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Matthias Nott
6 days ago e07a553414967d3a090c9b2feea2d1fdfab082a7 
 SPL Exam Questions EN/20 - Aircraft General Knowledge.md
....@@ -115,6 +115,8 @@
115115 
116116 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q6) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q6)
117117 
118
+![](figures/Anatomy_sailplane_EN.png)
119
+
118120 - **A)** Ailerons and elevator.
119121 - **B)** Horizontal tail and vertical tail.
120122 - **C)** Rudder and ailerons.
....@@ -312,6 +314,8 @@
312314 
313315 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q15) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q15)
314316 
317
+![](figures/Anatomy_sailplane_FR.png)
318
+
315319 - **A)** Rudder.
316320 - **B)** Trim tab.
317321 - **C)** Elevator.
....@@ -397,6 +401,8 @@
397401 
398402 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q19) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q19)
399403 
404
+![](figures/Anatomy_sailplane_EN.png)
405
+
400406 - **A)** Flaps, slats, and speedbrakes.
401407 - **B)** All movable components on an aircraft that help control its flight.
402408 - **C)** Elevator, rudder, and aileron.
....@@ -461,6 +467,8 @@
461467 ### Q22: In which direction does the trim tab deflect when trimming for nose-up? ^t20q22
462468 
463469 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q22) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q22)
470
+
471
+![](figures/Anatomy_sailplane_EN.png)
464472 
465473 - **A)** It depends on the CG position.
466474 - **B)** It deflects upward.
....@@ -837,6 +845,8 @@
837845 ### Q37: The vertical speed indicator compares the pressure difference between ^t20q37
838846 
839847 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q37) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q37)
848
+
849
+![](figures/t20_q37.png)
840850 
841851 - **A)** The current dynamic pressure and the dynamic pressure from a moment earlier.
842852 - **B)** The current static pressure and the static pressure from a moment earlier.
....@@ -1255,6 +1265,8 @@
12551265 
12561266 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q54) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q54)
12571267 
1268
+![](figures/Anatomy_sailplane_EN.png)
1269
+
12581270 - **A)** To trim the glider.
12591271 - **B)** To steer the glider.
12601272 - **C)** To stabilize the glider.
....@@ -1664,10 +1676,15 @@
16641676 
16651677 #### Explanation
16661678 
1667
-Under European and ISO standards, aviation oxygen cylinders are conventionally painted black. This distinguishes them from other gas types in the color coding system. Medical oxygen bottles may be white, but aviation oxygen specifically uses black as the standard identification color.
1679
+Under the **older European convention** (pre-EN 1089-3), oxygen cylinders had a **black body** with a white shoulder — that is the answer this exam expects.
16681680 
1669
-- **Option A** (red) typically indicates flammable gases like hydrogen or acetylene.
1670
-- **Option B** (orange) and D (blue/white) do not correspond to the standard aviation oxygen bottle color coding.
1681
+However, the current European standard **EN 1089-3** (fully transitioned by 2025) specifies **white body + white shoulder** (RAL 9010) for all oxygen cylinders, including aviation breathing oxygen. In practice, both black (legacy) and white (new standard) cylinders are still encountered in the field.
1682
+
1683
+- **Option A** (red) indicates flammable gases (hydrogen, acetylene).
1684
+- **Option B** (orange) does not correspond to any standard oxygen coding.
1685
+- **Option D** (blue/white) is not the standard either — blue typically identifies nitrous oxide.
1686
+
1687
+**Note:** If you encounter this question on the actual exam, answer **black** (the legacy convention the exam bank uses). In real life, oxygen cylinders are increasingly **white** per EN 1089-3.
16711688 
16721689 ### Q73: During a turn, what does the ball (inclinometer) indicate? ^t20q73
16731690 
....@@ -1898,6 +1915,8 @@
18981915 
18991916 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q83) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q83)
19001917 
1918
+![](figures/t20_q90.png)
1919
+
19011920 - A) 80 litres.
19021921 - B) 70 litres.
19031922 - C) 90 litres.
....@@ -2062,19 +2081,23 @@
20622081 
20632082 #### Answer
20642083 
2065
-B)
2084
+D)
20662085 
20672086 #### Explanation
20682087 
2069
-Using the loading table from the flight manual (attached figure) for a glider with 275 kg empty weight: the correct combination that keeps total mass within the maximum takeoff weight and CG within approved limits is 100 kg payload with 80 liters of water ballast.
2088
+The question asks for the **maximum payload** (heaviest cockpit load) with its **permitted water ballast**. To find this, plot each answer on the loading chart at y=275 kg empty weight:
20702089 
2071
-- **Option A** (85 kg/100 L) and D (105 kg/70 L) do not satisfy the loading table constraints.
2072
-- **Option C** (110 kg/65 L) exceeds the payload-ballast relationship shown in the table.
2073
-- Only **Option B** provides a valid combination that respects both mass and CG limits.
2090
+1. Find **275 kg** on the Y-axis (left = empty weight). Draw a horizontal line to the right.
2091
+2. For each answer, check the cockpit load on the X-axis and whether the point is in the white (allowed) zone or the hatched (forbidden) zone.
20742092 
2075
-#### Key Terms
2093
+- **A** (85 kg + 100L): at x=85, the point is in the white zone. Valid, but 85 kg is not the maximum payload.
2094
+- **B** (100 kg + 80L): at x=100, the point is in the white zone. Valid, but 100 kg is not the maximum payload either.
2095
+- **C** (110 kg + 65L): at x=110, the point is in the hatched forbidden zone. Not permitted.
2096
+- **D** (105 kg + 70L): at x=105, the point is right at the boundary of the hatched zone, on the 70L diagonal. This is the **maximum** cockpit load (105 kg) that's still permitted, with 70L water ballast.
20762097 
2077
-CG = Centre of Gravity
2098
+Answer D gives the **maximum payload** (105 kg) with the corresponding **permitted water ballast** (70L) — exactly at the limit of the loading envelope.
2099
+
2100
+Ref: [Astir CS 77 Flight Manual, p.5](https://www.northumbriagliding.co.uk/wp-content/uploads/2019/06/Astir-CS-77-Flight-Manual.pdf)
20782101 ### Q91: To which loading category of a glider does the parachute belong? ^t20q91
20792102 
20802103 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q91) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q91)
....@@ -2116,14 +2139,14 @@
21162139 - **A** is wrong because the artificial horizon (gyroscopic) and compass (magnetic) do not use static pressure.
21172140 - **B** and D are wrong because the turn indicator is gyroscopic and does not depend on static pressure.
21182141 
2119
-### Q93: Under what conditions is the use of weak links on tow ropes mandatory? ^t20q93
2142
+### Q93: What is the function of a weak link (Sollbruchstelle) in a glider tow rope? ^t20q93
21202143 
21212144 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q93) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q93)
21222145 
2123
-- **A)** Only for two-seat gliders.
2124
-- **B)** When using natural fibre ropes and as specified in the flight manual.
2125
-- **C)** Only when using synthetic ropes.
2126
-- **D)** In all cases.
2146
+- **A)** To make the tow rope easier to attach to the glider.
2147
+- **B)** To break under a calibrated tensile load and protect the glider and tow aircraft from excessive forces.
2148
+- **C)** To prevent the tow rope from twisting during the launch.
2149
+- **D)** To absorb shock loads elastically without failing.
21272150 
21282151 #### Answer
21292152 
....@@ -2131,7 +2154,11 @@
21312154 
21322155 #### Explanation
21332156 
2134
-The correct answer is B because weak links are mandatory when natural fibre tow ropes are used (since their breaking strength is less predictable than synthetic ropes) and whenever the aircraft flight manual specifies their use.
2157
+A weak link is a calibrated breaking element installed in the tow rope. Its purpose is to **fail at a predetermined tensile load** that is below the structural limit of either the glider or the tow aircraft (or winch system). When the load on the rope exceeds that limit — for example because of a sudden manoeuvre, a winch that pulls too hard, or an abnormal climb angle — the weak link parts before the airframe is overstressed.
2158
+
2159
+- **Option A** is wrong: weak links have nothing to do with attachment ergonomics.
2160
+- **Option C** is wrong: that is the role of swivels and rope construction, not the weak link.
2161
+- **Option D** is wrong: a weak link is *designed to fail*, not to absorb loads elastically. Shock absorption is handled by the elasticity of the rope itself or by dedicated dampers.
21352162 
21362163 - **A** is wrong because the requirement is not limited to two-seat gliders.
21372164 - **C** is wrong because synthetic ropes already have a more controlled and predictable breaking strength.
....@@ -2183,7 +2210,7 @@
21832210 
21842211 [DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q96) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q96)
21852212 
2186
-![](figures/t20_q96.png)
2213
+![](figures/t20_q90.png)
21872214 
21882215 - **A)** 90 litres.
21892216 - **B)** 95 litres.
....@@ -3109,4 +3136,137 @@
31093136 
31103137 #### Key Terms
31113138 
3112
-D — Drag
3139
+D — Drag
3140
+### Q138: How does the maximum permitted speed VNE of a glider change as altitude increases? ^t20q138
3141
+
3142
+[DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q138) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q138)
3143
+
3144
+- **A)** It remains the same.
3145
+- **B)** It increases.
3146
+- **C)** It decreases as altitude increases.
3147
+- **D)** The change depends on temperature.
3148
+
3149
+#### Answer
3150
+
3151
+C)
3152
+
3153
+#### Explanation
3154
+
3155
+VNE (never-exceed speed) is specified as an indicated airspeed (IAS) in the flight manual, but the structural limit is actually a true airspeed (TAS). At higher altitudes, air density decreases: for the same IAS, TAS is higher, increasing aerodynamic loads and flutter risk. Therefore the published IAS-based VNE decreases with altitude to maintain structural safety margins. A (unchanged) is incorrect. B (increases) is incorrect. D (depends on temperature) is partially true but not the expected exam answer.
3156
+
3157
+#### Key Terms
3158
+
3159
+- **VNE** = Never-Exceed Speed
3160
+- **IAS** = Indicated Airspeed
3161
+- **TAS** = True Airspeed
3162
+
3163
+### Q139: What happens inside a Venturi nozzle? ^t20q139
3164
+
3165
+[DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q139) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q139)
3166
+
3167
+- **A)** An overpressure.
3168
+- **B)** A depression (negative pressure).
3169
+- **C)** Strong heating of the air.
3170
+- **D)** A constant dynamic pressure.
3171
+
3172
+#### Answer
3173
+
3174
+B)
3175
+
3176
+#### Explanation
3177
+
3178
+According to Bernoulli's principle, in a Venturi nozzle the narrowing cross-section accelerates the airflow. This increase in velocity is accompanied by a decrease in static pressure, creating a depression (pressure below ambient). This principle is used in various aircraft instruments and systems. A (overpressure) is the opposite of what occurs. C (heating) does not occur significantly. D (constant dynamic pressure) is incorrect as dynamic pressure changes with velocity.
3179
+
3180
+#### Key Terms
3181
+
3182
+- **Venturi nozzle** = A tube with a constricted section that exploits the Bernoulli effect
3183
+- **Depression** = Static pressure below ambient atmospheric pressure
3184
+
3185
+### Q140: How often is a glider inspected by the aeronautical authority (OFAC in Switzerland)? ^t20q140
3186
+
3187
+[DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q140) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q140)
3188
+
3189
+- **A)** Every year.
3190
+- **B)** Every 3 years.
3191
+- **C)** Only after major damage.
3192
+- **D)** Only when ownership changes.
3193
+
3194
+#### Answer
3195
+
3196
+B)
3197
+
3198
+#### Explanation
3199
+
3200
+In Switzerland, OFAC (Federal Office of Civil Aviation) requires a periodic airworthiness review of gliders every 3 years (Nachprufung / airworthiness review). This review confirms the aircraft remains compliant with its type certification basis and that all applicable airworthiness directives have been complied with. A (annually) is too frequent for the official OFAC review. C and D (only after damage or ownership change) are insufficient as standalone triggers.
3201
+
3202
+#### Key Terms
3203
+
3204
+- **OFAC** = Swiss Federal Office of Civil Aviation
3205
+- **Airworthiness review** = Periodic triennial certification check
3206
+
3207
+### Q141: How does true airspeed (TAS) change as a glider climbs at constant indicated airspeed (IAS)? ^t20q141
3208
+
3209
+[DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q141) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q141)
3210
+
3211
+- **A)** It increases.
3212
+- **B)** It decreases.
3213
+- **C)** It stays the same.
3214
+- **D)** Altitude has no influence on TAS.
3215
+
3216
+#### Answer
3217
+
3218
+A)
3219
+
3220
+#### Explanation
3221
+
3222
+The airspeed indicator measures dynamic pressure (q = 1/2 x rho x V2). At higher altitude, air density (rho) is lower. To maintain the same dynamic pressure (constant IAS), true airspeed (TAS) must therefore be higher. As a rule of thumb, TAS increases by approximately 2% per 300 m (1,000 ft) of altitude at constant IAS. B (decreases) and C (stays the same) are incorrect. D is incorrect because air density varies with altitude and directly affects the IAS/TAS relationship.
3223
+
3224
+#### Key Terms
3225
+
3226
+- **TAS** = True Airspeed
3227
+- **IAS** = Indicated Airspeed
3228
+- **rho** = Air density
3229
+
3230
+### Q142: What does the term "empty mass" of a glider mean? ^t20q142
3231
+
3232
+[DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q142) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q142)
3233
+
3234
+- **A)** Barograph, battery and parachute.
3235
+- **B)** Mass of the completed glider with instruments and fixed equipment.
3236
+- **C)** Ballast and tools.
3237
+- **D)** Baggage, water ballast and occupants.
3238
+
3239
+#### Answer
3240
+
3241
+B)
3242
+
3243
+#### Explanation
3244
+
3245
+The empty mass (Leermasse / basic empty weight) of a glider is the mass of the fully constructed glider including all installed instruments, fixed equipment (radio, ELT, fixed oxygen system, etc.) and non-usable fluids. It excludes variable useful loads such as the pilot, parachute, water ballast, and baggage. A (barograph, battery, parachute) mixes fixed equipment with payload. C (ballast and tools) is not part of empty mass. D (baggage, water ballast and occupants) constitutes the useful load.
3246
+
3247
+#### Key Terms
3248
+
3249
+- **Empty mass** = Basic mass of the flight-ready glider, excluding variable loading
3250
+- **Useful load** = Pilot, passenger, parachute, water ballast, baggage
3251
+
3252
+### Q143: Which of the following items is NOT considered part of the "useful load" (payload) of a glider? ^t20q143
3253
+
3254
+[DE](../SPL%20Exam%20Questions%20DE/20%20-%20Allgemeine%20Luftfahrzeugkunde.md#^t20q143) · [FR](../SPL%20Exam%20Questions%20FR/20%20-%20Connaissances%20g%C3%A9n%C3%A9rales%20de%20l%27a%C3%A9ronef.md#^t20q143)
3255
+
3256
+- **A)** Pilot and passenger.
3257
+- **B)** Parachute.
3258
+- **C)** Portable barograph.
3259
+- **D)** Fixed oxygen installation.
3260
+
3261
+#### Answer
3262
+
3263
+D)
3264
+
3265
+#### Explanation
3266
+
3267
+A fixed (permanently installed) oxygen system is part of the aircraft's fixed equipment and is therefore included in the empty mass, not in the variable useful load. The useful load comprises only variable items that can be added or removed between flights: pilot and passenger (A), parachute (B), portable instruments such as a portable barograph (C). A fixed installation, whether in use or not, remains permanently in the aircraft and is counted in the empty mass.
3268
+
3269
+#### Key Terms
3270
+
3271
+- **Empty mass** = Includes permanently installed equipment
3272
+- **Useful load** = Variable items (pilot, parachute, ballast, baggage)