CFM56 engines don’t stay on their stands for too long

Though newer engine models as LEAP are already entering the market, the old-timers like CFM56 are keeping their strong positions above the ground. Counting its history since 1981, currently, there are more than 31 000 CFM56 engines up in the air. Their official information (1) claims, that every 2 seconds CFM56 powered aircraft takes of somewhere in the world. So, five for this paragraph alone?

Carrying many Boeing 737 and Airbus A320, these engines are valued for their performance and reliability. Through their long history (2), there were many upgrades and these days CFM56 brings optimal efficiency — it stays on the wing for 30000 hours before they need to go for their first service-shop visit, and later their maintenance costs stay manageable.

Still, on the airlines’ side, days when the engine is put on its stand, are never the good ones and they always cost too much. It is forecasted that shop visits of CFM56 family engines will be increasing in the next two to five years (3), so what to expect?

There are many calculations on the costs of planned or AOG repairs. For example, a day of A380 AOG can cost up to 925 000 eur (4). Focusing only on the engine, maintenance for mature-run CFM 56 in 2015 cost from 2,5M $ to 3M $ (5). Divide from 3 or 5, which is how long a detailed inspection and repair program takes and AOG cost for Airbus will start to make sense.

To avoid expensive surprises, industry experts are working on developing practices, that help to maintain their engines throughout their use and keep the AOG situations rare (6).

Constant engine monitoring helps to detect defects at an earlier stage, predict future deterioration and avoid major damages. Growing accessibility to data analytics allows MROs to experiment with various indicators, quickly process them and make decisions based on these calculations.

Precise detection of defects allows to deal with them during on-wing and on-site maintenance and in this way avoid shop visits. More MROs are starting to offer these services in their effort to lower the aircraft’s time on the ground and create added value for their clients.

Finally, shop visits themselves have plenty of room for improvements ensuring they happen fast, smooth and with fewest mistakes. Here technology is again a big help, but practices of continuous improvement alone can already make a positive impact.

As always in our industry, great results are created by people who find innovative solutions for old problems. Forty years ago GE Aviation and Safran Aircraft Engines joined their minds in developing the first CMF56 to keep passenger jets longer in the air. Now, proper maintenance can help keep them out of the engine stands for even longer.

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