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Missing Questions Report

Comparison: Backup EN vs Current EN question sets Matching method: explanation text similarity (threshold >= 0.80) Questions below threshold are considered missing from the current set

Summary

| Subject | Backup EN | Current EN | Missing | With Figures | DE Count | DE vs EN diff | |---------|-----------|------------|---------|--------------|----------|---------------| | 10 - Air Law | 50 | 113 | 0 | 0 | 50 | -63 | | 20 - Aircraft General Knowledge | 50 | 77 | 6 | 0 | 0 | -77 | | 30 - Flight Performance and Planning | 30 | 89 | 0 | 0 | 30 | -59 | | 40 - Human Performance | 50 | 111 | 32 (2⚠) | 2 | 50 | -61 | | 50 - Meteorology | 50 | 182 | 3 | 0 | 50 | -132 | | 60 - Navigation | 80 | 111 | 32 | 0 | 80 | -31 | | 70 - Operational Procedures | 50 | 68 | 0 | 0 | 50 | -18 | | 80 - Principles of Flight | 50 | 135 | 35 (7⚠) | 7 | 0 | -135 | | 90 - Communications | 50 | 101 | 1 | 0 | 50 | -51 | | TOTALS | 460 | 987 | 109 | | 360 | -627 |

Figure note: ⚠ = count of missing questions that reference a figure/image

Matching Methodology

Questions are matched using explanation text similarity (difflib SequenceMatcher). Since the current EN set was heavily reworded compared to the backup, question text alone would miss most matches. The explanations, however, are identical or near-identical even when the question text was reformulated.

Missing Question Details

Subject 10 - Air Law: No missing questions ✓

Subject 20 - Aircraft General Knowledge: 6 Missing Questions

Missing 20.1 — was Q19 in backup

(best match ratio: 0.65)

Question: Which of the following options states all primary flight controls of an aircraft?

Correct: C)

Explanation: The three primary flight controls are elevator (pitch), rudder (yaw), and aileron (roll) — these directly control the aircraft's rotation about its three axes and are essential for flight. Option A lists secondary/high-lift devices. Option B mixes primary and secondary controls together. Option D is too broad — not all movable parts are primary controls. Flaps, trim tabs, and speedbrakes are secondary controls.

Missing 20.2 — was Q37 in backup

(best match ratio: 0.50)

Question: The vertical speed indicator measures the difference of pressure between...

Correct: D)

Explanation: The VSI compares the current ambient static pressure (which changes as altitude changes) with the static pressure from a short time ago (stored in the metering reservoir through a calibrated restriction). The rate at which static pressure changes indicates the rate of climb or descent. Dynamic pressure (A, C) plays no role in the VSI. Total pressure (B) is measured by the Pitot tube for the ASI, not used in the VSI.

Missing 20.3 — was Q38 in backup

(best match ratio: 0.58)

Question: An aircraft cruises on a heading of 180° with a true airspeed of 100 kt. The wind comes from 180° with 30 kt. Neglecting instrument and position errors, which will be the approximate reading of the airspeed indicator?

Correct: B)

Explanation: The airspeed indicator measures Indicated Air Speed (IAS), which reflects the airspeed relative to the surrounding air mass — not relative to the ground. The aircraft is flying at 100 kt through the air. The wind (also moving at 30 kt from 180°, meaning a tailwind) affects the aircraft's ground speed (which would be 70 kt, option D), but it does not affect the relative airspeed between aircraft and surrounding air. The ASI always reads the aircraft's speed through the air mass, regardless of wind.

Missing 20.4 — was Q41 in backup

(best match ratio: 0.60)

Question: What is necessary for the determination of speed (IAS) by the airspeed indicator?

Correct: D)

Explanation: IAS is determined from the difference between total pressure (Pitot tube) and static pressure (static port). This difference equals dynamic pressure (q = ½ρv²), from which airspeed is derived. Option A (total minus dynamic) would equal static pressure — not useful for airspeed. Option B (dynamic minus static) is not a meaningful aerodynamic quantity in this context. Option C (standard minus total) has no aerodynamic significance for airspeed measurement.

Missing 20.5 — was Q42 in backup

(best match ratio: 0.72)

Question: What is the meaning of the red range on the airspeed indicator?

Correct: A)

Explanation: The red line on the ASI marks VNE — the never-exceed speed — which is an absolute structural limit that must not be exceeded under any circumstances, including smooth air. Exceeding VNE risks flutter, structural failure, or loss of control. Option B describes the yellow arc (caution range), where flight is only permitted in smooth air. Option C describes VFE (flap extension speed). Option D describes no standard speed marking — maneuvering speed (VA) relates to gust/maneuver loads but is not marked by color range on the ASI.

Missing 20.6 — was Q48 in backup

(best match ratio: 0.44)

Question: An aircraft in the northern hemisphere intends to turn on the shortest way from a heading of 360° to a heading of 270°. At approximately which indication of the magnetic compass should the turn be terminated?

Correct: B)

Explanation: The shortest turn from 360° to 270° is a left turn (turning from north through west). In the northern hemisphere, the compass lags during turns away from north (toward south) and leads during turns toward north. When turning away from north (southward turn), the compass lags — it under-reads the turn. However, when turning through west (270°), the turning error is minimal. For turns to southerly headings the pilot must overshoot, but for 270° (west), the compass reading is approximately accurate at the completion point. The answer is to stop at 270° as indicated.

Subject 30 - Flight Performance and Planning: No missing questions ✓

Subject 40 - Human Performance: 32 Missing Questions

WARNING: 2 of these questions contain figure/image references.

Missing 40.1 — was Q2 in backup

(best match ratio: 0.62)

Question: The "swiss cheese model" can be used to explain the...

Correct: D)

Explanation: James Reason's Swiss Cheese Model illustrates how accidents occur when multiple layers of defence each have "holes" (latent and active failures) that align simultaneously, allowing a hazard to pass through all layers and cause an accident. Each slice of cheese represents a safety barrier, and an accident results from an error chain — not a single isolated failure.

Missing 40.2 — was Q3 in backup

(best match ratio: 0.77)

Question: What is the percentage of oxygen in the atmosphere at 6000 ft?

Correct: C)

Explanation: The percentage composition of atmospheric gases remains constant at approximately 21% oxygen and 78% nitrogen regardless of altitude. What changes with altitude is the partial pressure of oxygen: as total atmospheric pressure decreases, there are fewer oxygen molecules per breath, which is why hypoxia becomes a risk at altitude despite the unchanged percentage.

Missing 40.3 — was Q5 in backup

(best match ratio: 0.74)

Question: At which altitude is the atmospheric pressure approximately half the MSL value (1013 hPa)?

Correct: A)

Explanation: At 18,000 ft (approximately 5,500 m), atmospheric pressure is roughly 500 hPa — half of the standard sea-level pressure of 1013.25 hPa. This means the partial pressure of oxygen is also halved, severely reducing the oxygen available to the body and making supplemental oxygen mandatory for unpressurised flight above this altitude.

Missing 40.4 — was Q6 in backup

(best match ratio: 0.74)

Question: Air consists of oxygen, nitrogen and other gases. What is the approximate percentage of other gases?

Correct: B)

Explanation: The remaining approximately 1% of the atmosphere is composed of trace gases, primarily argon (about 0.93%), with very small amounts of carbon dioxide, neon, helium, methane, and others. While these gases are present in only tiny amounts, carbon dioxide in particular plays a significant role in the body's respiratory drive and acid-base balance, relevant to hyperventilation physiology.

Missing 40.5 — was Q7 in backup

(best match ratio: 0.79)

Question: Carbon monoxide poisoning can be caused by...

Correct: D)

Explanation: Carbon monoxide (CO) is produced by incomplete combustion of carbon-containing fuels and is present in cigarette smoke. CO binds to haemoglobin with an affinity approximately 200 times greater than oxygen, forming carboxyhaemoglobin and preventing oxygen transport to tissues. In aviation, CO poisoning is also a risk from exhaust fume ingestion via heating systems, producing symptoms similar to hypoxia.

Missing 40.6 — was Q11 in backup

(best match ratio: 0.79)

Question: Which of the human senses is most influenced by hypoxia?

Correct: D)

Explanation: Vision is the sense most sensitive to hypoxia because the retina has extremely high oxygen demands. Night vision is particularly affected first, with rod cell function degrading noticeably even at altitudes as low as 5,000-8,000 ft in the dark. Peripheral vision loss and reduced colour discrimination follow at higher altitudes, making hypoxia especially dangerous for flight.

Missing 40.7 — was Q12 in backup

(best match ratio: 0.71)

Question: From which altitude on does the body usually react to the decreasing atmospheric pressure?

Correct: D)

Explanation: The body begins to show measurable physiological responses to reduced partial pressure of oxygen at around 7,000 ft, though healthy individuals can usually compensate through increased respiratory rate and cardiac output. Below this altitude, the body maintains adequate oxygenation without significant stress; above it, compensatory mechanisms become progressively taxed.

Missing 40.8 — was Q13 in backup

(best match ratio: 0.74)

Question: Which altitude marks the lower limit where the the body is unable to completely compensate the effects of the low atmospheric pressure?

Correct: C)

Explanation: Above approximately 12,000 ft, the body's compensatory mechanisms — increased breathing rate and heart rate — are no longer sufficient to maintain adequate blood oxygen saturation. Hypoxic symptoms become increasingly apparent and performance degradation is measurable. This is why EASA regulations require oxygen supplementation above 10,000 ft for extended periods, and above 13,000 ft at all times.

Missing 40.9 — was Q15 in backup

(best match ratio: 0.71)

Question: Which of the following is responsible for the blood coagulation?

Correct: C)

Explanation: Blood platelets (thrombocytes) are small cell fragments that aggregate at sites of vascular injury and initiate the clotting cascade, forming a platelet plug to stop bleeding. They work together with clotting factors to form a stable fibrin clot. This function is distinct from the oxygen transport role of red blood cells and the immune role of white blood cells.

Missing 40.10 — was Q19 in backup

(best match ratio: 0.69)

Question: What is an appropriate reaction when a passenger during cruise flight suddenly feels uncomfortable?

Correct: B)

Explanation: A passenger feeling unwell in flight may be experiencing motion sickness, discomfort from temperature, or mild physiological stress. Adjusting cabin temperature to a comfortable level and minimising bank angle (reducing vestibular and acceleration stimuli) addresses the most likely causes without introducing new risks. Excessive bank aggravates motion sickness, and unnecessary oxygen administration can cause hyperventilation in some individuals.

Missing 40.11 — was Q20 in backup

(best match ratio: 0.54)

Question: What ist the correct term for an involuntary and stereotypical reaction of an organism to the stimulation of a receptor?

Correct: D)

Explanation: A reflex is an involuntary, stereotyped neural response to a specific sensory stimulus, mediated through a reflex arc in the spinal cord or brainstem without conscious brain involvement. In aviation, understanding reflexes matters because some trained responses can become automatic (procedural memory), while unexpected reflexes — such as startle responses — can interfere with controlled aircraft handling in emergencies.

Missing 40.12 — was Q21 in backup

(best match ratio: 0.63)

Question: What is the correct term for the system which, among others, controls breathing, digestion, and heart frequency?

Correct: B)

Explanation: The autonomic nervous system (ANS) regulates involuntary physiological functions including heart rate, breathing rate, digestion, and glandular secretion. It has two branches: the sympathetic ("fight or flight") and parasympathetic ("rest and digest") systems. In high-stress flight situations, sympathetic activation increases heart rate and alertness but can also impair fine motor control and narrow attentional focus.

Missing 40.13 — was Q23 in backup

(best match ratio: 0.78)

Question: Which characteristic is important when choosing sunglasses used by pilots?

Correct: B)

Explanation: Pilots must use non-polarised sunglasses because polarised lenses eliminate horizontally reflected light, which can make LCD displays, glass cockpit instruments, and certain reflective surfaces — such as water or other aircraft — invisible or severely distorted. UV protection and good optical quality are desirable, but the non-polarised requirement is the safety-critical aviation-specific characteristic.

Missing 40.14 — was Q25 in backup

(best match ratio: 0.46)

Question: In which situation is it NOT possible to achieve a pressure compensation between the middle ear and the environment?

Correct: D)

Explanation: When the Eustachian tube is blocked — typically due to a cold, sinus infection, or allergic congestion — the mucous membrane swells and prevents the tube from opening. This traps air in the middle ear at the previous ambient pressure, creating a painful pressure differential during ascent or descent. Pilots are advised not to fly with upper respiratory infections for this reason.

Missing 40.15 — was Q26 in backup

(best match ratio: 0.51)

Question: Wings level after a longer period of turning can lead to the impression of...

Correct: C)

Explanation: This is the "leans" or graveyard spiral illusion, rooted in semicircular canal adaptation. During a prolonged coordinated turn, the fluid in the relevant semicircular canal adapts to the rotation and ceases sending turn signals. When the pilot levels the wings, the canal detects a rotation in the opposite direction, creating the false sensation of turning the other way — which can cause a pilot to re-enter the original bank.

Missing 40.16 — was Q27 in backup

(best match ratio: 0.72)

Question: Which of the following options does NOT stimulate motion sickness (disorientation)?

Correct: A)

Explanation: Motion sickness is triggered by conflicting sensory signals — typically between the visual system and the vestibular (balance) system. Constant, non-accelerated straight-and-level flight produces no vestibular stimulation and no sensory conflict, so it does not provoke motion sickness. Head movements during turns, turbulence, and alcohol (which alters endolymph density) all create or amplify sensory conflicts.

Missing 40.17 — was Q28 in backup

(best match ratio: 0.55)

Question: Which optical illusion might be caused by a runway with an upslope during the approach?

Correct: D)

Explanation: A runway that slopes upward away from the pilot appears shorter and steeper than a flat runway, giving the visual impression of being higher than the actual glide slope. The pilot, perceiving the approach as too high, instinctively descends below the correct approach path — creating a dangerous undershoot risk. This illusion is a well-documented cause of controlled flight into terrain (CFIT) on visual approaches.

Missing 40.18 — was Q29 in backup

(best match ratio: 0.57)

Question: What impression may be caused when approaching a runway with an upslope?

Correct: C)

Explanation: Note: this question asks about the impression (what the pilot feels), not the actual outcome. An upsloping runway makes the pilot feel too high, so they perceive an overshoot situation. In response, the pilot may descend below the correct glide path, which in reality leads to an undershoot — but the perceived impression driving that incorrect correction is of being too high and overshooting.

Missing 40.19 — was Q30 in backup

(best match ratio: 0.65)

Question: The occurence of a vertigo is most likely when moving the head...

Correct: A)

Explanation: Vertigo (specifically the Coriolis illusion) is most likely when the head is moved in a different plane during an ongoing turn. The semicircular canals are already stimulated by the turn, and adding a head movement (such as looking down at a chart) stimulates a second set of canals simultaneously, creating an overwhelming and disorienting sensation of tumbling or rotation. This is one of the most incapacitating spatial disorientation illusions.

Missing 40.20 — was Q31 in backup

(best match ratio: 0.63)

Question: A Grey-out is the result of...

Correct: D)

Explanation: Grey-out is a progressive loss of colour vision and peripheral vision caused by positive g-forces pulling blood away from the head toward the lower body. As blood pressure in the retinal arteries drops, the retina (which has the highest oxygen demand of any body tissue) first loses colour perception (grey-out), then vision altogether (blackout), and finally consciousness (G-LOC — g-induced loss of consciousness).

Missing 40.21 — was Q33 in backup

(best match ratio: 0.77)

Question: The average decrease of blood alcohol level for an adult in one hour is approximately...

Correct: A)

Explanation: The liver metabolises alcohol at a roughly constant rate of approximately 0.01% (0.1 g/L) blood alcohol concentration per hour, largely independent of body weight or the amount consumed. This means that after a night of drinking, significant alcohol impairment can persist well into the following day. EASA regulations prohibit flying with a blood alcohol level above 0.2 g/L, and the "8-hour bottle to throttle" rule is a minimum — not a guarantee of sobriety.

Missing 40.22 — was Q34 in backup

(best match ratio: 0.74)

Question: Which answer states a risk factor for diabetes?

Correct: B)

Explanation: Overweight and obesity are the primary modifiable risk factors for type 2 diabetes, as excess adipose tissue — particularly visceral fat — causes insulin resistance. Type 2 diabetes is a significant concern in aviation medicine because it can cause hypoglycaemic episodes that impair consciousness and cognitive function, and because many diabetes medications are incompatible with a medical certificate.

Missing 40.23 — was Q36 in backup

(best match ratio: 0.64)

Question: Which statement is correct with regard to the short-term memory?

Correct: A)

Explanation: George Miller's classic 1956 research established that short-term (working) memory has a capacity of 7 ± 2 chunks of information, retained for approximately 10-20 seconds without active rehearsal. In aviation, this limitation is critically important: ATC clearances, frequencies, and altitudes must be written down immediately because they will be lost from working memory within seconds if not rehearsed or recorded.

Missing 40.24 — was Q37 in backup

(best match ratio: 0.71)

Question: For what approximate time period can the short-time memory store information?

Correct: B)

Explanation: Without active rehearsal or encoding, items held in short-term (working) memory fade within approximately 10-20 seconds. This is why read-back procedures in aviation communication are essential — they force the pilot to actively process and repeat information, moving it from passive short-term storage into a more durable encoded state, and simultaneously allow ATC to verify correct receipt.

Missing 40.25 — was Q41 in backup

(best match ratio: 0.47)

Question: In what different ways can a risk be handled appropriately?

Correct: B)

Explanation: The four standard risk management strategies are: Avoid (eliminate the activity or hazard), Reduce (implement controls to lower probability or severity), Transfer (shift the risk to another party, e.g., insurance), and Accept (consciously acknowledge the residual risk when it is within acceptable limits). Ignoring a risk is never an acceptable strategy in aviation risk management.

Missing 40.26 — was Q43 in backup

(best match ratio: 0.60)

Question: Which dangerous attitudes are often combined?

Correct: C)

Explanation: The FAA identifies five hazardous attitudes in aviation: macho, invulnerability, impulsivity, resignation (self-abandonment), and anti-authority. Macho ("I can do it") and invulnerability ("It won't happen to me") are frequently found together because both stem from overconfidence and underestimation of risk. A pilot who thinks they are immune from accidents (invulnerability) is also prone to taking unnecessary risks to demonstrate skill (macho).

Missing 40.27 — was Q44 in backup

(best match ratio: 0.75)

Question: What is an indication for a macho attitude?

Correct: A)

Explanation: The macho attitude is characterised by the need to demonstrate bravery, skill, or daring — often to an audience. Performing risky manoeuvres to impress observers is a textbook example: the pilot prioritises ego and external validation over safety margins. This attitude is particularly dangerous because it actively creates hazardous situations that would otherwise never arise. The antidote is the reminder: "Taking chances is foolish."

Missing 40.28 — was Q45 in backup

(best match ratio: 0.76)

Question: Which factor can lead to human error?

Correct: B)

Explanation: Confirmation bias — the tendency to perceive and interpret information in a way that confirms pre-existing expectations — is a major source of human error in aviation. Pilots may misread an instrument, misidentify a runway, or fail to notice an abnormality because their brain filters incoming information through what it expects to see. This is why structured scan patterns, checklists, and cross-checking are essential countermeasures.

Missing 40.29 — was Q46 in backup

(best match ratio: 0.54)

Question: What is the best combination of traits with respect to the individual attitude and behaviour for a pilot?

Correct: C)

Explanation: Aviation psychology research identifies extroversion and emotional stability as the most beneficial personality traits for pilots. Extroversion supports effective communication, crew coordination, and assertiveness needed for CRM. Emotional stability (low neuroticism) ensures the pilot remains calm and rational under pressure, maintains consistent performance, and does not overreact to stress — all critical for safe flight operations.

Missing 40.30 — was Q47 in backup

(best match ratio: 0.69)

Question: Complacency is a risk due to...

Correct: A)

Explanation: Automation complacency occurs when pilots over-rely on automated systems and progressively reduce their active monitoring of aircraft state. As cockpit automation becomes more sophisticated and reliable, pilots may become less vigilant, lose situational awareness, and suffer skill degradation. When automation fails — precisely when manual flying skills are most needed — the complacent pilot may be unprepared to take over effectively.

Missing 40.31 — was Q48 in backup [HAS FIGURE/IMAGE REFERENCE]

(best match ratio: 0.70)

Question: The ideal level of arousal is at which point in the diagram? See figure (HPL-002) P = Performance A = Arousal / Stress

Correct: A)

Explanation: The Yerkes-Dodson law describes the inverted-U relationship between arousal (stress) and performance. Point B represents the peak of the curve — the optimal level of arousal where performance is maximised. Too little arousal (Point A: boredom, fatigue) leads to poor performance due to inattention; too much arousal (Points C, D: high stress, panic) degrades performance through tunnel vision, cognitive narrowing, and loss of fine motor control.

Missing 40.32 — was Q49 in backup [HAS FIGURE/IMAGE REFERENCE]

(best match ratio: 0.71)

Question: At which point in the diagram will a pilot find himself to be overstrained? See figure (HPL-002) P = Performance A = Arousal / Stress

Correct: D)

Explanation: Point D represents the far right of the Yerkes-Dodson curve — excessive arousal and stress — where performance collapses. At this level, the pilot is overwhelmed, unable to process information effectively, and may exhibit tunnel vision (fixating on one problem while ignoring others), panic responses, or cognitive freezing. Recognising the signs of overstrain and applying stress management techniques (slowing down, prioritising tasks) is a core CRM skill.

Subject 50 - Meteorology: 3 Missing Questions

Missing 50.1 — was Q41 in backup

(best match ratio: 0.58)

Question: "Foehn" conditions usually develop with...

Correct: C)

Explanation: Foehn is a warm, dry, descending wind on the lee side of a mountain range. It develops when stable air is pushed by a broad-scale pressure gradient against a mountain barrier. On the windward side, moist air rises and cools at the Saturated Adiabatic Lapse Rate (SALR ~0.6°C/100 m) after reaching the dew point, precipitating moisture. On the lee side, dry air descends at the Dry Adiabatic Lapse Rate (DALR ~1°C/100 m), arriving warmer and drier than it started — the Foehn effect.

Missing 50.2 — was Q43 in backup

(best match ratio: 0.79)

Question: Light turbulence always has to be expected...

Correct: D)

Explanation: Cumulus clouds are the visible tops of thermal columns. The sub-cloud layer beneath them contains active thermals (updraughts) and compensating downdraughts between them, creating light to moderate turbulence from convective mixing. This is the normal turbulent environment of thermal soaring. Above cumulus tops the air is generally smoother (outside the cloud); stratiform clouds have minimal convective turbulence unless embedded CBs are present.

Missing 50.3 — was Q44 in backup

(best match ratio: 0.77)

Question: Moderate to severe turbulence has to be expected...

Correct: C)

Explanation: Rotor clouds (roll clouds) on the lee side of mountains are the visible indicator of the highly turbulent rotor zone beneath mountain waves. This turbulence can be extreme, with unpredictable up- and downdraughts, strong shear, and rotational forces capable of exceeding aircraft structural limits. Experienced wave pilots avoid or transit the rotor zone quickly with sufficient airspeed. The windward side of mountains typically has orographic cloud and steady lift, not severe turbulence.

Subject 60 - Navigation: 32 Missing Questions

Missing 60.1 — was Q24 in backup

(best match ratio: 0.72)

Question: Given: TC: 179°; WCA: -12°; VAR: 004° E; DEV: +002° What are MH and MC?

Correct: A)

Explanation: TH = TC + WCA = 179° + (-12°) = 167°. Then MH = TH - VAR (E is subtracted): MH = 167° - 4° = 163°. For MC: MC = TC - VAR = 179° - 4° = 175°. Alternatively: MC = MH + WCA = 163° + (-12°) = 151° — wait, that doesn't match; MC is measured from magnetic north to the course line, so MC = TC - VAR = 179° - 4° = 175°. East variation is subtracted when converting from True to Magnetic ("East is least").

Missing 60.2 — was Q50 in backup

(best match ratio: 0.71)

Question: Given: True course from A to B: 283°. Ground distance: 75 NM. TAS: 105 kt. Headwind component: 12 kt. Estimated time of departure (ETD): 1242 UTC. The estimated time of arrival (ETA) is...

Correct: A)

Explanation: Ground speed = TAS - headwind = 105 - 12 = 93 kt. Flight time = 75 NM / 93 kt = 0.806 h = 48.4 min ≈ 48 min. ETA = 1242 + 0:48 = 1330 UTC. Option B (1356) would correspond to a GS of about 62 kt; option D (1320) would correspond to a GS of about 113 kt. Carefully subtracting the headwind from TAS before dividing gives the correct result. --- ## Swiss Navigation Exercises (SFVS)

Source: Segelflugverband der Schweiz - SFCLTheorieNavigationVersionSchweiz_Uebungen.pdf Download: https://www.segelflug.ch/wp-content/uploads/2024/01/SFCLTheorieNavigationVersionSchweiz_Uebungen.pdf Permitted aids at the exam: ICAO 1:500'000 Switzerland chart, Swiss gliding chart, protractor, ruler, mechanical DR calculator, compass, non-programmable scientific calculator (TI-30 ECO RS recommended). No alphanumeric or electronic navigation computers allowed.

Missing 60.3 — was Q51 in backup

(best match ratio: 0.39)

Question: Wann muessen wir spaetestens landen? (Landing deadline)

Explanation: Swiss VFR regulations define the end of the flying day as 30 minutes after official sunset (or a specified time after evening civil twilight). The landing deadline is looked up in official sunset tables and adjusted for the applicable time zone (MEZ = UTC+1 in winter, MESZ = UTC+2 in summer). June 21 is near the summer solstice, giving the latest sunset of the year; March dates are in standard time (MEZ). Always verify the current eVFG tables, as these values are date and location dependent.

Missing 60.4 — was Q52 in backup

(best match ratio: 0.42)

Question: Was bedeutet die grosse Zahl 87 bei Freiburg auf der ICAO-Karte?

Explanation: On the Swiss ICAO 1:500,000 chart, large bold numbers printed near certain cities or waypoints indicate the Minimum Safe Altitude (MSA) in hundreds of feet for that area (so "87" means 8,700 ft MSL). The MSA provides obstacle clearance of at least 300 m (1000 ft) within a defined radius. Pilots use these values for en-route safety altitude planning, especially important in mountainous terrain like the Swiss Jura and Alps.

Missing 60.5 — was Q53 in backup

(best match ratio: 0.43)

Question: Welcher Eintrag sollte auf der Navigationskarte vor einem Streckenflug immer gemacht werden?

Explanation: Before a cross-country flight, the pilot should measure and mark the True Course (TC) on the navigation chart using a protractor referenced to the nearest meridian. The TC is the foundation for all subsequent heading calculations: TC → apply variation → MC → apply wind correction → TH → apply deviation → CH. Marking the TC on the chart ensures consistent reference throughout the flight planning process and allows in-flight verification of track.

Missing 60.6 — was Q54 in backup

(best match ratio: 0.35)

Question: Wie sollte ein Endanflug ueber navigatorisch schwierigem Gelaende gemacht werden?

Explanation: When approaching a destination over navigationally challenging terrain (forests, featureless plains, or complex topography), the pilot should monitor progress using elapsed time against a pre-calculated time scale, and positively identify known landmarks (towns, rivers, roads) and mark them on the chart. This technique — essentially dead reckoning with regular position fixes — prevents the pilot from overflying the destination or becoming lost. In a glider without GPS, time management is critical to ensure arrival with sufficient altitude.

Missing 60.7 — was Q55 in backup

(best match ratio: 0.41)

Question: Was bedeutet GND auf dem Deckblatt der Segelflugkarte?

Explanation: On the Swiss gliding chart cover page, "GND" indicates the lower limit (ground) of certain restricted areas, and the term specifically refers to the upper boundary of LS-R (Luftraum-Segelflug-Reservate) available for gliders operating with reduced cloud separation minima. These zones allow gliders to fly in conditions that would otherwise require instrument flight rules, provided specific weather minima are met. Understanding the legend on the gliding chart cover page is essential for Swiss exam candidates.

Missing 60.8 — was Q56 in backup

(best match ratio: 0.29)

Question: Segelflugfrequenzen (Boden-Luft, Luft-Luft, Regionen)?

Explanation: The Swiss gliding chart cover page contains a complete list of glider frequencies, including ground-to-air and air-to-air communication frequencies organized by region. Common Swiss glider frequencies include 122.300 MHz (universal glider frequency) and regional variants. These must be known before flight as gliders may need to coordinate with each other and with ground stations, especially in busy areas like the Alps or near controlled airspace.

Missing 60.9 — was Q57 in backup

(best match ratio: 0.37)

Question: Militaerische Flugdienstzeiten?

Explanation: The operating hours of Swiss military airspace and military air traffic services are printed in the lower right corner of the Swiss gliding chart. Military restricted areas (such as those associated with Payerne, Meiringen, and Emmen air bases) may only be active during specific hours, and knowing these hours is critical for planning routes through or near militarily controlled areas. Outside activation times, these areas revert to standard civil airspace classifications.

Missing 60.10 — was Q58 in backup

(best match ratio: 0.40)

Question: Hoehe des Stockhorns in ft und m? Hoehe der Stockhornbahn AGL?

Explanation: The Stockhorn (2190 m / 7185 ft MSL) is a prominent peak in the Bernese Prealps visible on the Swiss ICAO chart. Its elevation appears in meters on the chart, and pilots must be able to convert to feet (using ft = m x 10/3: 2190 x 10/3 = 7300 ft, closely matching 7185 ft). The Stockhorn gondola cable (Stockhornbahn) represents an aerial obstacle 180 m AGL — cables and lifts are marked with AGL heights on the gliding chart as they pose significant hazards to low-flying gliders.

Missing 60.11 — was Q59 in backup

(best match ratio: 0.34)

Question: Wie hoch ist der Turm auf dem Bantiger (46 58,7 N / 7 31,7 E)?

Explanation: The Bantiger tower near Bern is a communication mast shown on the Swiss ICAO and gliding charts at coordinates N46°58.7' / E7°31.7'. Its height is 188 m AGL (615 ft AGL). On the chart, obstacle heights are given in both meters and feet — exam candidates must be able to read the chart and convert between units. Obstacles above 100 m AGL are typically marked with their height and may have obstruction lighting.

Missing 60.12 — was Q60 in backup

(best match ratio: 0.38)

Question: Wie hoch darfst du ueber Egerkingen (32,4 km, 060 von LSZG) steigen?

Explanation: Egerkingen lies beneath the Tango Sector — a portion of Swiss airspace associated with the Basel/Mulhouse (LFSB/EuroAirport) TMA. When the Tango Sector is inactive (check with Basel Info on the appropriate frequency), the area is uncontrolled airspace up to FL100. When active, the upper limit drops to 1750 m MSL and operations above require a clearance from Basel Approach. This dynamic airspace structure is specific to the Swiss airspace system and requires checking NOTAMs and AIP Switzerland before flight.

Missing 60.13 — was Q61 in backup

(best match ratio: 0.33)

Question: Welche Infos finden wir auf der SF-Karte zum Flugplatz Les Eplatures (47 05 N, 6 47,5 E)?

Explanation: Les Eplatures (LSGC) near La Chaux-de-Fonds appears on the Swiss gliding chart with symbols decoded in the chart legend. The legend distinguishes between towered (controlled) and non-towered airfields, glider-specific aerodromes, military fields, and emergency landing strips. Candidates must be able to read the legend and determine the relevant operational information (radio frequencies, runway orientation, airspace class) for any airfield depicted on the chart.

Missing 60.14 — was Q62 in backup

(best match ratio: 0.35)

Question: Benuetzungsbedingungen LS-R69 T (bei Schaffhausen)?

Explanation: LS-R69 is a glider restricted area near Schaffhausen that lies within the Zurich TMA structure. The area overlaps with TMA LSZH 3 (lower limit 1700 m MSL), not TMA LSZH 10 (2000 m) — this distinction is critical because it determines the altitude at which a clearance becomes necessary. Usage conditions are found in the chart legend lower right, and the text boxes on the chart itself clarify which TMA segment applies. Misidentifying the applicable TMA layer could lead to an airspace infringement.

Missing 60.15 — was Q63 in backup

(best match ratio: 0.44)

Question: Koordinaten vom Flugplatz Birrfeld?

Explanation: Birrfeld (LSZF) is a glider aerodrome in the canton of Aargau, Switzerland. Reading exact coordinates from the ICAO 1:500,000 chart requires careful use of the latitude and longitude graticule — each degree is divided into minutes, and at this scale, individual minutes of arc are clearly readable. The ability to read and record precise coordinates is tested because pilots may need to report positions to ATC or verify their location against chart features.

Missing 60.16 — was Q64 in backup

(best match ratio: 0.38)

Question: Koordinaten vom Flugplatz Montricher?

Explanation: Montricher (LSTR) is a glider airfield in the canton of Vaud, in the French-speaking region of Switzerland. Its coordinates place it on the Swiss Plateau west of Lausanne. Locating it precisely on the ICAO chart and reading the graticule accurately requires practice — at 1:500,000 scale, 1 minute of latitude ≈ 1 NM ≈ 1.85 km, allowing sub-minute precision to be interpolated visually from the grid.

Missing 60.17 — was Q65 in backup

(best match ratio: 0.36)

Question: Welcher Ort ist auf N 47 07', E 8 00'?

Explanation: Given a set of coordinates, the candidate must locate the point on the Swiss ICAO chart by finding the correct latitude (47°07'N) and longitude (8°00'E) lines and reading the nearest landmark. Willisau is a town in the canton of Lucerne, on the Swiss Plateau. This exercise tests reverse coordinate lookup — starting from numbers and finding the geographic feature, as opposed to the forward direction (finding coordinates from a named place).

Missing 60.18 — was Q66 in backup

(best match ratio: 0.36)

Question: Welcher Ort ist auf N 46 11', E 6 16'?

Explanation: These coordinates place the point south of Lake Geneva (Lac Léman) at approximately N46°11' / E6°16', which corresponds to Annemasse aerodrome — a French airfield just across the Swiss-French border near Geneva. This question tests not only chart reading but also awareness that the Swiss ICAO chart extends into neighboring countries (France, Germany, Austria, Italy), and pilots should recognize aerodromes in border regions.

Missing 60.19 — was Q67 in backup

(best match ratio: 0.33)

Question: TC von Grenchen Flugplatz nach Neuenburg Flugplatz?

Explanation: To find the true course between two airfields, place a protractor on the chart aligned to the nearest meridian and measure the angle of the straight line connecting the two points. Grenchen (LSZG) is northeast of Neuenburg/Neuchâtel (LSGN), so the course from Grenchen to Neuchâtel runs roughly southwest — approximately 239° true. On the Lambert conformal chart, straight lines closely approximate great circles, and courses are measured from true north at the midpoint meridian.

Missing 60.20 — was Q68 in backup

(best match ratio: 0.37)

Question: TC von Langenthal Flugplatz nach Kaegiswil Flugplatz?

Explanation: Langenthal (LSPL) is northwest of Kaegiswil (LSPG near Sarnen), so the course from Langenthal to Kaegiswil runs roughly southeast — approximately 132° true. This is measured with a protractor on the ICAO chart, aligned to the meridian passing through or near the midpoint of the route. The course of 132° places the destination to the SE, consistent with Kaegiswil's position in the foothills near Lake Sarnen.

Missing 60.21 — was Q69 in backup

(best match ratio: 0.38)

Question: Distanz Laax - Oberalp in km, NM, sm?

Explanation: The distance is measured with a ruler on the 1:500,000 chart and converted using the scale bar. At 1:500,000, 1 cm on the chart = 5 km in reality. Once the distance in km is known, conversion follows: NM = km / 1.852 ≈ km / 2 + 10% (exam formula), and statute miles = km / 1.609. This route runs along the Vorderrhein valley from Laax ski area toward the Oberalp Pass — a classic Swiss glider cross-country segment.

Missing 60.22 — was Q70 in backup

(best match ratio: 0.32)

Question: Flugzeit Laax 14:52 nach Oberalp 15:09?

Explanation: Simply subtract departure time from arrival time: 15:09 - 14:52 = 17 minutes. This elapsed flight time, combined with the distance from Q69, gives the speed for Q71. In practice, timing legs of a cross-country flight allows the pilot to verify actual groundspeed against planned groundspeed and detect headwind or tailwind differences from the forecast.

Missing 60.23 — was Q71 in backup

(best match ratio: 0.31)

Question: Geschwindigkeit in km/h, kts, mph?

Explanation: Ground speed = distance / time = 46.3 km / (17/60) h = 46.3 / 0.2833 = 163.4 km/h ≈ 163 km/h. Converting: kts = km/h / 1.852 ≈ 163 / 2 + 10% ≈ 88 kts; mph = km/h / 1.609 ≈ 101 mph. This three-unit speed result is typical of Swiss navigation exam questions, requiring fluency with all three speed units and their conversion relationships.

Missing 60.24 — was Q72 in backup

(best match ratio: 0.34)

Question: Strecke LSTB-Buochs-Jungfrau-LSTB: Wie lang in km und NM?

Explanation: This is a triangular cross-country task measured on the chart: from Bellechasse (LSTB) to Buochs, then to the Jungfrau, and back to Bellechasse. Each leg is measured separately with a ruler on the 1:500,000 chart and the distances summed: 56 + 43 + 59 + 80 = 238 km total. Converting each leg to NM individually then summing (or converting the total: 238 / 1.852 ≈ 128 NM) gives the total task distance used for competition scoring and exam questions.

Missing 60.25 — was Q73 in backup

(best match ratio: 0.38)

Question: Von Eriswil bis Buochs in 18 Min - wie schnell?

Explanation: Ground speed = (distance / time) x 60 to convert minutes to hours: (43 km / 18 min) x 60 = 143.3 km/h ≈ 143 km/h. The 43 km distance is taken from the chart measurement for this leg. Converting: kts ≈ 143 / 1.852 ≈ 77 kts; mph ≈ 143 / 1.609 ≈ 89 mph. This type of in-flight speed check — measuring elapsed time between two known points — is how glider pilots monitor actual vs. planned groundspeed during cross-country flights.

Missing 60.26 — was Q74 in backup

(best match ratio: 0.42)

Question: Welche Luftraeume zwischen Bellechasse und Buochs auf 1500 m/M?

Explanation: This question requires reading all airspace layers on the route between Bellechasse and Buochs at 1500 m MSL, using both the ICAO chart and the gliding chart. Airspace Class D areas (TMA LSZB1, CTR LSMA/LSZC) require an ATC clearance before entry. Airspace Class E areas (TMA PAY 7, LR E MTT, LR E Alpen) are accessible under VFR without clearance but IFR flights have priority. LS-R15 is a glider area that may be active. Systematic left-to-right reading of the chart along the route is the required technique.

Missing 60.27 — was Q75 in backup

(best match ratio: 0.39)

Question: TC zwischen Jungfrau und Bellechasse?

Explanation: The Jungfrau is located southeast of Bellechasse (LSTB), so the course FROM Jungfrau TO Bellechasse points northwest. A bearing of 308° is northwest of north, consistent with this geometry. The TC is measured with a protractor on the Lambert conformal chart, aligned to the meridian at the midpoint of the route. Note that this is the reciprocal of the course from Bellechasse to Jungfrau (approximately 128°), which confirms 308° is directionally correct.

Missing 60.28 — was Q76 in backup

(best match ratio: 0.36)

Question: Gleitflug von Jungfrau (4200 m/M) nach Bellechasse mit Gleitwinkel 1:30 bei 150 km/h - Ankunftshoehe?

Explanation: With a glide ratio of 1:30, the glider covers 30 meters forward for every 1 meter of altitude lost. Height loss over 80 km = 80,000 m / 30 = 2,667 m. Starting at 4200 m MSL: arrival altitude = 4200 - 2667 = 1533 m MSL. Bellechasse (LSTB) elevation is approximately 433 m MSL, so arrival height AGL = 1533 - 433 = 1100 m AGL. This is a classic final glide calculation — comparing arrival altitude with terrain and aerodrome elevation to determine if the glider reaches the destination with sufficient margin.

Missing 60.29 — was Q77 in backup

(best match ratio: 0.36)

Question: Winddreieck Jungfrau-Bellechasse: TAS 140 km/h, Wind 040/15 kts

Explanation: The wind triangle (Winddreieck) is solved graphically or with a mechanical DR calculator: the TC is 308°, TAS is 140 km/h (≈76 kts), and wind is from 040° at 15 kts (≈28 km/h). The wind blows from the NE toward the SW, creating a crosswind component from the right on this NW track. The WCA of +12° (right wind → head left) gives TH = TC + WCA = 308° + 12° = 320°. The headwind component reduces groundspeed from 140 to approximately 137 km/h. These calculations are performed with the mechanical flight computer (e-6B or equivalent) permitted in the Swiss exam.

Missing 60.30 — was Q78 in backup

(best match ratio: 0.38)

Question: MH von Jungfrau nach Bellechasse (Variation 3 E)?

Explanation: To convert True Heading (TH) to Magnetic Heading (MH), apply the local magnetic variation. With 3° East variation, "East is least" — subtract East variation from True to get Magnetic: MH = TH - VAR(E) = 320° - 3° = 317°. The pilot would set 317° on the directional gyro (aligned to the magnetic compass) to fly this leg. Switzerland has a small easterly variation of about 2-3° in most regions.

Missing 60.31 — was Q79 in backup

(best match ratio: 0.39)

Question: Falls Variation 25 W - MH?

Explanation: With 25° West variation, "West is best" — add West variation to True Heading to get Magnetic Heading: MH = TH + VAR(W) = 320° + 25° = 345°. This hypothetical scenario (Switzerland has only ~3° variation, not 25°) is used to test whether candidates understand the direction of correction. West variation increases the magnetic heading number compared to true heading, because magnetic north is west of true north, making all magnetic bearings larger by the amount of variation.

Missing 60.32 — was Q80 in backup

(best match ratio: 0.43)

Question: Transponder Codes

Correct: A)

Explanation: These four transponder codes are universal ICAO emergency and standard VFR codes, memorized by all pilots. Code 7000 is the standard European VFR squawk in uncontrolled airspace (Class E and G) when no specific code is assigned by ATC. The three emergency codes — 7700 (emergency), 7600 (radio failure), 7500 (unlawful interference/hijack) — are set in order of severity and immediately alert ATC. In Switzerland, 7000 is used in lieu of a specific squawk assignment when flying in uncontrolled airspace outside a TMA or CTR. ---

Subject 70 - Operational Procedures: No missing questions ✓

Subject 80 - Principles of Flight: 35 Missing Questions

WARNING: 7 of these questions contain figure/image references.

Missing 80.1 — was Q1 in backup

(best match ratio: 0.52)

Question: With regard to the forces acting, how can stationary gliding be described?

Correct: D)

Explanation: In steady (stationary) gliding flight, there is no thrust, so only two forces act: gravity (weight) and the total aerodynamic force (the vector sum of lift and drag). For the glider to be in equilibrium, these two must be equal and opposite — meaning the resultant air force exactly compensates gravity. Lift and drag are merely components of this single aerodynamic resultant; neither lift alone nor drag alone balances weight.

Missing 80.2 — was Q2 in backup

(best match ratio: 0.70)

Question: What is the result of extending flaps with increasing aerofoil camber?

Correct: C)

Explanation: Extending flaps increases wing camber, which raises the maximum lift coefficient (CLmax). From the stall speed formula Vs = sqrt(2W / (rho * S * CLmax)), a higher CL_max directly lowers the minimum flying speed Vs. This allows the aircraft to fly slower without stalling, which is why flaps are used during approach and landing. The maximum permissible speed typically decreases with flaps extended (not increases), because flap structures are not designed for high dynamic pressure.

Missing 80.3 — was Q3 in backup

(best match ratio: 0.66)

Question: Following a single-wing stall and pitch-down moment, how can a spin be prevented?

Correct: B)

Explanation: An incipient spin begins when one wing stalls before the other — the stalled wing drops, creating a yawing and rolling moment. The correct response is to apply rudder opposite the direction of yaw/lower wing to stop the rotation, and simultaneously release elevator back-pressure (or push forward) to reduce the angle of attack below the critical value, allowing airflow to re-attach and lift to be restored. Pulling the elevator (D) would increase AoA and deepen the stall; pushing alone (C) without rudder does not stop the yaw.

Missing 80.4 — was Q4 in backup

(best match ratio: 0.68)

Question: Stabilization around the lateral axis during cruise is achieved by the...

Correct: B)

Explanation: The lateral axis is the pitch axis (nose up/down). The horizontal stabilizer provides longitudinal (pitch) stability: it generates a restoring moment whenever the nose pitches up or down from trim, because its lift force changes with AoA at the tail. Ailerons control roll (longitudinal axis), the vertical rudder controls yaw (vertical axis), and flaps are high-lift devices, not stability surfaces.

Missing 80.5 — was Q5 in backup

(best match ratio: 0.73)

Question: Flying with speeds higher than the never-exceed-speed (vNE) may result in...

Correct: D)

Explanation: VNE is the red-line speed above which structural or aeroelastic failure becomes possible. At excessive speeds, dynamic pressure (q = 0.5 * rho * V^2) rises dramatically, and control surfaces and wing structures may enter flutter — a self-reinforcing oscillation where aerodynamic forces and structural elasticity feed each other, potentially causing rapid structural disintegration. The airspeed indicator remains usable at high speeds; glide ratio does not improve beyond the best-glide speed.

Missing 80.6 — was Q6 in backup

(best match ratio: 0.55)

Question: Considering longitudinal stability, which C.G. position is most dangerous with a normal gliding plane?

Correct: D)

Explanation: Longitudinal (pitch) stability requires the centre of gravity to be ahead of the neutral point. When the C.G. moves aft beyond the rear limit, the static margin becomes negative: a pitch disturbance produces a moment that amplifies rather than corrects the disturbance, making the aircraft unstable and potentially uncontrollable. A forward C.G. (A) increases stability but requires more elevator force — it is uncomfortable but recoverable. Rearward C.G. beyond limits is the most dangerous condition because recovery from pitch divergence may be impossible.

Missing 80.7 — was Q7 in backup

(best match ratio: 0.71)

Question: The static pressure of gases work...

Correct: A)

Explanation: Static pressure is a scalar thermodynamic quantity representing the random kinetic energy of gas molecules. Because molecular collisions occur in all directions equally, static pressure acts omnidirectionally — it presses equally on all surfaces of a container regardless of orientation. This contrasts with dynamic pressure (q = 0.5 * rho * V^2), which is directional and associated with the bulk flow velocity. Bernoulli's equation combines both: ptotal = pstatic + q.

Missing 80.8 — was Q10 in backup

(best match ratio: 0.59)

Question: All aerodynamic forces can be considered to act on a single point. This point is called...

Correct: D)

Explanation: The center of pressure (CP) is the single point on an aerofoil through which the resultant of all distributed aerodynamic pressure forces acts. It is analogous to the center of gravity for weight distribution. The CP moves with angle of attack — generally forward as AoA increases toward the critical angle. The center of gravity is where weight acts, not aerodynamic forces; the transition point is where the boundary layer changes from laminar to turbulent.

Missing 80.9 — was Q12 in backup [HAS FIGURE/IMAGE REFERENCE]

(best match ratio: 0.67)

Question: Number 2 in the drawing corresponds to the... See figure (PFA-010)

Correct: C)

Explanation: The chord line is a straight reference line connecting the leading edge to the trailing edge of an aerofoil. It is the baseline from which the angle of attack is measured (the angle between the chord line and the undisturbed freestream direction). In standard aerofoil diagrams, the chord line (item 2) is typically the straight baseline of the cross-section, while the mean camber line curves above it and the thickness is measured perpendicular to the chord.

Missing 80.10 — was Q13 in backup [HAS FIGURE/IMAGE REFERENCE]

(best match ratio: 0.71)

Question: Number 3 in the drawing corresponds to the... See figure (PFA-010)

Correct: A)

Explanation: The mean camber line (also called the mean line) is the locus of points equidistant between the upper and lower surfaces of the aerofoil, measured perpendicular to the chord line. It describes the aerofoil's curvature or camber — a cambered (curved) aerofoil generates lift even at zero angle of attack because the asymmetry in curvature accelerates flow more over the upper surface. Maximum camber and its location are key parameters defining aerofoil character.

Missing 80.11 — was Q15 in backup

(best match ratio: 0.66)

Question: The ratio of span and mean chord length is referred to as...

Correct: C)

Explanation: Aspect ratio (AR) = wingspan (b) / mean chord (c) = b^2 / S, where S is wing area. High aspect ratio wings (long, narrow) produce less induced drag because the wingtip vortices are proportionally weaker relative to the total span. Gliders have very high aspect ratios (typically 20–40) for this reason — minimising induced drag is essential for maximum glide ratio. Low-aspect-ratio wings produce more induced drag but are structurally lighter and more agile.

Missing 80.12 — was Q16 in backup [HAS FIGURE/IMAGE REFERENCE]

(best match ratio: 0.69)

Question: Which point on the aerofoil is represented by number 3? See figure (PFA-009)

Correct: D)

Explanation: The transition point is where the boundary layer changes character from laminar to turbulent flow. Laminar flow (near the leading edge) has lower friction drag but is fragile and prone to separation. The turbulent boundary layer that follows is thicker and has higher friction drag but resists separation better. The position of the transition point depends on Reynolds number, surface roughness, and pressure gradient — aerofoil designers try to delay transition as far back as possible to minimise skin friction.

Missing 80.13 — was Q17 in backup [HAS FIGURE/IMAGE REFERENCE]

(best match ratio: 0.69)

Question: Which point on the aerofoil is represented by number 4? See figure (PFA-009)

Correct: D)

Explanation: The separation point is where the boundary layer detaches from the aerofoil surface. Beyond this point, the smooth attached flow breaks down into a turbulent, reversed-flow wake. As angle of attack increases, the adverse pressure gradient on the upper surface intensifies, and the separation point moves progressively forward toward the leading edge. When separation reaches the leading edge, the wing is fully stalled — CL drops abruptly and CD rises sharply.

Missing 80.14 — was Q18 in backup [HAS FIGURE/IMAGE REFERENCE]

(best match ratio: 0.69)

Question: Which point on the aerofoil is represented by number 1? See figure (PFA-009)

Correct: B)

Explanation: The stagnation point is the location on the aerofoil's leading edge region where the oncoming airflow divides — some going over the upper surface, some beneath. At this point, the local flow velocity is zero and static pressure reaches its maximum (equal to total pressure, since dynamic pressure is zero). With increasing angle of attack, the stagnation point moves slightly downward on the leading edge, as more flow is directed over the upper surface to generate greater lift.

Missing 80.15 — was Q19 in backup

(best match ratio: 0.72)

Question: What pattern can be found at the stagnation point?

Correct: D)

Explanation: The stagnation point is precisely the dividing location where incoming streamlines bifurcate — the streamline that arrives at the stagnation point splits, with air flowing around the upper and lower surfaces separately. At this point, kinetic energy is fully converted to pressure (V = 0, p = p_total). Boundary layer transition (C) occurs further aft on the upper surface; separation (A) is further aft still; aerodynamic forces are considered to act at the center of pressure, not the stagnation point.

Missing 80.16 — was Q20 in backup

(best match ratio: 0.59)

Question: What pressure pattern can be observed at a lift-generating wing profile at positive angle of attack?

Correct: A)

Explanation: Lift is generated by a pressure differential: lower pressure on the upper (suction) surface and higher pressure on the lower surface. On the upper surface, flow accelerates around the curved upper side — by Bernoulli's principle, higher velocity means lower static pressure. On the lower surface, flow is slowed and compressed, increasing static pressure. The net upward pressure force integrated over the entire surface constitutes lift: L = CL * 0.5 * rho * V^2 * S.

Missing 80.17 — was Q21 in backup

(best match ratio: 0.64)

Question: In which way does the position of the center of pressure move at a positively shaped profile with increasing angle of attack?

Correct: B)

Explanation: As angle of attack increases, the suction peak on the upper surface intensifies and moves toward the leading edge, causing the center of pressure to migrate forward. This continues until the critical (stall) angle of attack is reached. Beyond the stall, the suction peak collapses as flow separates, and the center of pressure moves abruptly rearward. The forward movement of the CP with increasing AoA is important for stability analysis and contributes to the pitching moment characteristics of the aerofoil.

Missing 80.18 — was Q23 in backup

(best match ratio: 0.63)

Question: Which statement about the airflow around an aerofoil is correct if the angle of attack increases?

Correct: A)

Explanation: As angle of attack increases, the relative airflow meets the wing at a steeper upward angle. The streamline that arrives exactly at the stagnation point shifts downward (toward the lower surface of the leading edge), because more airflow is now directed over the upper surface. Simultaneously, the centre of pressure moves forward (not up or down — it moves chordwise), and the suction on the upper surface increases as flow accelerates more strongly over the curved upper side.

Missing 80.19 — was Q24 in backup

(best match ratio: 0.60)

Question: Which statement about the airflow around an aerofoil is correct if the angle of attack decreases?

Correct: A)

Explanation: As angle of attack decreases, the aerodynamic loading on the forward portion of the upper surface diminishes, shifting the resultant pressure force rearward — so the center of pressure moves aft (toward the trailing edge). The stagnation point also moves upward (not down) as less flow is forced over the upper surface. Understanding CP movement is important because it affects the pitching moment balance of the aircraft throughout the flight envelope.

Missing 80.20 — was Q25 in backup [HAS FIGURE/IMAGE REFERENCE]

(best match ratio: 0.60)

Question: The angle (alpha) shown in the figure is referred to as... See figure (PFA-003) DoF: direction of airflow

Correct: B)

Explanation: The angle of attack (alpha, α) is the angle between the chord line and the direction of the oncoming airflow (relative wind). In the figure, the direction of airflow (DoF) vector and the chord line form angle alpha — this is the fundamental angle that determines the lift coefficient and stall behaviour. The angle of incidence is a fixed structural angle between the chord line and the aircraft's longitudinal axis (set during manufacturing), and does not change in flight.

Missing 80.21 — was Q26 in backup

(best match ratio: 0.59)

Question: In order to improve the stall characteristics of an aircraft, the wing is twisted outwards (the angle of incidence varies spanwise). This is known as...

Correct: C)

Explanation: Geometric washout means the wing is physically twisted so that the angle of incidence (and thus the local angle of attack) decreases from root to tip. This ensures that the wing root reaches the critical stall angle before the wingtips, so the ailerons (located outboard) remain effective even as the inboard section stalls. This gives the pilot aileron control during the approach to stall, enabling better roll control and safer stall behaviour. Aerodynamic washout (D) achieves the same effect through changing aerofoil sections rather than physical twist.

Missing 80.22 — was Q29 in backup

(best match ratio: 0.70)

Question: When increasing the airflow speed by a factor of 2 while keeping all other parameters constant, how does the parasite drag change approximately?

Correct: D)

Explanation: Parasite drag follows the formula Dparasite = CDp * 0.5 * rho * V^2 * S. Since dynamic pressure q = 0.5 * rho * V^2 is proportional to V^2, doubling the speed (V × 2) quadruples dynamic pressure (2^2 = 4), and thus quadruples parasite drag. This square-law relationship is fundamental: halving your speed reduces parasite drag by a factor of four, while doubling speed costs four times as much drag — which is why high-speed flight is energetically expensive.

Missing 80.23 — was Q30 in backup

(best match ratio: 0.60)

Question: The drag coefficient...

Correct: D)

Explanation: Every aerofoil has a minimum drag coefficient (CDmin) greater than zero, because skin friction and form drag exist even at the optimal low-drag AoA. The drag coefficient cannot reach zero for a real body in viscous flow — there is always some irreducible friction drag. It can increase without bound as AoA increases (especially post-stall), but has a finite positive minimum. The drag polar (CD vs CL curve) shows CDmin as the lowest point of the parabolic curve.

Missing 80.24 — was Q31 in backup

(best match ratio: 0.59)

Question: Pressure compensation on an wing occurs at the...

Correct: A)

Explanation: High pressure below the wing and low pressure above create a tendency for air to flow around the wingtip from the high-pressure lower surface to the low-pressure upper surface. This spanwise flow wraps around the wingtip, creating trailing vortices (wingtip vortices). These vortices are the physical mechanism of induced drag — they impart a downward component (downwash) to the oncoming flow, effectively reducing the local angle of attack and tilting the lift vector rearward, creating an induced drag component.

Missing 80.25 — was Q32 in backup

(best match ratio: 0.69)

Question: Which of the following options is likely to produce large induced drag?

Correct: B)

Explanation: Induced drag is proportional to CL^2 / (pi * AR * e), where AR is aspect ratio and e is Oswald efficiency factor. A small aspect ratio (short, stubby wing) produces high induced drag for a given lift coefficient because the wingtip vortices are strong relative to the span. Conversely, high aspect ratio (long, slender) wings minimise induced drag — hence gliders use very high AR wings. Low CL (option C) would reduce induced drag, not increase it.

Missing 80.26 — was Q33 in backup

(best match ratio: 0.70)

Question: Which parts of an aircraft mainly affect the generation of induced drag?

Correct: D)

Explanation: Induced drag originates from the pressure difference between the upper and lower wing surfaces causing spanwise flow that rolls up into concentrated vortices at the wingtips. The strength of these vortices — and thus the induced drag — is directly related to what happens at the wingtips. This is why winglets, raked wingtips, and elliptical planforms are used to reduce wingtip vortex strength. The fuselage, ailerons, and landing gear primarily generate parasite drag, not induced drag.

Missing 80.27 — was Q35 in backup

(best match ratio: 0.74)

Question: Pressure drag, interference drag and friction drag belong to the group of the...

Correct: A)

Explanation: Total drag = parasite drag + induced drag. Parasite drag encompasses all drag not associated with lift production: skin friction drag (viscous shear on surfaces), form/pressure drag (pressure difference between leading and trailing edges due to boundary layer separation), and interference drag (junction effects). Induced drag is separately caused by the lift generation process itself (wingtip vortices and downwash). Parasite drag increases with V^2, while induced drag decreases with V^2.

Missing 80.28 — was Q36 in backup

(best match ratio: 0.48)

Question: How do induced drag and parasite drag change with increasing airspeed during a horizontal and stable cruise flight?

Correct: B)

Explanation: In level flight, lift must equal weight, so CL decreases as speed increases (L = CL * 0.5 * rho * V^2 * S = W, thus CL = 2W / (rho * V^2 * S)). Induced drag ∝ CL^2 / V^2 ∝ 1/V^2 — it decreases with increasing speed. Parasite drag ∝ V^2 — it increases with speed. The speed where induced drag equals parasite drag is the speed of minimum total drag, which corresponds to the best lift-to-drag ratio and maximum glide range in a glider.

Missing 80.29 — was Q37 in backup

(best match ratio: 0.76)

Question: Which of the listed wing shapes has the lowest induced drag?

Correct: C)

Explanation: The elliptical wing planform produces the minimum possible induced drag for a given span and total lift. This is because it creates a perfectly elliptical spanwise lift distribution, which results in a uniform downwash across the span — the theoretical optimum. An elliptical distribution means no "wasteful" concentration of lift near the root or sudden drops near the tips. The Spitfire used an elliptical wing for this reason. Tapered (trapezoidal) wings approximate this and are easier to manufacture; rectangular wings have higher induced drag.

Missing 80.30 — was Q38 in backup

(best match ratio: 0.50)

Question: Which effect does a decreasing airspeed have on the induced drag during a horizontal and stable cruise flight?

Correct: C)

Explanation: As speed decreases in level flight, the angle of attack must increase to maintain sufficient lift (since CL must increase to compensate for lower dynamic pressure). Higher CL means stronger wingtip vortices and greater induced drag: D_induced ∝ CL^2 ∝ 1/V^2. This is why slow flight is dominated by induced drag — at very low speeds near stall, induced drag is very high and is the main component of total drag, while parasite drag is relatively small.

Missing 80.31 — was Q40 in backup

(best match ratio: 0.64)

Question: Which kinds of drag contribute to total drag?

Correct: B)

Explanation: The standard aerodynamic breakdown of total drag is: Total drag = Induced drag + Parasite drag. Induced drag arises from lift generation (wingtip vortices). Parasite drag is the collective term for all non-lift-related drag: form/pressure drag, skin friction drag, and interference drag. Options C and D list sub-components of parasite drag but omit induced drag or incorrectly combine them. Option A omits induced drag, which is a major component especially at low speeds.

Missing 80.32 — was Q41 in backup

(best match ratio: 0.50)

Question: How do lift and drag change when approaching a stall condition?

Correct: A)

Explanation: As the critical angle of attack is reached, flow begins to separate from the upper surface, starting at the trailing edge and progressing forward. Once past the critical AoA, the clean attached flow that generated lift breaks down — CL drops sharply. Simultaneously, the separated flow creates a large turbulent wake with very high pressure drag, so CD rises dramatically. The drag polar shows this clearly: the nose of the polar curves sharply as the stall condition is approached, with CL falling and CD rising.

Missing 80.33 — was Q42 in backup

(best match ratio: 0.54)

Question: In case of a stall it is important to...

Correct: B)

Explanation: Stall recovery requires reducing angle of attack below the critical value so that airflow can re-attach to the upper surface and lift can be restored. The pilot must push forward on the elevator control to lower AoA, which also allows the aircraft to accelerate (or the pilot applies power if available). Increasing AoA (A, C) deepens the stall. Reducing speed (C, D) worsens the condition. Banking (D) increases the load factor, which raises the stall speed — exactly the wrong input.

Missing 80.34 — was Q43 in backup

(best match ratio: 0.56)

Question: During a stall, the lift...

Correct: A)

Explanation: This is the definitive stall characteristic: lift collapses because boundary layer separation destroys the pressure differential that generates it, while drag rises dramatically due to the large turbulent separated wake. The CL vs. AoA curve shows CL_max at the critical angle, then a steep drop — this is the stall. The CD vs. AoA curve rises steeply through and beyond the stall. This combination (less lift, more drag) is why the stall is critical — the aircraft loses lift while simultaneously experiencing high drag that would further reduce speed.

Missing 80.35 — was Q50 in backup [HAS FIGURE/IMAGE REFERENCE]

(best match ratio: 0.76)

Question: What structural item provides lateral stability to an airplane?

Correct: A)

Explanation: Lateral (roll) stability — the tendency to return to wings-level after a roll disturbance — is primarily provided by wing dihedral (the upward angle of the wings from horizontal). When a gust rolls the aircraft, the lower wing descends and its angle of attack increases (it meets more airflow), generating more lift and creating a restoring moment back to level. The vertical tail provides directional (yaw) stability; ailerons are roll control surfaces (not stability), and the elevator controls pitch. High-wing aircraft achieve similar lateral stability through the pendulum effect of the fuselage hanging below the wings. ## BAZL/OFAC — Series 1 Questions

Subject 90 - Communications: 1 Missing Questions

Missing 90.1 — was Q14 in backup

(best match ratio: 0.58)

Question: Urgency messages are messages...

Correct: D)

Explanation: An urgency message (PAN PAN, spoken three times) concerns a serious condition that requires timely assistance but does not yet pose a grave and imminent danger. Examples include medical situations, engine problems that are controllable, or a pilot who is uncertain of position. Urgency ranks below distress (MAYDAY) but above all routine traffic in priority.

Low Confidence Matches (ratio 0.80–0.91)

These backup questions found a match but with lower confidence. They are probably matched correctly but may warrant manual review.

Subject 20 - Aircraft General Knowledge: 5 Low Confidence Matches

Subject 40 - Human Performance: 12 Low Confidence Matches

Subject 50 - Meteorology: 2 Low Confidence Matches

Subject 80 - Principles of Flight: 10 Low Confidence Matches

Subject 90 - Communications: 1 Low Confidence Matches

German vs Current EN Question Count Analysis

| Subject | DE Count | Current EN Count | Difference | Possible untranslated (DE only) | |---------|----------|------------------|------------|----------------------------------| | 10 - Air Law | 50 | 113 | -63 | Investigate | | 20 - Aircraft General Knowledge | 0 | 77 | -77 | Investigate | | 30 - Flight Performance and Planning | 30 | 89 | -59 | Investigate | | 40 - Human Performance | 50 | 111 | -61 | Investigate | | 50 - Meteorology | 50 | 182 | -132 | Investigate | | 60 - Navigation | 80 | 111 | -31 | Investigate | | 70 - Operational Procedures | 50 | 68 | -18 | Investigate | | 80 - Principles of Flight | 0 | 135 | -135 | Investigate | | 90 - Communications | 50 | 101 | -51 | Investigate |