Instrument Rating Oral Exam Guide: Topics, Format, and How to Study

The DPE is following the Instrument Rating ACS (FAA-S-ACS-8). Every task area in that document is fair game. But instrument orals are heavily weighted toward applied knowledge — the DPE will present you with scenarios and ask you to reason through them, not just recite rules.

Common scenario formats: "You're filing IFR from A to B. Walk me through your weather evaluation." Or: "You lose comms at this point in the flight. What do you do?" The ACS defines the knowledge; the DPE decides how to probe it.

Alternate airport requirements (14 CFR 91.169). Know the 1-2-3 rule for when an alternate is required, and know the separate standard for what makes a location acceptable as an alternate — 600-2 for airports with a precision approach, 800-2 for airports with only non-precision approaches. These are two different questions that students routinely confuse.

Lost communications (14 CFR 91.185). The AVE F memory aid: Assigned, Vectored, Expected, Filed for route selection; highest of MEA, ATC assigned altitude, or expected altitude for altitude selection. Know when to leave a clearance limit and begin the approach.

IFR flight plan requirements, fuel reserves (45 minutes at cruise for IFR), and the difference between VFR and IFR currency requirements (61.57d — instrument currency is only required to operate under IFR or in less-than-VFR conditions).

Precision vs. non-precision approaches. Know the definitions and examples of each. Know what DA (Decision Altitude) means versus MDA (Minimum Descent Altitude) and how you use each during an approach. A common DPE question: "At what point can you descend below DA on an ILS?" — the answer involves both the aircraft position and what you must have in sight.

RNAV (GPS) approaches. Know the difference between LPV, LNAV/VNAV, and LNAV minima. Know what WAAS is and why it matters for LPV approaches. Know what RAIM is and when to check it.

Circling approaches. Know the circling minimums category for your aircraft, the protected area radius, and what to do if you lose visual contact during the circling maneuver.

Missed approach procedures. Know how to read them on a plate and when the missed approach point is — for both precision and non-precision approaches.

Pitot-static system. Know which instruments use pitot, which use static, and which use both. Know what happens when the pitot tube is blocked but the drain hole is open versus completely blocked. Know what happens when the static port is blocked, and what the alternate static source does to instrument indications (slight over-read on altimeter, slight over-read on airspeed due to lower cabin pressure).

Gyroscopic instruments. Know which are vacuum-driven and which are electrically driven in your aircraft. Know what precession is, what rigidity in space means, and how gyroscopic errors affect the attitude indicator and heading indicator.

Magnetic compass errors: OSCA (Oscillation, Sluggishness, Compass/magnetic dip, Acceleration/deceleration errors). Know that acceleration errors only affect the compass when on easterly or westerly headings, and that turning errors are most pronounced when turning through north and south.

AIRMETs versus SIGMETs. AIRMETs (Sierra, Tango, Zulu) cover conditions significant to light aircraft. SIGMETs cover severe conditions affecting all aircraft. Convective SIGMETs cover thunderstorms, hail, and tornadoes and are issued automatically when thresholds are met.

Icing. Know the difference between structural icing types (clear, rime, mixed). Know that carburetor icing can occur even at relatively warm outside air temperatures with high humidity. Know that a standard IFR-equipped aircraft is not the same as an aircraft certified for flight into known icing (FIKI).

Forecast products. Know how to read an FA (Area Forecast), a TAF, and an AIRMETs/SIGMETs briefing. Know what a prog chart shows and how to use it for preflight planning.

Holding pattern entries. The three entry types — direct, teardrop, and parallel — are determined by your heading relative to the holding course on arrival at the fix. DPEs often draw a holding pattern and ask you to determine the entry from a specific heading. Know how to do this without hesitation.

Timing in the hold. 1 minute legs below 14,000 feet MSL, 1.5 minutes at or above. Wind correction: adjust the outbound leg timing to achieve the target inbound time. Know that EFC (expect further clearance) times are used to plan your departure if you lose comms.

Start with the ACS. Download it, read through every task area, and honestly rate your knowledge on each one. The gaps you find are your study list.

Practice being questioned out loud. The instrument oral is not a written test. You need to be comfortable explaining concepts in spoken sentences while someone listens and follows up. Read a chapter, then close the book and explain it to someone — or to an AI that can ask follow-up questions.

Work through IFR scenarios. Pick a real departure airport, file a real IFR route, and walk through the entire flight — weather eval, fuel planning, alternate selection, clearance readback, lost comm plan, approach selection, missed approach. Do this repeatedly with different airports and weather.