> =0A>
=0A>href="http://www.matronics.com/Navigator?Zenith601-List">http://www
.matronics.com/Navigator?Zenith601-List=0A>href="http://forums.matronics.
com">http://forums.matronics.com=0A>href="http://www.matronics.com/contri
bution">http://www.matronics.com/c=0A =0A =0Ahttp://www.matronics.com/Nav
igator?Zenith601-List=0Ahttp://forums.matronics.com=0Ahttp://www.matronics.
===0A=0A=0A
Message 18
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| Subject: | Re: Flying times |
Very erudite and thought provoking. This is about what common sense would
suggest.
On Wednesday 28 October 2009 16:36, Doug - SportAviation wrote:
> Paul's right that nobody knows the actual number of "grounded" 601s, or
> those "still flying." And there are some weak arguments offered which claim
> some statistical backup for what one might conclude. He's also correct that
> this isn't a consensus activity.
>
>
> If one could gather data on a reasonable sample of people who have XLs, and
> mine their experiences, then one could apply simple non-parametric
> statistics and get a handle on what the likely status is.
>
>
> So. I took a couple of hours and went on the Zenith.Aero site to gather
> what data there might be. I went and pulled the member data from the site
> for all the 601 XLs which are flying in the US. I then divided them into
> four categories:
>
> 1) Those who list themselves as "flying," but there's not enough data
> to put them clearly into flying or not flying (as determined by there being
> no activity on the site. They registered, described themselves, but no
> other data is there to conclude whether they are actually flying or not).
>
> 2) Those who are clearly flying as determined by pictures, discussions
> with others, etc.
>
> 3) Those who list themselves as flying, but are explicit about keeping
> themselves on the ground, or where one can reasonably infer that they are
> not flying
>
> 4) Those who register as "other" and who might have changed their
> listing from "flying" based on them grounding themselves.
>
>
> Remember, these are only for those people who have registered on the site.
> The details are below for those who want to check my math.
>
>
> The results are clear: people, as a rule, are not grounding themselves. The
> explanation for the continuing belief that they are grounding themselves
> must be due to those who are asserting this without any data to support
> their contention. In fact I wasn't able to find a single example of someone
> who had voluntarily grounded themselves on the site. But we know they
> exist. Paul is one. Therefore, they must represent a small slice of the
> owners/operators of Xls. Essentially, statistically insignificant (yet loud
> with assertions).
>
>
> This invalidates a number of assertions I've seen which suggest that the
> reason there are few additional episodes is probably due to the lack of
> flight hours. Sorry, that suggestion is not supportable.
>
>
> The most likely explanation is that people are flying within the limits of
> the airplane in a reasonable, responsible manner. And, isn't that what
> everyone should do at all times? Fly your airplanes and enjoy them.
>
>
> ----------------------------------------------------------
>
> Here are the results:
>
>
> - Total 601 XLs Flying in the US: 92
>
> - "Flying" but indeterminate: 32
>
> - "Flying" and flying: 60
>
> - "Flying" but grounded: 0
>
> - "Other" and grounded: 0
>
>
> We now have sufficient data to test a number of hypotheses
>
> ---------------------------------------------------
>
> Hypothesis 1: "90% of the fleet are voluntarily grounded"
>
>
> To allow the best possibility of this, we'll assign all "Flying but
> indeterminate" to the "voluntarily grounded" category.
>
> Now we'll perform a Chi Square in the following way:
>
> Flying:
>
> Observed: 60 Expected: 9 (10% of 92)
>
> Grounded:
>
> Observed: 32 Expected: 83 (90% of
> 92)
>
>
> Chi Square = 0.0001 Thus, this hypothesis is exceedingly unlikely,
> and we reject it.
>
> -------------------------------------------------------
>
>
> Hypothesis 2: "50% of the fleet are voluntarily grounded"
>
>
> Again, to allow for the reading of the data which would most support this
> possibility we assign all "Flying but indeterminate" to the "voluntarily
> grounded category"
>
>
> Flying:
>
> Observed: 60 Expected: 46
>
> Grounded:
>
> Observed: 32 Expected: 46
>
>
> Chi Square = 0.0035 Thus, as before, we reject the hypothesis
>
> -----------------------------------------------------------------
>
>
> Hypothesis 3: "Everybody is flying"
>
>
> Flying:
>
> Observed: 60 Expected: 91
>
> Grounded:
>
> Observed: 32 Expected: 1
>
>
> Chi Square = 0.0001 Thus this must be rejected too. Thus, because
> we can't assign the indeterminate category, we can't make this statement
> either.
>
>
> It turns out the largest supportable global distribution of voluntarily
> grounded aircraft turns out to be about 20% IF you assume ALL
> indeterminates are voluntary groundings. This is probably not correct;
> thus, one might conclude that, among the Zenith.Aero community, there are
> few voluntary groundings.
>
>
> I suspect that, since there were NO explicit statements of voluntary
> grounding, they probably are pretty rare.
>
>
> Thus, fleet-hours are being accumulated at a rate consistent with what one
> would expect absent this unfortunate set of issues.
>
>
> From: owner-zenith601-list-server@matronics.com
> [mailto:owner-zenith601-list-server@matronics.com] On Behalf Of KARL
> POLIFKA Sent: Wednesday, October 28, 2009 3:08 PM
> To: zenith601-list@matronics.com
> Subject: Re: Zenith601-List: Flying times
>
>
> Rubbish.
>
>
> Karl
>
> ----- Original Message -----
>
> From: Paul Mulwitz <mailto:psm@att.net>
>
> To: zenith601-list@matronics.com
>
> Sent: Wednesday, October 28, 2009 2:44 PM
>
> Subject: Re: Zenith601-List: Flying times
>
>
> Hi Roger,
>
> I hope you are not including me in the "nay-sayers of the opinion that only
> a few people are flying" but I suspect this is indeed your interpretation.
> I also object to your characterization of the problems with the Zodiac XL
> as "Flutter" mess. Let me try to clear up my own position.
>
> Flutter never was a serious likelihood to explain the XL problems. Indeed,
> the problems are a considerable number of fatal in-flight structural
> failures in the last few years. I don't know the exact number of these
> events but I think it is somewhere between 5 and 10 worldwide.
>
> As to the number of grounded XLs, my belief is that nobody knows the answer
> to this question. There is no official registry of flights world-wide to
> give a definitive answer. We all know that several countries in Europe
> have grounded the XL and that one of them, the UK, has released a long list
> of changes that will enable owners in that country to resume flights. As
> far as I know the other countries still have the XLs grounded.
>
> I appreciate the idea of having list members announce their own recent
> flight records. This is a haphazard way to determine how many planes are
> flying vs. grounded, but it is the best one I have heard of yet.
>
> So far I have counted around 8 owners who replied that they are still
> flying their XLs. For reference, the 2008 Kitplanes lists the number of
> completed and flying XLs as 950. I don't know how to interpret these
> related numbers, but it does seem only a few are still flying. Of course
> the number of responses is only a small percentage of the number actually
> in use. This is a limited, but large, email list of Zodiac builders and
> owners, and I am sure there are a number of owners flying that have not
> responded. Several list members have made it clear they are flying and
> have not responded to this query.
>
> If only 10 percent of the flying Zodiac XL owners have responded and the
> Kitplanes number is reasonably accurate that would suggest 90 percent of
> the fleet is grounded. This doesn't surprise me since the NTSB asked for
> this result and indeed several countries (not including the USA) have
> responded with regulatory force on the subject.
>
> Still, I am not sure of the real numbers, and I don't even think this
> really matters. My position always has been that we don't need a consensus
> on this issue. It is a decision each owner should make according to his
> own judgement and situation. It is only a few very vocal folks still
> flying their Zodiac XLs that seem to want a justification for their choice
> by citing numbers of people who agree with them.
>
> My own position since the NTSB letter has been, and remains, my plane is
> grounded until we get a formal release of engineering changes from Chris
> Heintz or one of his related companies to resolve this problem. That
> change has been promised to me by Sebastian Heintz as coming "Soon". I
> have no idea when his promise will be filled, but I will wait for it. I
> don't know why it seems to annoy some people so much that I have chosen
> this path, but apparently it does.
>
> Paul
> XL awaiting engineering changes
>
>
> At 11:06 AM 10/28/2009, you wrote:
>
>
> Approximately 90 hrs/year. 220 in total on this airframe. The real question
> is: how many of you have stopped flying the airplane because of this
> "flutter" mess. The nay-sayers are of the opinion that only a few people
> are flying, and they're in the majority with their decision not to fly. I
> don't see anyone on ZenithAero having made that decision, and no, I don't
> include those don't have a finished airplane and spend their days wringing
> their hands and looking for another reason not to complete.
>
>
> href="http://www.matronics.com/Navigator?Zenith601-List">http://www.matroni
>c s.com/Navigator?Zenith601-List
> href="http://forums.matronics.com">http://forums.matronics.com
> href="http://www.matronics.com/contribution">http://www.matronics.com/c
--
============================================
Do not archive.
============================================
Jim B Belcher
BS, MS Physics, Math, Computer Science
A&P/IA
Retired aerospace technical manager
Mathematics and alcohol do not mix.
Do not drink and derive.
============================================
Message 19
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| Subject: | Re: Flying Times |
I've been flying almost every week (spring, summer, fall and winter)
since May 2007. Longest down time was three and a half weeks do to
weather.
Randy
601xl
360hrs since May 2007
----- Original Message -----
From: BobbyPaulk@comcast.net
To: zenith601-list-digest@matronics.com
Sent: Wednesday, October 28, 2009 8:50 AM
Subject: Zenith601-List: Flying Times
Guys
can we get a show of hands on who is flying and how much. i would have
done much more except for weather and runway construction. went to a
fly-in 100 miles away. good time, good food. indicated 125 mph at 5500'
with a 155 mph ground speed
hopefully we are getting better weather.
N131BP
601 XL E-AB
14hrs since June
Message 20
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| Subject: | How Many of You Have Grounded... |
I grounded my plane from April 16th to April 24th. After reading the
NTSB report thoroughly, I did some reading of the accident reports
online. I decided for myself that the conclusions in the NTSB report
were not supported by enough probative evidence and corroboration from
the actual accident reports to keep my Zodiac XL grounded. I have flown
my airplane ever since.
I would love to see all the NTSB files on these accidents to look at
site investigation photos and the notes of the investigators.
I inform prospective passengers of the NTSB report and offer a copy to
them before they fly with me. Usually they decline the report and ask
"what does it say?" I tell them my reading and conclusions and why I
fly my airplane. So far no one has declined to fly with me. My social
friends know me as cautious. I won't bungy jump and I won't ride
rollercoasters. So I guess they trust my judgment and cautious nature.
Some of my flying friends who own other makes and models of experimental
airplanes have volunteered their unsolicited thoughts. But, they all
sincerely wish me well and safe flying. Those around my hanger flying
certified aircraft are just curious and really don't know an issue
exists with my airplane make and model.
I do a really thorough pre-flight and follow the recommendations of
Chris Heintz.
As time goes by, and I continue to observe many (not just a few) Zodiacs
flying without incident, it is hard for me to accept that a problem
exists without pilot error as the primary and significant cause.
Therefore, I fly and hope my piloting skills are up to snuff.
Brad DeMeo
N601BD
2008 Zodiac XL (QBK)
Message 21
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| Subject: | Re: Flying Times |
N493TG: 601XL (ser 6-5342)/Jab3300;
first flight Jul 05
540 hrs;
1210 landings; (231 landings on rough, short farm strip) - now "based"
on my farm
4 annual condition inspections
Easy to fly. Lots of fun, inexpensive (relativity speaking) flying.
(NO, I do not plan to balance my ailerons - modal surveys and flight
testings for flutter, and my own flight testing has convinced me there
is no flutter problem within the flight envelop. YES - I do believe you
can fail the wings with the wing removal device found on the XL and on
all airplanes, sometimes called the "stick" and on others the "yoke".)
Tony Graziano
Buchanan, Tn
Message 22
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| Subject: | Re: Jabiru USA 3300 engine mount NOT to Specs |
I purchased a damaged 601xl earlier this year from a insurance company and have
been repairing it for the last couple of months. It had suffered a bent nose
gear also on one of it's first taxi test. It looked exactly like yours. The
top of the firewall did not bend any, and the bottom was pushed back about 4
inches. The good thing is that the damage was contained to the firewall, cabin
floor, engine mount, oil cooler, muffler and cowl. It did not get back into
the wing spar carry through. It was fairly easy to fix the airframe. On my
plane the nose gear was bent straight backward and up into the cabin floor.
My engine mount was bent also. I also found that it the 2 lower bars were built
from .035 and not .058. I called and e-mailed the Zenith print to Jabiru USA.
They informed me that they used .035 tubing for the entire mount. I also
talked with Pete at the Zenith Fly-in this year and he confirmed that the built
their mounts out of all .035. I replaced the 2 lower bars with .058 as the
Zenith print called for. He also told me that there had been several prop strikes
on the 3300, and all the engines where ok. He did say to be sure to replace
the flywheel bolts as well as the bolts that hold the crank extension/prop
adaptor to the crankshaft. The muffler is expensive, but it only takes a couple
of hours to make a new "Skin" for it.
I almost have my plane back ready to fly.
--------
Mike
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Message 23
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| Subject: | Re: Flying Times |
What Randy are you? Are you my Pal Randy Stout of San Antonio? Are you
Randy, Las vegas? No wait that's me. Are you another Randy? Need to
add an identifyer here.
Regards,
Randy, Las Vegas
----- Original Message -----
From: Randy
To: zenith601-list@matronics.com
Sent: Wednesday, October 28, 2009 4:49 PM
Subject: Re: Zenith601-List: Flying Times
I've been flying almost every week (spring, summer, fall and winter)
since May 2007. Longest down time was three and a half weeks do to
weather.
Randy
601xl
360hrs since May 2007
Message 24
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| Subject: | Re: Nose wheel fork failure |
Here's a question for the structural engineers out there,what affect did the wrong
wall thickness[.035" instead of .058" ] of the engine mount have on allowing
the two lower mounting points to move towards the middle to accommodate the
the crushing of the firewall and lower bearing support structure as the nose
wheel tube moved back due to the loads.The thin wall tube no.6-7 bent forward
[the triangle piece] Cheers T87
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