onetrack

The Jabiru piston is produced in a plant that manufactures pistons for ACL. There are subtle differences but it is similar in most dimensions with the old 3.8L V6 Commodore engine, however the rest of the story is really a moot point.

The pistons are never the cause of any failure I have ever seen or heard about.

The biggest causes are likely to be the RAAus fleet and their tinkering owners.

If you think buying a C172 with an O/IO-360 in it means you have some highly scientifically special genuine Lycoming piston in it you are in for a shock. What is more it may have say a Superior Air Parts piston, and if you are ever in Texas and visit the Superior company you will find lots of parts, but not a factory, as they manufacture by sub contract from many and varied suppliers.

:ok:

No, but if you look at an exhaust valve from a Jabiru engine and compare it to a 0-320 you might be in for more of a shock. Compare shaft diameters, note the head and tip welded on the Jab. Even Don from Jabiru commented that should a Jabiru valve get a bit of lead stopping it from seating correctly the head could burn off in about 15 minutes!

One of the downsides of being both light and powerful.

A new valve design is out there and already being used, so let's hope that isn't something that will continue.

Luckily the valves are only $42 each versus $270 EACH for a Rotax 912 valve :ok:

Don't get me wrong....I like my Lycoming IO540 :ok:

This video is well worth the watch !

Young pilots praised for 'textbook' crash landing at Victoria Point - ABC News (Australian Broadcasting Corporation)

Just watched the video and a very impressive effort by the instructor. Although there was no sound he appeared to be pattering his way through the whole event. You could tell that his first concern after they stopped was how his student was going.:D

Don't Jabirus get dizzy up that high? and >5500 fpm descent rate is a smidge on the high side.

http://lh4.googleusercontent.com/-5A...ABC+report.jpg

Edit: I thought quoting it was enough :rolleyes:

Young Doug is well used to landing in farm strips and his home airfield has an interesting approach for a normal landing. You should have seen it before the new big strip went in. So Old Man Ron Field should be proud of the young fella.

Well done Doug!

I like the use of the spare booster seats cushions. Very good work.

:D :ok:

The ABC use of the term "crash landing" is odd, too. All landings are controlled crashes, and this one seemed pretty well controlled. Seen worse at the Sunday PFL competition :)

One thing I don't see easily available are incident/accident reports for RAA aircraft (don't know if either/both of the aircraft in this thread were RAA). Having both RAA and CASA licences, I was discouraged to read in the last RAA mag that they think that reporting to members on accidents is an optional activity for the organization. I'd say it was core business.

Just as pertinently, I don't know of any single sources of individual aircraft and engine stats for this branch of aviation. If I want to know how my certified puddle-jumper compares in the accident stats, I can look up a few FAA or similar statistics. It's slightly inconvenient in that databases in different jurisdictions probably need combining, but at least there is data available publicly. If Joe Pilot wants to have a look at the stats for non-certified aircraft, to whom does he turn? For example, if I wanted to compare the Jab stats (across various models/engines) with those from other manufacturers, is the data actually available?

If it has a VH tail whether it is Experimental, Limited or whatever it is logged and published.

If it is RAAus it is kept under lock and key by them. So you have no hope of answering that question.

The reason they do not publish is that they are not covered by the same laws that cover the ATSB. (read as ass covered)

RA-Aus is quite a private association of which you need to be a member to view pertinent information. It is also one of the reasons why their aircraft register remains private except to the tax man. You can request to view the information on premises, but nobody wants to have to do that, so overall agreed tecman, it's a crap system.

The recent absence of crash reports in the magazine was due to someone "preparing them in their own time" and that person no longer preparing them! :mad:

Some basic reports have now been produced again but don't contain anything much more than aircraft type, location and TTIS.

I would happily volunteer to prepare some crash reports with specific details however the reports would only be as good as the information provided :( Getting them to the stage of being useful to others could be difficult unless there's something blatantly common such as an engine issue that could help someone else prevent their own failure in that area. In the GA LAME world, they've seen it all before and know what to look for so there's little value in a LAME reading crash reports for pistons falling off a Lycoming, but in the RA-Aus world where most of the pilots are the maintainers, the required information is somewhat different to the GA world.

As the FTDK says, nobody is yet to invent a new way to crash an aircraft. We've been doing the same thing since aircraft were invented and we still continue to repeat history :ouch:

Bl**dy good job Mr. Field!! (Volumex, if you have another look at the article, it says 1,100 feet)

Excellent job boys, well done to walk away :ok:

Just a couple of observations from the video ( which may not be correct!! )

I've never flown a Jab and are not familiar with switch location:--

1/ they didn't appear to do to many checks after the failure? Is there any fuel pump to turn on? Mags to switch over? Mixture to play with? Fuel to check switched on? Could they have attempted to use the starter motor to get it going again?

2/ they appeared to already be at low power in a glide before the prop stopped as they didn't need to quickly lower the nose to maintain IAS. Indeed is it normal for the prop to stop windmilling in a Jab at normal glide speeds? ( unless it seized of course )

I am probably wrong but they looked way to calm under the situation.....!!

As I said at the top, well done on a successful outcome.

even without sounds, it looks to me like it would have been a very sudden failure, accompanied by a very loud and Instant BANG. maybe just a quick hit of the starter button/key would be enough to confirm that there would be no point in fuel/mag/throttle checks.

There is an electric fuel pump.
There are two ignition switches for the coils. Switch them on to ground and the engine stops. Not much you can do in a restart if they are already on.
No mixture control but it does have a fuel selector (on/off). He possibly glanced down to look at it but probably should have turned it off in preparation for a forced landing. (easy in hindsight)
Seems strange he didn't try the started (assumed) however as ultralight says she may have gone out with a big bang and a thump.

A prop won't windmill on a Jab as there's a faid wad of compression.
At a guess from experience it would take 140 knots before it will even think about turning over.


All valid questions from a GA driver as Jabs are a little different to the norm.

No doubt he did a brilliant job of getting her down safely and he appeared to do a good job of briefing the pilot on the pending doom.

Reading a newspaper report, if correct, there is a claim of engine surging before failure. Suggesting fuel tap probably checked before vid starts.






.

FYI - The cause was a cylinder popping off. The original article showed the front wheel spat covered in oil.

Ouch! Ha Ha! :D

In general I'd agree with the comments re crash comics, XXX. It's always interesting to read someone else's analysis but there may not be much new. What would be invaluable, though, is an accessible database with some stats. For example, anecdotes might lead to the hypothesis that Jabs fall out of the sky regularly although, with better engines, less often than they used to. But I've been around science and engineering long enough to know that humans are incredibly bad at intuiting things like real risk and failure rates.

The only way for Joe Pilot to answer the question I posed earlier is to have access to an objective database and derived stats. If that database is confined to objective data, I don't see that the ass covering Jaba mentions need be a great worry. I'm not idealist enough to expect manufacturers to hand over the data they undoubtedly do accumulate but surely we might expect our representative organizations to be able to derive and publish basic summaries.

Mmmmmmmm I let that observation go through to the keeper Bloggsy :hmm:

Wasn't sure if I should feel honored or insulted!!