A Sample Feature From Aviation News
Power for the Airline

The successful pairing of French company Snecma with General Electric in 1970 produced a fan engine which has become one of the standard powerplants for Airbus and Boeing airliners. The CFM56 has matured into a long-life, reliable engine against which other, similar powerplants are judged. The Editor reports on a commercial engineering success story.

Above: Like all engine manufacturers, CFM test each new model, subjecting it to every environmental element it is likely to encounter in service.

Below: The low-slung CFM56 on the Boeing 737 series makes maintenance relatively easy.

AT a particularly difficult time in French-US relations, the close liaison between Snecma and GE Aircraft Engines must seem at odds with the political climate pervading over the recent Iraq War. Yet the long-standing joint venture between the two companies is a buoyant enterprise which continues to build, supply and support a family of engines which is keeping a large number of the world’s airlines flying and appears likely to maintain a significant lead in the 24-34,000lb-thrust segment of the engine market. Quiet, powerful and technically brilliant, the big-mawed CFM56 has become the preferred choice for hundreds of customers across the world.

But not everything in the powerplant world is that rosy. September 11, 2001, saw to that in a cataclysmic, far-reaching way that has affected almost every aspect of life in today’s modern, civilised industrialised society. Snecma/CFM has not gone unscathed in the aftermath of 9/11. As a supplier, it has been just as affected as the airframe manufacturers; ergo, no airframes, no engines.

However, after the dramatic down-turn in air travel following the terrorist attacks, the market was showing a gradual return towards the earlier projected figures for growth when the Iraq War once again forced a further reappraisal by all elements of the commercial aerospace industry. CFM delivered 600 engines in 2002, less than half the 1,600 delivered in 1999. Their figures for this year involve the production of 717 engines which is not as good as in the past but encouraging. A significant boost for the company’s fortunes were the recent orders for Airbus A320-family aircraft placed by easyJet, China Southern and China Eastern.

Below: Basic components of the CFM56.

Background to success

In 1974, CFM offered onto the market the world’s first high by-pass ratio engine aimed at replacing the large number of fuel-guzzling low by-pass engines then in use. Called the CFM56-2 (an abbreviation for Commercial Fan with the M standing for Mars, God of War, relating to Snecma’s mostly military engine product line at the time; 56 is the project number). After five years and no orders, the programme was on the verge of cancellation when the engine was selected by Cammacorp for their Douglas DC-8 upgrade, followed in 1981 by a similar programme for US Air Force KC-135 Stratotankers. The same year the -3 version was launched on the Boeing 737-300 and the next year the first CFM56 was delivered for service. The main competitors in the market are International Aero Engines with the V2500 and Pratt & Whitney with the PW6000, both holding a smaller share of the market for this size of engine.

There are currently six CFM56 models:

A seventh model, the -5C/P (31,200/34,000lb thrust) for the A340-300 will join the fleet when certificated this year.

Above: One of Southwest Airlines’ fleet of 194 Boeing 737-300s, most of which will receive an engine upgrade over the next two years.

To gain a measure of the durability of modern engines, in 1997 a CFM56-3 powering a Germania Airlines Boeing 737 flying high-cycle operations reached 30,300hr without being removed from the wing for a major overhaul. This record was broken recently when a -3 on lease to Malev from Hapag-Lloyd was still running without problems after nearly 40,000hr.

The work share between the two companies, GE and Snecma, is a 50/50 split with the US Cincinnati factory producing the core engine with system design integration and the main engine controls/FADEC, while at Villeroche, France, the fan, low-pressure turbine and accessory drive is produced. There are assembly lines at each site using common procedures and quality standards. The two companies have split the world into two regions, GE covering the Americas, China, Japan and Australasia, with Snecma undertaking sales and product support in Europe, Africa and Asia. To date, CFM has 361 customers/operators and has delivered more than 13,370 engines.

Re-engine revolution
Boeing KC-135
Fuel savings, reliability and lower costs resulted in the USAF programme to re-engine a substantial portion of its KC-135 Stratotanker fleet with CFM56-2s, beginning in 1981. The USAF has more than 1,774 engines in its inventory powering 424 KC/RC-135s and an on-going programme requires CFM to deliver some 20 engines per year. Worldwide, CFM engines equip 489 re-engined military aircraft with nine air forces.
Douglas DC-8-70
The programme to re-engine the DC-8 with CFM56 turbofans was launched in 1979 by the US Cammacorp company. The initial up-engined DC-8 Srs 60 conversion first flew on August 15, 1981, and the various types took the designations Series 71, 72 and 73. Aircraft were operated initially by United Airlines and the first engine delivered to that operator in March 1982 is still flying - now with Tampa Airlines - and had completed 47,068 hours as of December 2002. A total of 109 DC-8-70s were re-engined and most are still flying.

For the rest of this article please see the July 2003 issue.