### Q1: Exceeding the maximum allowed aircraft mass is… ^t30q1
- A) Not allowable and essentially dangerous
- B) Exceptionally allowable to avoid delays
- C) Compensated by the pilot's control inputs.
- D) Only relevant if the excess is more than 10 %.

**Correct: A)**

> **Explanation:** The correct answer is A because the maximum takeoff mass (MTOM) is a hard certification limit set by the manufacturer based on structural strength, stall speed, and climb performance. Exceeding it increases wing loading, raises the stall speed, reduces climb performance, and may overstress the airframe beyond its certified load factors. B is wrong because no operational convenience justifies exceeding a safety limit. C is wrong because no pilot technique can compensate for structural overloading. D is wrong because there is no regulatory tolerance or percentage margin — any exceedance is prohibited.

### Q2: The center of gravity has to be located… ^t30q2
- A) Between the front and the rear C.G. limit.
- B) In front of the front C.G. limit.
- C) Right of the lateral C. G. limit.
- D) Behind the rear C.G. limit

**Correct: A)**

> **Explanation:** The correct answer is A because the aircraft's stability and controllability are only certified within the approved C.G. envelope, which lies between the forward and aft C.G. limits. B is wrong because a C.G. ahead of the forward limit requires excessive elevator authority to flare or rotate, potentially making landing impossible. D is wrong because a C.G. behind the aft limit causes longitudinal instability and uncontrollable pitch-up. C is irrelevant — lateral C.G. limits are not the primary concern in standard mass-and-balance calculations for gliders.

### Q3: An aircraft has to be loaded and operated in such a way that the center of gravity (CG) stays within the approved limits during all phases of flight. This is done to ensure... ^t30q3
- A) That the aircraft does not stall.
- B) That the aircraft does not exceed the maximum allowable airspeed during a descent
- C) That the aircraft does not tip over on its tail while it is being loaded.
- D) Both stability and controllability of the aircraft.

**Correct: D)**

> **Explanation:** The correct answer is D because the C.G. position relative to the neutral point determines longitudinal static stability (the tendency to return to equilibrium after a disturbance), while the elevator's ability to command pitch changes provides controllability. Both properties must be maintained throughout flight, and the C.G. envelope ensures this. A is wrong because stall speed depends primarily on wing loading and angle of attack, not C.G. position. B is wrong because Vne is an airframe limit unrelated to C.G. C describes a ground-handling issue, not an in-flight safety requirement.

### Q4: The empty weight and the corresponding center of gravity (CG) of an aircraft are initially determined… ^t30q4
- A) For one aircraft of a type solely, since all aircraft of the same type have the same mass and CG position
- B) By calculation.
- C) By weighing.
- D) Through data provided by the aircraft manufacturer.

**Correct: C)**

> **Explanation:** The correct answer is C because each individual airframe must be physically weighed — typically on calibrated scales at three support points — to determine its actual empty mass and C.G. position. Manufacturing tolerances, repairs, modifications, and installed equipment vary between serial numbers. A is wrong because no two aircraft of the same type are guaranteed to have identical mass and C.G. B is wrong because calculation alone cannot account for all variables. D is wrong because manufacturer data provides type-level reference values, not the specific values for each individual aircraft.

### Q5: Baggage and cargo has to be properly stowed and fastened, otherwise a shift of the cargo may cause... ^t30q5
- A) Structural damage, angle of attack stability, velocity stability.
- B) Continuous attitudes which can be corrected by the pilot using the flight controls.
- C) Uncontrollable attitudes, structural damage, risk of injuries.
- D) Calculable instability if the C.G. is shifting by less than 10 %.

**Correct: C)**

> **Explanation:** The correct answer is C because unsecured cargo can shift suddenly during turbulence or manoeuvres, moving the C.G. outside approved limits instantaneously — faster than a pilot can react. A sudden aft C.G. shift can cause an unrecoverable pitch-up, loose items can become projectiles injuring occupants or jamming controls, and asymmetric loading can overstress the structure. A is wrong because the terminology is inaccurate. B is wrong because a large sudden C.G. shift may be uncontrollable, not merely "continuous." D is wrong because no amount of prior analysis makes unsecured cargo acceptable.

### Q6: The total weight of an aeroplane is acting vertically through the… ^t30q6
- A) Center of gravity
- B) Stagnation point.
- C) Center of pressure.
- D) Neutral point.

**Correct: A)**

> **Explanation:** The correct answer is A because the center of gravity is, by definition, the single point through which the resultant gravitational force (the weight vector) acts on the entire aircraft. B is wrong because the stagnation point is where airflow velocity reaches zero on the wing's leading edge — an aerodynamic concept unrelated to weight. C is wrong because the center of pressure is where the net aerodynamic force acts. D is wrong because the neutral point is the aerodynamic reference used for stability analysis.

### Q7: The term "center of gravity" is described as... ^t30q7
- A) The heaviest point on an aeroplane.
- B) Half the distance between the neutral point and the datum line.
- C) Another designation for the neutral point.
- D) Half the distance between the neutral point and the datum line.

**Correct: B)**

> **Explanation:** The correct answer is B. The center of gravity is the mass-weighted average position of all individual mass elements — the point where the total weight force is considered to act. It is found by summing all moments about the datum and dividing by total mass. A is wrong because the C.G. is not a "heaviest point" but a balance point. C is wrong because the neutral point is a separate aerodynamic concept relating to stability. D duplicates one of the other options and does not correctly define C.G. either.

### Q8: The center of gravity (CG) defines… ^t30q8
- A) The point on the longitudinal axis or its extension from which the centers of gravity of all masses are referenced.
- B) The point on the longitudinal axis or its extension from which the centers of gravity of all masses are referenced.
- C) The product of mass and balance arm
- D) The point through which the force of gravity is said to act on a mass.

**Correct: D)**

> **Explanation:** The correct answer is D because the C.G. is the point through which the entire gravitational force (weight) acts as if all mass were concentrated there. This is the fundamental definition used in physics and aircraft mass-and-balance. A and B both describe the datum (reference point), not the C.G. itself. C describes a moment (mass times arm), which is a calculation quantity, not the definition of the center of gravity.

### Q9: The term "moment" with regard to a mass and balance calculation is referred to as… ^t30q9
- A) Sum of a mass and a balance arm.
- B) Difference of a mass and a balance arm.
- C) Product of a mass and a balance arm.
- D) Quotient of a mass and a balance arm.

**Correct: C)**

> **Explanation:** The correct answer is C because in mass and balance, moment equals mass multiplied by balance arm (M = m x d), expressed in units such as kg-m or lb-in. The total C.G. position is then found by dividing the sum of all moments by the total mass. A is wrong because adding mass and arm has no physical meaning. B is wrong because subtracting them is equally meaningless. D is wrong because dividing mass by arm does not produce a moment — it would yield an incorrect dimension.

### Q10: The term "balance arm" in the context of a mass and balance calculation defines the… ^t30q10
- A) Point through which the force of gravity is said to act on a mass.
- B) Point on the longitudinal axis of an aeroplane or its extension from which the centers of gravity of all masses are referenced.
- C) Distance from the datum to the center of gravity of a mass.
- D) Distance of a mass from the center of gravity

**Correct: C)**

> **Explanation:** The correct answer is C because the balance arm (or moment arm) is the horizontal distance measured from the aircraft's datum to the center of gravity of a specific mass item. This distance determines the leverage that mass exerts about the datum. A is wrong because that defines the center of gravity, not the arm. B is wrong because that defines the datum point itself. D is wrong because balance arms are measured from the datum, not from the aircraft's overall C.G.

### Q11: The distance between the center of gravity and the datum is called… ^t30q11
- A) Span width.
- B) Balance arm.
- C) Torque.
- D) Lever.

**Correct: B)**

> **Explanation:** The correct answer is B because in mass-and-balance terminology, the balance arm is the horizontal distance from the datum to any point of interest, including the overall C.G. once calculated. A is wrong because span width is a wing geometric parameter. C is wrong because torque (or moment) is the product of force and distance, not the distance itself. D is wrong because "lever" is a general mechanical term, not the specific aviation mass-and-balance term used.

### Q12: The balance arm is the horizontal distance between… ^t30q12
- A) The C.G. of a mass and the rear C.G. limit.
- B) The front C.G. limit and the datum line
- C) The C.G. of a mass and the datum line.
- D) The front C.G. limit and the rear C.G. limit.

**Correct: C)**

> **Explanation:** The correct answer is C because the balance arm of any mass item is measured as the horizontal distance from the aircraft's datum to that item's center of gravity. The datum is a fixed reference point defined in the flight manual. A is wrong because it references the rear C.G. limit, not the datum. B is wrong because it describes the distance between the forward C.G. limit and the datum. D describes the allowable C.G. range, not a balance arm.

### Q13: The required data for a mass and balance calculation including masses and balance arms can be found in the… ^t30q13
- A) Documentation of the annual inspection.
- B) Certificate of airworthiness
- C) Performance section of the pilot's operating handbook of this particular aircraft.
- D) Mass and balance section of the pilot's operating handbook of this particular aircraft.

**Correct: D)**

> **Explanation:** The correct answer is D because the Pilot's Operating Handbook (POH) or Aircraft Flight Manual (AFM) contains a dedicated mass and balance section with the aircraft's empty mass, empty C.G. position, datum reference, C.G. limits, and loading configurations. A is wrong because annual inspection documents record maintenance work, not loading data. B is wrong because the certificate of airworthiness merely certifies the aircraft type. C is wrong because the performance section covers speeds and climb rates, not mass-and-balance data.

### Q14: Which section of the flight manual describes the basic empty mass of an aircraft? ^t30q14
- A) Normal procedures
- B) Performance
- C) Weight and balance
- D) Limitations

**Correct: C)**

> **Explanation:** The correct answer is C because the Weight and Balance section of the flight manual contains the basic empty mass, empty C.G. location, allowable C.G. range, and loading instructions. A is wrong because Normal Procedures covers checklists and operational sequences. B is wrong because Performance covers speeds, climb rates, and glide distances. D is wrong because Limitations covers maximum speeds, load factors, and the operating envelope — not the basic empty mass data.

### Q15: Which factor shortens landing distance? ^t30q15
- A) High pressure altitude
- B) Strong head wind
- C) Heavy rain
- D) High density altitude

**Correct: B)**

> **Explanation:** The correct answer is B because a headwind reduces the groundspeed at touchdown for a given indicated airspeed, so the aircraft crosses the threshold with less kinetic energy relative to the ground, shortening the ground roll significantly. A is wrong because high pressure altitude means lower air density, higher true airspeed at the same IAS, and therefore longer landing distance. C is wrong because heavy rain can degrade braking effectiveness and contaminate the wing surface. D is wrong for the same reason as A — high density altitude increases groundspeed and lengthens the landing roll.

### Q16: Unless the aircraft is equipped and certified accordingly… ^t30q16
- A) Flight into forecast icing conditions is prohibited. Should the aircraft enter an area of icing conditions inadvertantly, the flight may be continued as long as visual meteorological conditions are maintained.
- B) Flight into known or forecast icing conditions is prohibited. Should the aircraft enter an area of icing conditions inadvertantly, it should be left without delay.
- C) Flight into known or forecast icing conditions is only allowed as long as it is ensured that the aircraft can still be operated without performance degradation.
- D) Flight into areas of precipitation is prohibited.

**Correct: B)**

> **Explanation:** The correct answer is B because for non-FIKI certified aircraft, flying into known or forecast icing is a regulatory prohibition. If icing is inadvertently encountered, the pilot must exit immediately by changing altitude or heading. A is wrong because maintaining VMC does not make icing safe — ice accumulates regardless of visual conditions. C is wrong because it implies icing flight is permissible with performance monitoring, which is not the case. D is wrong because not all precipitation involves icing conditions.

### Q17: The angle of descent is described as... ^t30q17
- A) The ratio between the change in height and the horizontal distance distance travelled within the same time, expressed in degrees [°].
- B) The angle between a horizontal plane and the actual flight path, expressed in degrees [°].
- C) The ratio between the change in height and the horizontal distance travelled within the same time, expressed in percent [%].
- D) The angle between a horizontal plane and the actual flight path, expressed in percent [%].

**Correct: B)**

> **Explanation:** The correct answer is B because the angle of descent (glide angle) is geometrically defined as the angle between the horizontal and the flight path vector, measured in degrees. A is wrong because a "ratio expressed in degrees" is contradictory — a ratio is dimensionless or expressed as a percentage, not in degrees. C describes a gradient (percentage), not an angle. D incorrectly expresses an angle in percent. For a glider with a 1:30 glide ratio, the glide angle is approximately 1.9 degrees.

### Q18: Which is the purpose of "interception lines" in visual navigation? ^t30q18
- A) They help to continue the flight when flight visibility drops below VFR minima
- B) To visualize the range limitation from the departure aerodrome
- C) To mark the next available en-route airport during the flight
- D) They are used as easily recognizable guidance upon a possible loss of orientation

**Correct: D)**

> **Explanation:** The correct answer is D because interception lines (also called catching lines) are prominent linear ground features — rivers, motorways, railways, coastlines — selected during pre-flight planning that the pilot can navigate toward if orientation is lost. Flying to the nearest interception line provides an unmistakable landmark for position recovery. A is wrong because nothing permits continuing flight below VFR minima. B is wrong because interception lines are not range indicators. C is wrong because they are geographic features, not airport markers.

### Q19: The upper limit of LO R 16 equals… ^t30q19
> *Note: This question originally references a chart excerpt (PFP-056) showing LO R 16 airspace boundaries.*
- A) 1 500 m MSL.
- B) FL150.
- C) 1.500 ft GND.
- D) 1 500 ft MSL.

**Correct: D)**

> **Explanation:** The correct answer is D because low-level restricted areas (LO R) on VFR charts typically express their vertical limits in feet MSL (above mean sea level). The value 1,500 ft MSL is a fixed, absolute altitude reference. A is wrong because 1,500 metres MSL would be approximately 4,900 ft — a different altitude entirely. B is wrong because FL150 (15,000 ft pressure altitude) is far too high for a typical low-level restriction. C is wrong because 1,500 ft GND (above ground level) would vary with terrain and is not the published limit.

### Q20: The upper limit of LO R 4 equals… ^t30q20
> *Note: This question originally references a chart excerpt (PFP-030) showing LO R 4 airspace boundaries.*
- A) 4.500 ft MSL
- B) 1.500 ft AGL
- C) 4.500 ft AGL.
- D) 1.500 ft MSL.

**Correct: A)**

> **Explanation:** The correct answer is A because LO R 4 has its upper limit published at 4,500 ft MSL — a fixed altitude above mean sea level. B is wrong because 1,500 ft AGL references above ground level, which varies with terrain. C is wrong because 4,500 ft AGL would not be a fixed boundary. D is wrong because 1,500 ft MSL is too low and does not match the chart data for this particular restricted area.

### Q21: Up to which altitude is an overflight prohibited according to the NOTAM? ^t30q21
> *Note: This question originally references a NOTAM excerpt (PFP-024).*
- A) Flight Level 95
- B) Height 9500 ft
- C) Altitude 9500 ft MSL
- D) Altitude 9500 m MSL

**Correct: C)**

> **Explanation:** The correct answer is C because NOTAM altitude references follow ICAO conventions where "altitude" refers to height above MSL. The NOTAM prohibits overflight up to 9,500 ft MSL. A is wrong because FL 95 is a pressure altitude reference (based on 1013.25 hPa), not the same as an MSL altitude. B is wrong because "height" implies above ground level (AGL). D is wrong because 9,500 m MSL would be approximately 31,000 ft — clearly inconsistent with a typical VFR restriction.

### Q22: What must be considered for cross-border flights? ^t30q22
- A) Transmission of hazard reports
- B) Approved exceptions
- C) Requires flight plans
- D) Regular location messages

**Correct: C)**

> **Explanation:** The correct answer is C because under ICAO Annex 2 and national regulations, a flight plan is mandatory for any international flight crossing state borders, even for VFR glider flights. This ensures coordination for border control, search and rescue alerting, and customs/immigration procedures. A is wrong because hazard reports (PIREPs) are a separate communication procedure. B is wrong because approved exceptions is too vague and not the primary requirement. D is wrong because regular position reports are separate from the flight plan requirement.

### Q23: During a flight, a flight plan can be filed at the… ^t30q23
- A) Next airport operator en-route.
- B) Flight Information Service (FIS).
- C) Aeronautical Information Service (AIS)
- D) Search and Rescue Service (SAR).

**Correct: B)**

> **Explanation:** The correct answer is B because the Flight Information Service (FIS), reached on the published FIS frequency, can accept an airborne flight plan (AFIL) during flight. This is the standard procedure for filing when airborne. A is wrong because airport operators handle local ground operations, not en-route plan filing. C is wrong because AIS distributes aeronautical publications but does not accept real-time flight plans. D is wrong because SAR is a response service activated when an aircraft is overdue or in distress.

### Q24: While planning a cross country gliding flight, what ground structure ought to be avoided enroute? ^t30q24
- A) Stone quarries and large sand areas
- B) Moist ground, water areas, marsh areas
- C) Highways, railroad tracks and channels.
- D) Areas with buildings, concrete and asphalt.

**Correct: B)**

> **Explanation:** The correct answer is B because moist ground, water bodies, and marshes have high thermal inertia and specific heat capacity — they absorb solar radiation without heating quickly, suppressing thermal development above them. Flying over these areas means less lift and potentially a forced landing in unsuitable terrain. A is wrong because stone quarries and sandy areas heat up well and often produce good thermals. C is wrong because linear features like highways and railways are useful navigation aids. D is wrong because built-up areas with dark surfaces (asphalt, concrete) generate strong thermals.

### Q25: During a cross-country flight, you approach a downwind turning point. The point ought to be taken ... (2,00 P.) ^t30q25
- A) As high as possible.
- B) With as less bank as possible
- C) As low as possible.
- D) As steep as possible.

**Correct: A)**

> **Explanation:** The correct answer is A because at a downwind turning point, the glider must reverse direction and fly back into the wind. This immediately reduces groundspeed and shortens the achievable glide distance over the ground. Arriving high provides maximum altitude reserve for the subsequent upwind leg. B is wrong because bank angle is a secondary concern compared to altitude. C is wrong because arriving low with a turn ahead and headwind return is tactically dangerous. D is wrong because steep turns lose more altitude, compounding the problem.

### Q26: After getting around a turning point, what should a glider pilot be prepared for? (2,00 P.)... ^t30q26
- A) For weakening thermals due to the progressing time
- B) For a changed horizontal picture due to lower cloud bases
- C) For increased cloud dissipation due to the progressing time
- D) For a changed cloud picture due to the apparently changed position of the sun

**Correct: D)**

> **Explanation:** The correct answer is D because when a glider turns 90 or 180 degrees at a waypoint, the pilot's entire visual perspective of the sky shifts dramatically. The sun appears to have moved relative to the heading, and cumulus clouds that were behind or beside the aircraft now appear in different positions. This perceptual shift can make the sky look completely different. A is wrong because thermal weakening is a time-of-day issue, not a turning-point issue. B is wrong because cloud bases do not change from turning. C is wrong because cloud dissipation is unrelated to heading changes.

### Q27: According ICAO, what symbol indicates a group of unlighted obstacles? ^t30q27
![ICAO Obstacle Symbols](figures/t30_q27.svg)
- A) D
- B) C
- C) B
- D) A

**Correct: B)**

> **Explanation:** The correct answer is B (symbol C in the figure) because ICAO Annex 4 chart symbology uses distinct symbols to differentiate between single obstacles versus groups, and lighted versus unlighted. The symbol for a group of unlighted obstacles is specifically designated in the PFP-061 reference figure as C. A, C, and D represent other obstacle categories such as single obstacles, lighted groups, or other types. Knowing these symbols is critical for cross-country planning and obstacle avoidance.

### Q28: According ICAO, what symbol indicates a civil airport (not international airport) with paved runway? ^t30q28
![ICAO Airport Symbols](figures/t30_q28.svg)
- A) C
- B) A
- C) B
- D) D

**Correct: B)**

> **Explanation:** The correct answer is B (symbol A in the figure) because ICAO aeronautical chart symbology differentiates airports by civil versus military status, international versus domestic, and runway surface type. A civil domestic airport with a paved runway has a specific symbol shown as A in the PFP-062 annex. A, C, and D represent other aerodrome categories such as international airports, military airfields, or unpaved-runway airports. Glider pilots use these symbols when planning outlanding fields or alternate airports.

### Q29: According ICAO, what symbol indicates a general spot elevation? ^t30q29
![ICAO Spot Elevation Symbols](figures/t30_q29.svg)
- A) C
- B) B
- C) A
- D) D

**Correct: A)**

> **Explanation:** The correct answer is A (symbol C in the figure) because ICAO charts use specific symbols to differentiate between general spot elevations, surveyed elevation points, and obstruction heights. A general spot elevation marks a notable terrain high point for situational awareness and is depicted according to ICAO Annex 4 standards. B, C, and D represent other elevation-related symbols such as maximum elevation figures or obstruction markers. Familiarity with these symbols is essential for terrain clearance planning.

### Q30: What distance can be covered during a glide in a glider plane with glide ratio 1/30 from a height of 1500 m? (Neglect wind and thermal effects)... ^t30q30
- A) 45 NM
- B) 30 km
- C) 45 km
- D) 81 NM

**Correct: C)**

> **Explanation:** The correct answer is C because glide distance equals glide ratio multiplied by height: 30 x 1,500 m = 45,000 m = 45 km. The glide ratio of 1:30 means the glider covers 30 metres horizontally for every 1 metre of height lost. A is wrong because 45 NM equals approximately 83 km, which would require a glide ratio of about 1:55. B is wrong because 30 km would correspond to a glide ratio of only 1:20. D is wrong because 81 NM (150 km) would require a glide ratio of 1:100. Always verify that units are consistent — mixing nautical miles and metres is a common exam trap.

### Q31: Why can wing loading be increased when soaring conditions are good? ^t30q31
- A) Because the stall speed diminishes.
- B) Because the glider achieves a better glide ratio at high speed even though the minimum speed rises.
- C) Because the glider can fly more slowly and achieves a better glide ratio.
- D) Because the glider has a better climb rate even though it must fly more slowly.

**Correct: B)**

> **Explanation:** The correct answer is B because in strong thermal conditions, the glider benefits from flying faster between thermals (MacCready theory). Adding water ballast increases wing loading, which shifts the speed polar to the right — improving the glide ratio at high cruising speeds while accepting a higher stall and minimum sink speed. A is wrong because increasing wing loading raises the stall speed. C is wrong because higher wing loading means the glider must fly faster, not slower. D is wrong because a heavier glider has a worse climb rate in thermals due to its higher minimum sink speed.

### Q32: The tail wheel of a glider was not removed before departure. What will be the consequence? ^t30q32
- A) Better manoeuvrability at departure.
- B) The centre of gravity shifts forward.
- C) No consequence. The wheel represents only a tiny fraction of the total weight of the glider and has no effect on the centre of gravity.
- D) The centre of gravity will be further aft and possibly too far aft, which is dangerous.

**Correct: D)**

> **Explanation:** The correct answer is D because the tail wheel is mounted at the extreme rear of the fuselage, far aft of the nominal C.G. Even though its absolute mass is small, its large moment arm produces a significant moment that shifts the C.G. aftward — potentially beyond the aft limit, making the aircraft pitch-unstable and difficult to control. A is wrong because the tail wheel does not improve manoeuvrability. B is wrong because the tail wheel is aft of the C.G., so its presence shifts the C.G. backward, not forward. C is wrong because the long arm amplifies the effect of even a small mass.

### Q33: The pilot exceeds the maximum cockpit payload by 10 kg. What has to be done? ^t30q33
- A) Trim aft.
- B) Trim forward.
- C) Reduce the payload.
- D) Compensate by reducing the water ballast slightly.

**Correct: C)**

> **Explanation:** The correct answer is C because the maximum seat load is a certification limit that cannot be circumvented. Exceeding it may place the C.G. outside the forward limit and subjects the structure to loads beyond what was tested. The only remedy is to reduce the payload until the limits are respected. A and B are wrong because trimming changes the aerodynamic forces on the elevator but does not alter the aircraft's mass or C.G. position. D is wrong because reducing water ballast changes total mass but does not address the specific seat load limitation.

### Q34: What propels a pure glider forward? ^t30q34
- A) Ascending air currents.
- B) Drag directed forward.
- C) The component of gravity acting in the direction of the flight path.
- D) A tailwind.

**Correct: C)**

> **Explanation:** The correct answer is C because in steady gliding flight, the weight vector can be resolved into two components: one perpendicular to the flight path (balanced by lift) and one along the flight path. This along-path component of gravity provides the forward-driving force that balances drag and maintains airspeed. A is wrong because ascending air can reduce the descent rate but does not propel the glider forward through the air. B is wrong because drag always opposes the direction of motion. D is wrong because a tailwind affects groundspeed but does not propel the aircraft through the airmass.

### Q35: The current mass of an aircraft is 610 kg and the centre of gravity (C.G.) position is at 80.0. You remove a 10 kg item of baggage located at a moment arm of 150. Which is the new centre of gravity? ^t30q35
- A) 75.0
- B) 81.166
- C) 70.0
- D) 78.833

**Correct: D)**

> **Explanation:** The correct answer is D. The calculation proceeds as follows: Initial moment = 610 x 80.0 = 48,800. Removed moment = 10 x 150 = 1,500. New total moment = 48,800 - 1,500 = 47,300. New mass = 610 - 10 = 600 kg. New C.G. = 47,300 / 600 = 78.833. Since the baggage was located aft of the current C.G. (arm 150 > 80), removing it shifts the C.G. forward — consistent with the result (78.833 < 80.0). A (75.0) and C (70.0) are too far forward. B (81.166) incorrectly shows a rearward shift.

### Q36: The empty mass of the Discus B is 245 kg. You are planning to carry 184 kg of water ballast. What is the maximum load at the pilot's seat? ^t30q36
> **Extract from the Discus B Flight Manual — Loading table with water ballast**
> ![[figures/t30_q36.png]]
> Max. permitted all-up weight including water ballast : **525 kg**
> Lever arm of water ballast : **203 mm aft of datum (BE)**

> *Table of water ballast loads at various empty weights and seat loads:*

| Empty mass (kg) | Seat load 70 kg | 80 kg | 90 kg | 100 kg | 110 kg |
|---|---|---|---|---|---|
| 220 | 184 | 184 | 184 | 184 | 184 |
| 225 | 184 | 184 | 184 | 184 | 184 |
| 230 | 184 | 184 | 184 | 184 | 184 |
| 235 | 184 | 184 | 184 | 184 | 180 |
| 240 | 184 | 184 | 184 | 184 | 175 |
| 245 | 184 | 184 | 184 | 180 | 170 |
| 250 | 184 | 184 | 184 | 175 | 165 |

> *Water ballast in both wing tanks (kg). For empty mass 245 kg and ballast 184 kg: the maximum seat load is **90 kg** (column 90 kg → value 184, but column 100 kg → 180 and column 110 kg → 170; with ballast=184 required, read the 245 kg row and find the seat load corresponding to ballast=184, i.e. max 90 kg permitted according to the table).*
- A) 100 kg
- B) 110 kg
- C) 90 kg
- D) 80 kg

**Correct: C)**

> **Explanation:** The correct answer is C (90 kg). Reading the Discus B loading table at the row for empty mass 245 kg: with a seat load of 90 kg the permitted water ballast is 184 kg (matching our requirement), but at 100 kg seat load only 180 kg of ballast is permitted, and at 110 kg only 170 kg. Since we need the full 184 kg of ballast, the maximum seat load that still allows this is 90 kg. A (100 kg) and B (110 kg) would require reducing the water ballast below 184 kg. D (80 kg) is unnecessarily restrictive — the table shows 184 kg is still permitted at 90 kg.

### Q37: What important principle must be observed when making an off-field landing on sloping terrain? ^t30q37
- A) Only land with airbrakes fully extended.
- B) Land facing uphill with an approach speed slightly above normal.
- C) Always land into wind regardless of the slope.
- D) The landing flare must be initiated at a greater height than usual.

**Correct: B)**

> **Explanation:** The correct answer is B because landing uphill uses the slope to decelerate the glider — gravity assists braking, dramatically shortening the ground roll. A slightly higher approach speed provides a safety margin against wind shear and turbulence near unfamiliar terrain. A is wrong because full airbrakes may not always be appropriate on short or steep fields. C is wrong because on significant slopes, landing uphill takes priority over landing into wind. D is wrong because the flare height should be adapted to the terrain, but this is not the primary principle.

### Q38: You must land in heavy rain. What must you pay particular attention to? ^t30q38
- A) The approach speed is lower than usual because rain slows the aircraft.
- B) The landing is performed as in dry conditions.
- C) Due to poor visibility, the approach angle must be shallower than usual.
- D) A higher approach speed must be used.

**Correct: D)**

> **Explanation:** The correct answer is D because heavy rain on the wing surface degrades the aerodynamic profile through increased roughness, potentially raising the stall speed. A higher approach speed provides an adequate safety margin. A is wrong because rain does not lower the safe approach speed — if anything, the stall speed increases. B is wrong because rain significantly changes conditions (reduced visibility, wet surfaces, degraded aerodynamics). C is wrong because a shallower approach reduces obstacle clearance margins and extends the final approach in poor visibility.

### Q39: You are taking off from a grass runway that has become waterlogged after several days of rain. What should you expect? ^t30q39
- A) The takeoff distance is likely to be longer.
- B) The glider is wet and has reduced performance.
- C) The wet grass offers less resistance, which is why the takeoff distance will be shorter.
- D) The glider may skid sideways (aquaplaning).

**Correct: A)**

> **Explanation:** The correct answer is A because a waterlogged grass runway creates greater rolling resistance due to soft ground deformation and water drag on the wheels, slowing acceleration and increasing the takeoff distance. B is wrong because while a wet glider has slightly degraded performance, the primary issue is the runway condition. C is wrong because wet, soft grass increases resistance rather than reducing it. D is wrong because aquaplaning occurs on hard surfaces with standing water, not on soft grass — and the question asks about takeoff distance, not directional control.

### Q40: Which of these statements is correct at a speed of 170 km/h, taking into account the following speed polar? ^t30q40
> **ASK 21 Speed Polar:**
> ![[figures/t30_q40.png]]
> *Two curves: G=470 kp (light mass, min sink rate ~0.657 m/s at ~75 km/h) and G=570 kp (heavy mass, min sink rate ~0.724 m/s). The best glide ratio is read from the tangent from the origin. At 170 km/h, the sink rate is higher for G=570 kp than for G=470 kp.*
- A) Regardless of the mass of the ASK21, the sink rate stays constant.
- B) As the mass of the ASK21 rises, the sink rate increases.
- C) As the mass of the ASK21 increases, the sink rate increases.
- D) As the mass of the ASK21 decreases, the glide angle improves.

**Correct: C)**

> **Explanation:** The correct answer is C because at 170 km/h, reading both polar curves, the heavier configuration (570 kp) shows a higher sink rate than the lighter one (470 kp). A heavier glider requires more lift to maintain flight, producing greater induced drag and therefore a higher sink rate at any given speed. A is wrong because the two curves clearly show different sink rates at 170 km/h. B and C state the same thing — sink rate increases with mass — which is correct. D is wrong because at high speeds the glide angle is not necessarily better at lower mass.

### Q41: Which is the speed at the minimum sink rate in still air for a mass of 450 kg? ^t30q41
> **Speed Polar (AIRSPEED):**
> ![[figures/t30_q41.png]]
> *Two curves: 450 kg and 580 kg. The minimum sink rate (top of the curve) for 450 kg is at approximately 75 km/h. The 580 kg curve is shifted to the right (higher speeds) and downward (greater sink rate).*
- A) 75 km/h
- B) 95 km/h
- C) 50 km/h
- D) 140 km/h

**Correct: A)**

> **Explanation:** The correct answer is A because the minimum sink rate speed corresponds to the highest point on the speed polar curve — where the sink rate is smallest. For 450 kg, this peak occurs at approximately 75 km/h. This speed maximises flight endurance in still air and is optimal for centring thermals. B (95 km/h) would be closer to the best-glide speed or the minimum-sink speed at higher mass. C (50 km/h) is below the stall speed. D (140 km/h) is far into the high-speed range where sink rate is much greater.

### Q42: From what altitude on the route between Murten (approx. N46°56'/E007°07') and Neuchâtel aerodrome (approx. N46°57'/E006°52') are you required to request permission to cross the PAYERNE TMA? ^t30q42
- A) 950 m AMSL (3100 ft).
- B) 3050 m AMSL (FL 100).
- C) 700 m AMSL (2300 ft).
- D) At any altitude since the lower limit of the TMA is represented by the ground surface (GND).

**Correct: C)**

> **Explanation:** The correct answer is C because on the route between Murten and Neuchatel, the relevant sector of the PAYERNE TMA has a lower limit at 700 m AMSL (2300 ft). Below this altitude, flight can proceed in uncontrolled airspace without clearance. Above 700 m AMSL, ATC authorisation is required. A (950 m) does not match the published boundary. B (FL 100) is far too high — that is the upper limit of some TMAs, not the lower limit here. D is wrong because the TMA does not extend to the ground in this sector.

### Q43: In which airspace class are you flying at 1400 m AMSL (QNH 1013 hPa) over Birrfeld aerodrome (47°25'36"N/007°14'02"E), and what are the visibility and cloud distance minima in that airspace? ^t30q43
- A) Airspace class E, horizontal visibility 5 km, horizontal cloud distance 1.5 km, vertical 300 m.
- B) Airspace class D, horizontal visibility 5 km, horizontal cloud distance 1.5 km, vertical 300 m.
- C) Airspace class G, horizontal visibility 1.5 km, clear of cloud with permanent ground contact.
- D) Airspace class C, horizontal visibility 5 km, horizontal cloud distance 1.5 km, vertical 300 m.

**Correct: A)**

> **Explanation:** The correct answer is A because at 1400 m AMSL over Birrfeld, you are in Class E airspace. VFR minima in Class E require 5 km horizontal visibility, 1500 m horizontal cloud clearance, and 300 m vertical cloud clearance. B is wrong because Class D applies within specific CTRs or TMAs, not over Birrfeld at this altitude. C is wrong because Class G applies below a certain altitude and has reduced minima. D is wrong because Class C begins at a higher altitude in this area (typically FL 130 in Switzerland).

### Q44: The route shown below towards SCHWYZ (dotted line) is planned for 20 June 2015 (summer time) between 1515–1545 LT at 6500 ft AMSL. Which of the following statements is correct? ^t30q44
> **DABS — Daily Airspace Bulletin Switzerland (extract)**
> ![[figures/t30_q44.png]]

| Firing-Nr D-/R-Area NOTAM-Nr | Validity UTC | Lower Limit AMSL or FL | Upper Limit AMSL or FL | Location | Center Point | Covering Radius | Activity / Remarks |
|---|---|---|---|---|---|---|---|
| B0685/14 | 0000–2359 | 900m / 3000ft | FL 130 | SION TMA SECT 1 | 461610N 0072940E | 4.7 KM / 2.5 NM | TMA SECT 1 ACT HX ONLY |
| W0912/15 | 1145–1300 | GND | FL 120 | MORGARTEN | 470507N 0083758E | 10.0 KM / 5.4 NM | R-AREA ACT. ENTRY PROHIBITED. FOR INFO CTC ZURICH INFO 124.7 |
| W0957/15 | 1400–1700 | 2150m / 7000ft | FL 120 | HINWIL | 471721N 0084859E | 7.0 KM / 3.8 NM | TEMPO R-AREA ACTIVE. ENTRY PROHIBITED. CTC 118.975 |
| W0960/15 | 0800–1700 | GND | 1200m / 4050ft | 1.7 KM SE CERNIER | 470352N 0065442E | 1.5 KM / 0.8 NM | D-AREA ACT |
- A) It is not possible to fly the planned route that day.
- B) You can ignore the DABS as it only applies to commercial aviation.
- C) You can pass through all relevant danger and restricted areas below 1000 ft AGL or above 12,000 ft AMSL.
- D) The route can be flown without coordination between 1500 and 1600 LT.

**Correct: D)**

> **Explanation:** The correct answer is D. On 20 June 2015 (CEST = UTC+2), the planned time of 1515-1545 LT corresponds to 1315-1345 UTC. Zone W0912/15 (MORGARTEN) was active 1145-1300 UTC and has already expired. Zone W0957/15 (HINWIL) activates at 1400 UTC (1600 LT) — it is not yet active. The route can therefore be flown without coordination between 1500 and 1600 LT. A is wrong because the route is flyable during the given time window. B is wrong because the DABS applies to all airspace users including gliders. C is wrong because it incorrectly suggests blanket altitude-based exemptions.

### Q45: According to the ICAO aeronautical chart at 1:500,000, at what altitude over Schwyz (approx. 47°01' N, 8°39' E) must you request permission to enter Class C airspace? ^t30q45
- A) FL 90
- B) 4500 ft
- C) FL 130
- D) FL 195

**Correct: C)**

> **Explanation:** The correct answer is C because over Schwyz, the Swiss ICAO 1:500,000 chart shows Class C airspace beginning at FL 130. Below FL 130, the airspace is Class E. Entering Class C requires ATC clearance regardless of flight rules. A (FL 90) is below the actual boundary. B (4500 ft) is far too low and in uncontrolled airspace. D (FL 195) is the upper limit of Swiss controlled airspace, not the lower limit of Class C over Schwyz.

### Q46: Until what time is La Côte aerodrome (LSGP) open in the evening? ^t30q46
> **AD INFO 1 — LA CÔTE / LSGP**
> ![[figures/t30_q46.png]]

| Data | Value |
|--------|--------|
| ICAO | LSGP |
| Elevation | 1352 ft (412 m) |
| ARP | 46°24'23"N / 006°15'28"E |
| Runway | 04 / 22 — true/mag: 041°/040° and 221°/220° |
| Dimensions | 560 x 30 m — GRASS |
| LDG distance available | 490 m |
| TKOF distance available | 490 m |
| SFC strength | 0.25 MPa |
| Status | Private — Airfield, **PPR** |
| Location | 25 km NE Geneva |
| Hours MON–FRI | 0700–1200 LT / 1400–**ECT –30 min** |
| Hours SAT/SUN | 0800–1200 LT / 1400–**ECT –30 min** |
| ECT reference | → VFG RAC 1-1 |

> *ECT = End of Civil Twilight. The aerodrome closes 30 minutes before end of civil twilight.*
- A) Until half an hour before the start of civil twilight.
- B) Until half an hour before sunset.
- C) Until half an hour before the end of civil twilight.
- D) Until the end of civil twilight.

**Correct: C)**

> **Explanation:** The correct answer is C because the AD INFO sheet for LSGP shows afternoon hours as "1400-ECT -30 min," meaning the aerodrome closes 30 minutes before the end of civil twilight. A is wrong because it references the start of civil twilight, not the end. B is wrong because sunset occurs earlier than the end of civil twilight. D is wrong because the aerodrome closes 30 minutes before ECT, not at ECT itself.

### Q47: On which frequency do you receive information about winch launches at Gruyères aerodrome (LSGT) at weekends? ^t30q47
> **Visual Approach Chart — GRUYÈRES / LSGT**
> ![[figures/t30_q47.png]]
> AD **124.675** — PPR — ELEV 2257 ft (688 m)

> *Key chart data (altitudes in ft, magnetic headings):*

| Data | Value |
|--------|--------|
| ICAO | LSGT |
| AD Frequency | **124.675 MHz** |
| Elevation | 2257 ft (688 m) |
| Status | PPR |
| Minimum AD overfly altitude (MNM ALT) | **4000 ft** |
| Glider ARR/DEP sector W (GLD ARR/DEP W) | **MAX 3100 ft** |
| Glider ARR/DEP sector E (GLD ARR/DEP E) | **MAX 3600 ft** |
| HEL ARR/DEP | 3000 ft |
| Preferred ARR sectors | WEST and EAST |
| CTN (cross-country traffic) | 3000 ft |
| MNM AD overfly | 4000 ft |
| Class C airspace above | FL 100 / 119.175 GENEVA DELTA |
| Winch launches | Intensive SAT/SUN (CTN: Intense winch launching SAT/SUN) |
| Nearby VOR/DME | SPR R076, 113.9 MHz |

> *Noise-sensitive areas (yellow) around Bulle/Broc. Avoid overflying the field during PJE (parachute dropping). Contact RTF 5 min before ETA.*
- A) 113.9
- B) 124.675
- C) 119.175
- D) 110.85

**Correct: B)**

> **Explanation:** The correct answer is B (124.675 MHz) because this is the aerodrome frequency shown on the Visual Approach Chart for LSGT Gruyeres. Local traffic information, including intensive winch launching activity on weekends, is broadcast on this frequency. A (113.9) is the VOR/DME SPR navigation frequency. C (119.175) is the Geneva Delta sector frequency for Class C airspace above. D (110.85) is not shown on this chart and does not relate to LSGT operations.

### Q48: What distance do you cover in 90 minutes at a ground speed of 90 km/h? ^t30q48
- A) 90 km
- B) 135 km
- C) 100 km
- D) 120 km

**Correct: B)**

> **Explanation:** The correct answer is B because distance = speed x time. Ground speed = 90 km/h, time = 90 minutes = 1.5 hours. Distance = 90 x 1.5 = 135 km. A (90 km) results from incorrectly using 1 hour instead of 1.5 hours. C (100 km) and D (120 km) do not correspond to any correct calculation. Remember to convert minutes to hours before multiplying: 90 minutes = 1.5 hours, not 0.9 hours.

### Q49: At an altitude of 6000 m, the airspeed indicator shows 160 km/h (IAS). The true airspeed (TAS)… ^t30q49
- A) is lower than the IAS.
- B) is also 160 km/h.
- C) can be higher or lower than the IAS depending on atmospheric pressure and temperature.
- D) is higher than the IAS.

**Correct: D)**

> **Explanation:** The correct answer is D because the airspeed indicator measures dynamic pressure, which depends on air density. At 6000 m, air density is significantly lower than at sea level. For the pitot tube to register the same dynamic pressure (same IAS), the aircraft must be moving faster through the thinner air. TAS increases by approximately 2% per 300 m of altitude gain, so at 6000 m, TAS is roughly 40% higher than IAS. A is wrong because TAS is always higher than IAS at altitude. B is wrong because they only equal each other at sea level in ISA conditions. C is wrong because at any altitude above sea level, TAS is always higher than IAS.

### Q50: You are flying in wave lift at 6000 m altitude. Which is the maximum speed you may fly? ^t30q50
- A) In the low-density air, at a higher speed than usual.
- B) Below the red V_NE mark on the airspeed indicator, according to the speed-altitude table displayed on the instrument panel.
- C) At the same speed as at sea level since V_NE is an absolute value.
- D) Maximum within the green arc.

**Correct: B)**

> **Explanation:** The correct answer is B because at high altitude the true airspeed corresponding to a given IAS is much higher, and it is the TAS that determines aerodynamic loads on the structure. Glider flight manuals provide a speed-altitude table (or V_NE reduction curve) displayed in the cockpit, giving the corrected maximum IAS at each altitude. At 6000 m, the allowable IAS is lower than the sea-level V_NE mark. A is wrong because you must fly slower (lower IAS), not faster. C is wrong because V_NE as indicated must be reduced with altitude. D is wrong because the green arc alone does not account for altitude corrections.