Navajo Spar Mod - Can we drop it yet?

[Lumps]

Anyone know who to write to get this thing rescinded?

Looking at importing Navajo from the US or UK and there are plenty of good ones out there but many are around 10-12k hours.

Our Australian-only 13,000 hour $60k+ spar strap mod for the PA31 means it just doesn't make any sense to import one.

Seeing as no other country in the world imposed this directive, and wings have not been peeling off PA31s around the planet one could deduce that it was a pointless, costly directive that has dried up the supply of good PA31s in the country, was based on faulty stress analysis and cost operators of the type lots of money.

Not everyone can afford a Caravan, plus, they're boring

On the plus side I guess Mahindra made a bit of money out of it

[john_tullamarine]

I don't know that your concern is totally correct.

You might like to have a natter with Steve Swift (http://steveswift.com.au/author/walknuts/) and Martin Aubury. I don't have a current contact for Martin but Steve certainly will.

Both are technical experts in this stuff as well as being good lads ...

[Lat3ralus]

Anyone know who to write to get this thing rescinded?

Looking at importing Navajo from the US or UK and there are plenty of good ones out there but many are around 10-12k hours.

Our Australian-only 13,000 hour $60k+ spar strap mod for the PA31 means it just doesn't make any sense to import one.

Seeing as no other country in the world imposed this directive, and wings have not been peeling off PA31s around the planet one could deduce that it was a pointless, costly directive that has dried up the supply of good PA31s in the country, was based on faulty stress analysis and cost operators of the type lots of money.

Not everyone can afford a Caravan, plus, they're boring

On the plus side I guess Mahindra made a bit of money out of it

Caravan boring?

[navajoe]

I think you will find that the navajo is 11000 hr and the chieftain is 13000hr, from memory.:confused:

[lo_lyf]

Caravan boring?

Does a Caravan excite you?

[Lat3ralus]

Does a Caravan excite you?

Yes making a business decision based on what planes are boring is perfectly reasonable.

[Band a Lot]

CASA will never rescind it, that implies they were wrong.


The best bet would be to campaign for a review of the requirement times based on new and current data of hours of current PA31's with no straps but still have wings attached and still in service.

It seems strange to have a C208 compared to a PA31-350, what type of operation is it?

[Stationair8]

Didn't Don Kendall do one of the first Navajo spar mods, back in the mid 1970's when they were using Pa-31's on Reg203 ops?

[kingRB]

Yes making a business decision based on what planes are boring is perfectly reasonable.

unless you are asetpa approved i'd imagine the van is a pretty boring business decision

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[Lat3ralus]

unless you are asetpa approved i'd imagine the van is a pretty boring business decision

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And operating a 40 year old aircraft with paying pax on board is a great business decision

[lo_lyf]

And operating a 40 year old aircraft with paying pax on board is a great business decision

What if said Navajo was immaculate with all round 10s? Would the age be an issue to you?

Caravans debuted in 1982 FYI

[Lat3ralus]

What if said Navajo was immaculate with all round 10s? Would the age be an issue to you?

Caravans debuted in 1982 FYI

Of course not, but how many all round 10s chieftains have you flown? certainly not any I have had the luxury of operating.

There is not much point comparing a chieftain to a caravan anyway really, different leagues all together.

Navajos and 400 series sure, thats a different ball game.

[Duck Pilot]

Old piston twins are dead in the water these days. Only good piston twins are the new ones which are only useful as luxury items if you are lucky enough to afford one. Even then if I had the cash to splash a low time second hand turboprop would probably be cheaper than a new Baron, with a lot more bang for the buck per mile.

[Lat3ralus]

Old piston twins are dead in the water these days. Only good piston twins are the new ones which are only useful as luxury items if you are lucky enough to afford one. Even then if I had the cash to splash a low time second hand turboprop would probably be cheaper than a new Baron, with a lot more bang for the buck per mile.

Nail on the head

[lo_lyf]

Old piston twins are dead in the water these days.

They are not dead in the water for what they are per se. Seat for seat nothing can do ad-hoc charter as cost effectively as a PA31 can. They are perceived to be dead in the water because they were the backbone of the industry, an industry that is very well dying. The OP is merely highlighting another stab wound.

And operating a 40 year old aircraft with paying pax on board is a great business decision

Let's be perfectly honest. That is spoken with the bias of a pilot. What is going to be a better business decision? You'll suggest something that involves tying up more capital, that costs more to operate resulting more in more expensive quotes which will turn more jobs away than it attracts.

[Lat3ralus]

They are not dead in the water for what they are per se. Seat for seat nothing can do ad-hoc charter as cost effectively as a PA31 can. They are perceived to be dead in the water because they were the backbone of the industry, an industry that is very well dying. The OP is merely highlighting another stab wound.



Let's be perfectly honest. That is spoken with the bias of a pilot. What is going to be a better business decision? You'll suggest something that involves tying up more capital, that costs more to operate resulting more in more expensive quotes which will turn more jobs away than it attracts.

The sooner we get rid of these old piston twins the sooner the industry will start to turnaround. A number of ga charter and rpt operators are doing just this and the tide is turning. Even the last chieftain off the production line will be around 32 years old this year.
I must say I am little biased however, there has always been something strange about chieftain/navajo-only charter operators.

[lo_lyf]

The sooner we get rid of these old piston twins the sooner the industry will start to turnaround.

I'm sorry. There is just no substance behind this statement. As I alluded to before, how is an industry which is already crippled by costs brought on by the regulator going to turn around simply because businesses buy new Caravans? Hell, You can't even just go an do IFR charter in them for some silly reason.

[Lat3ralus]

I'm sorry. There is just no substance behind this statement. As I alluded to before, how is an industry which is already crippled by costs brought on by the regulator going to turn around simply because businesses buy new Caravans? Hell, You can't even just go an do IFR charter in them for some silly reason.

I agree CASA adds unnecessary costs to a already struggling industry, however I'd say over half if not more of GA operators need to have a hard look at themselves as the source of the problem. Particularly rpt operators who think they can still get away with putting paying public on old tired piston twins. However, I agree you need capital to change it, just like any other business in any other industry.

[Mick Stuped]

I agree CASA adds unnecessary costs to a already struggling industry, however I'd say over half if not more of GA operators need to have a hard look at themselves as the source of the problem. Particularly rpt operators who think they can still get away with putting paying public on old tired piston twins. However, I agree you need capital to change it, just like any other business in any other industry.

I don't know of any RPT guys "putting paying passengers in tired old twins"....If you look around, charter GA guys are moving to Caravans and King Airs. Smaller GA guys are still operating pistons, but they are generally not RPT.

We also have to look at how much a company is willing to pay for a charter. LCC RPT has led the general public to believe that $50 is a perfectly acceptable price for a flight Melbourne to Sydney, and therefore anyone who charges $200 for a 30 minute scenic is a complete rip off merchant. Only the government can afford to pay $8k for a Conquest charter YPAD / YPAG / YPAD, as reported in the weekend papers.

And if piston twins are so tired and old, why is the thread-starter trying to import one? Why doesn't he / she go straight to the turbines that we apparently should all be flying - could it be because turbines are expensive bits of kit to buy and to operate (particularly with our regulators assistance) which is why GA are still using pistons?

[Lat3ralus]

I don't know of any RPT guys "putting paying passengers in tired old twins"....If you look around, charter GA guys are moving to Caravans and King Airs. Smaller GA guys are still operating pistons, but they are generally not RPT.

We also have to look at how much a company is willing to pay for a charter. LCC RPT has led the general public to believe that $50 is a perfectly acceptable price for a flight Melbourne to Sydney, and therefore anyone who charges $200 for a 30 minute scenic is a complete rip off merchant. Only the government can afford to pay $8k for a Conquest charter YPAD / YPAG / YPAD, as reported in the weekend papers.

And if piston twins are so tired and old, why is the thread-starter trying to import one? Why doesn't he / she go straight to the turbines that we apparently should all be flying - could it be because turbines are expensive bits of kit to buy and to operate (particularly with our regulators assistance) which is why GA are still using pistons?

Yes here in Australia we shall remain a couple of decades behind the rest of the developed world with our infinite wisdom, that includes the regulator.

[aeromariner]

No good talking to Steve Swift ... he'll just send you on to me. In the first instance I'd worry more about the J2BDs. Possibly the worst piston engine in the world, and you are looking at 100K a side. Piper did the original fatigue assessment and it was they who put the life limits on it in accordance with the requirements from CASA. It was designed as a corporate aircraft, and Piper thought 13,000 hours good enough - they could have done better.. Nobody foresaw Reg 203 exempt ops and by 1989 (yes 28 years ago) there were time-x chieftains pushed up against fences everywhere. Come the pilots strike - everybody wanted a mod, and that was what gipps did. We moved it across from fatigue to Damage Tolerance and everybody (including Max Hazelton who I think had 20 plus) was happy. Sure you can get the AD rescinded just get piper to provide CASA with the relevant information. It is no different for Boeings or Pipers - what the manufacturer says goes unless you can find some poor underpaid bunny to recrank the numbers. And you will need a cuppla mill to do that. Mahindra no longer does the mod - mostly I suspect because of sentiments like the above. I'd have a long hard look for corrosion especially between the lower spar cap and the thick splice plate and study up on detonation

[lo_lyf]

Possibly the worst piston engine

This reputation only exists because its a highly strung engine intolerant to any neglect. Only now, in 2017, am I starting to truely believe that more people than not are educated on how to 'properly' operate them. Every time I come across a Navajo without an EDM all I can think about the owner is 'Hah, chump, he probably hires it out too'.

[aeromariner]

No good talking to Steve Swift ... he'll just send you to me. I'd be more worried about the J2BDs .. $100K aside. The AD is based on data supplied by Piper as the manufacturer. There is no difference between Boeings and Pipers. CASA writes the requirements and Piper gives the data. It was a corporate aircraft. Piper did a simple test and came up with 13,000 hours for the -350 - it should have been better but Piper did not want to revise it. That is the way it is unless you can get some underpaid bunny to recrank the calculations. That was not going to happen until the pilots strike in 1989. Even then (28 years ago) there were timeX PA31s pushed up against fences. Rather than do a fatigue test again, it was taken across to safety by inspection and all those timeX were back in service. There were a lot of happy faces, particularly at Hazo's who had twenty odd. The FAA have found cracks in a Chieftain spar cap (not good). I suspect it was a "Friday arvo" aircraft ... I found a couple. They do have corrosion problems. ... And I'd learn a lot about detonation ... 100LL can't last forever.

[porch monkey]

In over 4000 hrs and 8 years with TIO540's, I found them very reliable, to the point of never losing one, had maybe 4 or 5 dead cylinders in all that time. And we worked them pretty hard. But we looked after them, and had good guys looking after them.......

[aeromariner]

Last sentence is the key. EDMs are essential, but they can only tell you what happened while the EDM is fitted. and I must admit it has nothing on the TIGO 541 for cost

[Connedrod]

Just recently a ndt check was carried out resulting in cracks found in the modified spar. As a result ive been infromed that casa is now looking at the modified spar and talk is now grounding aircraft with this mod.

[Lumps]

Firstly, thanks to aeromariner for illumination. I didn't know the history.

So in the US are they replacing spar caps as per the Piper-approved way of extending wings for another 13,000 hours (-350)? Or just parking them as per original Piper approved method.

Just recently a ndt check was carried out resulting in cracks found in the modified spar. As a result ive been infromed that casa is now looking at the modified spar and talk is now grounding aircraft with this mod.

Why go for the red button straight away? Wouldn't it be more prudent to check other planes out first?

And I second those that have defended the J2BD, a good engine that is highly intolerant of ignorance. This ignorance was not only the throttle jockeys but also from the heavens of 'approved' sources, refer the Climb Power Leaning Chart in the AFM :eek:

100LL won't last forever, no, but I'm pretty sure George Braley has been feeding J2BDs G100UL with fine results!

And comparing PA31 to C208 was done on purpose to try and keep the 'piston twins should be banned' folks at home. A lot of good businesses come from a great idea that then earns money. Not from a lot of money looking for an idea.

RFDS didn't start out with King Airs, should they have just shelved the whole idea until they could afford them?

[Tinstaafl]

I've flown J2Bs for 20+ years. I think they're a great engine. But(!)....ignore the aircraft manual's advice to lean at climb power settings. I used to, but now I leave it full rich until after setting cruise MP/RPM.

[aeromariner]

Just recently a ndt check was carried out resulting in cracks found in the modified spar. As a result ive been infromed that casa is now looking at the modified spar and talk is now grounding aircraft with this mod.

who did the ndt inspection?

[porch monkey]

Wot Lumps and Tinny said.:ok:

[aeromariner]

Just recently a ndt check was carried out resulting in cracks found in the modified spar. As a result ive been infromed that casa is now looking at the modified spar and talk is now grounding aircraft with this mod.
It wasn't the gippy aero mod, and I can find no one in CASA talking about a grounding

[Stationair8]

Does the vortex generator kit have any effect on the spar life on Pa-31/310?

[Lumps]

Hi aeromariner,

Me again! This from a PA31 operator in the US:We have had a 27,000 and a 39,000 hour plane inspected via eddy current along the holes of this stack and the only thing found was 'indications'.

We send a portion of the latest (39k) one to NAIR for further analysis and are awaiting results.

We currently life-limit these to 40,000 and have two more set to retire (one at 38k and one at 39k). We have yet to find anything significant so will continue on this path.

T
Piper said the aircraft is no good after 13,000 hours, how is this operator getting the FAA to ok them out to 40,000 hours? Why can't this be done in Australia? What am I missing!

I'm trying not to be provocative, just would like to know the facts and whether, in hindsight, we got this right in Australia.

[A37575]

Old piston twins are dead in the water these days
Especially if an engine fails just after lift off..