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Low Emergency Air Pressure
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dsavarese0812(at)bellsout
Guest

Posted: Tue Sep 06, 2011 7:39 am Post subject: Low Emergency Air Pressure

Yak 52 or CJ6?



A. Dennis Savarese

334-285-6263

334-546-8182 (cell)

Skype: Yakguy1

www.yak-52.com

On 9/6/2011 10:05 AM, Bill1200 wrote:

 	  Quote: 	
		   



 Just noticed emergency air pressure low, reading about 1, otherwise everything else normal pressure, compressor brings pressure up to normal on the other side during flight, just not the emergency side. Any suggestions on where to start looking for leak?





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=351539#351539

kingcj6(at)aol.com
Guest

Posted: Tue Sep 06, 2011 7:50 am Post subject: Low Emergency Air Pressure

Probably the check valve located on the upper right firewall.  Doug has the rebuild kits.

 

 

   --

byronmfox(at)gmail.com
Guest

Posted: Tue Sep 06, 2011 7:57 am Post subject: Low Emergency Air Pressure

Most likely the check valve on the starboard firewall above the start solenoid. Mine was leaking not so long ago. Doug Sapp has an overhaul kit, assuming your referring to a CJ.



Sent from my iPhone



On Sep 6, 2011, at 8:36 AM, "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net> wrote:



 	  Quote: 	
		   

 

 Yak 52 or CJ6?

 

 A. Dennis Savarese

 334-285-6263

 334-546-8182 (cell)

 Skype: Yakguy1

 www.yak-52.com

 

 

 On 9/6/2011 10:05 AM, Bill1200 wrote:

> 

> 

> Just noticed emergency air pressure low, reading about 1, otherwise everything else normal pressure, compressor brings pressure up to normal on the other side during flight, just not the emergency side. Any suggestions on where to start looking for leak?

> 

> 

> 

> 

> Read this topic online here:

> 

> http://forums.matronics.com/viewtopic.php?p=351539#351539

> 

> 

> 

> 

> 

> 

> 

> 

> 

> 

>

brian(at)lloyd.com
Guest

Posted: Tue Sep 06, 2011 7:59 am Post subject: Low Emergency Air Pressure

On Tue, Sep 6, 2011 at 8:05 AM, Bill1200 <billdykes52(at)gmail.com (billdykes52(at)gmail.com)> wrote:

 	  Quote: 	
		   --> Yak-List message posted by: "Bill1200" <billdykes52(at)gmail.com (billdykes52(at)gmail.com)>

 

 Just noticed emergency air pressure low, reading about 1, otherwise everything else normal pressure, compressor brings pressure up to normal on the other side during flight, just not the emergency side. Any suggestions on where to start looking for leak?

 	




Look for a corroded check valve going over to the emergency side. If it is stuck closed the compressor won't be able to charge the emergency side.



-- 

Brian Lloyd, WB6RQN/J79BPL

 3191 Western Dr.

Cameron Park, CA 95682

brian(at)lloyd.com (brian(at)lloyd.com)

+1.767.617.1365 (Dominica)

+1.916.877.5067 (USA)



  [quote][b]

yakplt(at)yahoo.com
Guest

Posted: Tue Sep 06, 2011 8:30 am Post subject: Low Emergency Air Pressure

On a YAK-52, the emergency bottle is not filled by the compressor.  Only by the external fill port.  

  

 On the YAK-50, the compressor charges both main and emergency.  

  

 Mark Bitterlich

  

 



   

From: Brian Lloyd <brian(at)lloyd.com>

To: yak-list(at)matronics.com

Sent: Tuesday, September 6, 2011 11:56 AM

Subject: Re: Low Emergency Air Pressure



 



 On Tue, Sep 6, 2011 at 8:05 AM, Bill1200 <billdykes52(at)gmail.com (billdykes52(at)gmail.com)> wrote:

  	  Quote: 	
		  --> Yak-List message posted by: "Bill1200" <billdykes52(at)gmail.com (billdykes52(at)gmail.com)>



Just noticed emergency air pressure low, reading about 1, otherwise everything else normal pressure, compressor brings pressure up to normal on the other side during flight, just not the emergency side. Any suggestions on where to start looking for leak?

	
 



 Look for a corroded check valve going over to the emergency side. If it is stuck closed the compressor won't be able to charge the emergency side.

 

-- 

Brian Lloyd, WB6RQN/J79BPL

3191 Western Dr.

Cameron Park, CA 95682

brian(at)lloyd.com (brian(at)lloyd.com)

+1.767.617.1365 (Dominica)

+1.916.877.5067 (USA)



[quote]



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[b]

Bill1200

Joined: 19 Oct 2008
Posts: 111
Location: medford oregon

Posted: Tue Sep 06, 2011 10:27 am Post subject: Re: Low Emergency Air Pressure

It is a YAK 52, didn't know the compressor doesn't fill it. I'll fill it externally and listen for leak, thanks. Are the check valve post only for CJ, or does that apply to 52 as well?

Bill1200

Joined: 19 Oct 2008
Posts: 111
Location: medford oregon

Posted: Tue Sep 06, 2011 11:30 am Post subject: Re: Low Emergency Air Pressure

Found schematic for air system. What does the "protection" valve do? On the schematic it is between the taps and the gear actuator.

dsavarese0812(at)bellsout
Guest

Posted: Tue Sep 06, 2011 11:37 am Post subject: Low Emergency Air Pressure

Protection valve is a check valve.



For the Yak 52, the check valve for the emergency system is inside the 

fuselage, just behind the external air fill port.  You can test this 

fairly easily, if it is a check valve leak.  After filling the system 

from the external air fill port, spray some soapy water on the external 

port opening and see if it bubbles.  If it does, the check valve I just 

mentioned is leaking.



Before going further, let's do the simple test above and let me know 

what you find.

Dennis



A. Dennis Savarese

334-285-6263

334-546-8182 (cell)

Skype: Yakguy1

www.yak-52.com

On 9/6/2011 1:27 PM, Bill1200 wrote:

 	  Quote: 	
		   



 It is a YAK 52, didn't know the compressor doesn't fill it. I'll fill it externally and listen for leak, thanks. Are the check valve post only for CJ, or does that apply to 52 as well?





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=351562#351562

Bill1200

Joined: 19 Oct 2008
Posts: 111
Location: medford oregon

Posted: Tue Sep 06, 2011 11:55 am Post subject: Re: Low Emergency Air Pressure

Thank you Dennis. Won't be back home until tomorrow. But when I do that test, I'll post results.

LawnDart

Joined: 05 Jun 2006
Posts: 64

Posted: Tue Sep 06, 2011 12:04 pm Post subject: Re: Low Emergency Air Pressure

I'm betting on the square o-ring in one of the red emergency valves in either the front or rear cockpit.  I've had two leaks in 11 years - each time it was one of these o-rings.  Item 6 on the attached diagram (the one on the bottom fitting).

em_valve.jpg

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dsavarese0812(at)bellsout
Guest

Posted: Tue Sep 06, 2011 12:24 pm Post subject: Low Emergency Air Pressure

Good point.  There is a test that one can do to see if the problem is 

one of the emergency air valves.  Very easy to do.

- Observe and write down the pressure in both the emergency and main 

systems.

- With the main air valve off,  (assuming both emergency valves are 

closed tightly), squeeze the brake handle until all air is depleted in 

the system or until you no longer hear the "woosh" sound when you 

release the brake handle.

- Now leave the pneumatic system alone overnight or for at least for a 

few hours.

- When you come back to the airplane, squeeze the brake handle again and 

if you hear the "woosh" sound again AND the emergency side of the 

pressure instrument has leaked down, one of the two emergency air valves 

is leaking.



Now it is just a matter of isolating which valve is leaking.

Dennis



A. Dennis Savarese

334-285-6263

334-546-8182 (cell)

Skype: Yakguy1

www.yak-52.com

On 9/6/2011 3:04 PM, LawnDart wrote:

 	  Quote: 	
		   



 I'm betting on the square o-ring in one of the red emergency valves in either the front or rear cockpit.  I've had two leaks in 11 years - each time it was one of these o-rings.  Item 6 on the attached diagram.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=351569#351569





 Attachments:



 http://forums.matronics.com//files/em_valve_904.jpg

brian(at)lloyd.com
Guest

Posted: Tue Sep 06, 2011 2:12 pm Post subject: Low Emergency Air Pressure

On Tue, Sep 6, 2011 at 9:25 AM, Yak Pilot <yakplt(at)yahoo.com (yakplt(at)yahoo.com)> wrote:

 	  Quote: 	
		   On a YAK-52, the emergency bottle is not filled by the compressor.  Only by the external fill port.  

   

 On the YAK-50, the compressor charges both main and emergency.  

  

 Mark Bitterlich

	




Sorry Mark. I was thinking CJ6A. Emergency side is filled from the compressor.



-- 

Brian Lloyd, WB6RQN/J79BPL

 3191 Western Dr.

Cameron Park, CA 95682

brian(at)lloyd.com (brian(at)lloyd.com)

+1.767.617.1365 (Dominica)

+1.916.877.5067 (USA)



  [quote][b]

brian(at)lloyd.com
Guest

Posted: Tue Sep 06, 2011 2:12 pm Post subject: Low Emergency Air Pressure

On Tue, Sep 6, 2011 at 11:27 AM, Bill1200 <billdykes52(at)gmail.com (billdykes52(at)gmail.com)> wrote:

 	  Quote: 	
		   --> Yak-List message posted by: "Bill1200" <billdykes52(at)gmail.com (billdykes52(at)gmail.com)>

 

 It is a YAK 52, didn't know the compressor doesn't fill it. I'll fill it externally and listen for leak, thanks. Are the check valve post only for CJ, or does that apply to 52 as well?

	


 

Mark answered. The CJ6A fills the emergency system from the engine-driven compressor through a check valve.



-- 

Brian Lloyd, WB6RQN/J79BPL

3191 Western Dr.

Cameron Park, CA 95682

 brian(at)lloyd.com (brian(at)lloyd.com)

+1.767.617.1365 (Dominica)

+1.916.877.5067 (USA)



  [quote][b]

k7wx

Joined: 24 May 2010
Posts: 117

Posted: Tue Sep 06, 2011 2:46 pm Post subject: Low Emergency Air Pressure

Dennis,



Some air leaks can be insidious. Picked up a used ultrasonic leak detector on eBay for a little over $100 and this has helped me to cure all the leaks in both the main and emergency systems. With the probe tip properly placed, even the smallest leak is easy to locate. 



Warren

On Sep 6, 2011, at 1:21 PM, A. Dennis Savarese wrote:



 	  Quote: 	
		   

 

 Good point.  There is a test that one can do to see if the problem is one of the emergency air valves.  Very easy to do.

 - Observe and write down the pressure in both the emergency and main systems.

 - With the main air valve off,  (assuming both emergency valves are closed tightly), squeeze the brake handle until all air is depleted in the system or until you no longer hear the "woosh" sound when you release the brake handle.

 - Now leave the pneumatic system alone overnight or for at least for a few hours.

 - When you come back to the airplane, squeeze the brake handle again and if you hear the "woosh" sound again AND the emergency side of the pressure instrument has leaked down, one of the two emergency air valves is leaking.

 

 Now it is just a matter of isolating which valve is leaking.

 Dennis

 

 A. Dennis Savarese

 334-285-6263

 334-546-8182 (cell)

 Skype: Yakguy1

 www.yak-52.com

 

 

 On 9/6/2011 3:04 PM, LawnDart wrote:

> 

> 

> I'm betting on the square o-ring in one of the red emergency valves in either the front or rear cockpit.  I've had two leaks in 11 years - each time it was one of these o-rings.  Item 6 on the attached diagram.

> 

> 

> 

> 

> Read this topic online here:

> 

> http://forums.matronics.com/viewtopic.php?p=351569#351569

> 

> 

> 

> 

> Attachments:

> 

> http://forums.matronics.com//files/em_valve_904.jpg

> 

> 

> 

> 

> 

> 

> 

>

dsavarese0812(at)bellsout
Guest

Posted: Tue Sep 06, 2011 5:19 pm Post subject: Low Emergency Air Pressure

Warren,

You are 110% on the money.  I have one myself.  But yours must be better 

than mine.  Probably because I paid too much for it in the first place. 

  I assumed Bill did not have one and gave him the two easiest 

troubleshooting procedures based on the most common causes of emergency 

system leaks.  Hopefully the soapy water on the external air fill port 

will show the problem.  If not, I'll help him figure it out.

Dennis



A. Dennis Savarese

334-285-6263

334-546-8182 (cell)

Skype: Yakguy1

www.yak-52.com

On 9/6/2011 5:44 PM, Warren Hill wrote:

 	  Quote: 	
		   



 Dennis,



 Some air leaks can be insidious. Picked up a used ultrasonic leak detector on eBay for a little over $100 and this has helped me to cure all the leaks in both the main and emergency systems. With the probe tip properly placed, even the smallest leak is easy to locate.



 Warren

 On Sep 6, 2011, at 1:21 PM, A. Dennis Savarese wrote:



> 

>

> Good point.  There is a test that one can do to see if the problem is one of the emergency air valves.  Very easy to do.

> - Observe and write down the pressure in both the emergency and main systems.

> - With the main air valve off,  (assuming both emergency valves are closed tightly), squeeze the brake handle until all air is depleted in the system or until you no longer hear the "woosh" sound when you release the brake handle.

> - Now leave the pneumatic system alone overnight or for at least for a few hours.

> - When you come back to the airplane, squeeze the brake handle again and if you hear the "woosh" sound again AND the emergency side of the pressure instrument has leaked down, one of the two emergency air valves is leaking.

>

> Now it is just a matter of isolating which valve is leaking.

> Dennis

>

> A. Dennis Savarese

> 334-285-6263

> 334-546-8182 (cell)

> Skype: Yakguy1

> www.yak-52.com

> On 9/6/2011 3:04 PM, LawnDart wrote:

>> 

>>

>> I'm betting on the square o-ring in one of the red emergency valves in either the front or rear cockpit.  I've had two leaks in 11 years - each time it was one of these o-rings.  Item 6 on the attached diagram.

>>

>>

>>

>>

>> Read this topic online here:

>>

>> http://forums.matronics.com/viewtopic.php?p=351569#351569

>>

>>

>>

>>

>> Attachments:

>>

>> http://forums.matronics.com//files/em_valve_904.jpg

>>

>>

>>

>>

>>

>>

>>

>>

>

wlannon(at)persona.ca
Guest

Posted: Tue Sep 06, 2011 8:33 pm Post subject: Low Emergency Air Pressure

On the CJ if you wish to charge the emergency tank  only, for example with nitrogen rather than air simply leave the main air valve  closed.

  

 Probably applies to the Yak 50 as well

  

 Walt

 [quote]   ---

Rob Rowe

Joined: 10 Jan 2006
Posts: 124
Location: Berkshire, UK

Posted: Wed Sep 07, 2011 2:52 am Post subject: Re: Low Emergency Air Pressure

Dennis / Bill,



Believe the protection valve Bill enquired about is the one located under the starboard side of the front cockpit seat (YAK-52). 



Its vents the emergency air line (between the tap(s) and gear shuttle valves / uplocks) to atmosphere below 5 kgf/cm2 line pressure, to stop MINOR leaks from the taps or shuttle valve 'peas' interfering with normal gear operation.



For that very reason if you need to operate the emergency air system for real then open the tap quickly and fully to make sure the protection valve snaps shut (>5 kgf/cm2), otherwise you'll just waste the precious 3 litres reserve air ventilating the P1's derriere! Keeping in mind, having lowered the gear, you may well need what emergency air is left to also operate the brakes post landing.



Similarly the overnight air tap leak test suggested will probably be inconclusive for a YAK-52 because the air will most likely have been dumped externally by the protection valve as <5 kgf/cm2.



If the emergency air bottle has recently been disturbed for maintenance then I believe they can be troublesome to seat back on their seals ... which may be another aspect to consider in your leak down quest.



Good luck.



brgds, Rob R



 	  dsavarese0812(at)bellsout wrote: 	
		  

Protection valve is a check valve.



For the Yak 52, the check valve for the emergency system is inside the 

fuselage, just behind the external air fill port ...

yakplt(at)yahoo.com
Guest

Posted: Wed Sep 07, 2011 6:08 am Post subject: Low Emergency Air Pressure

No, it does not.  The YAK-50 has four check valves.  Two for air input:  One from the compressor, one from the external air.  These come together at the pressure relief valve and prevent reverse flow.  

  

 Out of the pressure relief valve you go to a "T" connector which feeds an air strainer.  The output of the air strainer, goes to another "T" connector where there are two more check valves.  Top one goes to emergency air bottle, bottom one goes to main air bottle.  Both go DIRECTLY to the bottles.  The air shut off valve in the cockpit does not control air INPUT in any way to either bottle.  It only controls air output. 

  

 Mark Bitterlich

  

 



   

From: Walter Lannon <wlannon(at)persona.ca>

To: yak-list(at)matronics.com

Sent: Wednesday, September 7, 2011 12:30 AM

Subject: Re: Yak-List: Low Emergency Air Pressure



    On the CJ if you wish to charge the emergency tank only, for example with nitrogen rather than air simply leave the main air valve closed.

  

 Probably applies to the Yak 50 as well

  

 Walt

 [quote] ---

brian(at)lloyd.com
Guest

Posted: Wed Sep 07, 2011 7:00 am Post subject: Low Emergency Air Pressure

On Wed, Sep 7, 2011 at 7:05 AM, Yak Pilot <yakplt(at)yahoo.com (yakplt(at)yahoo.com)> wrote:

 	  Quote: 	
		   No, it does not.  The YAK-50 has four check valves.  Two for air input:  One from the compressor, one from the external air.  These come together at the pressure relief valve and prevent reverse flow.  

   

 Out of the pressure relief valve you go to a "T" connector which feeds an air strainer.  The output of the air strainer, goes to another "T" connector where there are two more check valves.  Top one goes to emergency air bottle, bottom one goes to main air bottle.  Both go DIRECTLY to the bottles.  The air shut off valve in the cockpit does not control air INPUT in any way to either bottle.  It only controls air output. 

   

 Mark Bitterlich

	




Has anyone else noticed that there are a lot more check valves in our airplanes than are needed to ensure system integrity after a partial failure? While helping Dennis Nickson troubleshoot an intermittent problem with the pneumatic system in his CJ it was pretty obvious that I could replace several of the check valves with straight pipe and it would have no effect on either the normal operation or how the system would fail if it was breached at various places. And I suspect that pieces of straight pipe are less likely to fail and cause problems than the various unnecessary check valves.

 



I am thinking that, right after removing and throwing away the arcane and unnecessary complexity of the electrical system, we could probably to do the same for much of the pneumatic system as well. 

 

-- 

Brian Lloyd, WB6RQN/J79BPL

3191 Western Dr.

Cameron Park, CA 95682

brian(at)lloyd.com (brian(at)lloyd.com)

+1.767.617.1365 (Dominica)

+1.916.877.5067 (USA)

 

  [quote][b]

dsavarese0812(at)bellsout
Guest

Posted: Wed Sep 07, 2011 7:23 am Post subject: Low Emergency Air Pressure

All excellent points Robb.  Regarding the "fart" valve you mention and 

refer to as the protection valve, if there is a leak from either one of 

the emergency air valves and the protection valve bleeds the low 

pressure off as you suggest, then one could use either a leak detector 

or soapy water (or for that matter, stretch a balloon on the top of the 

valve which would expand slowly) to determine if the leak is from one of 

the emergency air valves.



I can say this with carnal knowledge; the overnight test I previously 

mentioned does work for a leaking main air valve.

Dennis



A. Dennis Savarese

334-285-6263

334-546-8182 (cell)

Skype: Yakguy1

www.yak-52.com

On 9/7/2011 5:52 AM, Rob Rowe wrote:

 	  Quote: 	
		   



 Dennis / Bill,



 Believe the protection valve Bill enquired about is the one located under the starboard side of the front cockpit seat (YAK-52).



 Its vents the emergency air line (between the tap(s) and gear shuttle valves / uplocks) to atmosphere below 5 kgf/cm2 line pressure, to stop MINOR leaks from the taps or shuttle valve 'peas' interfering with normal gear operation.



 For that very reason if you need to operate the emergency air system for real then open the tap quickly and fully to make sure the protection valve snaps shut (>5 kgf/cm2), otherwise you'll just waste the precious 3 litres reserve air ventilating the P1's derriere! Keeping in mind, having lowered the gear, you may well need what emergency air is left to also operate the brakes post landing.



 Similarly the overnight air tap leak test suggested will probably be inconclusive for a YAK-52 because the air will most likely have been dumped externally by the protection valve as





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=351640#351640

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