IFR Regulations Covered on the FAA Written Exam
Overview of Relevant FAR Parts (Part 61, 91, 71, 97)
The Part 91 IFR rules written test questions are drawn from several specific sections of the Federal Aviation Regulations (FARs). Part 61 governs the certification of pilots and flight instructors, specifically outlining the recent flight experience required to act as Pilot in Command (PIC) under IFR. Part 91 contains the general operating and flight rules, which form the core of the exam, covering everything from fuel requirements to lost communications. Part 71 defines the designation of Class A, B, C, D, and E airspace areas, air traffic service routes, and reporting points. Finally, Part 97 establishes Standard Instrument Procedures (TERPS), which dictate how instrument approaches are designed and the legal minimums associated with them. Understanding the hierarchy of these parts is essential; for instance, while Part 61 tells you if you are legal to fly, Part 91 tells you how to conduct that flight legally within the National Airspace System (NAS).
Key Definitions: IFR, IMC, Clearance, Alternate
Success on the IFR regulatory knowledge exam requires precise command of aviation terminology. A common point of confusion is the distinction between Instrument Flight Rules (IFR) and Instrument Meteorological Conditions (IMC). IFR refers to the set of regulations under which a pilot operates, regardless of the weather, while IMC refers to weather conditions below the minimums prescribed for flight under Visual Flight Rules (VFR). An ATC Clearance is an authorization by air traffic control, for the purpose of preventing collision between known aircraft, for an aircraft to proceed under specified traffic conditions within controlled airspace. An Alternate Airport is defined as an airport specified in a flight plan to which a flight may proceed when it becomes inadvisable to land at the airport of intended landing. The written exam often tests these definitions through scenario-based questions, such as determining if a clearance is required for a flight in Class E airspace when weather is below VFR minimums.
Regulatory Structure and Pilot Responsibilities
The PIC is the final authority as to the operation of the aircraft, a principle codified in 14 CFR §91.3. Under IFR, this responsibility extends to ensuring the aircraft meets all FAA IFR operating requirements before departure. This includes verifying the aircraft is equipped for the specific type of navigation to be used and that all required inspections are current. The regulatory structure places the burden of "see and avoid" on the pilot even when on an IFR flight plan, provided the aircraft is in Visual Meteorological Conditions (VMC). Furthermore, the PIC must be familiar with all available information concerning a flight, including weather reports, fuel requirements, and any known traffic delays advised by ATC. On the written exam, questions often probe the limits of this authority, particularly in emergency situations where a pilot may deviate from any rule in Part 91 to the extent required to meet that emergency.
Part 91 IFR Flight Rules and Operating Limitations
Fuel Requirements and Alternate Airport Rules
One of the most frequently tested instrument flight rules test questions involves the IFR fuel requirements found in 14 CFR §91.167. For flight in IFR conditions, the aircraft must carry enough fuel to fly to the first airport of intended landing, fly from that airport to the alternate airport (if required), and fly after that for 45 minutes at normal cruising speed. The requirement to file an alternate is governed by the "1-2-3 rule": an alternate is required if, for at least 1 hour before and 1 hour after the estimated time of arrival (ETA), the ceiling is forecast to be less than 2,000 feet above the airport elevation, or the visibility is forecast to be less than 3 statute miles. If an alternate is required, the weather at that alternate at the ETA must meet specific minimums: for a precision approach, a 600-foot ceiling and 2 statute miles visibility; for a non-precision approach, an 800-foot ceiling and 2 statute miles visibility.
Equipment Requirements for IFR Flight
To operate under IFR, an aircraft must have specific equipment beyond what is required for VFR day and night. This is often remembered by the acronym GRABCARD: Generator or alternator, Radios (two-way communication and navigation equipment appropriate for the ground facilities to be used), Altimeter (sensitive, adjustable for barometric pressure), Ball (slip-skid indicator), Clock (displaying hours, minutes, and seconds with a sweep-second pointer or digital representation), Attitude indicator, Rate-of-turn indicator, and Directional gyro. Additionally, 14 CFR §91.205 specifies that for flight at or above FL240, if VOR navigation equipment is required, the aircraft must be equipped with Distance Measuring Equipment (DME) or a suitable RNAV system. The exam will often present a list of failed equipment and ask if the flight can legally continue in IFR conditions.
Takeoff, Approach, and Landing Minimums
Under 14 CFR §91.175, no pilot may take off under IFR from a civil airport unless weather conditions are at or above the takeoff minimums prescribed in Part 97. If no minimums are prescribed, standard takeoff minimums apply: 1 statute mile visibility for aircraft having two engines or less, and 1/2 statute mile for aircraft having more than two engines. For the landing phase, a pilot may not operate an aircraft below the authorized Decision Altitude (DA) or Minimum Descent Altitude (MDA) unless the aircraft is in a continuous position to land using normal maneuvers, the flight visibility is not less than the visibility prescribed in the standard instrument approach, and at least one of the specified visual references for the intended runway is distinctly visible. These references include the approach light system (allowing descent to 100 feet above the touchdown zone elevation), the threshold, or the runway lights.
Air Traffic Control Procedures and Clearances
Understanding and Accepting ATC Clearances
Air traffic control procedures IFR require a pilot to receive a clearance before operating in controlled airspace under IFR. A standard clearance follows the CRAFT format: Clearance limit, Route, Altitude, Frequency (for departure), and Transponder code. When a pilot accepts a clearance, they are legally bound to comply with it unless an amended clearance is obtained or an emergency exists. The written exam emphasizes the pilot's duty to clarify any clearance that is not understood. For example, if ATC issues a "clearance void time," the pilot must understand that if the flight does not depart by that time, the clearance is void and the pilot must notify ATC within 30 minutes of their intentions. Failure to do so can result in a massive disruption of the IFR system as ATC must protect that airspace from other traffic.
Amending, Canceling, and Complying with Clearances
Pilots have the right to request a different clearance if the one provided is unacceptable for safety or operational reasons. However, once accepted, compliance is mandatory under 14 CFR §91.123. If a pilot deviates from a clearance in an emergency, they must notify ATC as soon as possible. If given priority by ATC in an emergency, the PIC may be required to submit a detailed report within 48 hours to the manager of that ATC facility, even if no rule was technically violated. Canceling an IFR flight plan is only permitted if the aircraft is operating in VFR weather conditions outside of Class A airspace. The exam often tests the specific scenario of "VFR-on-top," where a pilot operates on an IFR flight plan but maintains VFR cloud clearance and visibility requirements, allowing for altitude flexibility while remaining under ATC control.
Communication Failure Procedures under IFR
In the event of a two-way radio communication failure in IFR conditions, the procedures outlined in 14 CFR §91.185 are critical for exam success. For the route, a pilot follows the AVE F acronym in order: Assigned, Vectored, Expected, or Filed. For the altitude, the pilot must fly the highest of the MEA: Minimum IFR Altitude, Expected altitude, or Assigned altitude. If the failure occurs in VFR conditions, the pilot must continue the flight under VFR and land as soon as practicable. If in IFR conditions, the pilot should proceed to the fix from which the approach begins and commence the approach as close as possible to the Expect Further Clearance (EFC) time or the Estimated Time of Arrival (ETA) as calculated from the filed flight plan. These procedures ensure predictability, allowing ATC to clear the airspace around the silent aircraft.
Instrument Pilot Recent Flight Experience
Six-Month Instrument Experience Requirements
To maintain currency to act as PIC under IFR, a pilot must meet the requirements of 14 CFR §61.57. Within the 6 calendar months preceding the month of the flight, the pilot must have performed and logged at least six instrument approaches, holding procedures and tasks, and intercepting and tracking courses through the use of navigational electronic systems. This is commonly referred to as the "6-6-HIT" rule. These tasks can be performed in actual IMC or in simulated instrument conditions using a view-limiting device, provided a safety pilot is present. The safety pilot must hold at least a private pilot certificate with category and class ratings appropriate to the aircraft being flown. The exam frequently asks candidates to calculate the expiration date of IFR currency based on a list of previous flights.
Logging Instrument Approaches and Holding
Properly logging instrument time is a legal necessity. For the purposes of the IFR regulations FAA written, a pilot may log instrument flight time only for 그 time the pilot operates the aircraft solely by reference to instruments under actual or simulated instrument flight conditions. When logging an approach for currency, the pilot must record the location and type of each instrument approach completed and the name of the safety pilot, if required. The FAA requires that the approach be conducted down to the published minimums (MDA or DA) for it to count toward currency, unless the flight is in actual IMC and the aircraft transitions to visual flight before reaching minimums. The written test may present logbook entries and ask if the pilot is legal for a specific flight on a specific date, requiring careful subtraction of calendar months.
Instrument Proficiency Check (IPC) Overview
If a pilot fails to meet the instrument experience requirements within the first 6-month period, they have a second 6-month "grace period" to regain currency by flying with a safety pilot or instructor to complete the 6-HIT requirements. If the pilot is still not current after this 12-month total period, they must pass an Instrument Proficiency Check (IPC). The IPC must be administered by an authorized instructor, a FAA examiner, or a person approved by the FAA. The check consists of a representative number of tasks required by the Instrument Rating Practical Test Standards (PTS) or Airman Certification Standards (ACS). The exam tests the knowledge that an IPC is the only way to reset currency once the grace period has elapsed, and that a flight review (required by §61.56) does not satisfy the requirements of an IPC.
VOR, Altimeter, and Transponder Checks
Regulatory compliance involves periodic equipment inspections to ensure accuracy. 14 CFR §91.171 dictates that no person may use a VOR for IFR navigation unless it has been checked within the preceding 30 days. Acceptable checks include a VOT (signal from a VOR Test Facility, max error +/- 4 degrees), a ground checkpoint (+/- 4 degrees), or an airborne checkpoint (+/- 6 degrees). Furthermore, the altimeter and static system must be tested and inspected within the preceding 24 calendar months for IFR flight (14 CFR §91.411). The transponder must also be inspected within the preceding 24 calendar months (14 CFR §91.413). The written exam tests these specific timeframes and the required logbook entries, which must include the date, place, bearing error, and the signature of the person performing the check.
GPS and RNAV Equipment Requirements for IFR
Modern IFR flight relies heavily on Area Navigation (RNAV) and Global Positioning System (GPS) technology. For the IFR regulatory knowledge exam, candidates must know that any GPS unit used for IFR must be TSO-certified and have a current navigation database. If using GPS as the primary source of IFR navigation, the aircraft must generally be equipped with an alternate means of navigation (such as VOR/ADF) appropriate to the route, unless the GPS is equipped with Receiver Autonomous Integrity Monitoring (RAIM). RAIM is a technology that monitors the integrity of GPS signals; if RAIM is lost, the pilot must notify ATC and revert to an alternate navigation source. The exam often covers the requirement to check GPS NOTAMs and RAIM availability during preflight planning, especially for those conducting GPS-based instrument approaches.
Minimum Equipment List (MEL) and Inoperative Equipment
When equipment is found to be inoperative, pilots must refer to 14 CFR §91.213 to determine if the flight can proceed. If the aircraft has an approved Minimum Equipment List (MEL), the pilot follows the procedures outlined in that document. If no MEL exists, the inoperative equipment must not be part of the VFR-day type certification, required by the aircraft’s equipment list or Kind of Operations Equipment List (KOEL), required by Part 91.205, or required by an Airworthiness Directive (AD). If the flight can proceed, the inoperative equipment must be removed or deactivated and placarded "Inoperative." This regulatory logic is a staple of the written exam, requiring the pilot to evaluate whether a failed vertical speed indicator or a broken landing light renders the aircraft unairworthy for a specific IFR flight.
Special Use Airspace and IFR Operations
Operating in Class A Airspace
Class A airspace exists from 18,000 feet Mean Sea Level (MSL) up to and including Flight Level (FL) 600. According to 14 CFR §91.135, all operations in Class A airspace must be conducted under IFR and require a specific ATC clearance. Pilots must be instrument rated and the aircraft must be equipped for IFR flight, including a Mode C or Mode S transponder and Two-Way radio communication. Altimeter settings in Class A are standardized to 29.92" Hg to ensure vertical separation between aircraft, as they transition from MSL altitudes to Flight Levels. The exam tests the knowledge that VFR flight is prohibited in Class A, and that pilots must maintain the assigned flight level with high precision due to the high speeds and traffic density common in this stratum.
Procedures for Flying through Restricted and MOA Areas
Special use airspace requires specific pilot actions. Restricted Areas contain unusual, often invisible, hazards to aircraft such as artillery firing or guided missiles. Flight through a Restricted Area is prohibited unless the pilot has obtained permission from the using or controlling agency. In contrast, Military Operations Areas (MOAs) consist of airspace defined for the purpose of separating military training activities from IFR traffic. When an MOA is active, ATC will provide separation for IFR aircraft; if not active, ATC will route IFR traffic normally. The written exam focuses on the legal requirement to obtain clearance before entering Restricted airspace, whereas for MOAs, the responsibility lies largely with ATC to ensure the IFR aircraft remains clear of military activity.
IFR Operations in Class B, C, and D Airspace
Navigating terminal airspace under IFR streamlines many of the requirements faced by VFR pilots. For example, while a VFR pilot must specifically hear their tail number and the phrase "cleared to enter the Class Bravo airspace," an IFR pilot is considered cleared into the Class B once they receive their IFR clearance and are routed through it. However, the pilot must still comply with the equipment requirements of 14 CFR §91.131, such as having a transponder with altitude reporting capability (within the Mode C Veil and above the ceiling of Class B or C). The exam tests the nuances of these interactions, such as the requirement to maintain communication with ATC until being handed off to the tower, and the necessity of adhering to published speed limits (e.g., 250 knots below 10,000 feet MSL and 200 knots in the airspace underlying Class B).