Jetrader - July/August 2012 - 15

Engine Improvements Over Time
35,000 30,000 25,000 20,000 15,000 10,000 5,000 0
MTBO SFC

1970 5000 08

1980 10000 0667

1988 12000 06

1995 18000 055

1997 22000 055

2007 26000 05

2015 29000 047

0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0

baseline engine models (the latest 737NG/ CFM56-7B combination offers up to 2 percent improvements in fuel burn) to improve MTBO and fuel burn, a step-change in the design of current production narrow body engines was needed to satisfy operator requirements for double-digit percent fuel burn reduction. CFM has brought the Leap-X to the table as an engine option for the A320neo and the current sole engine choice for the 737MAX. Leap-X improvements versus previous CFM56-5B and -7B models include advances made in the development of the GE90 and GEnx engine. There is an increased use of lighter and more durable composite materials in the fan section, while the bypass ratio has been greatly increased. The new engine also has a new two-stage High Pressure Turbine (HPT) section which will enable hotter gas path temperatures. 3-D aerofoils are included throughout the turbine sections. A key element of maintenance cost input on the current-production CFM56 engines has been blade replacement in the turbine sections. The Leap-X incorporates an extra stage in the LP and HP modules, which indicates the part count will be higher, thus theoretically increasing shop visit costs. CFM have counteracted this argument by stating that the improved materials will withstand the higher temperatures of the Leap design without compensating EGT margin degradation patterns and removal rates. Overall, CFM is promising equivalent maintenance costs to today’s engines. Fuel burn savings are achieved by a new lean-burn combustor, a more efﬁcient and durable HP section as well as use of lighter materials, particularly in the fan section. While the Leap-X retains the traditional direct-drive architecture principles or previous engine designs, its principal rival in the A320 market, the Pratt & Whitney PW1000G GTF

will use a geared turbofan, which the OEM claims will reduce fuel burn by allowing the fan to turn at a slower speed than the rest of the engine. The PW1000G, as is with the V2500-A5 and the Leap-X, has two stages in the HP Turbine section but reduced stages in the HPC, LP Turbine and HP Compressor. The gearbox contains no life limited parts and will require little maintenance input over the life of the engine, according to the OEM. Indeed, Pratt & Whitney has stated that the engine will offer up to 20 percent maintenance cost reduction versus the current production CFM and V2500-A5. While CFM are claiming the Leap-X will offer equivalent maintenance cost to these existing engines, it is clear that Pratt & Whitney is claiming a distinct advantage in this area, mainly due to a signiﬁcantly lower part count and the gearbox system. However, given the fact that the ﬁrst wave of PW1000G/ Leap-X shop visits is unlikely until 8 to 10 years after service entry, it is some time yet before an actual comparison can be performed. Looking at the widebody market, GE’s GEnx engine has secured the majority of orders against its competitor, the Rolls-Royce Trent 1000 for the 787. GE has built this engine on advances made in the GE90 program, whereas Rolls-Royce has developed the Trent 1000 based on its successful Trent family of engines. While Rolls-Royce has 100 percent market share on the Airbus A350 XWB with the Trent XWB engine, the next battle for engine OEM market share could well be on the 777 replacement. While it is unlikely that the new aircraft will be ﬂying before 2020, both GE and Rolls-Royce have stated their intentions to launch an engine for the program, the GE9X and RB2035 respectively. Both claim to offer up to 10 percent lower fuel burn than the GE90. As with the Leap-X and PW1000G variants, key cost advantages

will come from increased use of composites, a lean-burn combustor and a reduced aerofoil count. Pratt & Whitney has also stated it may launch a scaled-up PW1000G GTF engine for the 777 replacement. While high-spec, high-demand engines, such as the current-production CFM56 and V2500 engines, as well as the incumbent PW1000G and Leap-X engines, demonstrate the strongest residual values on the market, increased reliability could harm the engine leasing model. Longer intervals and reduced spare parts requirements feasibly reduce the demand for spare engines and make MTBOs and spare engine requirements more difﬁcult to predict. Indeed, spare engine values can actually be strengthened by reliability issues, as witnessed with the PW4000-94 and Trent 500 models, as spare engine requirements are increased due to shorter intervals and increased shop visit rates. While operators will be happy with signiﬁcant fuel burn and maintenance cost reductions, lessors and engine MROs may struggle to develop proﬁtable business models from these more reliable engines, particularly if, as expected, more and more engines come under manufacturer FHAs. However, there are more than 8,000 engines on backlog (not including spares) across current-production A320 and 737NG aircraft models and roughly 7,000 engines have yet to have their first shop visit. This would indicate that there are plenty of opportunities for lessors and MROs with current-production engines. We are in no doubt that the current designs will offer signiﬁcant savings to the airlines, but was the timing right? This article is not focused upon the debt crisis and ailing secondary market for the “older” narrowbody aircraft—fueled by a lack of commercial debt and access of typically poorer credit airlines to export credit leading to an oversupply of younger aircraft—but you have to wonder when you consider that the current technology is already really efﬁcient. Maturity rates of the CFM56-7B have just settled down, and CFM and IAE are focused on constant improvements without an all new narrowbody airframe, so why release it now? Apart from cynical viewpoints, the pressure from airlines will be substantial in the face of fuel pricing. While fuel is expensive the focus will be costdriven rather than “green”-driven, but IATA will be striving toward new legislation soon, which give the OEMs little choice but release new technology as soon as possible. Jetrader 15

MTBO - Flight Hours

SFC - lbs/hr/lbst

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Jetrader - July/August 2012

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