Today's Message Index:
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1. 10:43 AM - CJ Air Leak and Landing Gear problem (Thomas McKeon)
2. 12:01 PM - Re: CJ Air Leak and Landing Gear problem (Walter Lannon)
3. 03:12 PM - Re: CJ Air Leak and Landing Gear problem (Warren Hill)
4. 04:20 PM - Re: CJ Air Leak and Landing Gear problem (Joe Howse)
5. 07:27 PM - Re: CJ Air Leak and Landing Gear problem (Byron Fox)
Message 1
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| Subject: | CJ Air Leak and Landing Gear problem |
Hello=2C
I just recently imported a CJ-6 from China to the US. I flew it from CA to
FL with no problems other than prehaps a bumpy landing or two. After arri
ving at my destination in FL=2C the next day I went to check on the plane a
nd noticed that the the air had dropped down to about 20 atm. A few days l
ater (gauge was at 0) I pumped it back up and took the plane for a few laps
in the pattern. The first thing I noticed was that the landing gear would
not retract. The brakes and flaps worked just fine. After landing I doub
le checked and the rear cockpit had the landing gear handle in the neutral
position. I parked the plane and then returned the next day to have a look
at it. Again the air had dropped to about 20 atm. One other thing I noti
ced was that I could hear air leaking out of the "snot valve" on the belly
of the plane. I'm not sure if that is residual from the filter or if it's
comming from the main air line. And I'm not sure how this ties into my lan
ding gear problem. Oh=2C and I made sure to tighten the main air valve eac
h time I shut down the plane.
The plane has a total of 25 hours since it's arrival in the United States.
I am also brand new to the CJ and not a mechanic. I'm hoping I can just r
eplace a check valve somewhere but I don't know where to start. Any advice
would be appreciated.
Thanks=2C
Tom
Message 2
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| Subject: | Re: CJ Air Leak and Landing Gear problem |
Tom;
Assuming you had approx. 40 or more atm=99s during the ferry
flight the loss of 20 atm=99s in the OPERATING SYSTEM one day
after closing the main valve is not that unusual. There is invariably
some loss in the system. A good tight system should hold some pressure
for a week or more but typically it is more like 2 =933 days.
When you recharge the system by opening the valve expect to see a loss
of 3 or 4 atm=99s from the pressure at last shut-down due to
re-fill of the system. Anything more than that may indicate a leak in
the STORAGE system.
Operating system leakage can be found and corrected with a lot of time
and patience.
How much pressure on the guage when the gear failed to retract? I
assume from your post that you know the rear gear and flap handles must
be in neutral for front operation.
Walt
From: Thomas McKeon
Sent: Sunday, September 02, 2012 10:41 AM
Subject: Yak-List: CJ Air Leak and Landing Gear problem
Hello,
I just recently imported a CJ-6 from China to the US. I flew it from CA
to FL with no problems other than prehaps a bumpy landing or two. After
arriving at my destination in FL, the next day I went to check on the
plane and noticed that the the air had dropped down to about 20 atm. A
few days later (gauge was at 0) I pumped it back up and took the plane
for a few laps in the pattern. The first thing I noticed was that the
landing gear would not retract. The brakes and flaps worked just fine.
After landing I double checked and the rear cockpit had the landing gear
handle in the neutral position. I parked the plane and then returned
the next day to have a look at it. Again the air had dropped to about
20 atm. One other thing I noticed was that I could hear air leaking out
of the "snot valve" on the belly of the plane. I'm not sure if that is
residual from the filter or if it's comming from the main air line. And
I'm not sure how this ties into my landing gear problem. Oh, and I made
sure to tighten the main air valve each time I shut down the plane.
The plane has a total of 25 hours since it's arrival in the United
States. I am also brand new to the CJ and not a mechanic. I'm hoping I
can just replace a check valve somewhere but I don't know where to
start. Any advice would be appreciated.
Thanks,
Tom
Message 3
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| Subject: | Re: CJ Air Leak and Landing Gear problem |
Thomas,
There are two possibilities. I had the exact same problem. If the gear
fails to retract, you have a leak in the emergency system.
First, and most likely is one of the two emergency system check valves
on the firewall. See the attached picture for what mine looked like. The
other is one, or both of the two emergency air on-off valves in the
forward and aft cockpits. You'll have to chase these systematically, but
I would start with the emergency system firewall check valves. For me,
it turned out that I had two bad firewall emergency system check valves
and a bad emergency on-off value in the forward cockpit.
When you turn off the main air, it's not unusual for the main air
pressure gauge to bleed down to zero after several hours. What matters
is that when you turn back on the main air that it comes back to 40
ATMs. The emergency system air gauge should stay at 40 ATMs, or more,
all the time.
If you would like some more detailed help, contact me off line and we
can work through this.
Welcome to the CJ-6A. The tired old clich=E9 is that flying a CJ is
mostly to discover what needs to be fixed next.
Good luck with everything,
Warren Hill
N464TW
On Sep 2, 2012, at 10:41 AM, Thomas McKeon wrote:
> Hello,
>
> I just recently imported a CJ-6 from China to the US. I flew it from
CA to FL with no problems other than prehaps a bumpy landing or two.
After arriving at my destination in FL, the next day I went to check on
the plane and noticed that the the air had dropped down to about 20 atm.
A few days later (gauge was at 0) I pumped it back up and took the
plane for a few laps in the pattern. The first thing I noticed was that
the landing gear would not retract. The brakes and flaps worked just
fine. After landing I double checked and the rear cockpit had the
landing gear handle in the neutral position. I parked the plane and
then returned the next day to have a look at it. Again the air had
dropped to about 20 atm. One other thing I noticed was that I could
hear air leaking out of the "snot valve" on the belly of the plane. I'm
not sure if that is residual from the filter or if it's comming from the
main air line. And I'm not sure how this ties into my landing gear
problem. Oh, and I made sure to tighten the main air valve each time I
shut down the plane.
>
> The plane has a total of 25 hours since it's arrival in the United
States. I am also brand new to the CJ and not a mechanic. I'm hoping I
can just replace a check valve somewhere but I don't know where to
start. Any advice would be appreciated.
>
> Thanks,
> Tom
>
>
>
>
>
>
Message 4
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| Subject: | Re: CJ Air Leak and Landing Gear problem |
Had a similar problem once, turned out to be a bad "O" ring on the
nose gear retraction piston, worked OK on the jacks but could not
overcome the air load in flight, air would bypass and exhaust through
the gear valve,
Cure was new "O" ring.
Air leak at snot valve probably corroded drain valve.
Joe
Message 5
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| Subject: | Re: CJ Air Leak and Landing Gear problem |
I assume the compressor is making good air.
First, take the slot apart and clean it. Having some garbage in the air syst
em in plane new to the US isn't uncommon.
Second, you may have emergency air bleeding through to the down side. If so,
the gear will not come up. Study the pneumatic system diagram and crack a n
ut on an emergency line to one of the main gear actuators. If air comes out,
and it should not, you have a leaking check valve. Pull the check valves on
the port firewall adjacent to the descendent filter. Chances are one of the
rubber disks in the two valves has failed. It'll be obvious when you open t
hem up. Doug Sapp has a kit which solve the problem. If your can find a rece
nt Red Alert archived on the RPA web, John Long wrote a great article on the
subject.
Blitz Fox
415-307-2405
On Sep 2, 2012, at 10:41 AM, Thomas McKeon <tmckeon79@hotmail.com> wrote:
> Hello,
>
> I just recently imported a CJ-6 from China to the US. I flew it from CA t
o FL with no problems other than prehaps a bumpy landing or two. After arri
ving at my destination in FL, the next day I went to check on the plane and n
oticed that the the air had dropped down to about 20 atm. A few days later (
gauge was at 0) I pumped it back up and took the plane for a few laps in the
pattern. The first thing I noticed was that the landing gear would not ret
ract. The brakes and flaps worked just fine. After landing I double checke
d and the rear cockpit had the landing gear handle in the neutral position.
I parked the plane and then returned the next day to have a look at it. Ag
ain the air had dropped to about 20 atm. One other thing I noticed was that
I could hear air leaking out of the "snot valve" on the belly of the plane.
I'm not sure if that is residual from the filter or if it's comming from t
he main air line. And I'm not sure how this ties into my landing gear probl
em. Oh, and I made sure to tighten the main air valve each time I shut down
the plane.
>
> The plane has a total of 25 hours since it's arrival in the United States.
I am also brand new to the CJ and not a mechanic. I'm hoping I can just r
eplace a check valve somewhere but I don't know where to start. Any advice w
ould be appreciated.
>
> Thanks,
> Tom
>
>
>
>
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