European Aviation Safety Agency - EASA - Europa

282 Pages·2010·7.73 MB·English

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S I
AFETY MPLICATION
B A
OF IOFUELS IN VIATION
Thomas Esch
Harald Funke
Peter Roosen
Aachen University of Applied Sciences
EASAReportNo. EASA.2008.C51
compilationdateJuly7,2010
Keywords
General Aviation, safety, gasoline, petrol, ethanol, blending, biofuels, MOGAS, AVGAS, E-0, E-5,
E-10, E-15, aircraft airworthiness, water, solved water detection, gasoline mixing, volatility, vapour
pressure, vapour locking, long-term storage, material compatibility, carburettor icing, gasoline
turbidity, phase separation, life-cycle analysis
2
Contents
Acknowledgements 11
1 IntroductionandOutlineofWork 12
2 SummaryandRecommendations 14
3 OperatingExistingEngineswithEthanol-AdmixedFuels 17
3.1 Definition of an “Old” Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.2 Survey of Aircraft Frames and Engines Authorized for MOGAS Operation . . . . . 17
3.3 Legislative and Practical Boundary Conditions for Biogenic Components Admixing 21
3.3.1 Usage Statistics of Various Fuel Types . . . . . . . . . . . . . . . . . . . . 23
3.4 Aircraft Fitness for Ethanol Admixtures . . . . . . . . . . . . . . . . . . . . . . . . 25
4 DeterminationoftheStatusQuoinGeneralAviation 26
4.1 Gasoline Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.1.1 Historic Development of Gasolines and their Alcohol Admixtures . . . . . 26
4.1.2 Prevailing Legal Boundary Conditions and Norms for Vehicle Gasolines . . 28
4.1.3 Assessment of Knocking Properties for Gasolines by Octane Numbers . . . 32
4.2 Synoptical Statistical Data on General Aviation (T 1) . . . . . . . . . . . . . . . . 35
5 Scientific and Technical Boundary Conditions for Ethanol-Admixed Gasoline Usage in
Aviation(T1) 38
5.1 Water-Induced Phase Separation in Gasoline-Ethanol Mixtures . . . . . . . . . . . 38
5.2 Vapour Locking Potential of Mixtures of Ethanol-Admixed Gasolines . . . . . . . . 43
5.3 Evaporation Enthalpy Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
5.4 Compatibility of Fuel System and Engine Materials with Ethanol Content in Fuel . 48
5.4.1 Metallic components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5.4.2 Plastics, Elastomers and Glues . . . . . . . . . . . . . . . . . . . . . . . . . 50
6 AssessmentofDangerPotentialsAttributedtoGasolineEthanolAdmixtures 51
6.1 Failure Mode and Effects Analysis (T 7) . . . . . . . . . . . . . . . . . . . . . . . 51
6.1.1 Methodology and Approach . . . . . . . . . . . . . . . . . . . . . . . . . . 51
6.1.2 Overall Results of the Failure Mode and Effects Analysis . . . . . . . . . . 53
6.1.3 FMEA Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
6.2 Task Spanning Activities for Experimentation . . . . . . . . . . . . . . . . . . . . . 63
3
6.3 Analysis of Phase Separation Hazard (T 2a, 2c) . . . . . . . . . . . . . . . . . . . 64
6.3.1 Methodology and Approach . . . . . . . . . . . . . . . . . . . . . . . . . . 64
6.3.2 High-Altitude Flight Experiments for Cool-Down Experiments Boundary
Conditions Determination (T 2a) . . . . . . . . . . . . . . . . . . . . . . . 64
6.3.3 Tank Air Throughput During a Flight (T 2a) . . . . . . . . . . . . . . . . . 66
6.3.4 Determination of Compositional Changes in Gasolines Stored in Aircraft
Tanks for Prolonged Periods (T 2c) . . . . . . . . . . . . . . . . . . . . . . 67
6.3.5 Onset of Hazing in Custom Mixed Ethanol-Containing Gasolines (T 2a) . . 72
6.3.6 Phase Separation: Conclusion (T 2a) . . . . . . . . . . . . . . . . . . . . . 74
6.4 Analysis of Carburettor Icing Hazard (T 2b) . . . . . . . . . . . . . . . . . . . . . 76
6.4.1 Methodology and Approach . . . . . . . . . . . . . . . . . . . . . . . . . . 76
6.4.2 Temperature Drop Determination in a ROTAX Engine . . . . . . . . . . . . 76
6.4.3 Temperature Drop Determination in a Lycoming O 360 A1A Engine . . . . 77
6.4.4 Icing: Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.5 Analysis of Intensified Vapour Locking Hazard Caused by Gasoline Mixing . . . . 80
6.5.1 Fuel Heat-Up Experiments with a MORANE MS 893 E-D Aircraft (T 3) . . 81
6.5.2 Investigation of Pressure Drops in the MORANE Fuel System Under Oper-
ating Conditions (T 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
6.5.3 Vibration Measurements in the MORANE Fuel System (T 3) . . . . . . . . 85
6.5.4 Vapour Locking Experiments on a Custom Test Rig (T 3) . . . . . . . . . . 86
6.5.5 Assessment of a Common Gasoline Volatility Test Device (T 3) . . . . . . 92
6.5.6 Vapour Lock: Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
6.6 Material Compatibility of Common Constructive Materials for Aircraft Parts (T 4) . 93
6.6.1 Approach / Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
6.6.2 Report on Plastic Materials Compatibility with Ethanol-Admixed Gasolines 94
6.6.3 Survey on Deployed Materials for Fuel Systems . . . . . . . . . . . . . . . 120
6.6.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
7 MetrologicalAidsforGasolineCompositionAssessment(T6) 126
7.1 Determination of an Ethanol Share in Gasoline . . . . . . . . . . . . . . . . . . . . 126
7.1.1 Colour Indicator Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
7.1.2 Ethanol Extraction by Water . . . . . . . . . . . . . . . . . . . . . . . . . . 127
7.2 Detection of Solved Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
7.2.1 Chemical Water Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
7.2.2 Optical Water Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
4
7.2.3 Electrical Water Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
7.2.4 Water detection by molecule-specific adsorption . . . . . . . . . . . . . . . 133
7.3 Detection of Solved Water: Conclusion . . . . . . . . . . . . . . . . . . . . . . . . 135
8 Life-CycleAnalysisofEthanol-AdmixedGasolines(T5) 137
8.1 Approach / Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
8.2 Experimental Investigation of Exhaust Gas Emissions for a ROTAX 912 ULS Engine 138
8.3 Life Cycle Analysis of Measured Exhaust Gas Emissions of the ROTAX 912 Engine 140
8.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
References 144
A EnginesandCellsCertifiedbytheUnitedStatesFAA 146
B StatisticalDataonGeneralAviationandUltralightAircraft(T1) 154
C TabulatedFMEAResults 160
D TaskSpanningActivitiesforExperimentation 196
D.1 Acquisition and Handling of Test Fuels . . . . . . . . . . . . . . . . . . . . . . . . 196
D.2 Instrumentation of ACUAS’s flying lab, a MORANE MS 893 E-D . . . . . . . . . . 200
D.3 Setup, Instrumentation and Test Matrix of a Test-Rigged ROTAX 912 ULS Engine
in Propeller Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
D.4 Custom Designed Test Rig for Vapour Locking and Water Detection Experimentation205
D.4.1 Rig Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
D.4.2 Procedures of Test Rig Operation for Nucleation Assessment . . . . . . . . 208
D.4.3 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
D.4.4 Measurement Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
D.4.5 Environment Protection and Safety Arrangements . . . . . . . . . . . . . . 210
D.4.6 Bubble Sensor Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
D.4.7 Calibration of the Test Rig . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
E Life-CycleAnalysisofEthanol-AdmixedGasolines—ReportbyLUDWIGBÖLKOWSYS-
TEMTECHNIK 213
F KeywordsandAbbreviationsIndex 277
5
List of Figures
1 Development of biogenic fuel shares from 2007 to 2009 in Germany . . . . . . . . 23
2 Ethanol content in random German Super Plus gasoline probes taken in June 2009 24
3 Shares of different fuel types (Diesel fuel excluded) for 2008 in Germany. The
share titled “Automotive Petrol Fuel” also contains the amount of gasoline taken for
aviation purposes, which is smaller than the AVGAS share (see Sect. B). Source:
Mineralölwirtschaftsverband Deutschland . . . . . . . . . . . . . . . . . . . . . . . 24
4 Ratio of Super Plus RON 100 to Super RON 98 gasolines . . . . . . . . . . . . . . 25
5 Qualitative evaporation curves for various gasoline types and two jet fuels. . . . . . 30
6 DVPE values of random test samples, June 2009 . . . . . . . . . . . . . . . . . . . 32
7 Octane numbers of 21 gasoline test samples and SIOBIA standard gasoline . . . . 34
8 German and United Kingdom numbers for the aircraft categories of interest. No
distinction is made with respect to used fuel type. . . . . . . . . . . . . . . . . . . 36
9 Estimated European total numbers for the aircraft categories of interest . . . . . . . 36
10 Graphical display of the distribution of small aircraft in Europe . . . . . . . . . . . 37
11 Ternary diagram for the substances gasoline, water and ethanol . . . . . . . . . . . 39
12 Maximum water concentrations in different gasoline/ethanol mixtures . . . . . . . . 40
13 Measured water concentrations in different commercially offered gasolines . . . . . 41
14 Binodal and spinodal limit curves in a ternary GEW diagram . . . . . . . . . . . . 42
15 Dependence of static vapour pressure on the amount of admixed ethanol . . . . . . 44
16 Dependence of dynamic vapour pressure on the amount of admixed ethanol . . . . 45
17 Mixing gasoline types with differing ethanol admixtures . . . . . . . . . . . . . . . 46
18 DVPE values of 21 test samples taken at different gasoline stations . . . . . . . . . 46
19 Enthalpy of vaporization for ethanol admixed gasoline blends . . . . . . . . . . . . 48
20 Temperature/humidity domains for increased danger of carburettor icing . . . . . . 49
21 Hard plastics typology pyramid . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
22 FMEA objectives overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
23 FMEA risk attribution classes overview . . . . . . . . . . . . . . . . . . . . . . . . 53
24 FMEA issues categories overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
25 Principal experimentation objects . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
26 Flight test card for tank heat drain experiments . . . . . . . . . . . . . . . . . . . . 65
27 Temperature developments at different positions on a MORANEfuel tank surface . . 65
28 Temperature developments inside a MORANEfuel tank . . . . . . . . . . . . . . . . 66
29 Temperature crossover point inside a MORANEfuel tank . . . . . . . . . . . . . . . 67
6
30 Air ingestion by tank ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
31 Storage tank design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
32 Normalized residual gasoline masses observed for the different storage tanks. . . . 70
33 Development of water contents for gasoline tanks stored under differing ambient
conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
34 Ambient humidity and temperature conditions for the gasoline storage experiment . 72
35 Onset of phase separation hazing in water admixture and cool-down experiments . 73
36 Three-dimensional approximation plane of turbidity onset . . . . . . . . . . . . . . 74
37 ROTAX 912 ULS temperature drop in the intake manifold, full load . . . . . . . . . 76
38 ROTAX 912 ULS temperature drop in the intake manifold, zero load . . . . . . . . 77
39 Morane icing test setup for operation with ethanol admixed fuels. . . . . . . . . . . 78
40 Temperature drop in a Lycoming O 360 A1A engine . . . . . . . . . . . . . . . . . 79
41 Flight Test Card for a heavy load circuit heat-up experiment . . . . . . . . . . . . . 82
42 Development of fuel hose temperatures near to the engine for consecutive starts
and fast touch-downs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
43 Fuel hose temperatures near to engine for low service ceiling starts and touch-downs 83
44 Dynamic pressure drops in the MORANE fuel system . . . . . . . . . . . . . . . . 84
45 Vibration frequencies and strengths in the MORANE fuel system . . . . . . . . . . 86
46 Viewport bubble images in test rig experiments . . . . . . . . . . . . . . . . . . . . 87
47 Bubble nascence of pure substances compared to calibration curves . . . . . . . . . 87
48 Bubble sensor readout field for AVGAS . . . . . . . . . . . . . . . . . . . . . . . . 88
49 Bubble sensor readout field for E-0 and E-5 . . . . . . . . . . . . . . . . . . . . . 89
50 Bubble sensor readout field for E-10 and E-15 . . . . . . . . . . . . . . . . . . . . 90
51 Pressure / Temperature limits for low bubble incidence limits . . . . . . . . . . . . 91
52 Pressure / Temperature limits for high bubble incidence limits . . . . . . . . . . . . 91
53 Hodges tester for gasoline volatility assessment. . . . . . . . . . . . . . . . . . . . 92
54 Temperature resistance of elastomers . . . . . . . . . . . . . . . . . . . . . . . . . 101
55 Oil resistance of elastomers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
56 Gasoline and ethanol resistance of elastomers . . . . . . . . . . . . . . . . . . . . . 102
57 Classification of thermoplastics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
58 Temperature resistance of thermoplastics . . . . . . . . . . . . . . . . . . . . . . . 113
59 Resistance of thermoplastics against gasoline and alcohol / ethanol . . . . . . . . . 114
60 Resistance of thermosettings against gasoline and alcohol / ethanol . . . . . . . . . 116
61 Results of compabitility tests of a fluorocarbon elastomer . . . . . . . . . . . . . . 118
7
62 Realisation of a test for environmental stress cracking . . . . . . . . . . . . . . . . 119
63 Materials questionnaire tree (partial) . . . . . . . . . . . . . . . . . . . . . . . . . . 121
64 Decrease of materials general questionnaire participation . . . . . . . . . . . . . . . 122
65 Production areas of questionnaire participants . . . . . . . . . . . . . . . . . . . . . 123
66 Distribution of materials for aviation parts . . . . . . . . . . . . . . . . . . . . . . 123
67 Estimate of ethanol admixture effect on aviation affairs . . . . . . . . . . . . . . . 124
68 Valuation of potential consequences of ethanol admixture on aviation parts . . . . . 124
69 Sensitivity determination schema for an ethanol detection kit working on colour
change reaction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
70 Water/ethanol mix excess volume . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
71 Maul’s Fuel-Alk Tester . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
72 Karl-Fischer water titration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
73 Electrical water detection in E-0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
74 Zeolite water absorption experiment . . . . . . . . . . . . . . . . . . . . . . . . . . 134
75 Zeolite water absorption evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . 135
76 Flight profile for comparative LCA studies . . . . . . . . . . . . . . . . . . . . . . 138
77 ROTAX exhaust temperatures with ethanol admixed fuels . . . . . . . . . . . . . . 139
78 ROTAX NOx emissions with ethanol admixed fuels . . . . . . . . . . . . . . . . . . 140
79 Pathways and by-effects for biogenic ethanol production . . . . . . . . . . . . . . . 140
80 Well to tank greenhouse gas emission analysis results . . . . . . . . . . . . . . . . 141
81 Well to propeller greenhouse gas emission analysis results . . . . . . . . . . . . . . 142
82 Graphical compilation of European General Aviation aircraft numbers . . . . . . . 155
83 Comparison of realized vs. potential MOGAS aircraft (Germany) . . . . . . . . . . 155
84 German and United Kingdom numbers for the aircraft categories of interest. No
distinction is made with respect to used fuel type. . . . . . . . . . . . . . . . . . . 157
85 Estimated European total numbers for the aircraft categories of interest . . . . . . . 157
86 German MOGAS operated aircraft engines . . . . . . . . . . . . . . . . . . . . . . 158
87 Graphical display of the distribution of small aircraft in Europe . . . . . . . . . . . 159
88 Ethanol contents of 23 random commercial vehicle gasoline samples . . . . . . . . 198
89 AcUAS’ flying laboratory MORANE MS 893 E-D . . . . . . . . . . . . . . . . . . 200
90 Schematic of the MORANE fuel system . . . . . . . . . . . . . . . . . . . . . . . . 201
91 ROTAX 912 ULS on test rig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
92 ROTAX 912 ULS measurement points for temperature drop and exhaust gas com-
position determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
8