### Q126: Where can information about maximum permissible airspeeds be found? ^t20q126 - A) POH, approach chart, vertical speed indicator - B) POH, cockpit panel, airspeed indicator - C) POH and posting in briefing room - D) Airspeed indicator, cockpit panel and AIP part ENR **Correct: B)** > **Explanation:** Maximum permissible airspeeds (VNE, VNO, etc.) are published in the Pilot's Operating Handbook (POH/AFM), displayed on the cockpit instrument panel (placard), and indicated on the airspeed indicator by the red line (VNE) and arc markings. The AIP ENR (A) does not contain aircraft-specific speed limitations. Approach charts and VSI (B) do not show speed limits. The briefing room posting (C) is informal and not authoritative. ### Q127: The airspeed indicator is unserviceable. The aircraft may only be operated... ^t20q127 - A) When the airspeed indicator is fully functional again. - B) If no maintenance organisation is available. - C) When a GPS with speed indication is used during flight. - D) If only aerodrome patterns are flown. **Correct: A)** > **Explanation:** The airspeed indicator is a required instrument for safe flight; without it a pilot cannot determine safe operating speeds, stall speed, or structural speed limits. An inoperative airspeed indicator means the aircraft must remain on the ground until the instrument is serviceable. No exception exists for local aerodrome patterns (B) or GPS substitute (D — GPS ground speed is not equivalent to IAS for aerodynamic purposes). Absence of maintenance (A) is irrelevant to the operational requirement. ### Q128: During a left turn, the yaw string deflects to the left. What rudder input can centre the string? ^t20q128 - A) More bank, less rudder in turn direction - B) Less bank, less rudder in turn direction - C) Less bank, more rudder in turn direction - D) More bank, more rudder in turn direction **Correct: A)** > **Explanation:** During a left turn, a yaw string deflecting to the left indicates the aircraft is slipping into the turn (too much bank relative to rudder input). To centre the string in a slip, the pilot needs to increase bank to steepen the turn and reduce rudder (less rudder in the turn direction). This is opposite to correcting a skid. Options B, C, and D use incorrect combinations for correcting a slip in a left turn. ### Q129: What is the purpose of winglets? ^t20q129 - A) Increase gliding performance at high speed. - B) Increase of lift and turning manoeuvering capabilities. - C) Reduction of induced drag. - D) Increase efficiency of aspect ratio. **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 (A — though functionally similar, they are a different mechanism), are not specifically for high-speed performance (C), and do not increase lift or turning agility (D). ### Q130: What does dynamic pressure depend directly on? ^t20q130 - A) Air pressure and air temperature - B) Air density and lift coefficient - C) Air density and airflow speed squared - D) Lift and drag coefficient **Correct: C)** > **Explanation:** Dynamic pressure (q) is defined by Bernoulli's equation as q = ½ρv², where ρ is air density and v is airflow speed. Dynamic pressure depends directly on air density and the square of velocity. Lift and drag coefficients (A) are aerodynamic effects that depend on dynamic pressure, not the other way around. Air pressure and temperature (D) influence density indirectly but are not the direct parameters in the formula. ### Q131: The airspeed indicator, altimeter and vertical speed indicator all display incorrect readings simultaneously. What could be the cause? ^t20q131 - A) Failure of the electrical system. - B) Leakage in compensation vessel. - C) Blocking of static pressure lines. - D) Blocking of pitot tube. **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 (C) 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. ### Q132: When is it necessary to adjust the pressure on the altimeter's reference scale? ^t20q132 - A) Every day before the first flight - B) Before every flight and during cross country flights - C) Once a month before flight operation - D) After maintenance has been finished **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 (C) or only after maintenance (A) settings would result in significant altitude errors. ### Q133: The term "inclination" is defined as... ^t20q133 - A) Angle between magnetic and true north - B) Angle between the airplane's longitudinal axis and true north. - C) Deviation induced by electrical fields. - D) Angle between Earth's magnetic field lines and horizontal plane. **Correct: D)** > **Explanation:** Magnetic inclination (dip) is the angle between the Earth's magnetic field vector and the horizontal plane at any given location. It is 0° at the magnetic equator and 90° at the magnetic poles. Deviation (A) is the error caused by magnetic fields within the aircraft. Magnetic variation/declination (B) is the angle between magnetic and true north. Option D describes aircraft heading, which is unrelated. ### Q134: As air density decreases, the airflow speed at stall increases (TAS) and vice versa. How should a final approach be flown on a hot summer day? ^t20q134 - A) With decreased speed indication (IAS) - B) With additional speed according to the POH - C) With increased speed indication (IAS) - D) With unchanged speed indication (IAS) **Correct: D)** > **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 (B). Adding speed (D) or reducing IAS (C) based on temperature alone is not correct for stall margin management with IAS. ### Q135: The load factor n describes the relationship between... ^t20q135 - A) Thrust and drag. - B) Drag and lift - C) Weight and thrust. - D) Lift and weight **Correct: D)** > **Explanation:** The load factor (n) is the ratio of the aerodynamic lift acting on the aircraft to the aircraft's weight: n = L/W. In level unaccelerated flight, n = 1. In turns or pull-ups, n increases. It does not describe weight/thrust (A), drag/lift (B), or thrust/drag (D) relationships. ### Q136: The term static pressure is defined as the pressure... ^t20q136 - A) Sensed by the pitot tube. - B) Inside the airplane cabin. - C) Resulting from orderly flow of air particles. - D) Of undisturbed airflow. **Correct: D)** > **Explanation:** Static pressure is the pressure of the undisturbed ambient airmass — the atmospheric pressure acting equally in all directions at a given altitude. It is sensed through flush static ports on the fuselage skin. It is not the cabin pressure (A), not related to orderly flow direction (C — that is dynamic pressure), and is not sensed by the pitot tube alone (D — the pitot senses total pressure). ### Q137: The term inclination is defined as... ^t20q137 - A) Angle between the airplane's longitudinal axis and true north. - B) Deviation induced by electrical fields. - C) Angle between Earth's magnetic field lines and horizontal plane. - D) Angle between magnetic and true north. **Correct: C)** > **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 (A) is caused by onboard magnetic interference. Variation/declination (B) is the angle between magnetic and geographic north. Option D describes aircraft heading relative to true north.