SB inspect heads

[jetjr]

Fair call Don, when its put like that

 

If it is an information gathering exercise, why before next flight?

 

Brave owner to ignore it even of it is advisory

 

 

[DonRamsay]

. . why before next flight?

Perhaps answered your own question with "Brave owner to ignore it even of it is advisory".

 

 

[facthunter]

There are two issues there . Legal (Now) and safety. The link must be established or people will regard the matter as not proven. To err on the side of safety is prudent and to err is human I err, suppose. Nev

 

 

[DonRamsay]

Nev, I was pleased to be able to shake your hand as I dashed out the door from the AGM. All these years and it finally happened! Hope to actually get to talk to you next time. :-)

 

 

[facthunter]

Keep up the good work Don We must converse. Nev

 

 

[biggles]

Biggles, what's creative about the pics?

Oh dear , sorry DS , blxxdy IPad again . Now removed

 

Bob

 

 

[biggles]

I have just finished an examination of my engine cylinder heads using magnifying glass , torch etc. The whole operation from start to finish took about 3 hours . Found nothing , as I expected , but certainly worth keeping a regular check on . The engine has done 350 hours ( trouble free ) but as indicated previously , runs very cool with CHT's around 210 F in cruise .

 

Bob

 

 

[jetjr]

Don the issue is by raising SA it has become legal, I wont be ignoring it for this fact alone. As discussed here the outcome of these cracks is likely to be very little and could maybe have waited until next service rather than before next flight

 

Bob, howd you get a good look around lower bolts, especially the center bottom one?

 

 

[bexrbetter]

Biggles, what's creative about the pics?

It was posted as a compliment to your artistic work!

 

 

[biggles]

Bob, howd you get a good look around lower bolts, especially the center bottom one?

JJR ,

 

It's a bit crowded down there and best if you can lay on some sort of elevated platform to get a bit closer , which I didn't have , so a fair bit of squirming around . As indicated elsewhere on this thread , a good light source , magnifying glass etc. are needed .

 

Bob

 

 

[DonRamsay]

. . . the outcome of these cracks is likely to be very little and could maybe have waited until next service rather than before next flight . . . .

I don't have the technical knowledge or experience to judge that.

 

However, if you are the Tech Mgr and you say "next service" and an engine fails before next service . . .

 

Also, the sooner everyone reports in, the sooner it can be determined whether this is unusual or an epidemic and the Tech Manager can go back to the manufacturer with the results - real evidence.

 

 

[jetjr]

Ok but who has assessed this has the potential to be an engine failure

 

3 or more hour maintenence before next flight is a significant impact.

 

If you make things advisory and difficult, it will be done poorly or not at all

 

 

[facthunter]

Certain cracks occur and are permitted on engines where they are inspected and considered safe for continued flight for "X" hours. where the progress of the crack is monitored but may reach a point where immediate action is required. This is usually in heads or sometimes crankcases, but each individual instance has it's own parameters for safe continuation of use. There can be no assumption that ALL cracks can be disregarded if you just look at them occasionally. They can be a sign of imminent failure of a structural part. Plenty of Cylinder heads on the P&W 1830 failed at the shrink band and the head comes right off the engine, putting a dangerous amount of oil all around the place. Nev

 

 

[JEM]

Had my Jab 2200 (22J 59) checked yesterday. No cracks. Engine has 370 since O. H.

 

 

[frank marriott]

Be an interesting argument develop if every time a cracked head was found on say a C182 [been quite a few] and an AD was produced requiring all Cessnas to be inspected before next flight - never has/will happen.

 

Form your own opinion of THIS AD.

 

 

[01rmb]

Seems to be a bit of an over reaction to me but it aligns with the anti Jabiru sentiment within RA Aus and some members of the board as displayed by the CEO's press statement following the recent forced landing of an aircraft (that had nothing to do with the engine) vowing to sort out the problems with Jabiru.

 

Why nothing from Jabiru and nothing from CASA (they have registered Jabiru and Jabiru powered aircraft)? And if it is so critical, why not email me rather the AD rather than put it on a web site which has no reason for me to go to .

 

We are all keen to improve safety so sure check it at the next service but why before next flight? Are we going to have this every time somebody finds some minor problem?

 

It isn't a conspiracy if they are actually out to get you!!

 

 

[ave8rr]

And if it is so critical, why not email me rather the AD rather than put it on a web site which has no reason for me to go to .

It is up to the aircraft owner to see that the aircraft complies with all AD/SB etc. It was pointed out at the last CASA Seminar I attended a few weeks back that it is up to the Registered Owner / Operator to check the CASA site for AD/SB etc.

I often check the Vans site for bulletins and I know Jabiru post on their site.

 

 

[facthunter]

Where was this requirement published in Australia and are there any other AD's on jabiru heads re crack's etc? Nev

 

 

[rhysmcc]

Where was this requirement published in Australia and are there any other AD's on jabiru heads re crack's etc? Nev

The AD was posted on the RA-AUS website, if that was what you were referring to.

 

 

[facthunter]

I thought it was published in Africa, but are there other AD's on the Jabiru heads? I know they were drilling little vent holes to allow oil to drain but that was a bit of a ????? wasn't it? . Nev

 

 

[Camel]

The posts about Jabiru providing SB and others overreacting , Jabiru are not as helpful as they could be ! Jabiru have a SB on valve washers to inspect, Do you want to rely on Jabiru to give you info or do you want the facts as it is seen by persons acting responsible for our safety. I find The UK site very believeable. The UK opinion has been shared by several other L2's here, so what do you think ?

 

Extract from Jab SB. http://www.jabiru.net.au/images/JSL008-1_Valve_Spring_Washer_Wear.pdf

 

• Two incidents, one year apart, have been reported to Jabiru Aircraft: in each a valve jammed in the collet, causing the top spring washer to rotate with the valve and wear against the valve spring, eventually causing a failure of the washer and engine stoppage.
   
   
   
  
•  In both cases the engines were operated in dusty conditions and dirt contamination was found within the carburettor and intake plenum.
   
   
   
   
  
•  It is likely that dirt contamination caused the valve to jam in its collets.
   
   
   
   
  
•  Jabiru Aircraft are releasing this document to alert owners and maintainers to the potential issue. The next revision of Jabiru engine service documentation will also incorporate the inspections detailed herein.
   
   
   
   
  
•  Jabiru Aircraft and Engines are designed to operate from “typical” airfields. If they are operated in dusty conditions additional maintenance is recommended as noted in Section 3.2.
   
  This is from UK, Extract from http://www.jabiruworkshop.com/valve-spring-washer-adverse-wear/
  Valve Spring Washer Adverse Wear
  Posted on April 22, 2013 by Roger Lewis
  On account of 2 incidents, Jabiru issued JSL 008-1on the subject. Reading the service letter we are led to believe that in each incident, the failure of the washer was due to the aircraft being operated in dusty conditions. To support this we are shown a picture of a carburettor.
   
  While ingestion of dust may be a contributing factor, I find it is difficult to believe that it is the major factor. Engines have been running for many years in all sorts of conditions without these washers failing. So what has changed within the engine to make it more susceptible to this type of failure?
   
  1. Older engines have oil feed lubricating the valve guides and collets. Engines fitted with hollow push rods do not have oil lubricating the collets.
  2. Older engines have G&S valves and collets. Newer engines use different valves and collets which sit differently on the valve washer.
  3. Older engines use heavy duty valve spring washers with different cross sectional profiles. New engines have lighter duty washers. The picture shows both types:
   
  
   
  Inspection of both types of washers removed from serviceable engines operating in the UK show witness marks on both types of washers. However, the curved profile of the heavier duty washers appears more resistant to possibility of a total washer failure.
   
  While the letter is advisory, during top end maintenance it is well worth removing the valves and inspecting the underneath of the washers. Look for radial wear caused by the spring. If the washers are of the light duty type and the wear is significant then replace them. Also smooth off any sharp ends of the spring that could be causing the wear.
   
  For those contemplating ‘upgrading’ to hollow pushrods, think of the consequences of removing the oil flow over the valve stems and guides.
   
   
   
  

 

 

 

 

[facthunter]

At the low RPM these engines operate at, that sort of failure should be unlikely. Fit and metal hardness would be the first place I would check. Nev

 

 

[Camel]

At the low RPM these engines operate at, that sort of failure should be unlikely. Fit and metal hardness would be the first place I would check. Nev

On inspection of my washer when pushing them around with screwdriver it marked the metal quite easily, obviously not that hard, mine has oil feed pipes to the heads with plenty of lubrication. I think you are on the right track Nev.

 

 

[Old Koreelah]

Oh dear , sorry DS , blxxdy IPad again . Now removedBob

I've done that a few times as well, Biggles. A bit like when you're around the other gender, it pays to be careful what you touch...

 

 

[DonRamsay]

Camel,

 

If you would like to know a bit more about this issue, have a word with Keith Rule. If you need his contact details, send me an email, PM or text.

 

Regards

 

Don