Free Practice Questions for Iran CAO ATPL Theory

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Sample Iran CAO ATPL Theory Practice Questions

Try these sample questions to review concepts for the Iran CAO ATPL Theory exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Under the 1944 Chicago Convention on International Civil Aviation, what is the definition of the 'Fifth Freedom of the Air'?

A.The right to fly into the territory of another state, take on commercial passengers and cargo, and carry them to the territory of a third state

B.The right to overfly another sovereign state's territory without landing

C.The right to land in another state for purely non-traffic technical purposes, such as refueling

D.The right to transport commercial traffic entirely within the borders of another state (cabotage)

Explanation: The Fifth Freedom of the Air grants an airline the commercial right to operate between two foreign nations on a flight that originates or terminates in the airline's own home state (e.g., an airline flying from State A to State B, picking up passengers in B, and flying onward to State C).

2Under CAO.IRI Part-FCL (FCL.500) and ICAO Annex 1, what is the minimum age required for the issuance of an Airline Transport Pilot License (ATPL)?

A.21 years of age

B.18 years of age

C.23 years of age

D.25 years of age

Explanation: An applicant for an Airline Transport Pilot License must be at least 21 years of age on the date of official license issuance.

3What total flight time experience is mandated by CAO.IRI Part-FCL for the unrestricted issuance of an ATPL(A)?

A.At least 1,500 hours of flight time in aeroplanes, including at least 500 hours in multi-pilot operations and 100 hours of night flight

B.1,000 hours of flight time with 250 hours as pilot-in-command

C.2,500 hours of total flight time with 1,000 hours in jet aircraft

D.1,200 hours of total flight time with 50 hours of instrument flight

Explanation: CAO.IRI Part-FCL (FCL.510.A) mandates that an applicant for an ATPL(A) must have completed at least 1,500 hours of flight time in aeroplanes, including at least 500 hours in multi-pilot operations on aeroplanes, 100 hours of night flight as PIC or co-pilot, 200 hours of cross-country flight time, and 75 hours of instrument time.

4In a Full Authority Digital Engine Control (FADEC) system on a commercial high-bypass turbofan, what happens if the active electronic engine control (EEC) channel suffers an internal processor fault?

A.The system automatically switches seamlessly to the redundant secondary EEC channel without engine surge or thrust disruption

B.The engine immediately shuts down and dumps fuel through the jettison nozzles

C.The hydromechanical fuel unit freezes at maximum takeoff thrust permanently

D.The engine reverts to manual mechanical throttle cable linkages to the cockpit

Explanation: Modern FADEC architectures feature dual-channel electronic engine controllers (EEC / ECU). Both channels are identical and independent. If the active controlling channel detects an internal fault or sensor loss, control transfers automatically and seamlessly to the standby channel with no disruption to engine operation.

5Why do modern high-bypass turbofan engines incorporate Active Clearance Control (ACC) around the turbine casing?

A.To modulate cooling airflow around the turbine casing to match thermal expansion between casing and blade tips, minimizing tip clearance leakage and improving specific fuel consumption

B.To control the lateral separation distance between the engine nacelle and the fuselage

C.To adjust the gap between the propeller blades and the runway surface during takeoff

D.To dynamically trim the elevator angle during high-thrust go-around maneuvers

Explanation: High-pressure and low-pressure turbine casings expand at different thermal rates than spinning turbine rotor discs and blades. Active Clearance Control (ACC) directs cooling air (from fan or compressor bleed) onto the external turbine casing, shrinking or expanding the casing to maintain microscopic tip clearances, dramatically reducing aerodynamic gas leakage and boosting thermal efficiency.

6In a split-bus commercial jet electrical system, what is the function of the Bus Tie Breaker (BTB)?

A.To connect the left and right AC electrical buses together if one engine generator fails, allowing the remaining generator or APU to power both buses

B.To permanently isolate the main battery from the DC emergency bus during flight

C.To step down 115V AC electricity into 28V DC charging current

D.To ground electrostatic static charges into the engine exhaust stream

Explanation: Under normal operations, the left and right AC buses operate isolated in non-parallel split-bus architecture. If an engine generator fails, the Bus Tie Breaker closes automatically, routing electrical power from the operating generator (or APU generator) across the tie bus to feed the unpowered bus.

7In an advanced fly-by-wire transport aircraft operating in 'Normal Law', what flight envelope protections are continuously active?

A.Load factor protection (g-limiting), high angle of attack (alpha) protection, pitch attitude protection, high speed protection, and bank angle protection

B.Only mechanical rudder pedal stops that restrict ground steering

C.Automatic engine shutdown whenever bank angle exceeds 30°

D.Automatic flap retraction whenever turbulence is encountered

Explanation: In Normal Law, fly-by-wire flight control computers impose hard envelope protections: load factor protection (+2.5g / -1.0g clean), pitch attitude protection (preventing excessive pitch up/down), high angle of attack / alpha protection (preventing stall regardless of pilot stick pull), high-speed protection (preventing structural overspeed), and bank angle limiting (e.g., max 67°).

8What is the primary operational improvement introduced in TCAS II Version 7.1 over Version 7.0?

A.Reversal of Resolution Advisory logic to issue 'LEVEL OFF, LEVEL OFF' instead of 'ADJUST VERTICAL SPEED', and revised sense-reversal RA logic to resolve coordinated encounters

B.The addition of horizontal turning collision avoidance commands

C.Direct integration of satellite ADS-B to eliminate all radar antenna interrogations

D.Automatic deployment of emergency speed brakes during near-miss encounters

Explanation: TCAS II Version 7.1 addressed fatal accidents (such as the 2002 Überlingen mid-air collision). It replaced the confusing 'Adjust Vertical Speed, Adjust' RA with a clear, unambiguous 'Level Off, Level Off' command, and implemented improved reversal logic to detect and reverse an RA if the other aircraft fails to comply with its coordinated advisory.

9How does an Inertial Reference System (IRS) utilizing Ring Laser Gyroscopes (RLGs) determine aircraft angular rotation without mechanical moving parts?

A.By measuring the frequency shift / beat frequency produced by the Sagnac effect between two contra-rotating laser beams travelling around a closed optical triangular path

B.By detecting the physical deflection of a spinning brass flywheel against magnetic springs

C.By measuring electrostatic charge accumulation on quartz pendulums

D.By integrating GPS satellite carrier Doppler frequency shifts

Explanation: Ring Laser Gyroscopes utilize the Sagnac effect. Two monochromatic laser beams travel in opposite directions around a sealed triangular cavity. When the cavity rotates about its sensitive axis, one beam travels a slightly longer optical path than the other, creating a phase and frequency difference proportional to angular rotation rate.

10What is the purpose of 'Schuler Tuning' (84.4-minute tuning period) in an aircraft Inertial Navigation System (INS)?

A.To design the platform feedback loop so that accelerometer errors oscillate harmlessly without causing unbounded, runaway velocity and position errors over the curved Earth

B.To calibrate cabin environmental temperature sensors every 84.4 minutes

C.To synchronize cockpit Flight Management System clocks with UTC satellites

D.To tune the HF radio antenna coupler to atmospheric skip distance

Explanation: Schuler tuning dampens acceleration errors in inertial navigation. By modeling the inertial system as a pendulum whose length equals the Earth's radius, the natural oscillation period is T = 2π√(R/g) ≈ 84.4 minutes. Accelerometer bias and tilt errors oscillate within an 84.4-minute period rather than compounding quadratically over time.

About the Iran CAO ATPL Theory Exam

The Civil Aviation Organization of Iran (CAO.IRI) Airline Transport Pilot License (ATPL) theoretical knowledge examination is the highest level of pilot ground certification in Iran. Administered in technical English in alignment with ICAO Annex 1 and Part-FCL airline transport standards, the examination evaluates deep competency across jet transport aerodynamics, high-altitude meteorology, Class A performance, flight planning, advanced avionics, and international air transport law. This free practice bank provides 100 rigorous questions with in-depth technical explanations.

Exam sponsor: Civil Aviation Organization of the Islamic Republic of Iran (CAO.IRI). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

Written multiple-choice theoretical examinations administered by the Civil Aviation Organization of Iran across the 14 airline transport pilot subjects listed at FCL.515 of the CAO.IRI Air Crew Regulation: Air Law, Aircraft General Knowledge (Airframe/Systems/Powerplant), Aircraft General Knowledge (Instrumentation), Mass and Balance, Performance, Flight Planning and Monitoring, Human Performance, Meteorology, General Navigation, Radio Navigation, Operational Procedures, Principles of Flight, VFR Communications, and IFR Communications. Each paper must be passed at 70% within an 18-month window.

Time Limit

Timed per subject paper per CAO.IRI examination timetables.

Passing Score

70% on each subject paper under CAO.IRI Air Crew Regulation point FCL.025(b)(1), with a penalty of 1% of the marks for every 4 wrong answers. All papers must be passed within 18 months counted from the end of the calendar month of the first attempt, and the ATPL theoretical pass then remains valid for licence issue for 7 years from the last validity date of the instrument rating entered in the licence.

Exam / Certification Fees

Examination fees are established by CAO.IRI and paid through registered Approved Training Organizations during official registration.

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

Air Law & ATC Procedures

International conventions (Chicago, Montreal), ICAO Annexes, air operator certification, high-altitude airspace regulations, and security protocols.

10%

Aircraft General Knowledge — Airframe & Systems

Turbofan engine architectures, FADEC, bleed air systems, electrical AC generation, fly-by-wire flight controls, and fuel distribution.

Aircraft General Knowledge — Instrumentation

Electronic Flight Instrument Systems (EFIS), Flight Management Systems (FMS), TCAS II v7.1, EGPWS/TAWS, Weather Radar, and IRS/INS.

Mass & Balance

Transport category load sheets, index formulas, mean aerodynamic chord (% MAC) calculations, center of gravity limits, and fuel burn shifts.

10%

Flight Performance — Class A Aeroplanes

Takeoff field length, V1/Vr/V2 speeds, 4-segment net takeoff flight path, drift down obstacle clearance, and wet/contaminated runway factors.

10%

Flight Planning & Monitoring

Jet flight planning, Point of Equal Time (PET), Point of Safe Return (PSR), fuel policy, NAT HLA routes, and ETOPS/EDTO diversion planning.

Human Performance & Limitations

High-altitude physiology, time of useful consciousness, automation dependency, crew resource management, and circadian desynchronosis.

10%

Meteorology

Global atmospheric circulation, jet streams, clear air turbulence, high-altitude ice crystals, tropical meteorology, and high-level SIGWX charts.

General Navigation

Polar navigation, grid navigation, gyro steering, Great Circle trigonometry, convergences, and solar/sidereal time calculations.

10%

Radio Navigation & PBN

Instrument Landing System (ILS CAT I/II/III), microwave landing systems, GNSS architectures, GBAS/SBAS, RNAV, and RNP navigation specifications.

Operational Procedures

Low Visibility Operations (LVO), CAT II/III approach procedures, de-icing holdover times (HOT), emergency evacuation, and dangerous goods.

Principles of Flight

Transonic aerodynamics, critical Mach number, shock wave formation, drag divergence, Mach tuck, coffin corner, and aerodynamic damping.

VFR & IFR Communications

Standard radiotelephony phraseology, IFR clearance and readback discipline, CPDLC and datalink messaging, and communication failure procedures.

Preparing for the Iran CAO ATPL Theory Exam

What You Need to Know

Passing score: 70% on each subject paper under CAO.IRI Air Crew Regulation point FCL.025(b)(1), with a penalty of 1% of the marks for every 4 wrong answers. All papers must be passed within 18 months counted from the end of the calendar month of the first attempt, and the ATPL theoretical pass then remains valid for licence issue for 7 years from the last validity date of the instrument rating entered in the licence.
Assessment: Written multiple-choice theoretical examinations administered by the Civil Aviation Organization of Iran across the 14 airline transport pilot subjects listed at FCL.515 of the CAO.IRI Air Crew Regulation: Air Law, Aircraft General Knowledge (Airframe/Systems/Powerplant), Aircraft General Knowledge (Instrumentation), Mass and Balance, Performance, Flight Planning and Monitoring, Human Performance, Meteorology, General Navigation, Radio Navigation, Operational Procedures, Principles of Flight, VFR Communications, and IFR Communications. Each paper must be passed at 70% within an 18-month window.
Time limit: Timed per subject paper per CAO.IRI examination timetables.
Exam / certification fees: Examination fees are established by CAO.IRI and paid through registered Approved Training Organizations during official registration. Official sources

Using Our Practice Resources

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Frequently Asked Questions

What is the passing mark for the Iran CAO ATPL theoretical knowledge examination?

Candidates must achieve at least 70% on each of the 14 theoretical knowledge subject papers. CAO.IRI Air Crew Regulation point FCL.025(b)(1) sets 70% rather than the 75% used in the European Part-FCL baseline, and deducts 1% of the marks for every 4 wrong answers.

What is the time limit for completing all 14 ATPL theory papers?

All 14 examination papers must be successfully completed within an 18-month window starting from the end of the calendar month of the applicant's first examination attempt.

In what language are the CAO.IRI ATPL theoretical examinations administered?

The theoretical knowledge examinations are administered entirely in English, following international ICAO Annex 1 and Part-FCL technical aviation terminology.

What are the privileges of an Airline Transport Pilot License?

An ATPL holder is certified to act as pilot-in-command (Captain) or co-pilot of multi-pilot transport category civil aircraft engaged in commercial air transportation.

Is this practice question bank an official publication of CAO.IRI?

No. This practice bank is an independent educational training aid developed by OpenExamPrep to assist professional pilot candidates in mastering the theoretical concepts examined under the CAO.IRI ATPL syllabus.