My attempt to get this message onto the Jabiru engines list failed probably
since I'm unsubscribed or probably I used an incorrect address.
It occurs to me that a number of Europa Owners are running with Jabiru.
Perhaps you could circulate my message and get the points taken up by the
FAA Investigation Branch? I leave it to you:-
Regards
Bob Harrison G-PTAG Europa 337 Now with Rotax 914
Hi!
I used to contribute to this list and have recently picked up a FAA accident
report concerning a Jabiru 3300 engine.
The guy who made this report available is a Rotax "buff" and even may be a
maintenance engineer.
The said report is at :-
https://www.faasafety.gov/files/notices/2010/Apr/10-01%5B1%5D.pdf
However I have to contribute my experience on this matter for what it's
worth to satisfy my personal conscience that I have made my findings
available to any other Jabiru Engine/Bing Carb users and so ensure as far as
possible all souls are availed of this information.
It is quite possible that the FAA Accident Investigation organization
already have applied this information content but it is also possible that
people are still flying with a potential installation time bomb.
My deliberations follow below I hope those responsible will take a close
look at the installations in their domain to ensure that they are flying
safe:-
On Wed, Sep 8, 2010 at 1:44 AM, Robert C Harrison <ptag.dev@tiscali.co.uk>
wrote:
"Hi! Richard......
The symptoms of the Jabiru incident you publish here remind me of a
situation I had when I was test running mine (before I changed to a Rotax
914!)
There is a tiny brass nipple on the carb neck ( seeming by it's appearance
to call for a pipe to be attached ) there was no mention of this nipple in
the engine installation manual.
It looks like a carb float chamber overflow nipple. I reasoned therefore
that should fuel flow from it be likely then it should be directed into a
"catch bottle" so I put the pipe end into my oil breather separation bottle.
(later I think Jabiru issued an instruction that it was a fuel bowl pressure
stabilizing pipe and it should be directed into the carb intake air filter
after the filter / but before the carb intake.)
To continue :..my engine ran ok except I did get some oil spatter from the
oil catcher bottle and so put a loose fitting rag into the bottle neck.(
the amount of oil present in the bottle was minimal but I just may have,
whilst stuffing the rag into the neck, pushed the little pipe end below the
oil surface.)
The net result was on start up the engine ran rough and (unbeknown to me
smoked like a factory chimney for some time since I was working alone
outside the hangar ) I could not get a smooth running engine, someone
arrived and accused me of running up inside the hangar almost
simultaneously I had oil cover my screen from the engine compartment.
On stopping and further investigating I had massive fuel dilution to the
engine oil and the level was way over the top filling the breather bottle
to overflowing.
I sat and did a lot of head scratching and traced the sequence of events to
my stopping off the breather bottle with the rag. I removed the rag and the
pipe, changed the engine oil and the engine started flawlessly. As I said
above I eventually ran the pipe to new instructions.
If the unfortunate pilot had a similar installation and for some reason his
pressure balance pipe had been installed into the oil breather catch bottle
the same scenario would prevail. Why should the oil level in the bottle
suddenly increase? Well I discovered that the engine breather pipe was
attached to the neck of the oil filler/dip stick assembly and on filling
/top up of engine oil some would run down the breather pipe into the "catch"
bottle! So a simple top up of engine oil could have commenced the sequence
of events listed above.
Perhaps you would see that this info gets to the relevant authorities as an
unbiased contribution which if circulated will probably save further
incidents."
Needless to say the correspondent didn't wish to take the matter further
...wait for it ......because he is a Rotax man through and through!
So all he wanted to see was the Rotax publication section on carburetor
Installation the like of which I never saw during my Jabiru "infancy" but I
respect the fact that the Jabiru Installation Manual may include this
paragraph by now, and all is well so long as operators retro fitted the
pipes into the correct place.
Robert, Per the Rotax 912 Installation Manual Section 15.1.1, page 93:
CAUTION: The float chamber venting lines (3) lines have to be
routed into a ram-air and vacuum free zone or into the
airbox, according to the requirements and release of
BRP-Powertrain. See section 16. These lines must not
be routed into the slipstream or down the firewall.
Pressure differences between intake pressure and
pressure in the carburetor chambers may lead to
engine malfunction due to incorrect fuel supply.
Please someone take up the intent of this "chase" and see to it that the FAA
Accident Investigation people review the actual incident again in this
light.
Regards
Bob Harrison (G-PTAG Europa now with Rotax 914)
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