FAA Instrument Rating key terms

Weather conditions below the visibility and cloud-clearance minimums for visual flight rules. In IMC, flight under instrument flight rules is required, and pilots rely on instruments and clearances rather than outside references for navigation and traffic separation.

Weather conditions at or above specified visibility and cloud-distance minimums that permit visual flight. Under IFR, a pilot in VMC may still be required to maintain instrument skills, and VMC does not cancel clearance obligations.

Regulations governing flight in which navigation and traffic separation depend on instruments and air traffic control clearances. IFR flight requires an instrument-rated pilot, an equipped aircraft, and an ATC clearance in controlled airspace.

Regulations permitting flight with outside visual reference and specified cloud and visibility minimums. A VFR flight may not enter IMC, and the pilot remains responsible for seeing and avoiding other traffic and terrain.

The rule requiring an IFR flight plan to name a destination alternate when weather at the destination is forecast to be marginal. The alternate must meet prescribed forecast ceiling and visibility criteria at the estimated time of arrival.

A published series of maneuvers and altitudes allowing a pilot to transition from the en route environment to a landing under instrument conditions. Each procedure includes initial, intermediate, final, and missed-approach segments with specified minimums.

The lowest altitude, in feet above mean sea level, to which descent is authorized on a non-precision approach until the required visual reference is established. Reaching the MDA without visual reference requires executing the missed approach.

A specified altitude on a precision or approach-with-vertical-guidance procedure at which a missed approach must be initiated if the required visual reference is not established. It is referenced to the altimeter and expressed in feet above mean sea level.

A published sequence of turns, climbs, and holding instructions flown when a landing cannot be completed from an instrument approach. It protects obstacle clearance and returns the aircraft to a point from which another approach or diversion can begin.

A ground-based precision approach system providing lateral guidance from a localizer and vertical guidance from a glide slope. Category I minimums typically require a decision altitude and specified runway visual range.

The vertical guidance component of a precision approach, typically aligned near a three-degree descent path to the runway. Deviations above or below the path are displayed on the course deviation indicator or flight director.

An instrumented measurement of the horizontal distance a pilot can see down a runway, reported in feet. RVR is often the controlling visibility minimum for instrument approaches and may be reported by transmissometer.

An authorization for an aircraft to proceed under specified traffic conditions within controlled airspace. A clearance is not authorization to deviate from regulations or terrain-clearance responsibility, which remains with the pilot.

The pilot's verbatim repetition of critical clearance elements, including altitude assignments, heading vectors, and approach clearances. Proper readback confirms that the pilot and controller share the same understanding before the flight proceeds.

An ATC authorization permitting the pilot to climb or descend at their discretion within a defined block of altitude while maintaining assigned limits. It is commonly issued as 'climb and maintain' or 'descend and maintain' with a block.

A specific altitude or flight level issued by ATC for a segment of flight. The pilot must maintain it within tolerance and may not change it without a new clearance, except when responding to an emergency.

A published route connecting the en route structure to an instrument approach at a busy terminal area. A STAR may include altitude and speed restrictions, and clearance to fly it does not authorize descent below published minimums.

A racetrack-shaped maneuver used to keep an aircraft within a specified airspace while awaiting further clearance. Entry direction depends on aircraft heading relative to the holding fix, and legs are timed or distance-based.

The navigational point over which a holding pattern is based, identified by a VOR, intersection, or waypoint. The inbound course, turn direction, leg length, and minimum holding altitude are published or assigned by ATC.

A maneuver used to reverse direction when joining an approach or holding pattern, such as a procedure turn or a teardrop entry. The maneuver must remain within protected airspace and published altitude limits.

A published maneuver allowing an aircraft to reverse course and establish itself inbound on an approach course. It is flown within a specified distance and altitude, and may be omitted when radar vectors or a NoPT route is issued.

A notation on an instrument approach chart indicating that a procedure turn is not authorized or not required from the depicted direction of arrival. Flying NoPT requires arriving on the specified course or transition.

A heading issued by ATC to guide an aircraft toward a fix, approach course, or airway. The pilot must maintain the assigned heading and altitude, and terrain clearance remains the pilot's responsibility unless specifically advised otherwise.

The lowest altitude ATC may assign for radar vectors in a given area, providing obstacle clearance for radar-controlled flight. MVAs are charted for controllers and may be lower than minimum IFR altitudes on published routes.

An altitude providing a specified obstacle clearance within a defined area, used for emergency planning and off-route navigation. It is not a clearance limit and does not guarantee navigation signal coverage.

The barometric pressure value set in the altimeter to reference indicated altitude to a pressure datum. Below the transition level, local settings are used; at or above it, the standard setting of 29.92 inches of mercury is used.

The altitude at or below which the altimeter is set to the local altimeter setting and above which the standard setting is used. The transition level is the lowest flight level available above the transition altitude.

An altitude expressed in hundreds of feet referenced to the standard pressure setting of 29.92 inches of mercury. Flight levels provide a common reference for aircraft above the transition altitude, independent of local pressure changes.

The aircraft system that supplies ram and static pressure to the airspeed indicator, altimeter, and vertical speed indicator. Blocked pitot or static ports cause erroneous indications that the pilot must recognize and manage.

An instrument that displays indicated airspeed derived from the difference between pitot and static pressure. In IFR flight, the pilot cross-checks it with attitude and power to detect instrument failure or icing.

A gyroscopic instrument displaying aircraft pitch and bank relative to the horizon. It is the primary reference for controlling the aircraft in instrument flight, and its reliability depends on proper gyro operation.

A gyroscopic instrument showing the aircraft's heading, which must be periodically aligned with the magnetic compass because of precession. It supports turns and heading assignments during instrument flight.

The organized pattern of eye movements a pilot uses to cross-check flight instruments and detect changes in attitude, power, and performance. A disciplined scan prevents fixation and omission of critical instruments.

Instrument flight conducted after failure or loss of one or more primary instruments, using remaining instruments and alternate references. It requires a modified scan and greater reliance on pitot-static or standby instruments.

The needle or bar on a navigation display showing displacement from a selected course. Full-scale deflection corresponds to a defined distance from course, and sensitivity increases near the station or final approach course.

A ground-based navigation aid transmitting radial information that aircraft receivers use to determine bearing from the station. VOR approaches and airways remain common in the instrument system, often paired with distance measuring equipment.

A transponder-based system that measures slant range from the aircraft to a ground station, displayed in nautical miles. DME supports position fixing, approach timing, and arc navigation when paired with VOR or TACAN.

The pilot's ongoing awareness of surrounding terrain and obstacles, supported by charts, minimum altitudes, and warning systems. It remains the pilot's responsibility even when ATC issues vectors or clearances.

An ATC authorization allowing VFR flight in controlled airspace below basic VFR weather minimums, subject to conditions such as clear of clouds and ground visibility. It is not available to IFR flights and requires pilot request.