A pilot has had a lucky escape after his light plane crashed in western Queensland.

[bilby54]

A pilot has had a lucky escape after his light plane crashed in western Queensland.

 

Police say the plane ran out of fuel and crashed on to a dirt track about 20 kilometres from Longreach, at about 4:00pm yesterday.

 

The pilot was not injured.

This incident provided me with a distinct change in my friday night agenda as it was our club Jabiru that came to grief. It is never a fun thing to receive a call from the police even if no one was hurt.

 

The pilot was fortunately, uninjured other than a few bumps and bruises to contend with so something good was salvaged from the wreck but we now have a three day road trip and recovery exercise to contend with but aircraft, like most machines, can be repaired.

 

The worrying thing for me was that the aircraft did indeed run out of fuel but well and truly way before it was planned for. Yes it is the pilots responsibility to monitor the fuel situation but some other factor has caused the engine to use more fuel and run out approximately 1.5 hours early. This factor has quite probably increased the pilots stress level and with an airfield not far away....... the rest is now history. I

 

ncidently, the pilot made a near perfect landing but the nose wheel dug in and it went over onto its back....... pity it wasn't a tail dragger!

 

If the power setting was higher than normal cruise, then the fuel burn would increase but so would the speed so I find that not so convincing as a cause. The fuel boost pump on this aircraft is one that does not 'stall' on high pressure and the switch position is obscured from the pilot when normally seated. This is a possibile cause but I will not know until after the aircraft has been recovered and a detailed examination made.

 

As a matter of request, does anyone else have experience with unusually high fuel consumption on engines fitted with Bing 64 carburettors. I am not saying here that the carby is at fault, or the aux fuel pump, or the aircraft type, or anything else but I really would like to know if this has happened to anyone before to help prevent this from happening again.

 

I will keep you posted with any findings.

 

 

[Admin]

Bilby, I can't say for Jabs but the Rotax has Bing carbies and I presume a Rotax fuel pump and late last year there was an AD out on the fuel pump of the Rotax. My CT was affected and I got caught out with it using over 40 litres an hour with the crook pump. The fuel was just pumping out of one of the carbies

 

Not sure if there could be any realationship but it may be a place to start looking - the fuel pump - just a guess though and as I said I don't know anything about jab engines.

 

 

[IanR]

Another area to look at is if the fuel caps were properly in place - I think it has them in the wing ? I friend of mine was killed years ago when a fuel cap wasn't fitted properly and it sucked all the fuel out of the tank !

 

 

[jcamp]

Couple of things in a J160

 

Had a bit of trouble on a nrm-bud leg. Just had the new jets fitted and got nervous about the fuel gauge readings so went into cca to dip the tanks ~25l remaining so mutter grumble about the new jets. After some tests at bundy turned out to be an intermittent leak from header tank drain valve.

 

On another trip I had an engine failure due lack of fuel and restarted with highly unbalanced flight. Landed ~ 5 min later and taxied in. Subsequent draining on a level surface got 18L from the line to the engine. Action was fitting a level indicator in the header tank to show any departure from a full condition.

 

 

[bilby54]

I really appreciate the info and was not aware of the fuel pump AD as I don't really think that it matters what engine the carbs are fitted too.

 

I am really concerned that I missed this and may have inadvertently caused an unpleasant situation for someone with nearly fatal consequences. It is all so easy to say "pilot error" when it could well have been caused by events beyond the pilots control that has put them into a stressful and dangerous situation.

 

This model jab has the tank behind the seat but the fuel cap is still located in the low pressure air stream so will check that.

 

Thanks for the replies.

 

 

[Guest basscheffers]

If the power setting was higher than normal cruise, then the fuel burn would increase but so would the speed so I find that not so convincing as a cause.

You would need a whole lot of extra fuel for a little bit more speed, so I would not count it out entirely. If you fueled her up for 9 hours expecting 15lph, you would only need to burn 20% more fuel to fall 1.5 hours short. (18 lph) I doubt 20% more fuel burn will give you a significant speed advantage that would get you home 20% faster or that you would even notice.

Was it a multi-stop trip where the mistake might have been made to not allow for many climbs at much higher power settings?

 

I have no experience at all in these matters, but on a trip close the the J160 maximum duration, 1.5 hours doesn't seem like a whole lot of margin to me.

 

Is there anything in the manuals that gives fuel burn at anything other than 75% cruise? Work with Jabiru in finding out just how much higher the power setting must have been to run out 1.5 hours early.

 

Even if it turns out not to be practically a possible cause, knowing the answer would be good info for everyone here!

 

Strange, even most of the cheapest cars have flow meters that will tell you how many liters per 100 km you are doing. Are there any light planes equipped with such a device?

 

Bas.

 

 

[peterm]

Ive had my j170 use 25 L h or 100 L for 4 h flight @ 3000 fully loaded with cruse prop other times same power settings only using 75 L for 4 h flight.

 

 

[Captain]

Strange, even most of the cheapest cars have flow meters that will tell you how many liters per 100 km you are doing. Are there any light planes equipped with such a device?

Yes Bas. You can just go and buy them. I have a system that is resetable and records fuel used in each flight or each sector, shows Nm/litre and predicts fuel remaining at each waypoint ..... yet I still look regularly at the sight glass to make sure none is coming out somewhere else, just in case.

 

And I reckon it is a brave pilot (or one who is super confident in the performance of his fuel pickups) who allows any fuel tank to get below 1/4 full (I prefer at least 1/2).

 

Regards Geoff

 

 

[motzartmerv]

Hi bilby, havn't had this happen in a jab, but the other day i was on a nav with a student in a gazelle. We burnt 28 litres in a 55 min flight at 4900 rpm. Our level 2 (ex qantas engineer) thought it may have been a problem with the advanced spark system not working, so the thing ran on retarded spark the whole time. Im no engine man by any means, but apparently when the throttle is advanced above 3000 ropm this second lot of advanced spark is spose to kick in. He reckons it didnt so it was on delayed spark the entire time. We havn't been able to confirm or deny this as yet. But mabye some of you cleverer people could explain how this could happen and indeed if this would cause extra fuel burn.

 

cheers

 

 

[BigPete]

Interesting comment Geoff - I quite often allow my tanks to drain down to 10 liters a side with no problems. Whilst doing circuits I have let them down to 5 liters a side, again no problems.

 

Or are you talking about aircraft without a feeder tank?

 

regards

 

 

[bilby54]

I have no experience at all in these matters, but on a trip close the the J160 maximum duration, 1.5 hours doesn't seem like a whole lot of margin to me.

Bas.

I am not quite sure if what you wanted to say here came out the way that you wanted it to Bas. 1.5 hours fuel remaining is a lot of margin in aircraft terms.:confused: The old rule was to be on the ground with a minimum of 45 mins reserve.

 

The usual reason for high fuel usage is a loose or missing fuel cap but having recovered the aircraft from the accident site and made a close inspection; this is not the case. I can say that a mechanical situation has occurred in the fuel system to cause the fuel to be drained from the engine bay unexpectedly while the aircraft was in flight. This situation has occurred late in the flight and has apparently caught the pilot off guard as to the state of the fuel remaining and he was within sight of the airfield.

 

I will definitely get the info out on these forums as soon as I have determined the exact cause of the problem but Ian was on the right track.

 

Hey Motz, I'd get that Gazelle checked before you fly it again..... lame or no lame.:ah_oh:

 

Cheers

 

 

[Guest basscheffers]

I am not quite sure if what you wanted to say here came out the way that you wanted it to Bas. 1.5 hours fuel remaining is a lot of margin in aircraft terms.:confused: The old rule was to be on the ground with a minimum of 45 mins reserve.

What I mean is that 45 minutes is a good safety margin assuming your consumption is normal.

However, if you start of on a 9 hour run you, you only have to consistently use about 15% more fuel than you planned (either through mechanical failure or pilot error) to run out 1.5 hours short. It would be pretty strange not to notice of course as it is not a sudden thing, but then again stranger things have happened...

 

So yes, 1.5 hours of fuel remaining is a lot - slowly but consistently using an extra 1.5 hours on a long flight seems easy to do if you don't pay attention. (or the instruments fool you - fuel gauges can break. The one in my car is broken!)

 

 

[bushpilot]

re "Fuel gauges can break".. But on a J160 (the a/c in question here) there are 4 gauges - 2 directly in the wing tanks and 2 LEDs in the dash; I assume all with seperate sender units.. (Can someone confirm this?)

 

 

[Guest brentc]

Not all J160's have the dash display, but rather just the old fashioned site gauges in the wing roots. Some later 160's have the electronic displays. I've never trusted the site units in any Jabiru because I know they can be very unreliable. I cast my memory back to a J230 being written off when test flown at the factory for this very reason. The electronic ones aren't much better.

 

Even a calibrated dip-stick won't solve the problem as if the aircraft is on the slightest of leans it will give a largely erronous reading because of the skinny profile of the tanks.

 

Best bet is a fuel flow meter in conjunction with site gauges or average consumption based on what fuel went into the aircraft prior to the flight.

 

 

[Gibbo]

Breathers fitted in the wrong direction?

 

On a recent trip in a 160 I had a similar fuel burn issue of 34 lph. I started to get worried about the fuel consumption about 90 minutes into the flight.

 

When I landed at Renmark I noticed that the breather was mounted facing the rear on the right hand side with the left hand side facing forwards. The right hand side had a telltale Avgas 'stain' over the wing extending from the breather to the rear.

 

I reinstalled the breathers facing forwards and fuel burn reduced back to 21 lph.

 

I have never 'tested' my theory again but one plus one equaled two at the time.

 

I have flown seven different j-160's and have noticed on two of them that the breather can be installed facing either direction.

 

Has anyone ever tested or experienced the above?

 

Gibbo.

 

 

[Teckair]

Hi bilby, havn't had this happen in a jab, but the other day i was on a nav with a student in a gazelle. We burnt 28 litres in a 55 min flight at 4900 rpm. Our level 2 (ex qantas engineer) thought it may have been a problem with the advanced spark system not working, so the thing ran on retarded spark the whole time.

My understanding is the Gazelle has a Rotax 912 engine only and the 912 has fixed ignition timing with no auto advance above 3000 rpm. If this is correct you need to look further into why excess fuel was used.

 

Regards Richard.

 

 

[BigPete]

My J160c has a small pin which will only allow the breather to locate the right way. :thumb_up:

 

21 lph seems a tad high, :ah_oh: unless you were really pushing it a bit? (3000+ rpm) :big_grin:

 

regards

 

PS - Using the site glass in the wing root - add the level indicated for each side. I have found that this total gives me a good indication of all the fuel available, WHILST ON THE GROUND.

 

 

[Guest brentc]

I don't understand how the fuel burn could be high if the vent was on the wrong way. If there was a fuel stain and it was leaking, the fuel usage would still be the same because the fuel burnt by the engine would remain constant as the fuel flow meter has no way of measuring fuel lost from the fuel caps. If the fuel was somehow forced into the engine, it would run rich and not normally.

 

Pete, believe it or not, I've seen many a pilot put the caps on the wrong way. They usually mange to make them fit even though they won't be level when tightened.

 

 

[Gibbo]

Fuel burn

 

The two aircraft I mentioned had the pin holes in both directions and was the same on both sides so therefore the breather / fuel plug could be installed in both directions. The situation occurred with one breather (lhs) being fitted in the windward direction and the RHS being fitted towards the tail.

 

130l of fuel was being carried (ATO) and a definite stain was found on the RHS on landing.

 

'It appeared that a negative pressure on the RHS breather PLUS a positive pressure on the LHS was enough to stream fuel while in flight.'

 

The 21 lph was caused by a known factor that I won't go into any further into here other to say that I am a little on the large size and the aircraft normally cruises at around 17-18lph.

 

G

 

 

[BigPete]

I'm a bit short one end and I refuel using a ladder which puts me well above the wing. I've seen taller people than me refuel without the ladder and this may well let them replace the cap the wrong way simply because they can't see the cap properly.

 

regards

 

 

[bilby54]

A bit of an update on what happened.

 

The aircraft has been recovered from the crash site and apart from a broken prop, wing strut and windscreen, it is in great condition...... if you have to crash, do it in a Jab!

 

There is evidence of a fuel leak from the engine bay that has streamed out under the fuselage. It is very likely that the aux pump was left on for the flight and this has leaked past the needle and seat but will not know until I do some more testing this weekend.

 

There is also a possibility that the fuel level was not monitored sufficiently during the flight but I am not into a blame game just the safety aspects.

 

Cheers,

 

 

[Tomo]

G'day Bilby54,

 

I've just read the post and was sorry to hear of the accident.... I just wondered if you fitted a fuel pressure gauge or flow meter to the aircraft, would you notice a difference in pressure if it was leaking out the carby? but then again if the pump was left on it may even show higher pressure because it has backed up in the line, and that higher pressure is what made it push past the needle and seat?

 

And with a flow meter you may notice the excess fuel usage....

 

Just thought I'd throw you a few ideas that maybe you could think about.....

 

Cheers,

 

Tom

 

 

[Guest Bubba]

There is also a possibility that the fuel level was not monitored sufficiently during the flight

Hmmmmm! Would seem quite likely if it ran out short of its destination.

 

Bubba

 

 

[Ewen McPhee]

I worry that the fuel gauges make monitoring difficult

 

 

[Deskpilot]

KISS principle always wins. Take the Jab LSA55 for instance. Turn your head and see exactly how much fuel you have. Plenty of warning of a leak, provided you do turn your head occasionally.