First the Computer, Then the Toolbox

April 18, 2019
The Aviation Technician Advanced Training Program is designed to familiarize and train inspectors, certifying staff, and mechanics to perform regular maintenance and diagnoses on Continental Motors Diesel TMG engines

In last two decades we haven’t seen many new certified aviation engines in the gasoline engines world; in a diesel cycle field it was quite different. Only 10 years ago, the available combustion ignition engines around were not many, but in the last decade their number has steadily and radically grown. New diesel-cycle engines mean not only a different engine ignition principle and engine concept/layout but from the maintenance point of view this means even different changes in the engine maintenance style.

Continental Motors has become a market leader in the diesel engine field offering the highest number of diesel-cycle engines types in the power range from 130 to 300 hp on the market. Altogether, 6,000 plus Continental Diesel engines delivered to date have logged more than 7 million flight hours. Many of these engines and parts CMG manufactures in Germany, so this turned out to be the best place to attend one of CMG Diesel maintenance classes.

The CMG Germany plant is located in St. Egidien, province of Saxony, on the East German border. Today the plant is a leading manufacturer of certified diesel (jet-fuel) piston aircraft engines for general aviation, and is part of the Continental Motors Group (CMG) since July 2013.

The Roots of Continental Diesel Engines

In year 2002 Thielert started marketing diesel engines named “Centurion.” In times of the economic crisis which peaked in 2008, the company was forced to file for insolvency. In the following five years the company was restructured and made lean, continuing the production and improvement of the diesel engines. In July 2013 the purchase of all assets of Thielert Aircraft Engines GmbH was announced by the Chinese-based AVIC International Holding Corporation, the same company that bought Continental Motors Inc. in 2011 from Teledyne and then integrated the general aviation business under the wings of the Continental Motors Group (CMG).

CMG Diesel Cycle Engines

Continental rebranded its diesel engine range in 2014. All the diesel engines were renamed Continental Diesel, abbreviated as CD.

CD-100 series: The former Centurion 2.0/2.0s engines, in-line four-cylinder, liquid-cooled, and geared engines have become CD-100 series engines with 135 and 155 hp, today’s designation CD-135/155

CD-200 series: The former TD-300 engine was renamed to CD-230 and CD-245, four-cylinder, opposite, air-oil cooled, turbocharged, and direct-drive engine, with 230 to 245 hp. During AirVenture 2017, the CD-265 was introduced boosting the output to 265 hp and in the CDR (Rotorcraft) version 264 to 287 hp.

CD-300 series: The newest diesel engine, the V-6, is liquid-cooled, twin turbocharged, and geared 3.0-liter engine with 300-hp output. It gained already EASA certification and production certification. The FAA certification should arrive momentarily.

Continental® Motors has developed the Aviation Technician Advanced Training Program for certified aviation technicians which can be followed for avgas as well as for diesel engines.

The CMG avgas program is held in Mobile, AL, (US) and the diesel program is held in both Mobile, AL, (US) and St. Egidien, Germany. 

The main purpose of the CMG seminars is to familiarize and train inspectors, certifying staff and mechanics to perform regular maintenance and diagnoses on Continental Motors Diesel engines. Additionally, special skills can be gained for efficient fault isolation procedures as well as quick and safe diagnosis. This is required to become an authorized Continental Motors Diesel TMG maintenance organization according to the Service Bulletin "TM TAE 000-0003".

Tuition for the course at the Mobile, AL, facility is $950 and for the course at the German facility is €981,75. Training materials and lunches are included in fees. The same courses could be (and are) held in different locations and on different continents, all depending on demand.  This year, eight classes are offered from February 4 to December 3 in those two locations. For more information on classes, consult the Continental website:

The weekly course (five days) is designed as an initial or refresher course for certified technicians on Continental Motors current production piston engines and covers the following subject areas: engine performance; engine construction; engine fuel systems; fuel injection systems; engine controls; FADEC; starting and ignition systems; induction, exhaust and cooling systems; supercharging/turbocharging; lubricants and fuels; lubrication systems; engine indication systems; powerplant installation; engine monitoring and ground operation; and engine storage and preservation.

CMG Diesel Training

Diesel Training is concentrated on hands on and scenario-based training. Continental wanted, and succeeded, to bring to its trainees a real-life situation training. I went through the course and can testify to this.

The Jet-A training is conducted in an interactive mode, where the trainer encourages or gently pushes, all the students to develop their thought process after absorbing the course material. Interaction between students is important to trainers. The trainer is always challenging his students, making sure that all study subjects are assimilated and memorized while moving along the syllabus.

A part of the training is devoted to hands-on training too, each student goes through the various engine systems and components removal and re-install. This ensures that mechanics are familiar with every aspect of the maintenance. Most participants in the beginning are first faced with theoretical "stuff" and only later, comes the hands-on part. This is the essence of the different approach to maintenance of modern diesel cycle engines which can communicate with the mechanic thanks to their digital heart, the full authority digital engine control (FADEC).

Not the Sound of Silence

Up to now, mechanics have been trained to start maintenance activities by first doing a visual inspection of the engine. This is an excellent way to treat an engine that doesn’t talk. The Continental CD-100 and the CD-300 engine families are different, they "talk" to their caregiver. They not only talk a bit, they constantly communicate with you, or rather with the dual redundant engine control unit or FADEC. Therefore, the first thing that happens in the technical training is to convince the mechanics, which have a long experience with legacy piston engines, that they need to connect their computers with the engine to allow the engine to deliver its report. This is the reason why every trainee attending the course should bring his or her computer/laptop to the course. Once the connection with the engine is established, the mechanic will know quickly and precisely in which troubleshooting should start. This saves time for the mechanic and time and money to the aircraft operator.

I was told that the most difficult thing for trainers is "to convince the trainee/mechanic to leave, not even take out the toolbox or any tool when they initially approach the engine.".

You Are Not Alone

During the weeklong course (CMG called it "seminar" in my case) the process emphasized how much Continental believes in cooperation between the aircraft mechanic and the technical support. This explains why digital downloads from the FADEC system are systemically transferred to Continental. This helps to build a full performance archive of the engine. CMD technical support team members have years of experience and cano share this experience with mechanics when needed.

When in doubt, and this is (not only) in the beginning a frequent case, the mechanic can get immediately in touch with a support engineer and review the logged data together. This eliminates situations where a doubt could exist. This is such an important topic that Continental dedicates two full days to this somehow "digital" topic.

Predictive Maintenance

The FADEC system, which is a dual, redundant, and includes its own battery backup, transmits a full bill of health of the engine. This part of the training was for me a highlight of the course because one of the first readouts of the FADEC storage files gives you the engine health report. Each of two independent FADEC channels delivers its health report, side by side, making it clear to the mechanic what is the real status of the engine in an easy and clear way (color coded and in different alphanumerical levels of engine health). This points immediately to a potential system failure and allows the mechanic to trace down an existing problem. If a component is not operating at its peak performance, but functions within tolerances, the mechanic will know about it, allowing time to order a replacement part, account for shipping lead time, and making sure the part will be available at the next scheduled maintenance interval. Transforming unscheduled maintenance operations into scheduled maintenance is the game changer.

Final Comment

Each class takes five days and ends with an exam. The exam was more difficult than expected and is not a formal joke. Not the easiest, but doable specially if the student actively participates in the training. On the last day, the trainee receives a "Certificate of Recognition" and the "Confirmation" of the practical assessment and the result of examination. Training materials were in my opinion excellent and every student had the opportunity to put his or her hands on the engine. Every question was extensively answered by the trainer, this lasted even hours after the official end of a class.

Was it worth? Yes, it was! The value for me as a pilot is now, I can better understand this engine and I trust it more than prior to the course as I exactly know that this maintenance is light years ahead of the conventional engine maintenance. In the past there was plenty of guessing in troubleshooting an engine, now you know exactly what the problem is and when it may occur - this is predictive maintenance par excellence.

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