Today's Message Index:
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1. 12:36 AM - Re: YAK 52 - Procedure for emergency gear down (Jean-Philippe Martel)
2. 01:31 AM - Re: Re: Search for gear front selector as spare part (Jean-Philippe Martel)
3. 10:53 AM - Re: [Non-DoD Source] Re: YAK 52 - Procedure for emergency gear down (Bitterlich, Mark G CIV NAVAIR, WD)
4. 07:06 PM - Re: Seattle /Washington YAK52 owners & enthusiasts (AndyRutherford)
Message 1
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| Subject: | Re: YAK 52 - Procedure for emergency gear down |
Dennis,
thanks for your answer that fully complies with the version I was taught
here in Europe. Unfortunately, the English translation of the Russian
DOSAAF POH that we get with our G-registered machines does not mention the
emergency procedure for gear extension. Incredible but true. ANd there are
always some fellows who promote their own "tricks" ... Good to know but not
to follow.
And having a look at the exchanges in some forums, I note that the topic of
the position of the gear selector (before, during and after ...) always
provokes a lot of comments; more or less relevant ... let's stick to the
official version!
Now it's time for me to make an appointment with my workshop in order to
change both valves.
All the best!
Jean-Philippe "Marty"
France
2017-09-24 18:49 GMT+02:00 A. Dennis Savarese <dsavarese0812@bellsouth.net>
:
> No, you do not move the gear selector after you place it in neutral. The
> emergency air system is designed to extend the gear without the movement
of
> the front gear selector. The emergency system is totally independent of
> the main air system and the gear selectors.
>
> After you have extended the gear with the emergency system, th time to
> move the front gear selector back to the DOWN position is after you have
> parked the airplane and shut the engine down.
> Dennis
>
>
> ------------------------------
> *From:* Jean-Philippe Martel <marty.jpm@gmail.com>
> *To:* yak-list@matronics.com
> *Sent:* Sunday, September 24, 2017 8:43 AM
> *Subject:* Re: Yak-List: YAK 52 - Procedure for emergency gear down
>
> Indeed I don't doubt =F0=9F=98=8A I already saw what you described.
>
> Back to the procedure in flight, the selectors on neutral position +
> activation of the emergency valve are enough to provoke the emergency gea
r
> down? Or does one have to pull down the front selector as well?
>
> Le 24 sept. 2017 13:06, "A. Dennis Savarese" <dsavarese0812@bellsouth.net
>
> a =C3=A9crit :
>
> FYI - Flaps do not work from the emergency air system. If you doubt this
> to be true, then test it the next time you have the airplane on jacks doi
ng
> a gear retraction/extension test when doing the emergency gear extension
> test.
>
> With the rear gear selector in the neutral position and the main air valv
e
> closed, once you place the front gear selector in neutral, all the residu
al
> air pressure in the system forward of the main air valve, is depleted.
> Then open the emergency air valve to extend the gear. Now attempt to put
> the flaps down.
> Dennis
> ------------------------------
> *From:* Nigel Willson <nigel.willson@yakdisplay.com>
> *To:* yak-list@matronics.com
> *Sent:* Sunday, September 24, 2017 6:52 AM
> *Subject:* Re: Yak-List: YAK 52 - Procedure for emergency gear down
>
> Both gear selectors to neutral. Open emergency air valve. Do not use flap
s
> since this will use emergency air that could be used for braking.
>
>
> *Regards,*
> *Nigel Willson*
> *Flying Instructor & Examiner |
> Airsh3901238792082250297yiv2214189677MsoNormal">http://yakdisplay
> <http://yakdisplay/>. com*
> Tel. 07809 116676
>
> Sent from my Samsung Galaxy S7 - powered by Three
>
> -------- Original message --------
> From: Jean-Philippe Martel <marty.jpm@gmail.com>
> Date: 24/09/2017 09:51 (GMT+00:00)
> To: yak-list@matronics.com
> Subject: Yak-List: YAK 52 - Procedure for emergency gear down
>
> Hi!
>
> Could any YAK 52 driver kindly remind me the official emergency procedure
> to gear down in case of full pressure loss in the normal circuit, please?
>
> Thank you in advance! =F0=9F=98=8A
>
> Marty
> France
>
>
Message 2
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| Subject: | Re: Search for gear front selector as spare part |
Hi Tobias,
thanks for your kind feedback.
Indeed my priority number 1 is the front valve.
I'm trying to find a new one. I'm going to ask to AVIASERV, that's a good
idea.
Best regards,
Jean-Philippe "Marty"
France
2017-09-22 11:08 GMT+02:00 Yakjumper <tobias@macnews.de>:
>
> Hi,
>
> just replaced a leaky rear flap selector and sent it for overhaul to
> Aviaserv.
> He has new/overhauled ones.
> Or mail me (I am in Germany), I have a new rear gear selector as a spare.
>
> btw:
> The flap selector leaked so much that during flight the main air tank was
> drained, the compressor could not keep up. Had to close the air valve in
> flight to preserve some pressure for landing and braking. Luckily I already
> had a spare part in stock, so no waiting.
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=473055#473055
>
>
Message 3
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| Subject: | Re: YAK 52 - Procedure for emergency gear |
down
Yes can be a reason not to move it to the down position Walt. Give me a second.
First I'd like to add one more tidbit that is not mentioned in any of the
POH's. I managed to figure this one out while ferrying a YAK-50 from East
to West coast about 15 years ago.
Dennis mentioned that when both gear levers are in the middle, all air is relieved
downstream of the landing gear actuator. "Vented" is a better word to use
here. But what this also does is to isolate the whole landing gear pneumatic
system from the main air tank, and the compressor and lines. Why is this
important to know? Because let's say you have an internal actuator leak downstream
of the gear actuator levers? Landing gear selected up, or landing gear
selected down, there will be air leaking and it can be so drastic as to drain
the main bottle completely. If you isolate the landing gear with both (or one
in the case of the YAK-50) landing gear handles in the middle position, you
give time for the main bottle to fill up again completely. In the case of the
YAK-50, you actually can fill BOTH main AND emergency bottles up this way.
Both bottles are plumbed to the compressor on the 50, unlike on the 52 where only
the main bottle is filled from engine compressor air.
In any case, you can let the pressure fill back up and then try to make a second
attempt to lower the gear normally. You can do this as many times as you want,
if you feel this is the right thing to do.
In the case of the emergency system, once you open that valve, you cause shuttle
valves to change position on each landing gear. Two on the 50, three on the
52. That shuttle valve has two positions, emergency or main air supply. Anyone
who has tested the emergency system knows that you must drain all the emergency
air out of the lines, and then select DOWN on the landing gear actuator
lever in order to cause the shuttle valves to move back to the position where
MAIN AIR will be used to lower the gear.
If you lower the gear using the proper emergency procedure (with both gear handles
neutral) air on both sides of each gear actuator is vented, so when air is
applied via the emergency valve, there is no air pressure on the opposite side
of the actuator at all, that would in any way impede full and rapid movement
of the actuator and thus the landing gear. Once the gear is down, it is procedure
to keep air applied on the down side of each actuator, which is what is
happening at this point, unless there is some gross leak.
If you now move a landing gear handle DOWN, you will supply MAIN AIR (assuming
you have any) to the shuttle valve on each actuator. So now you have two air
supplies fighting each other to set the position of the shuttle valve, which I
submit no one intended.
Let me give you a real world YAK-50 example. Chevron seal in one actuator fails.
Gear is selected down. Gear does not come down and lock. Main air drains
to near zero. Gear handle is put in middle position and emergency air valve
is opened. Main gear locks down, but emergency air bottle drains to zero.
In the meantime main air bottle fills back up. Landing is made with main bottle
full with brakes being normal. If the brake handle had been selected down,
it's hard to prove what might have happened, but if the shuttle valve changed
positions, then the main bottle would have started draining.
So it's a complicated question, that requires full understanding of how this system
is plumbed and it differs between a YAK-50 and a 52 but understanding what
air goes where and why, along with a complete understanding of those shuttle
valves is important for all of us to grasp.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
Sent: Sunday, September 24, 2017 1:32 PM
Subject: [Non-DoD Source] Re: Yak-List: YAK 52 - Procedure for emergency gear down
Hi Dennis;
Is there some provision in the Yak 52 POH that prohibits movement of the gear selector
to down after an emergency down operation?
Of course every licensed and qualified CJ and Yak pilot thoroughly understands
that the emergency gear down operation completely by-passes the gear selectors
and directs emerg. air directly to the down side of the actuators. They know
this due to their enormous diligence in understanding their aircraft!
Moving the temporarily inoperable gear selector to the down postition is called
good housekeeping, probably because that is were it supposed to be during landing.
Cheers;
Walt
From: A. Dennis Savarese <mailto:dsavarese0812@bellsouth.net>
Sent: Sunday, September 24, 2017 9:49 AM
Subject: Re: Yak-List: YAK 52 - Procedure for emergency gear down
No, you do not move the gear selector after you place it in neutral. The emergency
air system is designed to extend the gear without the movement of the front
gear selector. The emergency system is totally independent of the main air
system and the gear selectors.
After you have extended the gear with the emergency system, th time to move the
front gear selector back to the DOWN position is after you have parked the airplane
and shut the engine down.
Dennis
________________________________
From: Jean-Philippe Martel <marty.jpm@gmail.com>
Sent: Sunday, September 24, 2017 8:43 AM
Subject: Re: Yak-List: YAK 52 - Procedure for emergency gear down
Indeed I don't doubt I already saw what you described.
Back to the procedure in flight, the selectors on neutral position + activation
of the emergency valve are enough to provoke the emergency gear down? Or does
one have to pull down the front selector as well?
Le 24 sept. 2017 13:06, "A. Dennis Savarese" <dsavarese0812@bellsouth.net> a crit
:
FYI - Flaps do not work from the emergency air system. If you doubt this to be
true, then test it the next time you have the airplane on jacks doing a gear
retraction/extension test when doing the emergency gear extension test.
With the rear gear selector in the neutral position and the main air valve closed,
once you place the front gear selector in neutral, all the residual air pressure
in the system forward of the main air valve, is depleted. Then open the
emergency air valve to extend the gear. Now attempt to put the flaps down.
Dennis
________________________________
From: Nigel Willson <nigel.willson@yakdisplay.com>
To: yak-list@matronics.com
Sent: Sunday, September 24, 2017 6:52 AM
Subject: Re: Yak-List: YAK 52 - Procedure for emergency gear down
Both gear selectors to neutral. Open emergency air valve. Do not use flaps since
this will use emergency air that could be used for braking.
Regards,
Nigel Willson
Flying Instructor & Examiner | Airsh3901238792082250297yiv2214189677MsoNormal">http://yakdisplay <http://yakdisplay/> . com Tel. 07809 116676
Sent from my Samsung Galaxy S7 - powered by Three
-------- Original message --------
From: Jean-Philippe Martel <marty.jpm@gmail.com>
Date: 24/09/2017 09:51 (GMT+00:00)
To: yak-list@matronics.com
Subject: Yak-List: YAK 52 - Procedure for emergency gear down
Hi!
Could any YAK 52 driver kindly remind me the official emergency procedure to gear
down in case of full pressure loss in the normal circuit, please?
Thank you in advance!
Marty
France
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
Message 4
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| Subject: | Re: Seattle /Washington YAK52 owners & enthusiasts |
Hi Jones,
I'm near you down in Kelso, WA. I bought a Yak-52 last April.
Regards,
Andy Rutherford
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=473153#473153
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