Today's Message Index:
----------------------
1. 03:24 AM - Re: More left horiZ (Jorgen Nielsen)
2. 06:46 AM - The REST of the story. (Roger Baker)
3. 09:20 AM - Re: More left horiZ (Walter Lannon)
4. 12:37 PM - Re: More left horiZ (Gpw678@aol.com)
5. 12:48 PM - Re: More left horiZ (Jan Mevis)
6. 01:06 PM - Weight & Balance Procedure (JOffice@aol.com)
7. 01:33 PM - Re: More left horiZ (Roger Kemp M.D.)
8. 01:34 PM - Re: More left horiZ (A. Dennis Savarese)
9. 01:38 PM - Re: Weight & Balance Procedure (A. Dennis Savarese)
10. 08:35 PM - Re: More left horiZ (cjpilot710@aol.com)
Message 1
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OK here goes - just got off the phone with the owner of the Yak that got
chopped up.
The other Yak pilot (that ran into the parked Yak) had a air low problem
before startup. They then handpropped the aircraft. There was apparently
enough air to taxi / brake. During the taxi the air obviously got depleted
faster than it was being replenished, and suddenly brakes did not work, and
she ran into the yak in front.
The mags were not switched off before impact. The emergency air for
gear/brakes was not deployed.
My analysis:
Contributing factors - low time on the Yak.
Seeming lack of familiarity of the systems.
Formo training environment probably contributed (i.e. looking at other
aircraft instead of keeping a beady eye on the air pressure gauge during
taxi).
This incident could have been avoided if:
1. the pilot had charged the air system on the ground
2. the pilot had waited for air pressure to rise substantially before taxi.
3. the pilot had monitored the air pressure.
4. the pilot deployed emergency air
5. the pilot turned the engine off.
Bottom line. Know your aircraft and systems, follow the procedures, and do
not get pressured into flying if things are not 100%.
Jorgen
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Baker
Sent: 11 May 2007 11:37 PM
Subject: Yak-List: More left horiZ
Thank guys for your comments.
However, I was trying to get someone who actually knows what
happened to CAUSE this particular accident....which did happen in
Durban, South Africa on April 22nd. It did happen in the run up area
while involved in some kind of formation activity.
I thought it would be educational if one of the folks from South
Africa with FACTUAL FIRST HAND knowledge were to post a debriefing
here on the list. Several days ago, I did ask, on the list, if
anyone from SA could update us on the list about this
collision...but, so far, no response. This lists main value is its'
ability to disseminate real world operational information. And this
might be a prime example of that ability.
We all know that a Yak 52 can be started and, depending on the
individual airplanes' air system, taxiied for some distance before it
becomes obvious that one can neither steer nor stop...because the
main air valve is not on.
I can tell you from personal experience that this is a bit of a
queezy feeling. Fortunately, the only thing in front of me was a
fence which was far enough away that I had time to get the air on and
turn before "spending a lot of money real fast" or worse. Some of
our fellow "listers" have not been so lucky.
So, from the photos....it appears obvious that the dark colored
airplane's prop did hit the silver airplanes' left horizontal
stabilizer and elevator. It appears that only one prop blade may be
damaged on the dark airplane...leading me to speculate that perhaps
the pilot of the dark airplane might have switched off his mags after
discovering that he couldn't stop or steer...but, just a bit too late
to avoid the silver airplane.
The above paragraph is just speculation, of course. But it is
speculation based on an incident that occurred only a year or so ago
involving our local area formation group...also in the run-up area.
That incident did not involve any damage, fortunately....but only
because when the "air off" airplane discovered he couldn't stop or
steer, he was pointed just enough to the side that he just sort of
"drifted" past me (and the rest of the formation) with his prop
stopped and a helpless look on his face. Fortunately, as he left the
paved area...he rolled onto quite level ground and coasted to a
stop....turned the air on, restarted the engine, and rejoined the
formation a bit the wiser (as were all of us who witnessed to event).
Enough of my what ifs. South Aftican Yak folks....what happened to
cause this incident?
Thanks,
Roger
Message 2
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| Subject: | The REST of the story. |
Hi Jorgen,
Thanks for getting the real story. It is an incident from
which we all can learn something.
Knowing the actual cause is much better than having to
speculate about what went on. Thanks for your effort and time.
Roger___________________________________________________________________
__________________
On May 12, 2007, at 3:19 AM, Jorgen Nielsen wrote:
> <jorgen.nielsen@mweb.co.za>
>
> OK here goes - just got off the phone with the owner of the Yak
> that got
> chopped up.
>
> The other Yak pilot (that ran into the parked Yak) had a air low
> problem
> before startup. They then handpropped the aircraft. There was
> apparently
> enough air to taxi / brake. During the taxi the air obviously got
> depleted
> faster than it was being replenished, and suddenly brakes did not
> work, and
> she ran into the yak in front.
>
> The mags were not switched off before impact. The emergency air for
> gear/brakes was not deployed.
>
> My analysis:
> Contributing factors - low time on the Yak.
> Seeming lack of familiarity of the systems.
> Formo training environment probably contributed (i.e. looking at other
> aircraft instead of keeping a beady eye on the air pressure gauge
> during
> taxi).
>
> This incident could have been avoided if:
> 1. the pilot had charged the air system on the ground
> 2. the pilot had waited for air pressure to rise substantially
> before taxi.
> 3. the pilot had monitored the air pressure.
> 4. the pilot deployed emergency air
> 5. the pilot turned the engine off.
>
> Bottom line. Know your aircraft and systems, follow the
> procedures, and do
> not get pressured into flying if things are not 100%.
>
> Jorgen
Message 3
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| Subject: | Re: More left horiZ |
Jorgen;
Very good analysis. If I may I would add one more
to the could have been avoided list. Ground operation of the aircraft is an
individual task. Formation begins after positioning for takeoff.
Walt
----- Original Message -----
From: "Jorgen Nielsen" <jorgen.nielsen@mweb.co.za>
Sent: Saturday, May 12, 2007 3:19 AM
Subject: RE: Yak-List: More left horiZ
> <jorgen.nielsen@mweb.co.za>
>
> OK here goes - just got off the phone with the owner of the Yak that got
> chopped up.
>
> The other Yak pilot (that ran into the parked Yak) had a air low problem
> before startup. They then handpropped the aircraft. There was apparently
> enough air to taxi / brake. During the taxi the air obviously got
> depleted
> faster than it was being replenished, and suddenly brakes did not work,
> and
> she ran into the yak in front.
>
> The mags were not switched off before impact. The emergency air for
> gear/brakes was not deployed.
>
> My analysis:
> Contributing factors - low time on the Yak.
> Seeming lack of familiarity of the systems.
> Formo training environment probably contributed (i.e. looking at other
> aircraft instead of keeping a beady eye on the air pressure gauge during
> taxi).
>
> This incident could have been avoided if:
> 1. the pilot had charged the air system on the ground
> 2. the pilot had waited for air pressure to rise substantially before
> taxi.
> 3. the pilot had monitored the air pressure.
> 4. the pilot deployed emergency air
> 5. the pilot turned the engine off.
>
> Bottom line. Know your aircraft and systems, follow the procedures, and
> do
> not get pressured into flying if things are not 100%.
>
> Jorgen
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Baker
> Sent: 11 May 2007 11:37 PM
> To: Yak List
> Subject: Yak-List: More left horiZ
>
>
> Thank guys for your comments.
>
> However, I was trying to get someone who actually knows what
> happened to CAUSE this particular accident....which did happen in
> Durban, South Africa on April 22nd. It did happen in the run up area
> while involved in some kind of formation activity.
>
> I thought it would be educational if one of the folks from South
> Africa with FACTUAL FIRST HAND knowledge were to post a debriefing
> here on the list. Several days ago, I did ask, on the list, if
> anyone from SA could update us on the list about this
> collision...but, so far, no response. This lists main value is its'
> ability to disseminate real world operational information. And this
> might be a prime example of that ability.
>
> We all know that a Yak 52 can be started and, depending on the
> individual airplanes' air system, taxiied for some distance before it
> becomes obvious that one can neither steer nor stop...because the
> main air valve is not on.
>
> I can tell you from personal experience that this is a bit of a
> queezy feeling. Fortunately, the only thing in front of me was a
> fence which was far enough away that I had time to get the air on and
> turn before "spending a lot of money real fast" or worse. Some of
> our fellow "listers" have not been so lucky.
>
> So, from the photos....it appears obvious that the dark colored
> airplane's prop did hit the silver airplanes' left horizontal
> stabilizer and elevator. It appears that only one prop blade may be
> damaged on the dark airplane...leading me to speculate that perhaps
> the pilot of the dark airplane might have switched off his mags after
> discovering that he couldn't stop or steer...but, just a bit too late
> to avoid the silver airplane.
>
> The above paragraph is just speculation, of course. But it is
> speculation based on an incident that occurred only a year or so ago
> involving our local area formation group...also in the run-up area.
> That incident did not involve any damage, fortunately....but only
> because when the "air off" airplane discovered he couldn't stop or
> steer, he was pointed just enough to the side that he just sort of
> "drifted" past me (and the rest of the formation) with his prop
> stopped and a helpless look on his face. Fortunately, as he left the
> paved area...he rolled onto quite level ground and coasted to a
> stop....turned the air on, restarted the engine, and rejoined the
> formation a bit the wiser (as were all of us who witnessed to event).
>
> Enough of my what ifs. South Aftican Yak folks....what happened to
> cause this incident?
>
> Thanks,
>
> Roger
>
>
>
Message 4
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| Subject: | Re: More left horiZ |
ok, first hand. ( I was there)
Enough spec, yes all of the above, however, there was a small prob with the
mentioned aircraft. the main Problem was that the "snot" Valve was turned
(due to a spring malfunction) a further 180 degrees and this then lead to a
pressure depleation.that then lead to a brake failure.
If you do not know exactly what happened, then please remain quiet untill
you do. You can speculate as much as you like like, but do not become the AAIB
untill you have all the facts!!!
it was unfortunate and was dealt with as best as could in the situation.
if you can contribute anything constructive, please let us know.
thanks
Message 5
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Sorry, but I don't understand how an open snot valve can cause a depletion
of the system, unless of course it was already as good as empty ?
Jan Mevis
RA2005K
YK50
_____
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Gpw678@aol.com
Sent: zaterdag 12 mei 2007 21:37
Subject: Re: Yak-List: More left horiZ
ok, first hand. ( I was there)
Enough spec, yes all of the above, however, there was a small prob with the
mentioned aircraft. the main Problem was that the "snot" Valve was turned
(due to a spring malfunction) a further 180 degrees and this then lead to a
pressure depleation.that then lead to a brake failure.
If you do not know exactly what happened, then please remain quiet untill
you do. You can speculate as much as you like like, but do not become the
AAIB untill you have all the facts!!!
it was unfortunate and was dealt with as best as could in the situation.
if you can contribute anything constructive, please let us know.
thanks
Message 6
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| Subject: | Weight & Balance Procedure |
Does anyone have a detailed description of the procedure for determining new
weight & balance for a standard YAK-52? N124FS has undergone enough
modification, paint, and fabric over the years to warrent a new set of numbers...
Any comments or assistance would be appreciated, as our local shop (with nice
electronic scales) will be completely lost on the levelling procedure...
Thanks-
Jon Lowrey
************************************** See what's free at http://www.aol.com.
Message 7
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If that is the case, then everytime you opened your snot valve you would
deplet the system not just blow off the pressurized oily condensation. You
need to look at the check valve proximal to the snot bottle. At least that
is the humble opinion of or YAK geru, Dennis Savarese, here in Al.
Good luck,
Doc
_____
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Gpw678@aol.com
Sent: Saturday, May 12, 2007 2:37 PM
Subject: Re: Yak-List: More left horiZ
ok, first hand. ( I was there)
Enough spec, yes all of the above, however, there was a small prob with the
mentioned aircraft. the main Problem was that the "snot" Valve was turned
(due to a spring malfunction) a further 180 degrees and this then lead to a
pressure depleation.that then lead to a brake failure.
If you do not know exactly what happened, then please remain quiet untill
you do. You can speculate as much as you like like, but do not become the
AAIB untill you have all the facts!!!
it was unfortunate and was dealt with as best as could in the situation.
if you can contribute anything constructive, please let us know.
thanks
Message 8
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| Subject: | Re: More left horiZ |
If the snot valve was open AND the system leaked down, the problem is
not with the snot valve being left open. The problem is the check valve
closest to the snot valve on the firewall has failed. If the
aforementioned check valve has failed, opening the snot valve or leaving
the snot valve open due to a failed spring will deplete the air in the
main air tank. The system will never leak down if the aforementioned
check valve is working properly even if the snot valve is left open.
Leaving the snot valve open with the engine running will prevent the
main air system from recharging.
Dennis
----- Original Message -----
From: Gpw678@aol.com
To: yak-list@matronics.com
Sent: Saturday, May 12, 2007 2:36 PM
Subject: Re: Yak-List: More left horiZ
ok, first hand. ( I was there)
Enough spec, yes all of the above, however, there was a small prob
with the mentioned aircraft. the main Problem was that the "snot" Valve
was turned (due to a spring malfunction) a further 180 degrees and this
then lead to a pressure depleation.that then lead to a brake failure.
If you do not know exactly what happened, then please remain quiet
untill you do. You can speculate as much as you like like, but do not
become the AAIB untill you have all the facts!!!
it was unfortunate and was dealt with as best as could in the
situation.
if you can contribute anything constructive, please let us know.
thanks
Message 9
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| Subject: | Re: Weight & Balance Procedure |
Yes, I do. Please contact me off-list.
Dennis
----- Original Message -----
From: JOffice@aol.com
To: yak-list@matronics.com
Sent: Saturday, May 12, 2007 3:05 PM
Subject: Yak-List: Weight & Balance Procedure
Does anyone have a detailed description of the procedure for
determining new weight & balance for a standard YAK-52? N124FS has
undergone enough modification, paint, and fabric over the years to
warrent a new set of numbers...
Any comments or assistance would be appreciated, as our local shop
(with nice electronic scales) will be completely lost on the levelling
procedure...
Thanks-
Jon Lowrey
-------------------------------------------------------------------------
-----
See what's free at AOL.com.
Message 10
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| Subject: | Re: More left horiZ |
In a message dated 5/12/2007 4:35:17 P.M. Eastern Daylight Time,
dsavarese@elmore.rr.com writes:
Dennis is correct, if the snot valve happens to remain open, the system can
not recharge. The check valve down stream can be perfectly good and hold
pressure. However, if the pilot is using normal brake applications, that alone
will deplete the system pressure. Each time you release the brake handle,
you release pressure from the system. If the system starts out low, it won't
take long to be down to nothing. I seem to remember reading somewhere the
minimum air pressure for brakes was 10 atoms.
It is a good idea to always take note of your air pressure right after
starting. You should see some rise (not a lot) on gage before you start to taxi.
Make sure you're making pressure. If you start out with low pressure, you
simply must monitor your pressure closely and be ready mentally to hit the mag
switch off and open emergency air. Remember the compressor does NOT recover
the pressure in the system very quickly and using the brakes a lot, can draw
down the pressure in the system even if every thing is tight.
Jim "Pappy" Goolsby
If the snot valve was open AND the system leaked down, the problem is not
with the snot valve being left open. The problem is the check valve closest to
the snot valve on the firewall has failed. If the aforementioned check
valve has failed, opening the snot valve or leaving the snot valve open due to
a
failed spring will deplete the air in the main air tank. The system will
never leak down if the aforementioned check valve is working properly even if
the snot valve is left open. Leaving the snot valve open with the engine
running will prevent the main air system from recharging.
Dennis
----- Original Message -----
From: _Gpw678@aol.com_ (mailto:Gpw678@aol.com)
Sent: Saturday, May 12, 2007 2:36 PM
Subject: Re: Yak-List: More left horiZ
ok, first hand. ( I was there)
Enough spec, yes all of the above, however, there was a small prob with the
mentioned aircraft. the main Problem was that the "snot" Valve was turned
(due to a spring malfunction) a further 180 degrees and this then lead to a
pressure depleation.that then lead to a brake failure.
If you do not know exactly what happened, then please remain quiet untill
you do. You can speculate as much as you like like, but do not become the AAIB
untill you have all the facts!!!
it was unfortunate and was dealt with as best as could in the situation.
if you can contribute anything constructive, please let us know.
thanks
href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics.com/Navigator?Yak-List
href="http://forums.matronics.com">http://forums.matronics.com
(http://www.matronics.com/Navigator?Yak-List)
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