Jab down at Wentworth

[kevinfrost]

Anyone heard of a Jab down on the airfield at Wentworth this afternoon. Heard it was from Murray Bridge.

 

 

[Compulsion]

I hope your wrong. The guys from RPA are away this weekend. I am not sure if that is where they went.

 

 

[kevinfrost]

It was a group fly away, one of the group from here phoned a friend to let him know it wasn't him in case we had heard about it.

 

I know no more than that.

 

 

[Thirsty]

It was one of the lsa55 from rpa. Not sure yet what made the engine stop but it was put down in the scrub and flipped over on landing. Pilot and pax both fine with nil injuries. Aircraft maybe written off. More to come.

 

 

[Thirsty]

Oh yeah, it wasn't mechanical failure based on what the pilot told me. Sounds like fuel exhaustion or some sort of problem related to fuel.

 

 

[kevinfrost]

Good to know they're fine.

 

 

[Compulsion]

Thank god they are fine. Had to be one of my instructors. Let us know if anyone knows who it was.

 

 

[Thirsty]

Wasn't an instructor, he was a pilot who flies with RPA.

 

 

[Guest Andys@coffs]

......Aircraft maybe written off. More to come.

So Ive seen some amazingly dinged up jab's that look like they should be written off, repaired and back within a relatively short time looking none the worse for wear.......

 

Andy

 

 

[turboplanner]

The information is dribbling out almost as if no one wants to say what actually happened.

 

 

[Thirsty]

Nothing to do with not wanting the story to come out. Here's what happened. The Aircraft in question was being flown from lake mungo to wentworth at 1500 feet agl when the engine stopped for reasons unknown (though based on what the pilot said it sounds like a fuel issue of some sort). The aircraft was put down on a small salt pan and during the landing the aircraft impacted some saltbush which bent the nose gear and flipped the aircraft over. The plot and pax got out with nil injuries.

 

That's all thats known at this stage. Hopefully we'll be able to retrieve the aircraft during the week and I'll post the results of the inspection once we find out what happened.

 

 

[Compulsion]

Just glad that all are ok. Aircraft can be replaced. Although the Jab haters will love it because it gives them more ammo. Put the safety down to the great safety training at RPA.

 

 

[Guest SAJabiruflyer]

I've spent a little bit of time in 0949 there, great fun little a/c. Glad everyone is ok :)

 

 

[turboplanner]

Just glad that all are ok. Aircraft can be replaced. Although the Jab haters will love it because it gives them more ammo. Put the safety down to the great safety training at RPA.

Well that's not giving us any clarity so how about these very rough figures:

 

MB - Wentworth = approx 185 Nm if they didn't wander off for some sightseeing, or spend distance forming up over MB

 

Trip time 2 hrs at 90 kts

 

3.1 hrs with a 30 kt headwind

 

Endurance:

 

approx 3.33 hrs to fuel exhaustion

 

approx 2.58 hrs with 45 minutes reserve

 

And a very simple fuel system where you can turn around and see what's in the tank.

 

and the Jab Haters would have been appeased by the earlier post clearly stating this wasn't an engine failure.

 

EDIT: Sorry didn't read about the diversion to Lake Mungo. Distance would have been 267 Nm without diversion, 205 with tail wind, 62 with reciprocal head wind, fuel burn 12 litre per hour, cruise 90 kt, 0949 landed with 75 mins fuel

 

Usable fuel 55 litres (if PIC and passenger were light enough not to exceed MTOW) = 4.58 hours endurance.

 

 

[Thirsty]

Yeah they are great little Aircraft. The one that went in was 5678.

 

 

[Thirsty]

We had a tail wind most of the trip and the sister ship 0949 landed back at wentworth with approx 15 liters on board after flying the exact same route. These jabs use about 12 liters per hour and hold slightly more than 60 liters. We run them at quite slow revs due to the 90 knot vma limitation hence the low fuel usage.

 

We'll know more once we get it back and have a good look over it. Don't really want to preempt the post accident inspection just making some guesses based on what we know at the moment.

 

 

[dazza 38]

So Ive seen some amazingly dinged up jab's that look like they should be written off, repaired and back within a relatively short time looking none the worse for wear.......Andy

Same here, I have seen a Jabby that looked written off.They rebuilt it in a few weeks. Jabiru are good at repairing smashed up Jabiru aircraft.They get alot of practise I think.

 

 

[Thirsty]

Yep well aware of this. All of the jabs I fly have been repaired in their lives. We'll see what happens.

 

 

[dazza 38]

I assume that RPA written above is not the Royal Prince Alfred Hospital.

 

 

[Guest SAJabiruflyer]

You assume correct Dazza. RPA = Recreational Pilots Academy, out of YMBD - http://www.rpa.net.au/

 

 

[planedriver]

Always sad to hear when a good days flying sometimes come to an abrupt end.

 

However, Jabiru's certainly seen to have a pretty durable fuselage shell, which must account for many walking away somewhat unscathed, when the fans stopped turning for whatever reason.

 

 

[J170 Owner]

We had a tail wind most of the trip and the sister ship 0949 landed back at wentworth with approx 15 liters on board after flying the exact same route. These jabs use about 12 liters per hour and hold slightly more than 60 liters. We run them at quite slow revs due to the 90 knot vma limitation hence the low fuel usage.

Now, this is interesting. A lot of jab engine problems are caused because of misuse rather than being crappy engines. One of the misuses is continual running at low revs. I am not a mechanic nor do I try to pass myself off as knowledgeable in that area (although I have rebuilt a holden red motor and a Triumph 650 twin!). I cannot recall exactly what problems occur if you run the engines at too low a power setting for too long. There is a service bulletin that mentions this. So, having said that I wonder if the operators are doing the right thing or should they be looking at a different propeller or something?

 

 

[rankamateur]

Always sad to hear when a good days flying sometimes come to an abrupt end.However, Jabiru's certainly seen to have a pretty durable fuselage shell, which must account for many walking away somewhat unscathed, when the fans stopped turning for whatever reason.

On the other hand the rigid shell of a Landcruiser tranfering more decelleration force on to the passengers is often attributed to the poorer outcome for passengers when they come to grief. No sustitute for arriving slower.

 

 

[Guest Andys@coffs]

Yep agree, survival has zero to do with the aircraft manufacturing materials (given the overriding need to keep weight down preventing G absorbing structures) and is all about the deceleration forces a human is subject to. Its that simple, exceed the G force limit and you will die. So, to put it more correctly, once they've washes out the blood and gore assuming a G force arrival that exceeds the known limit , they can probably resurect the aircraft if its a J.....

 

The following extracted from a useful webpage on the matter:-

 

"The NHTSA standard for a sudden impact acceleration on a human that would cause severe injury or death is 75 g's for a "50th percentile male", 65 g's for a "50th percentile female", and 50 g's for a "50th percentile child". These figures assume the human is taking the impact on the chest/stomach, the back, sides or the head. The average value is about 65 g's, so I used that for the fatal impact acceleration on a human being."

 

That and other material found here:- http://hypertextbook.com/facts/2004/YuriyRafailov.shtml

 

 

[turboplanner]

Yep agree, survival has zero to do with the aircraft manufacturing materials (given the overriding need to keep weight down preventing G absorbing structures) and is all about the deceleration forces a human is subject to. Its that simple, exceed the G force limit and you will die. So, to put it more correctly, once they've washes out the blood and gore assuming a G force arrival that exceeds the known limit , they can probably resurect the aircraft if its a J.....The following extracted from a useful webpage on the matter:-

 

"The NHTSA standard for a sudden impact acceleration on a human that would cause severe injury or death is 75 g's for a "50th percentile male", 65 g's for a "50th percentile female", and 50 g's for a "50th percentile child". These figures assume the human is taking the impact on the chest/stomach, the back, sides or the head. The average value is about 65 g's, so I used that for the fatal impact acceleration on a human being."

 

That and other material found here:- http://hypertextbook.com/facts/2004/YuriyRafailov.shtml

There are two peak causes of death:

 

1. If something hits you hard enough, or you slam into something hard enough, or a small area pokes into your body - and hits a vital organ/artery etc.

 

2. Sudden impact effect on the brain.

 

An example of catering for Item 1 is the introduction of seat belts

 

An example of catering for Item 2 is the introduction of engineered progressive crumple rate in cars

 

There has only ever been one death in the history of Sprintcars in Australia which run on quarter mile tracks, but on the half mile tracks in the US a lot of drivers have died unmarked and in their harnesses because of the higher G forces at the higher crash speeds. (so safety can be managed as we do in Australia).

 

Rankamateur:

 

"On the other hand the rigid shell of a Landcruiser tranfering more decelleration force on to the passengers is often attributed to the poorer outcome for passengers when they come to grief. No sustitute for arriving slower."

 

This is possible of course, but like the ads which tell you to slow down from 65 to 60 and you'll save lives (you would have been past the accident by several seconds at 130 km/hr), its being used by the politically correct hominoids who seem to infest some of our safety programmes. In the case of a 4WD most of the issues are likely to be sliding into compressed objects like trees where the crumple zone at the front is likely to be untouched. The suspension and height of 4WD's is also criticised by these people who don't understand that the design produces weight transfer which hugely increases traction on winding dirt tracks....but that's another story for another day.

 

For those who seem to be openly promising survival in Jabiru crashes, yes it's a very strong construction - weight for weight fibreglass reinforced plastic is stronger than steel, however bear this in mind:

 

FRP bends massively before fracturing then what's left springs back into its memory position, making it very easy to repair, but you may have been crushed in the process.

 

Histpry shows good survival from Jabs in incidents close to ground, but you're not likely to survive a spin or stall incident any more than you would in another aircraft because the impact forces are several grades higher than the popular incident reports.