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Distraction-the Best Medicine

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Jeff Linebaugh

Joined: 11 Jan 2006
Posts: 48
Location: Collierville, TN

Posted: Mon Feb 20, 2006 9:34 am Post subject: Distraction-the Best Medicine

One thing I have learned from being a parent is that sometimes the best way to end a tirade is by distraction...so....

  

 Distraction of the Week:

  

 At 500' after setting climb power on initial takeoff you observe your Main Air pressure at 28 and falling. (You DO always check your air pressure after takeoff, don't you?)  What should you do?

  

 a) Turn to the downwind and return immediately for landing

 b) Use the Emergency Air System to blow your gear down

 c) Both of the above

 d) none of the above...describe your actions....

  

  

  

 Jeff Linebaugh

 jefflinebaugh(at)earthlink.net (jefflinebaugh(at)earthlink.net)

 http://home.earthlink.net/~jefflinebaugh/

 Yakless

 Memphis, TN

        [img]cid:77223213-2C1C-4BBC-94EE-E999CC82F48F[/img]

_________________
Jeff Linebaugh
jefflinebaugh@earthlink.net
Collierville, TN

wlannon(at)cablerocket.co
Guest

Posted: Mon Feb 20, 2006 9:44 am Post subject: Distraction-the Best Medicine

d) ----- Open the air valve!

 [quote]   ---

dsavarese(at)elmore.rr.co
Guest

Posted: Mon Feb 20, 2006 10:09 am Post subject: Distraction-the Best Medicine

d) Since it was not described in the "distraction" if the gear  was retracted or not, if the landing gear indicated "up and locked" via the red  lights ON, with 28 ATM, there is enough air in the main system to extend the  landing gear into the down and locked position.  I would immediately 1)  verify the main air valve is fully ON (although with the gear up and lock it is  highly unlikely the main air valve is not open); 2) immediately extend the  landing gear and check for all green lights indicating "down and locked".   3) If the landing gear did not fully extend to indicate "down and locked" via  the green lights, then we would have the emergency air system to extend the  landing gear AND have air for braking upon landing.  No flaps in a Yak 52  though.

  

 If the landing gear did not indicate "down and locked", turn  off the main air supply; next move the gear selector to the neutral position and  allow the air in the shuttle valves and actuators to expel.  Once this is  accomplished (listen to the air expelling from the gear selector), open the  emergency air valve to extend the gear into the down and locked position (green  lights ON)

  

 Next, make a no flap landing.  Taxi to you hangar or  parking spot and then turn off the emergency air valve.

 Dennis

  

 [quote]   ---

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Mon Feb 20, 2006 10:23 am Post subject: Distraction-the Best Medicine

Jeff Linebaugh wrote:

 	  Quote: 	
		   One thing I have learned from being a parent is that sometimes the best

 way to end a tirade is by distraction...so....

  

 Distraction of the Week:

  

 At 500' after setting climb power on initial takeoff you observe

 your Main Air pressure at 28 and falling. (You DO always check your air

 pressure after takeoff, don't you?)  What should you do?


	


Didn't we just do this one not too long ago?



 	  Quote: 	
		   a) Turn to the downwind and return immediately for landing

 b) Use the Emergency Air System to blow your gear down

 c) Both of the above

 d) none of the above...describe your actions....


	


Put the gear down immediately using the normal system. Put the gear

handle in neutral. See if the air pressure stabilizes. If it doesn't, at

least the gear is already down and locked. If the gear won't come down I

would put the gear and flap levers in neutral and see if I get any

additional pressure. If not I would plan on flying to someplace with a

long, wide runway where I could put the gear down with the emergency

system. The leak will probably mean that, even if the gear does come

down, I probably will NOT have brakes.



It depends a lot on just how fast the pressure is going down. If it is

going down slowly I would plan to land back home and open the emergency

air valve just before touchdown to ensure I have air to stop the

airplane. If it is still going down rather rapidly I would assume I

would have to land without brakes even with the emergency air system

which means I would not have directional control once I slow below the

speed at which my rudder is effective. In that case I would fly to an

airport with a very large runway that is aligned with the wind where I

could get the airplane stopped on the runway without damage without

using the brakes.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

_________________
Brian Lloyd
brian-yak at lloyd dot com
+1.916.367.2131 (voice) +1.270.912.0788 (fax)

I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupery

dsavarese(at)elmore.rr.co
Guest

Posted: Mon Feb 20, 2006 10:46 am Post subject: Distraction-the Best Medicine

Brian,

The 52's emergency system does supply air to the brakes, but not the flaps 

and is more than adequate to stop the airplane and taxi to the ramp.

Dennis



---

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Mon Feb 20, 2006 11:34 am Post subject: Distraction-the Best Medicine

A. Dennis Savarese wrote:

 	  Quote: 	
		   

 <dsavarese(at)elmore.rr.com>

 

 Brian,

 The 52's emergency system does supply air to the brakes, but not the

 flaps and is more than adequate to stop the airplane and taxi to the ramp.


	


There is commonality in the two systems, normal and emergency. (I speak

for the CJ6A and am making that assumption for the Yak-52.) If the leak

is in a common component then you could end up with no brakes even if

using the emergency system. Hence my suggestion to find a long, wide

runway just-in-case.



We know that there is a leak because the pressure is dropping. We just

don't know where the leak is as isolating the systems by putting gear

and flap levers in neutral does not stop the leak.



Just off the top of my head it may be that the leak is in the braking

system as there is no way to isolate that loop in the pneumatic system

as you can with the gear and flap circuits. The braking system IS common

to both the main and emergency pneumatic systems.



Yes, I would question whether or not I would have brakes when I land.

Better be safe than sorry. It will take less time to fix a leak in the

braking system than to repair the airframe after running off the end of

the runway.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

ira.saligman(at)verizon.n
Guest

Posted: Tue Feb 21, 2006 2:45 am Post subject: Distraction-the Best Medicine

All very good  points.  I have one to add from the practical point of what should you have  been thinking if you find yourself rolling down a runway w/o  brakes:

  

  

 1) consider using  the longest runway and/or the runway with the best overrun situation (you should  know the overrun conditions at your home airport and already know which one you  would use)  also consider the other traffic at the  airport

 If the field has a  grass runway, consider landing on it, (higher resistance, quicker stop)   

 Consider taking off  again and flying Gear down to an appropriate grass field  

  

 2) Know how fast you  would want to be going if you needed( or could)  to taxi off the side of  the runway to the grass to stop. 

  

 3) don't expect a  lot of steering ability upon landing w/a brake failure

  

 4) Shut down the  engine upon realizing there is a brake failure.  The unless you have  reverse thrust, the spinning prop is not going to help you stop.  (Maybe an  aerodynamic expert can jump here with the value of pushing air over the rudder  to turn the brakeless plane) 

  

 5) open your canopy  prior to landing a little in case the plane rolls over. 

  

   

  Ira Saligman

  

 isaligman(at)saligman.com (isaligman(at)saligman.com)

HawkerPilot2015

Joined: 10 Jan 2006
Posts: 503

Posted: Tue Feb 21, 2006 5:10 am Post subject: Re: Distraction-the Best Medicine

Bail out and order a new airplane from Dennis.

dsavarese(at)elmore.rr.co
Guest

Posted: Tue Feb 21, 2006 5:26 am Post subject: Distraction-the Best Medicine

That works for me! -)

Dennis



---

Rob Rowe

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

Posted: Tue Feb 21, 2006 5:31 am Post subject: Re: Distraction-the Best Medicine

As a further thought  *** for a YAK-52 *** ... leave the circuit & turn the main air valve off for a few minutes to isolate air sources from air consumers.



If pressure continues to drop then return to circuit & follow emergency air procedures as documented.



If air pressure increases then upstream NRVs, pressure regulator, main air cylinder & air gauges will all be good ... & provides extra air to help fault find any potential gear problem (which if more difficult to do on the ground).



Open main air valve again & isolate flaps & gear (seperately) by setting each control to neutral ... if air loss continues then be aware that brake systems may be the compromised & plan accordingly ... return to circuit & follow emergency air procedures.



If flap isolation stops the pressure loss then return to circuit & make a flapless landing.



If gear isolation stops the pressure loss then cycle gear "down" to see if the problem is gear position specific ... note operation of gear lights for any unusual (slow) gear leg operation. If you've a GIB then consider having him repeat same using the the rear cockpit gear control to see if the front unit is leaking. Follow the emergency air procedures on rejoining the circuit.



FWIW ... once had an intermittent air pressure drop (YAK-52) post lowering gear that took months to diagnose. Pressure would drop to c.25 kgf/cm2 & then recover back to normal. Problem occured randomly ... but could never be repeated on ground jacks (50+ cycles). 



To make diagnosis even more interesting we found that when the air pressure drops to low levels the seal integrity of the control valves can become compromised ... making them audibly leak (the design relies on high pressure air pushing the machined metal faces together to form a seal) ... so false symptoms further clouded the root cause.



After spending a lot of time (& money) learning, stripping gear actuators & control valves the problem was eventually resolved by replacing the air pressure regulator valve unit. 



Seems this was prone to sticking open when a large downstream air demand was made (probably when regulating (at) 50 kgf/cm2) & was only in use when aloft. When the pressure differential became large enough it snapped shut again causing the system operation to return to normal!



Rob R.

Last edited by Rob Rowe on Tue Feb 21, 2006 8:49 am; edited 1 time in total

dsavarese(at)elmore.rr.co
Guest

Posted: Tue Feb 21, 2006 6:12 am Post subject: Distraction-the Best Medicine

Rob,

Very interesting FWIW discussion.  Also very helpful.



As for the in-flight trouble shooting, I am not sure I or many other Yak 52 

owners/pilots would go through the extensive trouble shooting initially 

since air pressure is THE most precious commodity on the 52.  (Exclusive of 

the engine and prop turning of course).  My first reaction is going to be to 

find out if the landing will extend using whatever pressure is still 

available in the main air system and land the airplane.  Then do some 

trouble shooting in the hangar and on the jacks.  If we're unable to isolate 

the problem on the ground, at least we now have some confidence in the 

system components.  Then we can go to the next level which would be to fly 

the airplane and follow your in-flight trouble shooting technique.



Simply put, I think your technique is excellent.  But for me, probably just 

a bit premature when a problem as described shows up after take off and at 

500 ft.  That's just me though.

Dennis



---

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Tue Feb 21, 2006 6:58 am Post subject: Distraction-the Best Medicine

Ira Saligman wrote:



 	  Quote: 	
		   4) Shut down the engine upon realizing there is a brake failure.  The

 unless you have reverse thrust, the spinning prop is not going to help

 you stop.  (Maybe an aerodynamic expert can jump here with the value of

 pushing air over the rudder to turn the brakeless plane)


	


The residual thrust will probably keep the airplane from stopping when

on a hard surface (runway). Turning off the engine as soon as you have

brake failure is part of the "normal" emergency procedure in that case.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Tue Feb 21, 2006 7:24 am Post subject: Distraction-the Best Medicine

Rob Rowe wrote:

 	  Quote: 	
		   

 

 As a further thought ... leave the circuit & turn the main air valve off for a few minutes to isolate air sources from air consumers.


	


Turning off the air valve in the CJ6A only isolates the storage tank

from the main pneumatic pressure bus. The compressor is still connected

and the loads are still connected. The only thing this will do is cause

the pressure to go up or down much more rapidly as the volume of the

system is now greatly reduced.



But the pneumatic system in the Yak-52 does indeed work as you suggest

it does. That means that troubleshooting a pneumatic problem in the CJ6A

 in flight will be different from troubleshooting a pneumatic system

problem in the Yak-52 in flight.



In the CJ6A, turning off the main air valve will preserve what pressure

that is left in the storage tank while you fiddle about trying to find a

combination that will stop the pressure loss. In that case you can use

the remaining pressure to lower the gear and preserve the air in the

emergency bottle to to provide braking on roll out.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

Rob Rowe

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

Posted: Tue Feb 21, 2006 8:10 am Post subject: Re: Distraction-the Best Medicine

 	  dsavarese(at)elmore.rr.co wrote: 	
		  Rob,

Very interesting FWIW discussion.  Also very helpful.



As for the in-flight trouble shooting, I am not sure I or many other Yak 52 

owners/pilots would go through the extensive trouble shooting initially 

since air pressure is THE most precious commodity on the 52.  (Exclusive of the engine and prop turning of course).[/color]

...

That's just me though. 



--- 	


Dennis,



Fair comment ... although *** for a YAK-52 ***  if the first thing you do is turn the main air off then you can establish within seconds the important information as to whether you've got an up or down stream problem.



If it's up stream then you'll need to use the emergency air anyway to ensure gear down & for braking ... so no delay incurred.



If it's down stream then you'll have preserved precious air (& start replacing what's been lost) providing both time & confidence to perform a few minutes of valuable in-flight diagnostics.



Aside from gaining time to collect your thoughts, it allows for a fuller assessment of the problem being faced & therefore the safest way to deal with it.



I guess we'll all make our own call on this ... but if there's a silver lining to the problems we experienced it's that we all got to know the systems very well & felt comfortable that we were not going to make the situation worse by our actions.



Believe me after several months of trying to diagnose this problem, and its random nature, the 5 guys in our syndicate could perform these procedures in their sleep!



Rob R

Last edited by Rob Rowe on Tue Feb 21, 2006 8:26 am; edited 1 time in total

Rob Rowe

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

Posted: Tue Feb 21, 2006 8:21 am Post subject: Re: Distraction-the Best Medicine

Brian wrote 

 	  Quote: 	
		  



But the pneumatic system in the Yak-52 does indeed work as you suggest

it does. That means that troubleshooting a pneumatic problem in the CJ6A

 in flight will be different from troubleshooting a pneumatic system

problem in the Yak-52 in flight.



	




You're quite right ... I'd failed to notice that an aircraft type was not specified ... and I'm YAK-52 biased anyway ;-)



Rob R

dsavarese(at)elmore.rr.co
Guest

Posted: Tue Feb 21, 2006 8:43 am Post subject: Distraction-the Best Medicine

Rob,

I disagree.  The first thing you want to do is get the gear back down.  Not 

try to figure out where the air is leaking from which by the time I get all 

that sorted out in my brain and still fly the airplane, may deplete 

everything in the main air system.  That in itself reduces the adrenalin 

flow.  I would not turn off my main air supply when I have 28 ATM's 

remaining until AFTER I get the gear back down regardless if it's leaking or 

not.  Turning off the main air supply before I put the gear down pretty much 

assumes I'm going to use the emergency air to get the gear down.  Why use 

what you don't have to?  Personally, I prefer to save that for when I really 

need it.  If the gear is down and locked and I land I can always turn on the 

emergency air to supply air to the brakes if the main air supply is 

depleted.  Just as long as the gear is down and locked, I have the emergency 

system as the backup, which is was it intended to be in the first place.



Once again, I don't disagree with you wanting to assess the problem.  I just 

personally prefer assessing this type of problem on the ground.    In 

reality, most (I did not say all) pilots in that situation will want to get 

the gear down and leave it down.  Then land and troubleshoot.

Dennis



---

Rob Rowe

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

Posted: Tue Feb 21, 2006 9:07 am Post subject: Re: Distraction-the Best Medicine

Dennis,



Ok guess we'll (dis)agree to differ ... you propose getting the gear down as being paramount (even if you don't know what the likely leak cause is .. so you'll have to assume flaps, brakes etc are all suspect).



My preference is to safely trouble shoot the problem to try and quantify what I've got to deal with ... and be prepared to use the back-up systems (if needed) because that's what they were designed to do.



Same problem ... two approaches ... pick the one you feel most comfortable in handling.



Rob R

dsavarese(at)elmore.rr.co
Guest

Posted: Tue Feb 21, 2006 9:23 am Post subject: Distraction-the Best Medicine

Now we agree.  <Same problem ... two approaches ... pick the one you feel 

most comfortable in handling.>

Dennis

---

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