Interesting. Cell unharmed basically but tail broken off. Maybe a bit of a stronger construction and the cell would not have had to be written off?
Mutton Gulash, Lamb Shank and 3 more seat covers out of the casualties I reckon?
Wonder what caused this. Have not heard of a lot of Thielert engine failures since the first couple where there were electrical problems.
Unfortunately the Thielerts have had more than just electrical (FADEC) problems. There’s been problems with the reduction gear, low-pressure fuel pump, high-pressure fuel pump, engine lubrication.
There is a safety study conducted by the French BEA that concludes that the rate of failure of Thielert engines is no worse than that of other GA aircraft engines. The failures experienced with the early models have been dealt with and must be considered as teething problems.
According to the CAA database, the engine type is a THIELERT TAE 125-02-99.
This is the 2nd generation Centurion 2.0 engine, which doesn’t suffer from the teething problems which the 1st generation Thielert 1.7 is known for.
The pilot said the engine started misfiring and then stopped, so he had to make an emergency landing.
This might be an engine failure, but could also be fuel related. Let’s wait for the investigation results…
Written off ?????
I think not !
I see no technical reasons to write this aircraft off from the evidence in the photos.
Far more detailed examination needs to be carried out before writing off this aircraft, if it was a very new aircraft the chances are it would be fixed but the write off decision will be made on solely economic grounds most likely largely influenced by engine life remaining.The reason for the engine stopping are most likely already known as the FADEC data will have been downloaded giving the engine data at the time of failure, while saying anything at the moment is pure speculation I would be happy to put a few quid on it not being an electrical problem ( as long as the aircraft took off with no electrical problems).
Actually also the Centurion engine has suffered from teething problems, but those should have been resolved by now.
The French BEA’s safety study referred to above states that they recorded
On page 26 of the report they provide some statistical comparisons of reliability compared to the rest of the GA fleet. They claim that the FAA estimates the rate of “basic” engine failures to 10 per 100.000 hours of flight. By comparison the rates of failure for the two Thielert engines (based on data reported by Thielert) are 5,9 and 4,8 respectively per 100.000 flight hours. If those data are correct (BEA do not seem to contest them), I must say they are very impressive and would mean that the Thielert engine failures have been hyped up beyond reason.
Could one possibly relevant factor be that most Lyco/Conti engines are field-maintained while most Thielert engines are factory dealer maintained?
The end-of-life process is also different. Thielerts go back to the factory (TBR). For the same engine, I would expect at least a 2x difference between field maintained and field overhauled engines, and engines which are not touched outside the factory (except for oil changes etc). There are a lot of dodgy engine builders… look at the UK scene for some atrocious examples.
One factor behind Thielert’s TBR system is likely to be that they don’t want “just anybody” to mess with an engine which is obviously a lot more complicated.
Yes, I can imagine Continental would not wish to have shops in the field to do overhaul on the Diesel engine.
Yet, if they want to remain competitive with the Austro Diesel (TBO at 1500 hrs, overhaul reasonably priced at around 15k€) they need to come up with a plan. Like doing the overhauls themselves. Or just throw away the core of the engine and replace with a new one at a reasonable price for existing clients.
Yes, the reliability of Diesels are at a comfortable level, and might even be better than the Avgas engines. But let’s bear in mind:
1. The Diesel engine fleet is 0-10 years old, vs an Avgas fleet age of 0-50 years (not even counting Harrison Ford’s engine)
2. Various components on the Conti Diesels are preventatively replaced/overhauled at regular intervals, so do not get a chance to fail.. Not just the famous clutches/gearboxes but also pumps, alternators, hoses and even the Electronic Control Units.
In general terms the cost of operating a Continental Diesel is still on par with operating an Avgas engine. What you save on fuel goes into maintenance and into your engine fund. The operation is great though. Just one lever, smooth as silk, starts immediately under any circumstance, and of course the availability factor of Avtur is a big plus.
Of course Conti/Austro are not the only ones. Various existing designs on the market and on the drawing board, much more resembling the design of a traditional Avgas engine, non geared.. Competition will keep all contenders on their toes. But the market needs to become a bit bigger to really get things going!
Having rebuilt a common rail turbo diesel engine just last week and having done extensive work on Lycomings in the last years, I have seen the dramatic difference in precision and tolerances between these two. Lycos are very easy to work on, everything is rather loosely connected, the valves seating is only half important, compression is very low etc. Even with the worst compression and valve performance imaginable, two strong sparks ignite just about everything.
The diesel engines operate under extremely high pressure and low tolerances and are much more complex by design. If something is out of tolerances such as compression, the power cycle simply doesn’t work. That for me is a strong reason to rely on medium-skilled field overhauls but the factory. It’s also a way to ensure the ongoing business of the factory.
In general terms the cost of operating a Continental Diesel is still on par with operating an Avgas engine. What you save on fuel goes into maintenance and into your engine fund.
At my airport, as with most airports where a substantial amount of GA operations occur (i.e. in the US), the difference between AVGAS and Jet A is not so great. Today’s prices are $5.09/USG for AVGAS and $3.95/USG for Jet A. I might save 1-2 GPH with a 150 HP diesel. The total hourly fuel saving for a 150 HP range engine is therefore on the order of $15. Over the life of a privately owned Lycoming engine (2000 hrs or let’s say 25 years in most people’s use) that means you spend $30,000 more on fuel, $1200/year or $100/month.
I can field overhaul my O-320 for about $15K every 25 years, let’s say $20K with accessories, or $800 per year. Accounting for the $1200 annually saved in fuel by the diesel it would have to cost under $2000 per year in total overhaul and costs to break even, including any cam belt, water pump, clutch, gearbox, hose etc replacements between overhauls, or $24K total assuming a 12 year mandatory diesel engine overhaul or replacement cycle. I think if the factory replacemeant/overhaul cost was $15K or less the diesel would be a reasonable proposition, allowing an additional $9K for scheduled periodic replacemements between overhauls. To actually save money it would have to be either more efficient, fuel/tax cost would have to increase, or replacement cost would have to be even less.
