ACS Task IR.I.C — IFR Cross-Country Flight Planning

What does ACS Task IR.I.C cover?

ACS Task IR.I.C falls under Area of Operation I (Preflight Preparation) of the FAA Instrument Rating ACS (FAA-S-ACS-8C). It evaluates whether you can plan an IFR cross-country flight from scratch — selecting a legal route, determining alternate requirements, computing fuel, reviewing NOTAMs, and analyzing departure procedures. This task is almost universally the first oral topic a DPE addresses because the scenario it creates (a city pair, an aircraft, a departure time, and weather) becomes the backbone for the entire oral exam.

The regulatory foundation for this task is three sections of 14 CFR Part 91:

• 14 CFR 91.103 — Preflight action: the PIC must review all available information including weather, fuel requirements, and alternatives if the flight cannot be completed as planned.
• 14 CFR 91.167 — Fuel requirements: destination + alternate (if required) + 45-minute cruise reserve.
• 14 CFR 91.169 — Alternate requirements: the 1-2-3 rule and planning minimums for the alternate airport.

What knowledge elements does IR.I.C test?

Route selection — airways, RNAV, and preferred routes

Route selection begins with the FAA's preferred IFR routes for your city pair, published in the Chart Supplement (formerly A/FD) and accessible through the FAA Route Management Tool. Filing a preferred route reduces the probability of an ATC-issued reroute before or after departure. When no preferred route exists, the general hierarchy runs from Victor airways (1,200 feet AGL to FL180, defined by VOR radials) to RNAV T-routes (low-altitude GPS-based routes requiring RNAV 1 capability) to direct RNAV routing. Above FL180, random RNAV routing is standard practice in Class A airspace. The DPE will ask you to explain why you chose the route you filed — "it was in the system" is not an acceptable answer.

Alternate planning — the 1-2-3 rule under 14 CFR 91.169

An alternate airport is required on your IFR flight plan unless your destination meets all three conditions of the 1-2-3 rule in 14 CFR 91.169(b): (1) a standard or special instrument approach procedure is published for the destination, (2) the weather forecast shows at least a 2,000-foot ceiling, and (3) at least 3 sm visibility — conditions (2) and (3) must hold from 1 hour before to 1 hour after your planned ETA. All three conditions must be satisfied to waive the alternate requirement. If any one fails, you must file an alternate.

When an alternate is required, 14 CFR 91.169(c) sets planning minimums at the alternate airport:

These are planning minimums for flight plan filing — not the approach minimums you will fly on arrival. The DPE will test whether you know the difference.

Fuel planning — the 14 CFR 91.167 computation

14 CFR 91.167(a) requires fuel sufficient to fly to the destination, then to the alternate (if required), then to cruise for an additional 45 minutes at normal cruising speed. The 45-minute reserve applies to airplanes; helicopters substitute 30 minutes. There is no regulation specifying how much fuel the destination-to-alternate leg must add beyond what is required to actually reach the alternate.

A correct oral answer walks through the computation explicitly:

1. 1
   Compute fuel from departure to destination at planned cruise fuel flow.
2. 2
   If an alternate is required, add fuel from destination to alternate at cruise fuel flow.
3. 3
   Add 45 minutes of fuel at normal cruising speed as the required reserve.
4. 4
   Sum all three legs. The aircraft must depart with at least this quantity on board.
5. 5
   Compare the computed requirement to usable fuel capacity and confirm the aircraft is legal.

NOTAM review

14 CFR 91.103 requires the PIC to review "known ATC delays." In practice, DPEs expect you to describe where NOTAMs are obtained (FAA NOTAM Search at notams.aim.faa.gov), what types to examine (FDC NOTAMs for approach procedure changes, local NOTAMs for runway/taxiway closures, TFR NOTAMs for airspace restrictions), and how a critical NOTAM — such as the ILS being out of service at your destination — would affect your planning.

Performance calculation and departure procedures

The Instrument Procedures Handbook (FAA-H-8083-16B, Chapter 2) addresses departure planning under IFR. You must identify whether a Departure Procedure (DP) exists — either a Textual DP (Obstacle Departure Procedure, ODP) or a Graphic DP (Standard Instrument Departure, SID). If a SID is assigned in the clearance, you must have it on board and brief it. If no DP is published, IPH Chapter 2 describes the diverse obstacle departure procedure: climb on the runway heading to 400 feet AGL before turning, unless the airport's standard takeoff minimums and DPs publication specifies otherwise.

Performance calculations for IFR departure include confirming climb gradient capability. Published DPs often specify a minimum climb gradient (e.g., 200 ft/nm) when obstacles require it. If the aircraft cannot achieve the published gradient, the DP cannot be used.

What risk management elements does IR.I.C cover?

The ACS requires candidates to identify hazards and mitigate risk throughout the planning process — not just comply with regulatory minimums. Risk management elements the DPE will probe include:

• Weather deterioration en route — what triggers an in-flight divert decision and how does your fuel plan account for it.
• Alternate weather: if conditions at your alternate are at planning minimums (600/2 or 800/2), what is your actual margin and does it remain adequate with forecast uncertainty.
• NOTAM impacts — a closed runway at the destination or a NAVAID outage at the alternate changes the legal picture and must change the filed plan.
• Pilot currency and recency — IR.I.C exists alongside IR.I.A; the DPE may ask whether you are current to fly the planned approaches given your recent instrument experience.
• Fuel contamination and mismatch — confirming the aircraft has the right fuel type and the correct quantity before departure.

What skill elements does IR.I.C test?

Unlike most ACS tasks, IR.I.C has no in-flight skill element — it is evaluated entirely in the oral portion of the checkride. The ACS (FAA-S-ACS-8C) lists the following skill outcomes the applicant must demonstrate:

• Select and interpret weather products relevant to the planned flight (METAR, TAF, AIRMET, SIGMET, PIREP, prog charts).
• Determine whether an alternate is required using the 1-2-3 rule and identify a qualified alternate with correct planning minimums.
• Compute the IFR fuel requirement under 14 CFR 91.167 and verify the aircraft departs with sufficient fuel.
• Review applicable NOTAMs and explain the impact of any that affect the planned route, destination, or alternate.
• Identify and brief any applicable Departure Procedure (ODP or SID) and verify the aircraft can meet any published climb gradient.
• Select a route using airways, RNAV routes, or preferred routes appropriate to the aircraft's avionics and the filed altitude.

What does the DPE look for in IR.I.C?

The DPE is evaluating systematic thinking, not memory recitation. Three patterns distinguish passing candidates from failing ones:

Regulatory precision. You cite the correct section — 91.169(b) for the 1-2-3 rule, 91.169(c) for alternate minimums, 91.167(a) for fuel. Confusing 91.167 and 91.169 is a common error that signals shallow preparation.

Integration across topics. The DPE will build on the scenario you plan in IR.I.C throughout the oral. A well-planned scenario (realistic city pair, challenging but not absurd weather, a valid alternate) shows you understand the system rather than reciting facts in isolation.

Honest risk identification. If the planned weather puts you at alternate planning minimums with a narrow margin, say so. DPEs respect candidates who identify risk proactively; they are skeptical of candidates who present every plan as comfortable and routine.

What are the most common errors in IR.I.C?

• Misapplying the 1-2-3 rule by checking METAR (current observation) instead of TAF (forecast) at the destination.
• Selecting an alternate that lacks a published instrument approach procedure — an airport with no approach cannot be a legal IFR alternate under 14 CFR 91.169(c).
• Omitting the 45-minute cruise reserve from the fuel computation or computing it at an incorrect speed (reserve is at normal cruising speed, not reduced power).
• Failing to check for FDC NOTAMs that may have changed approach minimums or placed a NAVAID NOTAM out of service at the destination or alternate.
• Not briefing departure procedures — especially at airports with obstacle-rich departure environments where an ODP is published but not formally assigned by ATC.
• Confusing planning minimums (for filing the alternate) with actual approach minimums (for flying the approach on arrival). The two are independent.

Practice Questions

This article was researched from FAA primary sources (Instrument Rating ACS FAA-S-ACS-8C, 14 CFR Part 91 via Cornell LII, FAA-H-8083-16B Instrument Procedures Handbook) and citing current regulatory text — drafted by MockDPE. Last updated: May 2026. If you spot an inaccuracy, email corrections@mockdpe.org.