### Q76: What does the term "aeronautical station" mean? ^t90q76 - A) A radio station of the aeronautical fixed service, on the ground or on board an aircraft, intended for the exchange of radio communications. - B) A land station of the aeronautical mobile service. In certain cases, an aeronautical station may be located on board a ship or offshore platform. - C) A radio station of the aeronautical fixed service. - D) Any radio station intended for the exchange of radio communications. **Correct: B)** > **Explanation:** An aeronautical station is defined as a land station in the aeronautical mobile service, providing two-way communication with aircraft. In certain cases, it may be located on a ship or offshore platform. Option A incorrectly refers to the fixed service (ground-to-ground) rather than the mobile service (ground-to-air). Option C is also an incorrect service designation. Option D is too broad and encompasses all radio stations regardless of service type. ### Q77: What does the abbreviation "HJ" mean? ^t90q77 - A) From sunset to sunrise. - B) From sunrise to sunset. - C) Continuous day and night service. - D) No fixed operating hours. **Correct: B)** > **Explanation:** HJ (from French "Heure de Jour") means daylight hours — from sunrise to sunset. This designation appears in AIPs and NOTAMs for facilities open only during daylight. Option A describes HN (sunset to sunrise). Option C describes H24 (continuous). Option D describes HX (no fixed hours). ### Q78: Which instructions and information must always be read back verbatim? ^t90q78 - A) Runway in use, altimeter settings, level instructions, SSR codes, heading and speed instructions. - B) Surface wind, runway in use, altimeter settings, level instructions, SSR codes. - C) Runway in use, visibility, surface wind, heading instructions, altimeter settings. - D) Surface wind, visibility, temperature, runway in use, altimeter settings, heading and speed instructions. **Correct: B)** > **Explanation:** The mandatory readback items are: runway in use, altimeter settings, level instructions, SSR codes, and heading/speed instructions. Surface wind is also included in some regional implementations. Options C and D include visibility and/or temperature, which are advisory and do not require readback. Option A is close but omits surface wind, while option B matches the ICAO standard list. ### Q79: In which message category can ATC clearances, take-off and landing clearances, and traffic information from the air traffic control service be classified? ^t90q79 - A) Messages concerning flight safety. - B) Messages concerning flight regularity. - C) Urgency messages. **Correct: A)** > **Explanation:** ATC clearances, take-off/landing instructions, and traffic information are all classified as flight safety messages, ranked third in the ICAO priority hierarchy after distress and urgency messages. Option B (regularity messages) covers administrative and logistical communications. Option C (urgency messages) specifically concerns aircraft or persons facing a serious safety condition, not routine ATC operations. ### Q80: What does the instruction "Squawk 1234" mean? ^t90q80 - A) Conduct a radio check on frequency 123.4 MHz. - B) Set code 1234 on the transponder and switch it to ON. - C) Be ready to monitor frequency 123.4 MHz. - D) Transmit briefly (1-2-3-4) for a bearing. **Correct: B)** > **Explanation:** "Squawk 1234" means the pilot must select code 1234 on the transponder and ensure it is operating. This enables radar controllers to identify the aircraft using the assigned code. Option A confuses a transponder code with a radio frequency. Option C also conflates frequency monitoring with transponder operation. Option D describes a procedure unrelated to transponder codes. ### Q81: What does the abbreviation "ATIS" stand for? ^t90q81 - A) Air Trafic Information Service - B) Automatic Terminal Information System - C) Airport Terminal Information Service - D) Automatic Terminal Information Service **Correct: D)** > **Explanation:** ATIS stands for Automatic Terminal Information Service — a continuously broadcast recording of current meteorological and operational information for an aerodrome, identified by a letter code that changes with each update. Option A misspells "Traffic" and uses "Air" rather than "Automatic." Option B uses "System" instead of "Service." Option C uses "Airport" instead of "Automatic." ### Q82: What is the call sign suffix of the Flight Information Service? ^t90q82 - A) FLIGHT CENTER - B) INFO - C) INFORMATION. - D) AERODROME. **Correct: C)** > **Explanation:** The Flight Information Service uses the call sign suffix "Information" (e.g., "Geneva Information" or "Zurich Information"). Option A ("Flight Center") is not a standard ICAO suffix. Option B ("Info") is an informal abbreviation not used as an official suffix. Option D ("Aerodrome") is not used as a call sign suffix for FIS. ### Q83: What does the term "QDR" mean? ^t90q83 - A) True heading to the station (zero wind) - B) Magnetic heading to the station (zero wind) - C) True bearing from the station - D) Magnetic bearing from the station **Correct: D)** > **Explanation:** QDR is the magnetic bearing from the station to the aircraft — the direction in which the aircraft lies as seen from the station, referenced to magnetic north. Option A describes QUJ (true heading to station). Option B describes QDM (magnetic heading to station). Option C describes QTE (true bearing from station). These Q-codes must be distinguished carefully to avoid navigation errors. ### Q84: What influences the reception quality of VHF radio? ^t90q84 - A) The twilight effect. - B) The ionosphere. - C) Atmospheric disturbances, in particular thunderstorm conditions. - D) Flight altitude and topographical conditions. **Correct: D)** > **Explanation:** VHF radio propagates by line-of-sight, so reception quality depends primarily on flight altitude (which determines how far the radio horizon extends) and topography (mountains and terrain can block signals). Option A (twilight effect) affects NDB/ADF reception, not VHF. Option B (ionosphere) affects HF sky-wave propagation, not VHF. Option C (thunderstorms) may cause some static but is not the primary factor for VHF reception quality. ### Q85: What does the term "QFE" mean? ^t90q85 - A) Altimeter setting that causes the instrument to indicate the aerodrome elevation on the ground. - B) Atmospheric pressure measured at the height of the highest obstacle on an aerodrome. - C) Atmospheric pressure at the aerodrome elevation (or runway threshold). - D) Atmospheric pressure measured at a point on the earth's surface. **Correct: C)** > **Explanation:** QFE is the atmospheric pressure at the aerodrome elevation or runway threshold. When set on the altimeter, the instrument reads zero on the ground and displays height above the aerodrome in flight. Option A describes QNH behaviour (reading aerodrome elevation on the ground). Option B is not a standard definition. Option D is too generic and could describe any surface pressure measurement. ### Q86: In the aeronautical mobile service, messages are classified by importance. What is the correct priority order? ^t90q86 - A) Distress messages, messages concerning flight safety, urgency messages. - B) Meteorological messages, radio direction-finding messages, messages concerning flight regularity. - C) Radio direction-finding messages, distress messages, urgency messages. - D) Distress messages, urgency messages, messages concerning safety. **Correct: D)** > **Explanation:** The correct ICAO priority order is: (1) Distress messages, (2) Urgency messages, (3) Flight safety messages, followed by meteorological, direction-finding, regularity, and other messages. Option A incorrectly places flight safety above urgency. Option B lists only lower-priority categories. Option C places direction-finding above distress, which is incorrect — distress always has absolute priority. ### Q87: What is the urgency signal in radiotelephony? ^t90q87 - A) PAN PAN (preferably spoken three times). - B) MAYDAY (preferably spoken three times). - C) URGENCY (preferably spoken three times). - D) ALERFA (preferably spoken three times). **Correct: A)** > **Explanation:** The radiotelephony urgency signal is "PAN PAN" spoken three times, indicating a serious condition that requires timely assistance but is not an immediate life-threatening emergency. Option B (MAYDAY) is the distress signal for grave and imminent danger. Option C ("URGENCY") is not standard phraseology. Option D (ALERFA) is an internal ATC alert phase designation, not a radiotelephony signal. ### Q88: On the readability scale, what does degree "5" mean? ^t90q88 - A) Readable intermittently. - B) Unreadable. - C) Readable, but with difficulty. - D) Perfectly readable. **Correct: D)** > **Explanation:** Readability 5 is the highest level on the ICAO scale, meaning the transmission is perfectly clear and intelligible. Option A describes readability 2 (intermittently). Option B describes readability 1 (unreadable). Option C describes readability 3 (with difficulty). The standard response is "I read you five." ### Q89: What is the name of the time system used worldwide by air traffic services and in the aeronautical fixed service? ^t90q89 - A) Local time (LT) using the 24-hour clock. - B) Coordinated Universal Time (UTC). - C) There is no particular time system, as generally only minutes are transmitted. - D) Local time using the AM and PM system. **Correct: B)** > **Explanation:** Coordinated Universal Time (UTC) is the universal time standard used by all air traffic services and aeronautical fixed services worldwide. It eliminates time zone ambiguity in international operations. Options A and D use local time, which varies by location and is not used in aeronautical communications. Option C is factually incorrect — a specific time system (UTC) is always used. ### Q90: What elements should a distress message contain? ^t90q90 - A) Aircraft callsign, departure point, position, level. - B) Aircraft callsign, position, assistance required. - C) Aircraft callsign and type, nature of the distress situation, pilot's intentions, position, level, heading. - D) Aircraft callsign, flight route, destination. **Correct: C)** > **Explanation:** A complete distress message (MAYDAY) should contain: aircraft callsign and type, the nature of the distress, the pilot's intentions, and position/level/heading — giving rescue services maximum information to coordinate assistance. Option A omits the nature of distress and pilot intentions. Option B omits aircraft type, pilot intentions, and heading. Option D omits all emergency-specific information and lists only flight plan data. ### Q91: What does "FEW" mean for cloud coverage in a METAR weather report? ^t90q91 - A) 3 to 4 eighths - B) 1 to 2 eighths - C) 8 eighths - D) 5 to 7 eighths **Correct: B)** > **Explanation:** In METAR cloud coverage reporting, FEW designates 1 to 2 oktas (eighths) of sky covered — the sparsest cloud category. Option A describes SCT (Scattered, 3-4 oktas). Option C describes OVC (Overcast, 8 oktas). Option D describes BKN (Broken, 5-7 oktas). These standardised ICAO designations ensure unambiguous weather reporting worldwide. ### Q92: What does "SCT" mean for cloud coverage in a METAR weather report? ^t90q92 - A) 1 to 2 eighths - B) 8 eighths - C) 5 to 7 eighths - D) 3 to 4 eighths **Correct: D)** > **Explanation:** SCT stands for Scattered, representing 3 to 4 oktas (eighths) of sky covered by cloud. Option A describes FEW (1-2 oktas). Option B describes OVC (Overcast, 8 oktas). Option C describes BKN (Broken, 5-7 oktas). Scattered cloud coverage does not necessarily restrict VFR flight, but pilots must check cloud base heights against applicable VFR minima. ### Q93: What does "BKN" mean for cloud coverage in a METAR weather report? ^t90q93 - A) 8 eighths - B) 3 to 4 eighths - C) 5 to 7 eighths - D) 1 to 2 eighths **Correct: C)** > **Explanation:** BKN stands for Broken, meaning 5 to 7 oktas (eighths) of the sky are covered — predominantly overcast with some gaps. Option A describes OVC (Overcast, 8 oktas). Option B describes SCT (Scattered, 3-4 oktas). Option D describes FEW (1-2 oktas). A broken layer may significantly impact VFR operations, especially if cloud bases are low. ### Q94: Which transponder code signals a radio failure? ^t90q94 - A) 7000 - B) 7500 - C) 7600 - D) 7700 **Correct: C)** > **Explanation:** Transponder code 7600 is the internationally standardised squawk for loss of radio communication (NORDO), alerting radar controllers to the communication failure. Option A (7000) is the standard VFR conspicuity code in European airspace. Option B (7500) signals unlawful interference (hijacking). Option D (7700) indicates a general emergency. These four codes must be memorised as they each trigger specific ATC responses. ### Q95: What is the correct phrase to begin a blind transmission? ^t90q95 - A) No reception - B) Transmitting blind - C) Listen - D) Blind **Correct: B)** > **Explanation:** When a pilot can transmit but cannot receive, the blind transmission must begin with the phrase "Transmitting blind" (or "Transmitting blind on [frequency]") to alert any receiving station of the one-way nature of the communication. Options A, C, and D are not standard ICAO phraseology for initiating blind transmissions. ### Q96: How many times shall a blind transmission be made? ^t90q96 - A) Three times - B) Four times - C) One time - D) Two times **Correct: C)** > **Explanation:** A blind transmission is made once on the current frequency (and optionally repeated once on the emergency frequency if appropriate). Making it multiple times would congest the frequency unnecessarily. Options A, B, and D specify excessive repetitions that are not part of standard ICAO procedure for blind transmissions. ### Q97: In what situation is it appropriate to set transponder code 7600? ^t90q97 - A) Flight into clouds - B) Emergency - C) Loss of radio - D) Hijacking **Correct: C)** > **Explanation:** Transponder code 7600 is specifically designated for loss of radio communication (NORDO), alerting radar controllers so they can provide appropriate separation and visual signals. Option A (flight into clouds) does not have a specific transponder code. Option B (emergency) requires code 7700. Option D (hijacking) requires code 7500. ### Q98: What is the correct course of action when experiencing a radio failure in class D airspace? ^t90q98 - A) The flight has to be continued according to the last clearance complying with VFR rules or the airspace has to be left by the shortest route - B) The flight has to be continued above 5000 feet complying with VFR flight rules or the airspace has to be left using a standard routing - C) The flight has to be continued according to the last clearance complying with VFR flight rules or the airspace has to be left using a standard routing - D) The flight has to be continued above 5000 feet complying with VFR flight rules or the airspace has to be left by the shortest route **Correct: A)** > **Explanation:** ICAO procedures for VFR radio failure in controlled airspace require the pilot to either continue the flight according to the last ATC clearance received while complying with VFR rules, or to leave the airspace by the shortest route. Options B and D incorrectly specify flying above 5000 feet, which is not part of the radio failure procedure. Option C incorrectly substitutes "standard routing" for "shortest route." ### Q99: Which phrase must be repeated three times before transmitting an urgency message? ^t90q99 - A) Mayday - B) Help - C) Urgent - D) Pan Pan **Correct: D)** > **Explanation:** An urgency message is preceded by "Pan Pan" spoken three times ("PAN PAN, PAN PAN, PAN PAN"). This alerts all stations on the frequency to a serious but not immediately life-threatening situation. Option A ("Mayday") is the distress signal for grave and imminent danger. Options B ("Help") and C ("Urgent") are not standard ICAO radiotelephony phrases. ### Q100: On which frequency should an initial distress message be transmitted? ^t90q100 - A) Emergency frequency - B) FIS frequency - C) Radar frequency - D) Current frequency **Correct: D)** > **Explanation:** The initial distress or urgency call should be made on the frequency currently in use, because that frequency is already being monitored by the appropriate ATC unit handling the aircraft. Switching frequencies risks losing contact and wastes critical time. Option A (emergency frequency 121.5 MHz) should be tried only if there is no response on the current frequency. Options B and C are not the correct first choice.