The CF34 Turns 20

A model for reliability with 10 versions to date.

This year marks the 20th anniversary for GE Aviation’s CF34 family of engines. The military version TF34 which powers the U.S. Air Force A-10 and U.S. Navy S-3A, was a key factor in developing engines for the regional jet market.

There have been 10 versions of the CF34 to date, beginning with the CF34-1 that was used on Bombardier CL-601-1A through the CF34-10E used on the Embraer E-195. The first commercial -3 model was installed on the CRJ 100 and CRJ 200 aircraft in 1992. This engine family has been on the GE Aviation’s best seller list for a long time.

On May 25, 2010, GE announced it had delivered the 5,000th CF34 engine. The CF34 engine has evolved over the decades with design changes and modifications to increase thrust, reduce parts, and strengthen the core engine resulting in improved performance and lower maintenance costs. The durability and reliability of these engines is incredible — with more than 80 million flight-hours and 65 million cycles completed, the dispatch reliably remains at 99.95 percent.

It is interesting to compare some of the specifications of the various models. The CF34-3 is 103 inches long, has a diameter of 49 inches, and a dry weight around 1,650 pounds. The core engine has a fan and 20 combined compressor and turbine stages. It has a power-to-weight ratio of 5.6:1 and thrust at sea level is 9,200 pound-feet. This engine would typically power aircraft like the Bombardier CL-601. The latest model, CF34-10, is only 90 inches long, has a larger diameter of 57 inches, and a dry weight of 3,700 pounds. The core engine has a fan with three additional “booster stages” and only 14 total stages for the compressor and turbine.

The new CF34-10E has a higher thrust rating of 20,000 pound-feet, and lower fuel burn and maintenance cost. This radical increase in thrust was produced by a single-stage high-pressure turbine, advanced wide chord fan blades, and advanced 3-D aero compressor and turbine airfoils. The CF34-10E engine powers the Embraer E190 and 195, and the new Embraer Lineage 1000 business jet that entered service in mid-2009.

Outlook for the CF34 family

The utility of the smaller 50-70 seat regional jet in some North American markets is being questioned. According to Judd Tressler, GE Aviation’s director for CF34-3 Commercial Engines, “There will be fewer numbers of those aircraft in North America but they won’t all go away, just move to other markets with demand for that seat capacity.”

Tressler was asked if the large numbers of CF34-3 engines that have been in service for the last 10 years are being pulled and sent to the shop for overhauls. “There was a large peak in aircraft production about eight years ago. Those engines reached their first shop visit over the last few years and there was a wave of shop visits.

“The GE overhaul facilities are seeing the back side of that peak now so they are working with operators to develop different services like shop visit optimization programs, fixed cost by the hour, and other creative ways to reduce maintenance cost.”

MROs and GE branded service

With more than 5,600 CF34 engines in service, GE must have a global network of service providers operating on a 7 by 24 schedule, providing spare leasing, major overhaul of engines and components, and a ready supply of parts. Major engine overhaul is completed at GE’s Strother facility near Arkansas City, KS, but GE has a network of service providers located around the globe.

Tom Hoferer, GE Aviation’s director for CF34 Engine Services, gives some insight to GE’s vetting process. “When selecting an MRO partner, we look for one that has made the necessary capital investment to be in business for the long term. The location of their operations is very important because we must ensure we have regional service coverage for our customers. They must have FAA or country-equivalent certifications and demonstrate an allegiance to the OEM so the MRO is perceived as an extension of GE services.

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