13.12.2012 Views

Aviation and the Global Atmosphere

Aviation and the Global Atmosphere

Aviation and the Global Atmosphere

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

<strong>Aviation</strong> <strong>and</strong> <strong>the</strong> <strong>Global</strong> <strong>Atmosphere</strong><br />

Significant improvements in aircraft fuel efficiency have been achieved since <strong>the</strong> dawn of <strong>the</strong> jet age in commercial aviation. Historically, <strong>the</strong>se improvements have<br />

averaged 1-2% per year for new production aircraft (Koff, 1991; Albritton et al., 1996; Condit, 1996). These advances have been achieved through incorporation of new<br />

engine <strong>and</strong> airframe technology. Changes have included incremental <strong>and</strong> large-scale improvements. Examined over several decades, however, <strong>the</strong>y represent a<br />

relatively steady <strong>and</strong> continuous rate of improvement. A similar trend is assumed when fuel efficiency improvements are projected forward to 2050.<br />

Table 7-1:Percentage production fuel-efficiency improvements (ASK kg -1 fuel).<br />

Time Period Airframe Propulsion Total Aircraft<br />

1950-1997 30 40 70a<br />

1997-2015b 10 10 20<br />

1997-2050 25 20 45 (40-50)c<br />

a) To date, approximately 3/7 of <strong>the</strong> total fuel efficiency improvement of 70% is attributable to advances in airframe technology.<br />

b) Based on improvement records to date <strong>and</strong> <strong>the</strong> discussion in Section 7.3.7, it is reasonable to expect an airframe production average fuelefficiency<br />

improvement of ~10% by 2015. This percentage improvement is fur<strong>the</strong>r substantiated in o<strong>the</strong>r reference material (Greene, 1995).<br />

Similarly, a 10% propulsion production average fuel-efficiency improvement is considered feasible in this time frame.<br />

c) In <strong>the</strong> longer term (2050) compared to 1997, a total aircraft production average fuel-efficiency improvement of 40-50% is considered feasible<br />

(ICCAIA, 1997g). These levels of efficiency improvement are assumed in <strong>the</strong> 2050 technology scenarios described in Chapter 9. The ratio of<br />

airframe to propulsion production average fuel-efficiency improvement over <strong>the</strong> period 1997 to 2050 is projected to be 55/45 in favor of airframe<br />

technology developments. This is equivalent to a 25% airframe fuel-efficiency improvement.<br />

Aircraft, airframe, <strong>and</strong> propulsion production fuel efficiency improvements from <strong>the</strong> 1950s to today <strong>and</strong> projected to 2015 <strong>and</strong> 2050 are summarized in Table 7-1.<br />

Chapter 9 addresses <strong>the</strong> development of equivalent projected (2015/2050) fleet fuel efficiency improvements from production average fuel efficiencies used in<br />

emission scenarios.<br />

Airframe <strong>and</strong> engine improvements are discussed in detail in Sections 7.3 <strong>and</strong> 7.4.<br />

http://www.ipcc.ch/ipccreports/sres/aviation/092.htm (3 von 4)08.05.2008 02:43:22

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!