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When will a diesel be available for my aircraft? |
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News, facts, and comments on the coming revolution for piston-engine aircraft.News of August 19, 2007Oshkosh season: Of Facts and Rumors around the Diamond Air family of diesel aircraft. Part TwoWe have solicited interviews with Diamond Air and Thielert Motoren. Chief Executive Officers Frank Thielert (FT) and Christian Dries (CD) were accessible, and we quote here their feedback as appropriate, beginning with Frank Thielert. FT. 'I know there was a meeting of British Diamond customers who are a little unlucky with downtimes which affect their business. A colleague of mine was there as a representative. The coolers used by Diamond have had corrosive effects causing damages to some engine parts. The corrosion issue (on cylinder head) occurred only on Diamonds and was connected to Diamonds decision to choose another cooler supplier than the one we recommended. But this problem took place years ago, on the older 1.7 liter engine, and is now solved. Diamond has published a Service Bulletin regarding this. Currently we deliver the Centurion 2.0 engines as kits to Diamond, to be mounted only with parts and consumables which we approved.' Regarding rumors of broken prop shaft, TF says: 'We have a gearbox designed as an integrated engine subsystem. It is not connected to the engine coolant, so it cannot be exposed to the coolant fluid. We have absolutely no report of any broken shaft; if that happened, it would be a very serious issue.' Regarding broken or damaged engine parts, he says: 'I have never heard about any camshaft problem. Once we had a case of a foreign object causing damage to a piston. Generally speaking these parts are highly reliable.' Regarding the gear and clutch system linking the crankcase to the propeller shaft: British customers complained about wear and tear and about a maintenance directive requesting an inspection and possible replacement every 300 hours. FT says: 'Some of the first serial production gearboxes have shown abnormal wear. Since then (2003-04) we have made further developments and undertaken several major revisions of the gearbox, and replaced all older gearboxes in Thielert-equipped aircrafts. At that time it meant less than 100 engines. Also we have seen abnormal wear which was caused by bad maintenance, typically a mechanics who forgets to change filters at oil change. The 300 hour inspection is imposed by the initial certification and will be extended as we demonstrate that the gear system consistently lasts longer if properly maintained. We expect the interval to be increased to 600hrs, and we are sure that all gearboxes will make that time.' Regarding reports on defects of oil pressure sensors. FT says: 'Yes, there was an issue with the oil pressure sensors. We have published a service bulletin and have changed all sensors. This is history now.' Regarding lack of response from Diamond Air customer service, FT says: 'We as engine manufacturer expand our service network all the time and now have 200 service centers trained with spare parts on stock. We cannot answer for Diamond, but did notice that in several cases minor incidents that can be fixed easily and quickly degenerate into a major issue because of lack of training at the end of the chain, whether it is a Diamond service shop or the operators own mechanics. We cannot insist too much on sticking exactly to the maintenance specs and to the instructions manual when inspecting and repairing. We have seen cases where we supported directly a Diamond customer through his maintenance problems and reduced downtime by 90%, see the Steve Read case to quote one. But there are also some complex cases: Thus, there was an accident on a DA42 in Germany with dual engine failure. That was caused by a total loss of the electrical system when retracting the gear. That case raised some disputes because there was a very long and complex chain of factors conditioning that accident. However, it ended up in two AD. We had to make a change in our installation handbook and a Diamond Air AD is about to prescribe installing an engine control back-up battery.' Regarding keeping an overall view and history of incidents and defects, FT says: 'In general, we have all events logged in the engine FADEC which helps us in nearly all cases to trace a problem. For example the logs proved that no accidents are directly caused by our engines. With over 500,000 flight hours we have a long track record on different aircraft and UAV types and can claim that the engines are more reliable than any other. If any of your readers witnesses a special issue with one of our engines and we obtain exact data (aircraft type, date, engine serial number, and nature of incident) we can match it with the full history we have for every engine in our database. Meanwhile we do notice that wild rumors are circulating which cannot be substantiated when we ask for specific data.' We mentioned to Frank Thielert that we havent heard of any incident coming from operators of Thielert-equipped Cessna 172s, Piper PA28s or others. Pipers and Cessnas represent the largest fleet, large enough for incidents pattern to become significant. FT says: 'We are very proud to hear that. Obviously Cessna Aircraft Company heard no negative rumor either which is why our cooperation with them is progressing fast.' Regarding Diamond Air new engine developed by their subsidiary Austro Engine, FT says: 'There is a very costly and long way from prototype to certification, so why make an announcement now for an engine which is not yet certified nor STCd on the plane model? It seems to me that the effect is to tell Diamond customers to hold back their decision to buy the plane until the hypothetical day at an uncertain date when the new, certified engine will effectively be available. Meanwhile this kind of message does hurt our business as supplier. But this is not the first time: Diamond Air did make similar announcements in the past, for instance regarding a 90HP rotary engine design they had acquired from Midwest Engines.' See in next story the interview of Christian Dries, CEO and main stockholder of Diamond Air, some late remarks from Frank Thielert, and our conclusion. Andre Teissier du Cros, DieselAir Newsletter, August 07. posted at 3:17 AM |
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