MT-Gyros 1,500 hour limit on airframes and rotors

[Learjet]

Some rather alarming claims on the Rotary Wing Forum about AutoGyro GmbH imposing a 1,500hour timex on their gyros airframe and rotor systems as per the revised POH.
This apparently in response to reports of airframe fractures, although AutoGyro GmbH are denying this, claiming that the 1500 hour restriction is being imposed in order for them to maintain their safety record and "gather data".

http://www.rotaryforum.com/forum/showthread.php?t=19197

http://www.auto-gyro.com/en/News-Support/News/

This is going to be a big blow to MT & Calidus owners. I came very close to buying an MT-03 a few years ago - I thought it was a very, very nicely manufactured gyro but I didn't like the the fact that they used Stainless Steel for the airframe (nor would they specify what grade of SS they were using!) and I so opted to go with another gyro model instead.

I don't believe that Stainless Steel is the appropriate choice of metal for use in airframes. The anti-corrosion benefits simply don't outweight the metallurgical shortcomings of SS when used in high-vibration applications, and I've said as much (and been taken to task for it) on this forum before.
On the positive side, at least the issue has been recognised and will hopefully be properly addressed by the manufacturer.

[t-bird]

1500 hours is 10 years of flying 150 hours a year. This is a lot of flying for personal use only.

Something to consider when buying second hand.

Replacement cost of rotors is a lot less than the other gyros.

[Gyronaut]

In my humble opinion its no big deal. As T-bird says, its 10 to 15 years (even 20 for some) and it will be cheaper and probably better than buying a new one (at the new price by then.. imagine)

The MTO3's and MTOSports that I have flown and trained in were superb machines. A pleasure to fly and well thought out, well applied design features. They are lighter than most machines in their class so consider that the benefit over the 1500 TBO. You're saving on fuel with every flight which pays for the TBO.

Still a very good choice of machine in the right environment.

[Learjet]

Yep, you guys are right about 1500hrs being a helluva lot of flying but I'm not sure that I'd be feeling all that positive about it if I'd spent hundreds of thousands of Rands only to find that I basically have a 1500hr "disposable gyro" with 25% life still on the engine before TBO.

[FO Gyro]

If you think that's expensive, you should consider how much of a Robbie helicopter is thow away when it reaches it's TBO. 90% of the machine get's trashed. Think about that when paying around R2 million for one of these.

Quite frankly, I'm not sure I would want to fly in any gyro that's got high hours on it be it a MT-03, Magni, ELA, RAF, Sycamore, Xenon etc. After so many hours, you just don't know what fatique has set in somewhere that the eye cannot see. I think replacing the frame and rotors is an excellent idea when the hours get to a certain point. Some manufacturers claim unlimited hours on their rotors and frames, but I'm not convinced. You can't fly a gyro that vibrates itself through the air forever. At some stage something will give. Unfortunately it will take an accident to prove to them that they were wrong. As someone once said, "If helicopters are so safe, how come you don't get any vintage helicopter fly-in's?"

This is not a new limitation. When I bought my MT-03 3 yrs ago, I was aware of the 1 500 hours limitation. When I spoke to the MT-03's manufacturer about the 1500hrs, he said this was a very conservative limitation. As part of Section T approval, they wanted a limit to be imposed for aluminium rotors and the stainless steel frame. He said 1500 was extremely conservative. I doubt there are many owners of gyro's that will end up flying 1500hrs on a single machine. According to Rotory Forum, the average flying per year for the average gyro is around 50 hours a year. At the rate I'm flying at the moment, it will take me 25 yrs to get to that limit.

[Learjet]

Good points you make FO Gyro (as always ).
I guess if MT owners aren't too perturbed about it then that is great news.

It does beg the question though as to why AutoGyro GmbH went the stainless steel airframe route if not for it's long term corrosion-resistant properties? Given the questionable suitability of SS as an airframe metal (I can't think of a single heli or fixed wing manufacturer that uses it - and only one other gyro manufacturer) it would have surely made more sense to go with an accepted airframe construction metal like chrome-alloy and not run the short to medium term risk of metal fatigue and stress fractures at the expence of long-term corrosion possibilities?

Given that the Rotax 914 TBO extension to 2000hrs is not totally straightforward and that the many older series 914's will require crankcase etc replacement at 1200hrs - I can't help but feel these owners are going to question the feasibility of incurring this sort of expense for a paltry 300 more hours of flying? So we're pretty much down to a 1200hr machine - and if that's the case I can think of at least three or four gyro owners in the Cape who would be facing the prospect of throwing away a still perfectly airworthy gyro (if it weren't for the fact that they aren't MT-gyros.)

And with respect to Rotary Forum pilots - from what I saw first hand, gyro flying in the US is a whole different ball-game to what it is here. It's mostly Bensen / Ken-Brock home-built derivitive, weekend buzzing around the cabbage-patch stuff and nowhere near the clocking of hundreds (if not thousands) of miles flying cross-country like we do in South Africa.

I think it''s safe to say that by comparison, in South Africa gyro pilots fly their gyros like proper aircraft...

[FO Gyro]

The 1 500 hour limit would definitely be a factor for the MT owners, particularly if they are clocking up the hours.

In monetary terms, the MT does come in at a lower price than some of the other gyro's, and even after having replaced the frame and rotors after 1 500 hours, I'm willing to bet that the MT would still be cheaper than some of the other brands available, so it's not really an issue in the long term. What one saves in the short term, you end up paying for in the long term.

[t-bird]

Hi Learjet

The cracks in the MT’s mast is due to poor design Chromalloy would have cracked as well a few hours later but would have cracked.
They had cracks on the VPM’s in the UK at 1700 hours.

My Magni cracked on the radiator bracket weld. Not as serious as the mast but the radiator could have gone through the prop.
This problem was sorted out with the new radiator and oil cooler combination.

Chromalloy is overrated. How many bushbaby’s have cracks due to the use of mild steel and not Chromalloy.

[Spatzi69]

Hi Learjet

The cracks in the MT’s mast is due to poor design Chromalloy would have cracked as well a few hours later but would have cracked.
They had cracks on the VPM’s in the UK at 1700 hours.

My Magni cracked on the radiator bracket weld. Not as serious as the mast but the radiator could have gone through the prop.
This problem was sorted out with the new radiator and oil cooler combination.

Chromalloy is overrated. How many bushbaby’s have cracks due to the use of mild steel and not Chromalloy.

The earlier Ela's had a big problem with the mast snapping! Ask Jannie from Okahandja! his snapped clean off in Flight, struggled to put it back on the ground as it shifted a bit ( there were still certain things attached which kept the rotor head more or less in place, I am not a gyro pilot so have no clue to what is what) He was indeed very lucky! I am not against this hour limit, I would however be interested in how much a new main frame will cost! It should in my opinion not cost more then 20 to 30k or am I wrong?

[t-bird]

“earlier Ela's had a big problem”

And also earlier Magni’s called VPM’s

And earlier MTo3 sports called the MT 03

The manufactures are constantly enhancing their products.

But it would be interesting to hear Jannies story.

[Condor]

Hi guys, relax.

I have read the original communication from the factory and your MT did not become disposable overnight.

The factory imposed (as a safety measure) a non destructive inspection and tests (I am sure details to follow on how it will be done) to set up a database on the results.

They mention that as Rotax have done to extend the TBO on the engines after more info was availble, these tests should give an indication as to the road ahead (maybe extend the TBO on the airframe)

I see this exercise as an effort to improve safety and nothing else.

[FO Gyro]

Eben, I moved your posting into a new thread dedicated to the RAF for those wanting to know more about the RAF's design features. viewtopic.php?f=20&t=13380

Regarding the cracking issues, it's good that gyro pilots inspect their machines very closely, and don't just rely on the AP to do a once a year check to see that all is well.

[saraf]

HI FO

MY APOLOGIES IF IT LOOKED LIKE I HIJACKED THE TREAD, WAS NOT MY INTENTION.

THANKS FOR REMOVING.

EBEN

[FO Gyro]

No sweat. We don't want to lose any posters here. At least your topic can be discussed fully in a thread of it's own, without digressing from the topic at hand. Keep the posts coming.

[whirly]

If you think that's expensive, you should consider how much of a Robbie helicopter is thow away when it reaches it's TBO. 90% of the machine get's trashed. Think about that when paying around R2 million for one of these.

The Robinsons have a calendar limit as well, that makes it even worse for a private owner! I would not mind an hour limit as then it would not matter if you only flew 30 hours per year.1 500 Hours seems reasonable.

Whirly.