1 Introduction
2 Proposed model and theoretical background
2.1 Proposed model of fuel consumption optimization (FCO) in air transport
2.2 Theoretical background of constructs and hypotheses
2.2.1 Aircraft operational area
2.2.2 Aircraft technology & design
2.2.3 Socio-economic, & political
2.2.4 Aviation infrastructural area
2.2.5 Alternate fuels & fuel properties
Factors/ constructs and variables | References |
---|---|
(1) Aircraft operations (AO) • Fuel tankering (AOA) • Fuel weight (AOB) • Stage length (AOC) • Payload weight (AOD) • Aircraft altitude (AOE) • Aircraft speed (AOF) • Aircraft extra weight (AOG) | Arushi and Drews [4], Airbus [10, 12], Stolzer [11], Majka et al. [13], Pilati [20], Dewees and Waverman [21], Greene [22], Whitehead [6], ICAO [26, 27], IATA [25], IEA [28], Vankan et al. [36], Green [23], Penner [33], CCC [17], Singh and Sharma [35], Singh et al. [14, 15], Lee et al. [30], Lee [31], Babikian et al. [34]; Bows and Anderson [60]; Filippone [45]; Collins [16]; Nash [39]; Bush [61]; Miller et al. [62]; Darnell and Loflin [38]; Goldsmith [63]; Turgut [64]; Turgut and Rosen [65]; Egbert Torenbeek [66]; Viscotchi [67]; Sachs [68]; Schilling [69]; Fan [44]; Stroup and Wollmer [40]; Abdelghany et al. [42]; Lathasree and Sheethal [70]; Mazraati [71]; Mazraati and Alyousif [50]; Zouein et al. [41]; Peeters et al. [72]; Covey et al. [43]; Root [73]; Archibald and Reece [74]; Andrew [75]; Olsthoorn [76]; Komalirani and Rutool [77] |
(2) Aircraft technology & design (ATD) • Engine types (ATDA) • Lift/drag (ATDB) • Engine by pass ratio (ATDC) • Design range (ATDD) • Engine thrust (ATDE) • New aircraft (ATDF) • Structural weight (ATDG) | Arushi and Drews [4]; Whitehead [6]; Greene [22]; ICAO [26, 27]; IATA [25]; IEA [28]; Vankan et al. [36]; Green [23]; Penner [33]; CCC [17]; Singh and Sharma [35], Singh et al. [14, 15]; Lee et al. [30]; Lee [31]; Bows and Anderson [60]; Alonso et al. [8]; Simões and Schaeffer [78]; McDonald et al. [79]; Constant [80]; Denning [81]; Sachs [68]; Sweet [82]; Harvey et al. [83]; Szodruch et al. [84]; Mazraati and Alyousif [50]; Mazraati and Alyousif [50]; Mazraati [71]; Antonie and Kroo [85]; Peeters et al. [73]; Archibald and Reece [74]; Henderson [49]; Megan and Mark [86]; Morrison [46]; Wilson and Paxson [87]; Olsthoorn [76]; Komalirani and Rutool [77] |
(3) Socio-economic & political issues (SEP) • Fuel price (SEPA) • Ticket price (SEPB) • Aircraft scheduling (SEPC) • Government regulations (SEPD) • Charges & taxes (SEPE) | Drake [29]; Arushi and Drews [4]; ICAO [26, 27]; IATA [25]; IEA [28]; Penner [33]; CCC [17]; Singh and Sharma [35], Singh et al. [14, 15]; Lee [31]; Craig and Smith [18]; Sweet [82]; Harvey et al. [83]; Brueckner and Zhang [88]; Vespermann and Wald [89]; Szodruch et al. [84]; Mazraati [71]; Megan and Mark [86]; Morrison [46]; Olsthoorn [76]; Singh and Sharma [35], Singh et al. [14, 15] |
(4) Aviation infrastructural area (AI) • Runway (AIA) • Weather conditions (AIB) • Flight profile (AIC) • Terminal area (AID) • Block hours (AIE) • Taxiway (AIF) • Fuel procurement (AIG) | Kazda and Caves [54]; Hubbard [24]; Correia and Alves [53]; Arushi and Drews [4]; ICAO [26, 27]; IATA [25]; IEA [28]; Penner [33]; CCC [17]; Singh and Sharma [35], Singh et al. [14, 15]; Babikian et al. [34]; Miller et al. [62]; Van Cleave [52]; Austin and Hogan [51]; Mazraati [71]; Mazraati and Alyousif [73]; Olsthoorn [76] |
(5) Alternate fuels & fuel properties (AFP) • Boiling point (AFPA) • Alternate fuel type (AFPB) • Energy content (AFPC) • Density (AFPD) | Arushi and Drews [4]; Veziroglu and Barbir [37]; ICAO [27]; IATA [25]; IEA [28]; Green [23]; Penner [33]; CCC [17]; Singh and Sharma [35], Singh et al. [14, 15]; Lee et al. [30] Lee [31]; Tsuchida et al. [32]; Mensch et al. [90]; Simões and Schaeffer [78]; Chevron [91]; AFQRJOS [92]; Contreras et al. [93]; Pruitt & Hardy [94]; Dell and Bridger [95]; Daggett et al. [96, 97]; Nygren et al. [98]; Turgut and Rosen [99]; Berry et al. [100]; Goodger [101]; Wang and Oehlschlaeger [102]; Hileman et al. [59]; Price [56]; Blakey et al. [103]; Blazowski [104]; Olsthoorn [76]; Komalirani and Rutool [77] |
3 Research methodology
3.1 Sample and data collection
3.2 Construct measures
3.3 Research steps
4 Results and findings
4.1 Exploratory factor analysis and results
Items of FCO | Factor loadings | CITC | Eigen-values | % of variance explained | KMO | Cronbach’s α |
---|---|---|---|---|---|---|
Aircraft operations (AO) | 3.53 | 69.72 | 0.877 | 0.911 | ||
AOB | 0.875 | 0.814 | ||||
AOF | 0.872 | 0.789 | ||||
AOE | 0.850 | 0.758 | ||||
AOD | 0.848 | 0.776 | ||||
AOC | 0.817 | 0.737 | ||||
AOA | 0.720 | 0.635 | ||||
Bartlett test: χ2 = 872.778, df = 15, p = 0.001 | ||||||
Technology & design (ATD) | 3.57 | 75.78 | 0.902 | 0.935 | ||
ATDB | 0.887 | 0.824 | ||||
ATDE | 0.881 | 0.816 | ||||
ATDG | 0.880 | 0.828 | ||||
ATDD | 0.875 | 0.825 | ||||
ATDC | 0.849 | 0.776 | ||||
ATDF | 0.847 | 0.787 | ||||
Bartlett test: χ2 = 1082.480, df = 15, p = 0.001 | ||||||
Socio-economic & political (SEP) | 2.63 | 78.45 | 0.837 | 0.906 | ||
SEPB | 0.907 | 0.804 | ||||
SEPE | 0.882 | 0.810 | ||||
SEPD | 0.879 | 0.795 | ||||
SEPA | 0.871 | 0.757 | ||||
Bartlett test: χ2 = 576.407, df = 6, p = 0.001 | ||||||
Aviation Infrastructure (AI) | 3.95 | 79.09 | 0.857 | 0.933 | ||
AID | 0.925 | 0.925 | ||||
AIC | 0.907 | 0.907 | ||||
AIB | 0.900 | 0.900 | ||||
AIA | 0.857 | 0.857 | ||||
AIE | 0.855 | 0.855 | ||||
Bartlett test: χ2 = 960.766, df = 10, p = 0.001 | ||||||
Alternate fuels & fuel properties (AFP) | 2.49 | 64.04 | 0.790 | 0.812 | ||
AFPB | 0.821 | 0.684 | ||||
AFPC | 0.802 | 0.615 | ||||
AFPD | 0.796 | 0.615 | ||||
AFPA | 0.784 | 0.614 | ||||
Bartlett test: χ2 = 282.484, df = 6, p = 0.001 |
4.2 Confirmatory measurement analysis of FCO
Constructs/items | Standardized factor loadings | Standard error | t-values | R2(Item-reliability) | AVEa | Composite reliability (CRb) |
---|---|---|---|---|---|---|
Aircraft operations (AO) | 0.72 | 0.91 | ||||
AOF | 0.798 | F | – | 0.636 | ||
AOE | 0.756 | 0.054 | 17.59 | 0.572 | ||
AOB | 0.834 | 0.073 | 13.71 | 0.697 | ||
AOD | 0.835 | 0.070 | 13.85 | 0.609 | ||
AOC | 0.780 | 0.073 | 12.67 | 0.482 | ||
AOA | 0.650 | 0.074 | 9.91 | 0.695 | ||
Technology & design (ATD) | 0.73 | 0.94 | ||||
ATDG | 0.784 | f | – | 0.615 | ||
ATDF | 0.760 | 0.055 | 17.17 | 0.578 | ||
ATDE | 0.804 | 0.069 | 16.19 | 0.646 | ||
ATDB | 0.894 | 0.083 | 14.91 | 0.800 | ||
ATDD | 0.871 | 0.073 | 14.42 | 0.758 | ||
ATDC | 0.816 | 0.084 | 13.27 | 0.666 | ||
Socio-economic & political (SEP) | 0.74 | 0.92 | ||||
SEPA | 0.771 | f | – | 0.594 | ||
SEPE | 0.875 | 0.075 | 13.42 | 0.766 | ||
SEPD | 0.872 | 0.080 | 13.13 | 0.761 | ||
SEPB | 0.831 | 0.077 | 14.59 | 0.691 | ||
Aviation infrastructure (AI) | 0.84 | 0.96 | ||||
AID | 0.939 | f | – | 0.542 | ||
AIC | 0.940 | 0.041 | 25.32 | 0.678 | ||
AIE | 0.808 | 0.052 | 16.50 | 0.653 | ||
AIB | 0.823 | 0.049 | 18.30 | 0.884 | ||
AIA | 0.737 | 0.055 | 14.39 | 0.882 | ||
Alternate fuels & fuel properties (AFP) | 0.53 | 0.81 | ||||
AFPB | 0.709 | f | – | 0.503 | ||
AFPC | 0.695 | 0.098 | 9.78 | 0.500 | ||
AFPA | 0.694 | 0.096 | 9.81 | 0.495 | ||
AFPD | 0.776 | 0.099 | 9.47 | 0.602 | ||
Fuel consumption optimization in air-transport (FLOATA) | 0.910 | 0.046 |
Constructs | AVE | AFP | SEP | ATD | AO | AI |
---|---|---|---|---|---|---|
AFP | 0.53 | 1 | ||||
SEP | 0.74 | 0.384*** (0.147)a | 1 | |||
ATD | 0.73 | 0.335*** (0.112) | 0.17** (0.029) | 1 | ||
AO | 0.72 | 0.414*** (0.171) | 0.339*** (0.115) | 0.561*** (0.315) | 1 | |
AI | 0.84 | 0.174** (0.03) | 0.001*** | 0.436*** (0.190) | 0.301*** (0.091) | 1 |
4.3 Evolution of model using SEM
Endogenous variable | Structural equations | Exogenous variables |
---|---|---|
Structural portion | ||
FCO(η) | FCO(η) = (ηξ1) (ξ1) + (ηξ2) (ξ2) + (ηξ3) (ξ3) + (ηξ4) (ξ4) + (ηξ5) (ξ5) + δ1 | AO(ξ1), ATD(ξ2), SEP(ξ3), AI(ξ4), AFP(ξ5) |
Measurement portion | ||
AOF(V1) | V1 = (1) ξ1 + e6 | AO(ξ1) |
AOE(V2) | V2 = (ξ1V2) ξ1 + e5 | |
AOB(V3) | V3 = (ξ1V3) ξ1 + e2 | |
AOD(V4) | V4 = (ξ1V4) ξ1 + e4 | |
AOC(V5) | V5 = (ξ1V5) ξ1 + e3 | |
AOA(V6) | V6 = (ξ1V6) ξ1 + e1 | |
ATDG(V7) | V7 = (1) ξ2 + e14 | ATD(ξ2) |
ATDF(V8) | V8 = (ξ2V8) ξ2 + e13 | |
ATDE(V9) | V9 = (ξ2V9) ξ2 + e12 | |
ATDB(V10) | V10 = (ξ2V10) ξ2 + e9 | |
ATDD(V11) | V11 = (ξ2V11) ξ2 + e11 | |
ATDC(V12) | V12 = (ξ2V12) ξ2 + e10 | |
SEPA(V13) | V13 = (1) ξ3 + e15 | SEP(ξ3) |
SEPE(V14) | V14 = (ξ3V14) ξ3 + e19 | |
SEPD(V15) | V15 = (ξ3V15) ξ3 + e18 | |
SEPB(V16) | V16 = (ξ3V16) ξ3 + e16 | |
AIA(V17) | V17 = (ξ4V17) ξ4 + e20 | |
AIB(V18) | V18 = (ξ4V18) ξ4 + e21 | AI(ξ4) |
AIE(V19) | V19 = (ξ4V19) ξ4 + e24 | |
AIC(V20) | V20 = (ξ4V20) ξ4 + e22 | |
AID(V21) | V21 = (1) ξ4 + e22 | |
AFPD(V22) | V22 = (ξ5V22) ξ5 + e30 | AFP(ξ5) |
AFPA(V23) | V23 = (ξ5V23) ξ5 + e27 | |
AFPC(V24) | V24 = (ξ5V24) ξ5 + e29 | |
AFPB(V25) | V25 = (1) ξ5 + e28 | |
FCOA(V26) | V26 = ( ηV26) η + e31 | FCO(η) |
Path coefficients of FCO model | ||||
Relationship | Standard path coefficients | C.R. | p-values | Support of hypothesis |
AO→ FCO | 0.333 | 2.765 | 0.006* | H1 Supported |
ATD→ FCO | 0.477 | 3.232 | *** | H2 Supported |
SEP→ FCO | 0.168 | 2.415 | 0.023** | H3 Supported |
AI→ FCO | 0.155 | 2.386 | 0.017** | H4 Supported |
AFP→ FCO | 0.218 | 2.352 | 0.019** | H5 Supported |
Goodness of fit indices for FLOAT model | Criteria | Indicators | ||
χ2 test | ||||
χ2 | 353 | |||
χ2/df | <3 | 1.283(353/275) | ||
Fit indices | ||||
GFI | >0.80 | 0.895 | ||
AGFI | >0.80 | 0.865 | ||
NFI | >0.90 | 0.924 | ||
RMR | ≤0.08 | 0.056 | ||
CFI | >0.90 | 0.982 | ||
TLI | >0.90 | 0.979 | ||
RMSEA | <0.06 to 0.08 | 0.036 |