77 questions
Correct: C)
Explanation: EASA standardizes cockpit lever colors in gliders: red for the cabin hood (canopy) release, blue for speed brakes (airbrakes), and green for elevator trim. This color coding ensures pilots can quickly identify critical controls under stress without confusion. Options A, B, and D mix up the color-to-function assignments — for example, no standard assigns red to gear or blue to cable release.
Correct: C)
Explanation: In gliders, the EASA color coding convention assigns red to the emergency canopy release lever. This warning color is reserved for critical safety controls that allow rapid egress from the aircraft. The landing gear uses green, the ventilation control has no standardized color, and the wheel brake is not coded red.
Correct: B)
Explanation: A grid (or truss/lattice) construction uses a framework of tubes or members to carry all structural loads, with the skin serving only as a fairing — it does not contribute to structural strength. Monocoque construction (D) has the skin carrying all loads with no internal framework. Semi-monocoque (A) uses both a frame and a load-bearing skin. Honeycomb (C) is a core material used in sandwich structures, not a fuselage type.
Correct: C)
Explanation: The primary longitudinal and transverse structural members of a traditional fuselage are frames (also called formers or bulkheads — running circumferentially) and stringers (running lengthwise). Together they form the skeleton over which the skin is attached. Covers and ribs are wing components, and "girders" is not standard fuselage terminology. The simplicity of frames + stringers makes C the correct fundamental answer.
Correct: D)
Explanation: Semi-monocoque construction uses both an internal framework (frames and stringers) AND a skin that actively bears structural loads (tension, compression, shear). This is the most common modern aircraft fuselage design. Pure monocoque relies entirely on the skin with no internal structure. Grid construction (A) has a non-load-bearing skin. Honeycomb (B) is a material/sandwich type, not a fuselage structural concept.
Correct: C)
Explanation: Honeycomb elements are characteristic of modern composite construction. The honeycomb structure serves as a lightweight core in composite sandwich panels, typically with glass fiber or carbon fiber skins. This type of construction provides an excellent strength-to-weight ratio, typical of today's high-performance gliders. Wood, metal or biplane configurations do not use this core material.
Correct: C)
Explanation: The tail assembly (empennage) consists of the horizontal stabilizer (with elevator) and the vertical stabilizer (with rudder). These are the two major structural groups. Ailerons (A, B) are located on the wings, not the tail. Steering wheel and pedals (D) are cockpit controls, not aircraft structure. The empennage provides pitch and yaw stability and control.
Correct: A)
Explanation: When the horizontal stabilizer (stabilizer and elevator) is mounted at the top of the vertical fin, the configuration forms a "T" when viewed from the front — hence the name T-tail. This is a common configuration on modern gliders such as the Discus B, as it places the horizontal stabilizer in undisturbed air above the wing wake. A cruciform tail places the stabilizer at mid-height; a V-tail combines both surfaces into two angled surfaces.
Correct: C)
Explanation: The fixed horizontal and vertical stabilizers of the tail unit have the primary purpose of stabilizing the glider — they provide static stability in pitch and yaw, automatically restoring the aircraft to its equilibrium attitude after a disturbance. Steering (A) is accomplished by the movable control surfaces (elevator and rudder). Trimming the control forces (B, D) is the role of the trim tab, not the fixed stabilizers.
Correct: D)
Explanation: A sandwich structure uses two thin, stiff face sheets (typically CFRP, glass fiber, or aluminum) bonded to a lightweight core material (foam, balsa wood, or honeycomb). The thin skins carry bending loads while the light core resists shear and keeps the skins separated, providing exceptional stiffness-to-weight ratio. A heavy core (A, B) would defeat the purpose of weight efficiency. Thick layers (A, C) would add unnecessary mass.
Correct: C)
Explanation: Sandwich structures excel at combining low weight with high stiffness, stability, and strength — the ideal combination for aerospace applications. By spacing two stiff face sheets apart with a lightweight core, the structure achieves very high bending stiffness (proportional to the cube of thickness). Temperature durability (A, D) is not a primary advantage — most cores (foam, honeycomb) are temperature-sensitive. Good formability (A, B) is limited compared to single-material sheets.
Correct: C)
Explanation: Ribs are the chordwise structural members that define the airfoil cross-section shape of the wing. They run perpendicular to the spar and give the wing its characteristic profile. The spar (A) is the main spanwise load-bearing beam. Planking/skin (B) covers the structure but follows the shape set by the ribs. The wingtip (D) is the outer end of the wing, not a profile-shaping element.
Correct: D)
Explanation: Wing thickness is defined as the maximum perpendicular distance between the upper and lower wing surfaces, measured at the thickest part of the cross-section (airfoil). This point is typically located between 20–30% of the chord from the leading edge. The thinnest part (A) or outer tip (B) would give a smaller, less meaningful measurement, and the inner root (C) describes spanwise location rather than airfoil thickness.
Correct: D)
Explanation: A torsion-stiffened leading edge is a structural design feature in which the leading edge of the wing (from the leading edge to the main spar) is planked (covered) on both upper and lower surfaces, creating a closed-section D-box that resists torsional (twisting) loads. This is not a spar component (B), not merely a shape descriptor (A), and not a reference to a torsion moment distribution point (C).
Correct: C)
Explanation: Carbon fiber reinforced plastic (CFRP) has an exceptional strength-to-weight ratio — higher tensile strength than steel at a fraction of the weight. This is why modern high-performance gliders are predominantly CFRP construction. Aluminium (B) is strong and lightweight but significantly weaker than CFRP. Magnesium (D) is even lighter than aluminum but lower in strength. Wood (A) has good specific strength but is the weakest in absolute terms of those listed.
Correct: A)
Explanation: The trim system adjusts the elevator trim tab (or spring trim) to hold a desired pitch attitude without continuous pilot input force on the stick. This reduces pilot workload on long final glides or thermalling. Ailerons (B) and rudder (D) are not trimmed by the standard glider trim lever. Adverse yaw (C) is a roll/yaw coupling phenomenon addressed by rudder coordination, not trim.
Correct: C)
Explanation: The load factor n = Lift / Weight. At straight and level flight, n = 1 (1g). In a banked turn or pull-up maneuver, lift must exceed weight to maintain altitude, increasing n above 1. For example, in a 60° bank, n = 2 (2g). Load factor is critical for structural design — gliders have maximum positive and negative g-limits that must not be exceeded to prevent structural failure.
Correct: C)
Explanation: Exceeding maneuvering speed (VA) in turbulent/gusty conditions can cause structural damage because gusts apply sudden load factors that may exceed the aircraft's design limit load. VA is defined as the speed at which a full control deflection or a maximum gust will not exceed the structural limit. Stall (A) itself does not damage the structure. Low airspeed (B) and neutralizing stick forces (D) do not create damaging structural loads.
Correct: C)
Explanation: Balanced control surfaces (mass-balanced) are designed primarily to eliminate the risk of flutter — a potentially catastrophic aeroelastic oscillatory phenomenon that can occur at high speeds. By placing balance weights forward of the hinge axis, the manufacturer moves the center of gravity of the control surface to its pivot axis, eliminating the coupling between aerodynamic forces and structural oscillations. Reduction of control forces (D) is a secondary objective, not the primary reason for balancing.
Correct: C)
Explanation: Winglets are upward (or downward) curving extensions at the wingtip that reduce induced drag by weakening the wingtip vortex — the main source of induced drag on a finite wing. They do not primarily increase aspect ratio efficiency (D — though functionally similar, they are a different mechanism), are not specifically for high-speed performance (B), and do not increase lift or turning agility (A).
Correct: B)
Explanation: An aircraft moves about three principal axes: the longitudinal axis (nose to tail — roll), the lateral axis (wingtip to wingtip — pitch), and the vertical axis (top to bottom — yaw). All three pass through the aircraft's center of gravity. Option C uses mathematical labels but omits their aviation names. Options A and D invent a non-existent fourth axis.
Correct: D)
Explanation: The ailerons control roll — rotation around the longitudinal axis (the axis running nose to tail). When one aileron deflects up and the other down, differential lift is created, rolling the aircraft. The elevator (A) controls pitch (rotation around the lateral axis). The rudder (C) controls yaw (rotation around the vertical axis). The trim tab (B) is a secondary control that modifies control forces, not a primary roll initiator.
Correct: B)
Explanation: When the stick is moved to the left, the left aileron deflects down (increasing lift on the left wing) and the right aileron moves up (reducing lift on the right wing). This produces a roll to the left. The direction of the stick indicates the desired direction of roll, not the direction in which the aileron on the same side moves.
Correct: C)
Explanation: Small piston aircraft and gliders use direct mechanical linkages — push-pull rods and/or steel control cables — to transmit pilot input directly to the control surfaces. This is simple, lightweight, and reliable with no power source required. Hydraulic systems (B, D) are used on larger aircraft. Fly-by-wire (A) is used on modern airliners and military aircraft where electrical signals replace mechanical connections.
Correct: C)
Explanation: Mechanical brake systems in gliders transmit braking force via a system of cables and pushrods (linkages) — without hydraulic fluid or electricity. This system is simple, lightweight and reliable. Hydraulic brakes (A) are used on heavier aircraft requiring greater braking force. Pneumatic (D) and electric (B) systems are not used in standard mechanical brake systems in gliders.
Correct: A)
Explanation: The primary effect of left rudder is yaw to the left — the nose swings left around the vertical axis. The secondary effect is a roll to the left: as the nose yaws left, the right wing moves forward and generates more lift, while the left wing slows and generates less, causing the aircraft to bank left. This coupling between yaw and roll is an important aerodynamic relationship for coordinating turns in gliders.
Correct: D)
Explanation: Pulling back on the stick deflects the elevator upward. This increases the downward aerodynamic force on the tail (the horizontal stabilizer + elevator generate a downward lift force). With the tail pushed down, the nose pivots up around the lateral axis. This seems counterintuitive but is correct: the tail goes down, nose goes up. Option B incorrectly states the tail force direction as upward.
Correct: B)
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 D mixes primary and secondary controls together. Option C is too broad — not all movable parts are primary controls. Flaps, trim tabs, and speedbrakes are secondary controls.
Correct: C)
Explanation: Secondary flight controls (trim tabs, flaps, speedbrakes, slats) serve to optimize performance and reduce pilot workload — they are not essential for basic flight control. Trim reduces stick forces for hands-off flight; flaps improve low-speed lift. Option B describes primary controls. Option A is wrong — secondary controls are not backups for primary controls. Option D is too narrow, applying only part of the secondary control function.
Correct: C)
Explanation: Trim is used to neutralize control forces so the pilot does not need to continuously push or pull the stick to maintain a desired flight attitude. By adjusting the trim, the pilot can fly hands-off at a set speed and attitude. Trim cannot move the center of gravity (B) — that requires shifting mass. Trim does not lock controls (A) or increase adverse yaw (D), which is a side-effect of aileron use.
Correct: B)
Explanation: Moving the trim lever aft (back) commands a nose-up trim. The trim tab deflects downward — the aerodynamic force on the tab then pushes the elevator upward (floating up). The elevated elevator deflects the tail downward and raises the nose. Trim tabs always move opposite to the elevator: when the trim tab goes down, the elevator goes up, and vice versa (anti-servo tab principle).
Correct: B)
Explanation: To trim nose up, the elevator must be held in an upward position. The trim tab moves down to achieve this: the downward tab creates an aerodynamic force that pushes the elevator up and holds it there without pilot input. This is the fundamental inverse relationship between trim tab and elevator deflection. CG position (A) affects trim authority but not the direction of tab movement. Rudder (D) is irrelevant to elevator trim.
Correct: B)
Explanation: The Pitot-static system measures two types of air pressure: total pressure (measured by the Pitot tube, which captures both static and dynamic pressure) and static pressure (measured by the static port, sensing ambient atmospheric pressure). These pressures are fed to the ASI, altimeter, and VSI. Preventing static buildup (A) or icing (D) are operational concerns, not the system's purpose. The ASI reading at rest on the ground is a consequence of zero dynamic pressure, not a calibration function.
Correct: D)
Explanation: The Pitot tube faces into the airflow and measures total pressure (also called stagnation pressure), which is the sum of static pressure and dynamic pressure (q = ½ρv²). It does not measure dynamic pressure alone (C) — that is derived by subtracting static pressure from total pressure in the ASI. Static pressure (A) is measured by the separate static port. Cabin pressure (B) is unrelated to the Pitot-static system.
Correct: B)
Explanation: The small flush-mounted orifices on the fuselage are the static pressure ports of the Pitot-static system. They sense the ambient atmospheric pressure (static pressure) and route it via internal flexible tubes to the altimeter, variometer and airspeed indicator. Their position on the fuselage is chosen to minimize local aerodynamic disturbances. They do not serve for ventilation (A, C) or temperature measurement (D).
Correct: D)
Explanation: The airspeed indicator is the only instrument connected to the Pitot tube (which supplies total pressure). The altimeter (A) and vertical speed indicator (B) are connected only to the static port — they measure changes in static pressure for altitude and climb/descent rate. The direct-reading compass (C) is a self-contained magnetic instrument with no connection to the Pitot-static system.
Correct: B)
Explanation: The static port supplies static pressure to three instruments: the altimeter (measures static pressure to indicate altitude), the vertical speed indicator (compares current static pressure to a stored reference), and the airspeed indicator (uses static pressure in combination with Pitot total pressure). The direct-reading compass is a self-contained magnetic instrument requiring no pneumatic input. The slip indicator is a gravity/inertial instrument, not connected to the static system.
Correct: C)
Explanation: Static pressure is the ambient atmospheric pressure of undisturbed air — the pressure exerted by the air molecules in all directions, independent of airflow velocity. It is measured by flush static ports on the aircraft's fuselage, positioned to minimize dynamic pressure effects. Cabin pressure (B) is a separate, regulated pressure. The Pitot tube (A) senses total pressure, not static pressure. Option D partially describes static pressure but is imprecise — it is the pressure of the air at rest or in undisturbed flow.
Correct: D)
Explanation: Static pressure decreases with increasing altitude in a predictable manner (in the ISA model). The altimeter measures static pressure from the static port and converts this pressure to an altitude reading using calibrated aneroid capsules. Dynamic pressure (C) depends on airspeed and is used by the ASI. Total pressure (A) is static + dynamic, used by the Pitot tube. Differential pressure (B) is the difference between total and static — that is what drives the ASI, not the altimeter.
Correct: C)
Explanation: The altimeter subscale (Kollsman window) allows the pilot to set a reference pressure (QNH, QFE, or 1013.25 hPa) so the altimeter reads altitude relative to that reference datum — sea level, airfield elevation, or the standard pressure surface for flight levels respectively. It does not correct for system errors (A), temperature errors (D — that requires a temperature correction calculation), or directly set the transponder (B).
Correct: B)
Explanation: QFE is the actual barometric pressure measured at a specific reference point, typically the airfield or runway threshold elevation. When QFE is set in the altimeter subscale, the altimeter reads zero on the runway — showing height above the airfield. QNH (not QFE) is the pressure adjusted to mean sea level (C). Flight levels use 1013.25 hPa (A). A magnetic bearing to a station (D) is QDM/QDR terminology, unrelated to altimetry.
Correct: D)
Explanation: QFE is the atmospheric pressure at aerodrome elevation. When an altimeter is set to QFE, it reads zero on the ground at the aerodrome and shows height above that aerodrome during flight. It does not show altitude above MSL (B — that would be QNH), the aerodrome elevation itself (C), or pressure altitude (A — that requires setting 1013.25 hPa).
Correct: A)
Explanation: If you set a higher pressure than the actual QNH, the altimeter "thinks" the reference pressure is higher, so it reads a higher altitude than your actual altitude — you are closer to the ground than the instrument shows. This is the dangerous scenario: you believe you have terrain clearance but you may not. The memory aid is "High to Low, look out below" — setting too high a pressure gives an over-reading.
Correct: D)
Explanation: When the altimeter is set to a higher reference pressure (without any change in actual pressure), the altimeter indicates a higher altitude — the reading increases. The mechanism: by increasing the reference pressure, the instrument "believes" it is at a lower altitude, so it adjusts its reading upward to match the actual pressure. This is a fundamental principle: setting a higher pressure = higher altitude reading.
Correct: D)
Explanation: The altimeter measures atmospheric pressure and converts it to altitude using the ISA pressure-altitude relationship. Increasing the QNH setting by 10 hPa causes the altimeter to indicate approximately 80 m more altitude (since 1 hPa corresponds to roughly 8 m at sea level). The reading is not zero (A), not less (B), and is not dependent on the QNH value itself (C) — the conversion factor is fixed by the ISA model.
Correct: B)
Explanation: The altimeter assumes ISA standard temperature to convert pressure differences to altitude. In colder-than-standard air, the air is denser and the pressure decreases more rapidly with altitude than ISA predicts. The altimeter over-reads — it indicates a higher altitude than the aircraft's actual altitude. The aircraft is closer to the ground than shown. The memory aid: "Cold air, you're lower than you think." The altimeter subscale (C) only sets pressure datum, not temperature correction.
Correct: C)
Explanation: In cold air, the atmosphere is compressed — air is denser and pressure falls faster with altitude than the ISA model assumes. The altimeter (which uses ISA pressure gradient) therefore over-reads: it shows a higher altitude than the aircraft's actual (true) altitude. The aircraft is lower in reality than the altimeter indicates. This is a significant safety concern near terrain. "High to low (pressure or temperature) — look out below."
Correct: B)
Explanation: When both the actual pressure (set correctly via QNH) and actual temperature exactly match ISA standard conditions, the altimeter's assumptions are perfectly valid. No temperature or pressure correction is needed, so the indicated altitude equals the true altitude (actual height above MSL). This is the ideal baseline condition. Any deviation in pressure or temperature from ISA will introduce errors.
Correct: C)
Explanation: A flight level (FL) is a pressure altitude expressed in hundreds of feet with the altimeter subscale set to 1013.25 hPa (standard pressure). FL100 = 10,000 ft on the standard pressure setting. All aircraft above the transition altitude use this common datum, ensuring separation between aircraft regardless of local QNH variations. True altitude (A) is the actual height above MSL. Altitude above ground (D) is height AGL. Density altitude (B) relates to performance calculations.
Correct: B)
Explanation: True altitude is the actual geometric height of the aircraft above mean sea level (MSL), corrected for non-standard temperature deviations from ISA. It differs from indicated altitude (which assumes ISA) and pressure altitude (referenced to 1013.25 hPa). It is referenced to MSL, not AGL (eliminating A and C). Option D is partially correct but incomplete — true altitude is the real MSL height, not just a pressure altitude with a temperature correction applied.
Correct: C)
Explanation: Hysteresis error in the altimeter occurs because the aneroid capsules (bellows) that expand and contract with pressure changes have a mechanical lag — they do not return to exactly the same position when pressure is restored to a previous value. This means the altimeter may give slightly different readings at the same altitude when climbing versus descending. The compass, tachometer, and VSI do not use elastic aneroid capsules in the same manner and are not subject to this specific error.
Correct: B)
Explanation: The altimeter's reference pressure (subscale) must be set before every flight to the correct local QNH/QFE so that the altimeter reads the correct altitude or height. During cross-country flights, QNH changes as the pilot moves between pressure regions, so updates are required when crossing into new altimeter setting regions. Monthly (A) or only after maintenance (D) settings would result in significant altitude errors.
Correct: A)
Explanation: The vertical speed indicator (VSI) works by comparing the current static pressure (from the static port) against a reference pressure stored in a sealed reservoir (or capsule with a calibrated leak). When climbing, static pressure drops faster than the reservoir bleeds down, creating a pressure difference that indicates a climb rate. The calibrated leak rate determines the instrument's response. Option C describes an accelerometer. Option B describes the ASI. Option D describes a simple pressure gauge, not a rate instrument.
Correct: C)
Explanation: If the static pressure port is blocked by ice, the static pressure transmitted to the variometer remains constant — the internal reservoir and the measuring chamber are both at the same frozen pressure. The variometer no longer detects any pressure variation and therefore reads zero, regardless of the aircraft's actual trajectory (climb or descent). Unlike the altimeter which freezes at its last value, the variometer reads zero because the pressure difference between its two sides is nil.
Correct: A)
Explanation: A total energy compensated vertical speed indicator (TE-VSI) uses a specially shaped nozzle (TE probe) to cancel out changes in indicated climb/sink caused by changes in airspeed (energy exchange). If the compensating tank is too large, the compensation overcorrects and the instrument indicates a sink rate that is larger than the actual sink rate — i.e., too high a reading. A too-large tank does not cause mechanical overload (C), no indication (B), or under-reading (D).
Correct: B)
Explanation: A total-energy compensated variometer (TE variometer) cancels the effect of the pilot's control inputs on indicated vertical speed by accounting for changes in kinetic energy. During a steady (stationary) glide with no vertical air movement, it correctly shows the vertical speed of the airmass being flown through (i.e., zero in still air, or the actual thermal/sink value). It does not show the glider's speed through the airmass uncompensated (A), the combined glider plus airmass movement (C), or a subtracted value (D).
Correct: B)
Explanation: A compensated variometer (total energy compensated) eliminates false readings caused by elevator movements (pull-ups, dives). It shows the true rate of climb/sink of the air mass, independent of maneuvers.
Correct: C)
Explanation: The ASI works by comparing total pressure (from the Pitot tube) against static pressure (from the static port). The difference between them is dynamic pressure (q = ½ρv²), which is proportional to airspeed squared. The ASI capsule expands proportionally to this pressure difference and drives the needle. Option B is incorrect because the Pitot tube measures total pressure, not dynamic pressure alone. Option A has no aerodynamic significance for airspeed measurement.
Correct: D)
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 affects the aircraft's ground speed (which would be 70 kt) 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.
Correct: B)
Explanation: The airspeed indicator measures IAS (Indicated Airspeed), which is derived from dynamic pressure. At lower air density (hot day, high altitude), TAS is higher than IAS for the same dynamic pressure. The aerodynamic behaviour of the wing (lift, stall) depends on dynamic pressure (and thus IAS), not on TAS. Therefore stall occurs at the same IAS regardless of density. The approach should be flown at the same IAS as always.
Correct: D)
Explanation: Red lines (radial marks) on aircraft instrument displays indicate never-exceed limits — the absolute operational limits that must not be exceeded. On the ASI, the red line marks VNE (never-exceed speed). Yellow arcs indicate caution areas (B) — the range between maneuvering speed and VNE where flight is only permitted in smooth air. Green arcs show normal operating range (C). There is no standard "recommended areas" marking (A).
Correct: C)
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). Option A describes VFE (flap extension speed). Option D describes no standard speed marking.
Correct: B)
Explanation: VNE (Velocity Never Exceed) is an absolute limit that must never be exceeded, under any circumstances and by any percentage whatsoever. Beyond this speed, the risks of aeroelastic flutter, structural failure or loss of control are real and immediate. Unlike other operational limits that allow temporary tolerances, VNE is categorically inviolable.
Correct: D)
Explanation: The yellow arc on an airspeed indicator marks the caution speed range between VNO and VNE. Flight in this range is only permitted in smooth air with no gusts, because at these higher speeds turbulence-induced loads could exceed structural limits. It does not indicate a flap/brake limitation range (C), best glide speed (B), or towing speed (A).
Correct: C)
Explanation: The green arc on a glider's ASI indicates the normal operating speed range usable in turbulence (maneuvering speed range). This is the speed range where the aircraft can be maneuvered with full control deflection.
Correct: C)
Explanation: The white arc on a glider's ASI indicates the flap operating speed range. Outside this arc, flaps must not be used.
Correct: C)
Explanation: The yellow triangle on a glider's ASI indicates the recommended approach speed for landing in normal conditions. It is the reference speed for approach.
Correct: D)
Explanation: Deviation is the compass error caused by the aircraft's own magnetic fields (from metal structures, electrical equipment, engines). It is measured in degrees and varies with aircraft heading — it is recorded on a deviation card in the cockpit. Variation (C, also called declination B) is the angle between true north and magnetic north — an earth-based error, not caused by the aircraft. Inclination (A) is the vertical dip of the earth's magnetic field, which causes turning and acceleration errors.
Correct: D)
Explanation: The magnetic compass is affected by deviation (from the aircraft's own magnetic field), turning errors (caused by magnetic dip/inclination — the compass card tilts and reads incorrectly during turns in the northern hemisphere), and acceleration errors (the compass reads incorrectly during speed changes on east/west headings). Variation/declination (A, B) is a geographic difference between true and magnetic north that applies to all magnetic compasses equally and is not an "error" in the same sense — it is a known, chartable quantity.
Correct: C)
Explanation: The dip error (also called northerly turning error or acceleration error) in a direct-reading magnetic compass is caused by the inclination of the Earth's magnetic field lines, which dip downward toward the magnetic poles at an angle to the horizontal. This causes the compass card's pivot point and the magnet system to be offset, leading to errors particularly during turns and accelerations. Temperature variations (A), deviation (B — a different compass error caused by onboard magnetic fields), and acceleration per se (D) are separate effects; the root physical cause of dip error is the field line inclination.
Correct: D)
Explanation: Magnetic inclination (dip) is the angle between the Earth's total magnetic field vector and the local horizontal plane. At the magnetic equator, field lines are horizontal (0° dip); at the poles, they are vertical (90° dip). Deviation (B) is caused by onboard magnetic interference. Variation/declination (C) is the angle between magnetic and geographic north. Option A describes aircraft heading relative to true north.
Correct: C)
Explanation: The compass must be compensated for errors caused by the metallic parts of the aircraft and electromagnetic fields from electrical equipment (magnetic deviation). This is not declination (A, which is geographical) nor turning errors (B), nor acceleration errors (D).
Correct: C)
Explanation: The magnetic compass is reliable up to approximately 30° of bank angle. Beyond this, turning errors and northerly turning errors become significant and readings are unreliable.
Correct: D)
Explanation: The radio produces a magnetic field when operating. If the compass and the radio are installed too close to each other, this stray magnetic field disturbs the compass and causes it to deviate systematically in the same direction. This is why regulations impose minimum separation distances between the magnetic compass and any electrical equipment on board. This phenomenon is a form of electromagnetic deviation.
Correct: D)
Explanation: The shortest turn from 270° to 360° is a right turn (northward, through west-to-north). In the northern hemisphere, the compass leads during turns toward north — it reads ahead of the actual heading. Therefore the pilot must stop the turn early, before the compass reaches 360°. A rule of thumb: stop 30° before the target heading when turning to north. 360° − 30° = 330°. If you wait until the compass shows 360°, you will have overshot.
Correct: B)
Explanation: The shortest turn from 030° to 180° is a right turn (clockwise through east and south). When turning toward southerly headings in the northern hemisphere, the compass lags — it under-reads the actual heading, showing a smaller heading than the aircraft has actually turned to. Therefore, the pilot must overshoot past the target — continue turning until the compass reads approximately 180° + 30° = 210°. The compass will then be lagging, showing 210° when the aircraft is actually on approximately 180°.
Correct: C)
Explanation: The airspeed indicator, altimeter, and vertical speed indicator are all connected to the static pressure port. If the static pressure system is blocked (e.g., by ice, water, or a cover left on), all three instruments will give erroneous readings simultaneously. A blocked Pitot tube (A) would affect only the airspeed indicator. A leaking compensating vessel (B) affects only the VSI. An electrical failure (D) does not affect these purely pneumatic instruments.
