Light aircraft crash near Palgrave, Qld. 19/10/23

[turboplanner]

1 hour ago, RFguy said:

I wonder if my concerns about the way Jabiru aircraft are wired is any contribution to the (post?) accident fire.

The fire percentages are too low. On the other hand I've seen a few positive to negative circuits with kit builds and boats as well as a few negatives to negatives with accessories and wornering why they don't work.

[RFguy]

With refernce to the post about the battery fire of the tasmanian  fire, :
Read what the ATSB wrote about the TASMANIAN  accident  and as usual t they've made mistakes and wild assumptions  that are not necessarily correct..(about battery chemistry) .. I have told them.... Lithium Iin (Polymer) batteries associated generally with scooter fires etc are different chemistry to the Lithium Iron Phospate. This was a Lithium Phosphate battery, most likely, and while they can experience thermal runaway, it's hard to acheive..... It would have to depend on the ratio of charge input to capacity .... The weight of the battery would be able to tell us that. 

Chargers and regulators  (for any chemstry - but particular Lithium chemistries ) should probably have battery temperature cutoff for disconnect of charge or discharge. 

 

Edited October 21, 2023 by RFguy

[Markdun]

He only recently had the Gen1 3300 in his J160  replaced with a Gen4 by Jabiru at Bundaberg (3 months ago). He was selling his old Gen1 3300 which has 860 hours on it. So unlikely to be lacking experience or being current.

 

 

 

 

Moderator edit: Comment posted 3 times. Extra copies deleted.

[facthunter]

Whether it did or not, your concerns are well founded. GA planes are more strict as far as I know. It's easy to get a little casual about these things but you can't lift the bonnet in the air and isolation is your only  method of dealing with it and trouble shoot if you have time.  Nev

[Vick1004]

Can everyone please refrain from making assumptions and comments on this tragedy as there is a family grieving. 

 

An investigation is currently underway with considerable feedback so far.

 

A distress call was made and the pilot had attempted to turn around to fly back to his point of origin (Warwick), witnesses heard the engine spluttering and running like a hairy dog and then saw it was engulfed in flames before impact, investigators have taken samples of fuel from Warwick for testing as the pilot and aircraft had no issues when flying the day prior from up the coast.

 

Until the investigation is completed and the family has their answers, please be kind with your words.

[RFguy]

An in flight fire... putting aside eletricals , and looking at a fluid induced fire :

At my last annual on the Piper, all fluid hoses under the cowling got replaced. Cost a bit.  They were pretty old , well outside the hose manufacturer  limit of 8 years, and various other requirements . They bent OK, so, OK.  I'm OK with the replacement requirement  - an oil or fuel hose leak under pressure  would be bad . 

 

Unlike the rotax setup, which weaves all around the cowling ,  The fuel line run in a Jabiru is short from firewall to fuel pump and carb direct.  

In a Jabiru, an overflowing Bing carby cannot easily end up on the exhaust manifold OR muffler ... it is behind the exhaust muffler  . A leaking gasket on the fuel pump might be possible, but it would likely be drops.  THose fuel lines are only a few psi, I would be surprised if the hose came off with or without a worm-band clamp. 

Oil leaks- any engine oil leak from the block and push rod tubes  is going to be SLOW. drops.... unless a hose to and from the oil cooler failed, that would end up on the muffler. 

 

The Rotax requirement of 5 year replacement on hoses also is a bit too much of an B-S overstretch by the Rotax  I think, There isnt much pressure in those hoses - the oil is  low pressure or under vaccuum, and the water, well if you lose water, that's your own problem. Fuel  - that's the $64 question- a fuel hose leak  is bad. A few are probably improperly terminated hoses (band clamp in the wrong place etc ). Fire sleeve is good but might mask leaks but will contain a serious leaf and provides additional protection .  Hence a good reason to go for high quality hose. A hose manufacturer that stands to cop reputational loss  if you have a problem  .

I would some hose failures in LSA  are related to friction between the hose and something else.  My Jabiru had a chafed fuel line hose.  I'd be much more concerned about fuel hoses in the rotax (long and many) , and I'd be more concerned about where the overflow from the carbys are (rotax)  - right over the exhaust manifold.  So take care with that... The Lyco has steel braided hoses everywhere. A good reason....

 

RAAus are going to have to expend money to get to the bottom of this.  
In flight with engine spluttering ( as reported above) could be anything, but suggests to me fuel starvation and a fuel fire AT A COMPLETE GUESS.

 

 

 

Edited October 21, 2023 by RFguy

[dlegg]

The only other possible leak point on the jab is the oil cooler and hoses to it, all under 50 + psi.

[RFguy]

yeah , like I said in my expose'  - ".. unless a hose to and from the oil cooler failed, that would end up on the muffler. "

Those are barbed fittings and must be clamped correctly. Oil filter could have failed, also, there have been a few oil filters split / come off.....

 

[facthunter]

50 PSI is plenty The radiator is only 13 and they often leak.  There's generally more vibration with aero stuff than a normal motor vehicle.  Nev

[RFguy]

MarkDunstone in conversation made a good point that high pressure leaks may well vapourize effectively the fluid into a nice combustable mist... Fire sleeve whilst becoming soaked, would contain the spray ultimately turning it into a drop/liquid, rather than an aerosol.

[dlegg]

Warwick to Palgrave direct is about 18nm, so only 10 mins or so flight time after taking off after refueling. So clearly catastrophic RIP

[facthunter]

Oil dripping on hot pipes ignites better than  liquid fuel. The liquid shrouds the area in rich mixture  too rich to  burn whereas the oil sticks to the hot area better and ignites.   Nev

[old fart]

Some years ago the GFA directed motor gliders to check their fire retardant coatings in engine bays. 

My factory built J160C had raw fibreglass faces on the inside of the upper and lower cowls. 

At that time I coated them with Fire Free 88 paint to possibly gain time in the event of a fire. 

Check their demo video as to the effectiveness.  Our backyard test was equally impressive. 

O F 

[RFguy]

excellent comment ! OK there it is : dont forget to re-calc /measure the W&B 

https://www.firefree.com/fire-retardant-fire-resistant-paint-products/ff88-intumescent-coating.php

 

https://www.firedefender.com.au/pdf/TECHNICAL-DATA-SHEET-AU-FINAL.pdf

 

A couple of things- the fibreglass going above its glass temperature will quickly lose its shape/strength. The fire guard stuff might be useful to prevent the fibreglass itself catching fire.

Others will no doubt have some experience here. 

 

[derekliston]

6 hours ago, RFguy said:

yeah , like I said in my expose'  - ".. unless a hose to and from the oil cooler failed, that would end up on the muffler. "

Those are barbed fittings and must be clamped correctly. Oil filter could have failed, also, there have been a few oil filters split / come off.....

 

The barbed fittings do have to be clamped, I agree, but having said that, when replacing oil hoses I have not yet succeeded in removing one from a barb without cutting it!

[derekliston]

5 hours ago, dlegg said:

Warwick to Palgrave direct is about 18nm, so only 10 mins or so flight time after taking off after refueling. So clearly catastrophic RIP

Assuming that he did in fact refuel at Warwick. I tried to refuel my CH701 at Warwick on Friday and discovered the stepladder has been nicked, or is otherwise missing! So I had to take my own ladder yesterday! Jabiru being high wing also, is it possible to refuel without a ladder?

[RFguy]

Enter the term : AutoIgnition temperature (AIT)  (not to be confused with flashpoint) ... OIl has a lower AIT  than gasoline.

 

Doing some reading, the autoignition temperature is probabalistic- to get reliable ignition, for gasoline LIQUID , you must be miles over, like 2x the AIT to get reliable combustion - around 580C  for gasoline. 450C for engine oil approx.

(ignition is where the rate of gain of heat is positive) 

The AIT for varies for varying  surface area to volume ratio is high (IE vapourized), amount of oxygen, pressure, turbulence  etc etc etc  . Someone here will know this stuff better than I . Please chime in. 

in my experience,  hard to get a fire if a little fuel drips on a exhaust or manifold,With oil, I've only had lots of smoke (vehicles). But, it's probabalistic, get enough action and it will ignite if above some temperature.

The AIT definition is temperature that  ignition occurs  at normal atmosphere and the state for that material in that atmosphere (ie liquid for gasoline, oil )  

Edited October 22, 2023 by RFguy

[facthunter]

There's more to it than Ignition temperature.  The richness comes into it . Too rich or lean and it won't ignite. Oil sits and runs longer with a more varied range of conditions prevailing. This was taught in Airlines when pilots were trained by the airline and no doubt well trained fire fighters would know also.  Nev

[onetrack]

There's been a substantial number of fires in earthmoving equipment, where the machine burnt to the ground. In virtually every case, the major fire cause was a burst high pressure oil line near the hot exhaust manifold.

Lube oil sprayed in a high pressure fan spray pattern over a hot manifold, most certainly does burst into flame, almost immediately.

You wouldn't think an item of heavy construction or mining equipment would burn, but I can assure you, they burn as well as anything else. I can well imagine how much a small initial fire on an aircraft would be fanned by airflow.

 

https://www.resourcesregulator.nsw.gov.au/sites/default/files/documents/fires-on-mobile-plant-january-to-march-2019.pdf

[Markdun]

Three points.  First, from my boating, the explosive combustion mixture range for petrol is extreme; not so for diesel/kerosene.  Second, from my repair of a Jab flap where I wanted to determine what the fibreglass reinforcement was in the layup, I burnt some small damaged segments. It pretty much caught alight like a candle; the epoxy melting and wicking along the fibreglass fibres…self sustaining very very quickly, not as quick as Stits doped fabric for sure, but fricking quick, and much harder to blow out than a candle. Three, how much combustible plastic firewall fwd eg. airbox, starter motor cable insulation, plastic relay housing, coolant overflow bottle.

Don Kendall always said the main decision for an on flight fire is whether to jump out to have a short, certain, sudden death vs the alternative.

[danny_galaga]

1 hour ago, Markdun said:

Three points.  First, from my boating, the explosive combustion mixture range for petrol is extreme; not so for diesel/kerosene.  Second, from my repair of a Jab flap where I wanted to determine what the fibreglass reinforcement was in the layup, I burnt some small damaged segments. It pretty much caught alight like a candle; the epoxy melting and wicking along the fibreglass fibres…self sustaining very very quickly, not as quick as Stits doped fabric for sure, but fricking quick, and much harder to blow out than a candle. Three, how much combustible plastic firewall fwd eg. airbox, starter motor cable insulation, plastic relay housing, coolant overflow bottle.

Don Kendall always said the main decision for an on flight fire is whether to jump out to have a short, certain, sudden death vs the alternative.

Dunno. The pilot of the Jab in the example linked earlier survived. He kept it together even once his clothes caught on fire. Not saying I would be as determined but it's a real example of hanging in there and surviving.

[derekliston]

Sorry if this seems like thread drift, it is related I promise! An awful lot of years ago whilst myself and a couple of mates were apprentices in Ferranti’s research lab, we were, as apprentices are wont to, mucking about one Saturday morning with a bit of fibreglass scrap from the case of one of the electronic boxes. Don’t remember how it came about, but we set light to it and it went up, as someone said elsewhere, like a candle! On the Monday the designer was completing a form for the Navy about the fire risk and he said nil risk! We told him he was wrong and demonstrated with another piece of scrap. Well that resulted in a complete redesign to comprise an aluminium case. I have been wary of resin based structures ever since and more so now, since I have seen what happens with these plastic fantastics! I have minimal plastic on my CH701 and I like it that way. My cowling, apart from a Jabiru supplied nosebowl, is aluminium.

[Markdun]

Danny, I dunno too.  There was also that Jab at Wagga a few years back that landed with a fire, & then completely burned and both occupants escaped unharmed.  And I feel the Jab might perhaps provide 30 seconds to a minute more than my all wood (mostly large matchsticks) Corby, or my fabric covered steel Cygnet.  It would be good to have some analysis of what data there is.

 

I also know of a guy (& his wife) that were left standing in just their swimmers when their 11m sailing catamaran caught alight.  They parked it on a sand bar in the Gulf of Carpentaria as you do. While doing a little bit of fiddling the commutator spark from a 12v fan to keep them cool in the cabin while waiting for the tide to come back in, ignited some acetone vapour used to clean a paint brush. Despite having fire extinguishers and sea water and two fit and active ppl to hold the hose/toss the bucket, the whole thing burnt down in minutes.

[Markdun]

Aluminium better for sure, but it burns too.  Ask the British navy about that.

[facthunter]

Set alight by  exocet  missiles. That's a high ignition temp. Usually aluminium just melts when cars burn. Gears sitting in a shield of molten aluminium on the road. Be good as a shed  Ornament.. "From the Hottest Car I ever had".  Nev