Does everyone fly jabirus overweight??

[Guest Condog]

Hi please dont incriminate yourself or anyone else.

 

But it seems like the more people i hear from about these the more it seems like lots of people who fly them disregard the 544 /600 limit. And fill them up with fuel upto about 650kg.

 

Now i know what the rules say and i know its technically not safe to do so. But if everyone is doing it, perhaps it is safe to do so.

 

I would appreciate peoples comments , but please dont lecture as i know what should happen. Ta.

 

 

[AVOCET]

If the design says 700kg MTOW ,

 

Then that's the safe limit ,

 

Nothing to do with the legal side of things .

 

I don't know to many people that weigh their aircraft each flight

 

 

[Guest Condog]

Yeh i see what you mean.

 

Also does an experimental with a 700kg limit, does the limit of 700kg transfer to new owner or does it revert to 600 kg once sold by the builder.

 

Sorry if these questions seem silly but theres no easy place to find some of this info.hopefully my questions will help others now or later.

 

 

[AVOCET]

Depends how the jabiruis registered .

 

VH 700kg or max design weight

 

RAA Aus 600kg. Ditto

 

Doesn't mater who owns the aircraft ,

 

The design weight limit has nothing to do with the owner , if you sell or buy , doesn't matter .

 

Cheers Mike

 

 

[Herm]

Well in my case my SK Jabiru was set to its original design weight at 344KG. This is far too light and with two ave passengers and a full tank of fuel puts me over weight. I first reg my aircraft last year and contacted Jabiru about the design limits of the aircraft. As long as your weight does not place the aircrafts stall limits above that allowed and the airframe is designed to take it, you can apply for a weight increase. I had to change the aircraft manual to reflect the changes and submit the weight and balance formulas to Jabiru and the RAUS. I Also had to have my cockpit placards changed to the new approved weight limit. This was also checked by a level 4 LAME and now my aircraft is registered to a higher weight limit that allows me to be legal and carry more items within the aircraft. In fact I would never be able to exceed the weight limit before exceeding CG limits. This change will always remain with the aircraft even if it is sold to a new owner. Bit of messing around, but better to be legal with all the ramp checks etc. You also need to be sure that you are safe loading up your aircraft also..

 

Mardy

 

 

[SAJ]

I brought a J400 which was VH registered and had a MTOW of 700kg, when I re-registered it as a RAA-AUS J200 my MTOW dropped to 544kg, it all depends on which registration category it is, my J200 is in the 19 category.

 

SAJ

 

 

[AVOCET]

Well in my case my SK Jabiru was set to its original design weight at 344KG. This is far too light and with two ave passengers and a full tank of fuel puts me over weight. I first reg my aircraft last year and contacted Jabiru about the design limits of the aircraft. As long as your weight does not place the aircrafts stall limits above that allowed and the airframe is designed to take it, you can apply for a weight increase. I had to change the aircraft manual to reflect the changes and submit the weight and balance formulas to Jabiru and the RAUS. I Also had to have my cockpit placards changed to the new approved weight limit. This was also checked by a level 4 LAME and now my aircraft is registered to a higher weight limit that allows me to be legal and carry more items within the aircraft. In fact I would never be able to exceed the weight limit before exceeding CG limits. This change will always remain with the aircraft even if it is sold to a new owner. Bit of messing around, but better to be legal with all the ramp checks etc. You also need to be sure that you are safe loading up your aircraft also..

 

Mardy

That applied to your early SK because later versions of the same design were found ,after testing to meet a higher design loading

 

The aircraft now ,have well tested and established load ratings and could not be changed that easy without modification ,and then more testing $$$

 

Mike

 

 

[coljones]

Now i know what the rules say and i know its technically not safe to do so. But if everyone is doing it, perhaps it is safe to do so.

.

"Now i know what the rules say and i know its technically legally not safe to do so. But if everyone is doing it, perhaps it is safe to do so."

 

The tech manual is a legal document, not a professional engineers specification

 

 

[turboplanner]

In the prescriptive legislation days most could get away with this clever play on words, with just a few being caught and prosecuted.

 

In these self-regulation days, while nothing happens, nothing happens, but if there's an accident EVERY pilot involved is not only likely to be found negligent, but culpably negligent, which is a criminal charge. The Insurance company would be within its rights to reject a claim, and I haven't looked up the CASA site, but there's probably a strict liability regulation with severe penalties as well.

 

In every case, with an injured or dead person lying on the ground, the weight can be measured against the regulation.

 

In short you'd have to be nuts to get sucked in by Col's slippery line above.

 

Herm took the correct path.

 

One of the weaknesses in the RAA structure is Performance and Operations, and this needs to become a much more important factor in giving Certificates to pilots, because key factors like incorrect balance, last light and overweight issues do show up regularly in discussions.

 

Full passengers and full fuel prohibit many aircraft from taking off, and this doesn't just apply to Jabiru or recreational aircraft, but right up through single engine GA aircraft. Not only that, but many aircraft do not have the undercarriage strength to land at MTOW, so a fuel burn has to occur until the reduce to maximum landing weight. That's why you hear of them flying round to burn off fuel - other than a few cases, they are not doing this in a perfectly safe aircraft because of fire, they are trying to land without bending their undercarriage.

 

The calculations are so simple and quick, that it's surprising so many don't do them.

 

 

[coljones]

In short you'd have to be nuts to get sucked in by Col's slippery line above.

Slippery? Not at all, the manuals are legal documents and should be treated as such. As you, Turbs, have pointed out more eloquently than me, don't mess with the law.

 

We were all warned at Natfly that there might be rampchecks. That could include examination of flight plans and weight and balance for your inbound flight. So arriving underweight after leaving overweight may have repercussions.

 

Some Jabs can be flown at 700Kg MTOW - if you need this then maybe a Jab with GA registration and licencing might be the way to go.

 

 

[turboplanner]

But if everyone is doing it, perhaps it is safe to do so.

It was this part Col, some people will see that as a loophole. It could ruin their life, but some people hang on those statements to justify what they do.

 

 

[coljones]

It was this part Col, some people will see that as a loophole. It could ruin their life, but some people hang on those statements to justify what they do.

Ah yes. I was quoting ConDog and fixing. I should have excluded the last bit. Everyone doing it is no excuse. Despite all of the illusions, it is very easy to be safe but sorry brings a lot of grief!

 

 

[Bruce Tuncks]

There can well be a difference between the legality of the weight and the engineering safety weight. The SK originally was rated at 430 kg. This was partly because the factory may have gone broke if any certification test ( like dropping it at max weight onto a greased floor ) was failed.

 

Now the airframe and u/c are much stronger than needed for the 430 kg limit, as was always known. Also, the stall-speed requirement was later officially raised by a couple of knots, and it is easy to show that this translates into a higher weight capacity. There was an SK where the builder had a letter signed by Hewitt-Cook of the then AUF approving his SK to 480 kg. I have a copy of this letter but it does not make me legal. I need to do what Mardy has done.

 

In an ideal world, the technical safe weight would be the same as the legal one, but that's not the case. If an identical aircraft is flying legally at the higher weight , for example as a VH registered aircraft, then this proves that the lower weight is "just" a legality.

 

Be careful of that word "just". There was a recent court case where I think the RAAus and CASA were both accused of "allowing" an aircraft to fly overweight.

 

So, Condog, the best advice is to keep to the legal weight and try to get that changed if you can, but I reckon Mike is right and it would be a hard thing to do. In the meantime, you may need to be careful about flying with overweight people. Anyway, being overweight ( 5 kg or more over ideal ) is twice as dangerous as flying.

 

regards, Bruce

 

 

[nong]

Hi please dont incriminate yourself or anyone else.But it seems like the more people i hear from about these the more it seems like lots of people who fly them disregard the 544 /600 limit. And fill them up with fuel upto about 650kg.

 

Now i know what the rules say and i know its technically not safe to do so. But if everyone is doing it, perhaps it is safe to do so.

 

I would appreciate peoples comments , but please dont lecture as i know what should happen. Ta.

There is overload as a legal consideration.

There is overload as an engineering and performance consideration.

 

Yes, Jabirus are often flown overgross, in a legal sense.

 

The outdated RAAus rule set presents a real temptation for pilots of certain Jabiru models, that are known to be engineered to operate at up to 700kg. Let your attitude to our poorly constructed laws be your guide! Bad law-making usually receives the observance and respect it deserves!!

 

Operating beyond the engineered weight, as ag pilots do, involves a whole lot of other considerations. I can only suggest that you refrain from this.

 

As an interesting aside...... In New Zealand, the Fletcher FU24 is typically and routinely operated on top-dressing work at design gross (4,860 lb) plus 31% (6,366 lb) or more.

 

Imagine the effect of this, on the undercarriage and centre section, when doing maybe ten take-offs per working hour off rough air-strips. The pilots and operators generally accept the risks and associated failures in the interests of greater productivity per flying hour.

 

 

[AVOCET]

There's a big difference in operating a jabiru type aircraft at 600 kg and 700kg especially on the base leg to final approach ,

 

Try landing a j200 at max gross at 60 /65 kts and you'll give yourself a bit more than a surprise tuning base if your in a bit of a skid , they become quite doey and ineffective on the aileron , also sink rate ,

 

I'm just saying , if you've only ever flown a jabiru at say 544kg and then as the rules have changed to 600kg be tempted to load them to max 700kg or more , they in fact become a different beast , with some care and understanding ,( and I don't mean flowers and a table for two ) !

 

Cheers Mike

 

Ps . This wont be the case for experianced pilots , having flown various types ,

 

 

[facthunter]

Have a bit of altitude and a hot day and it is worse. That is why it is silly to say I approach my Jab... at 58 knots Weight makes an increased airspeed needed and performance drops. A higher density altitude you don't necessarily need to increase the INDICATED airspeed but the performance certainly is not the same. a two place aircraft has potential for a larger weight variation. The payload on most aircraft is about 45% of AUW and it varies...The ability to climb, or the take-off distance available. runway slope, downwind, obstacles to clear, may limit your weight to well below the structural limit. Nev

 

 

[Powerin]

Yep, as Turbs says, whether it's safe or not is really not the point. If you fly (or drive for that matter) illegally and something goes wrong you will be held responsible, even if it's not strictly your fault, and your insurance will be void. In the event of you causing a death you won't have any insurance to help and perhaps have a $multi-million lawsuit on your hands.

 

Always look at the worst case scenario. Even if it's fairly low risk, can you and your family really afford for you to illegally carry those few extra kg if the worst happens?

 

 

[ianboag]

Always look at the worst case scenario. Even if it's fairly low risk, can you and your family really afford for you to illegally carry those few extra kg if the worst happens?

Dunno - I had a J200 once. The 544 kg limit two (not small) guys, about 40% fuel and two hankies for baggage. So as we headed into the sky with full fuel and about 50kgs of baggage (maybe 650 kgs AUW) we murmured to the aeroplane that it should pretend it was a (700 kg max-AUW) J400. We must have been convincing because it took off/ flew/ landed just fine. The takeoff/climb was a bit slower than we were used to, there was a bit more throttle needed for speed and landings were a bit quicker. But we knew the airframe was not about to disintegrate on us ......

 

 

[jetjr]

Stall speed in J200/400 goes up 3 kts for extra 160 kg MTOW.

 

 

[ianboag]

It sank quicker too. The J200 used to sometimes give me a bit of a problem on finals - you could easily descend and it wasn't hard to slow down. The tricky bit was making both happen together ......

 

 

[jetjr]

Overall I reckon they fly better at nearer full weight, certainly easier to land. More decisive and the floating is less. Use 1 stage flap and it flys like a larger aircraft

 

 

[Powerin]

Dunno - I had a J200 once. The 544 kg limit two (not small) guys, about 40% fuel and two hankies for baggage. So as we headed into the sky with full fuel and about 50kgs of baggage (maybe 650 kgs AUW) we murmured to the aeroplane that it should pretend it was a (700 kg max-AUW) J400. We must have been convincing because it took off/ flew/ landed just fine. The takeoff/climb was a bit slower than we were used to, there was a bit more throttle needed for speed and landings were a bit quicker. But we knew the airframe was not about to disintegrate on us ......

No, as noted by others, my comment was from a legal standpoint not one of safety. It's a bit like driving a car when your blood alcohol is .049. If someone hits you, it's their fault. If you are driving at .05 and someone hits you, you are one driving illegally, you will have a hard time proving it's not your fault and your insurance company won't want to know you.