ACS Task IR.I.B — Weather Information (Instrument Rating)

What does ACS Task IR.I.B require you to know?

ACS Task IR.I.B falls within Area of Operation I (Preflight Preparation) of FAA-S-ACS-8C. It evaluates three categories of elements: Knowledge (K), Risk Management (R), and Skill (S). Knowledge elements are evaluated orally; Risk Management elements probe your go/no-go decision framework; Skill elements assess your ability to use actual weather products during the flight scenario.

The task is directly tied to 14 CFR 91.103(a), which requires each PIC to become familiar with "weather reports and forecasts" before any IFR flight. The companion task, IR.I.C (Cross-Country Flight Planning), tests how you integrate that weather data into a complete flight plan — but IR.I.B focuses on whether you can interpret the products themselves and assess the hazards they describe.

What weather products does IR.I.B cover?

The Knowledge elements of IR.I.B require you to understand the source, content, validity, and operational significance of every standard aviation weather product. The AIM Chapter 7 is the definitive FAA reference for all of these.

What is the difference between AIRMETs and SIGMETs?

AIRMETs and SIGMETs are both in-flight advisories, but they address different severity levels and audiences. An AIRMET covers conditions significant primarily to light aircraft — IFR conditions that may be annoying for an airliner are operationally disqualifying for a Cessna 172. A SIGMET addresses conditions hazardous to all aircraft regardless of size or equipment.

The regulatory hook for both products is 14 CFR 91.103(a), which requires reviewing "weather reports and forecasts" before an IFR flight. The AIM Chapter 7 specifically names AIRMETs and SIGMETs among the products an IFR PIC is expected to obtain.

A common DPE probe: "There's a Convective SIGMET on your route. Does that affect your go/no-go?" The correct answer integrates equipment (does your aircraft have storm-detection capability?), pilot qualification, and operational judgment — not just a definition of the product.

What risk management elements does IR.I.B test?

Risk management in IR.I.B focuses on how you translate weather information into flight decisions. The DPE is not looking for a pre-memorized list of no-go conditions. They want to see that you can reason through actual hazards given your specific aircraft, route, and qualifications.

Key risk areas the DPE will probe:

• Icing: An AIRMET Zulu indicates moderate icing is forecast. If your aircraft has no deicing equipment, this is a no-go for that altitude or route — regardless of whether the icing is technically "known icing" under 14 CFR 91.527. The ACS tests whether you understand the practical risk, not just the regulatory definition.
• Thunderstorms: A Convective SIGMET on the route is a significant red flag. GA aircraft are not equipped to penetrate severe convective activity. The AIM Chapter 7 identifies thunderstorms as one of the most hazardous weather phenomena for flight.
• Low IFR and fog: An AIRMET Sierra covering your departure or destination may not be a no-go by itself, but it demands an operational alternate strategy and realistic assessment of approach minimums versus forecast conditions.
• Turbulence: An AIRMET Tango for moderate turbulence affects passenger comfort, aircraft structural loads, and your ability to maintain instrument tolerances. The DPE expects you to address passenger briefing, altitude alternatives, and route deviation options.
• Validity staleness: A PIREP filed 4 hours ago may no longer reflect actual conditions. The DPE may present you with a PIREP and ask whether you would rely on it — the age of the report is the critical variable.

What skill elements does IR.I.B test?

Skill elements in IR.I.B are evaluated during the practical test flight scenario. The DPE presents actual or simulated weather products and evaluates your ability to:

1. 1
   Obtain a standard weather briefing

   Demonstrate how you would obtain an IFR weather briefing from aviationweather.gov or a licensed flight service (1800wxbrief.com). The DPE may ask you to walk through the briefing workflow on a tablet or EFB.
2. 2
   Interpret a METAR and SPECI

   Decode a raw METAR aloud — wind, visibility, ceiling, weather phenomena, altimeter. Identify whether conditions are above or below IFR minimums for the aircraft category.
3. 3
   Interpret a TAF for alternate planning

   Read the TAF for the destination and alternate airports. Apply the 1-2-3 rule from 14 CFR 91.169 — the DPE often links IR.I.B weather interpretation directly to the alternate requirement in IR.I.C.
4. 4
   Identify AIRMET and SIGMET hazards on the route

   Given a scenario with AIRMETs and/or SIGMETs active, identify which hazards affect your planned route and altitude, and state your go/no-go decision with reasoning.
5. 5
   Apply PIREP data operationally

   Given one or more PIREPs, determine whether the reported conditions are still relevant (consider age, proximity, and aircraft type), and how the reports influence your altitude or route selection.
6. 6
   Make and justify a go/no-go decision

   Integrate all weather data — METARs, TAFs, AIRMETs, SIGMETs, PIREPs, prog charts — into a final go/no-go decision. Be specific: cite which product(s) drove the decision and why.

What does the DPE look for on IR.I.B?

DPEs evaluate operational fluency, not abbreviation recitation. Any instrument candidate can memorize that AIRMET stands for Airmen's Meteorological Information. The DPE wants to know whether you can sit down with an actual preflight weather package and fly the mission safely or make a defensible decision not to fly.

The most common passing performances on IR.I.B share these characteristics:

• Candidate anchors the weather review in 14 CFR 91.103(a) — citing the regulatory requirement without being prompted
• Candidate uses weather products sequentially: big picture first (prog charts, area forecasts), then route-specific (AIRMETs, SIGMETs, winds aloft), then terminal (TAF, METAR)
• Candidate distinguishes between observation (METAR, PIREP) and forecast (TAF, AIRMET) products and explains the significance of that distinction for planning
• Candidate's go/no-go decisions are grounded in the specific products presented, not generic rules of thumb
• Candidate proactively notes limiting factors: AIRMET Zulu in an aircraft without deicing, convective SIGMET on route, TAF showing sub-minimums conditions at destination without adequate alternate

What are the common errors on IR.I.B?

• Treating a METAR as a forecast — METARs are observations valid at the time of issue; TAFs are forecasts
• Ignoring PIREP age — a 4-hour-old severe icing PIREP may or may not reflect current conditions; always note when the report was filed
• Confusing AIRMET and SIGMET severity — describing moderate turbulence as a SIGMET (it is an AIRMET Tango) or severe icing as an AIRMET (it is a SIGMET) shows conceptual confusion
• Failing to connect weather to the alternate requirement — DPEs expect you to tie sub-minimums TAF data at the destination to the 1-2-3 rule and 14 CFR 91.169 without being led there
• Over-relying on digital weather apps without explaining the underlying product — saying 'ForeFlight showed green' is not an acceptable IR.I.B answer
• Leaving out prog charts — candidates often address METAR, TAF, and AIRMET but omit the synoptic picture; DPEs notice

Practice Questions

Frequently Asked Questions

Q: What ACS task covers weather information on the instrument checkride?

Task IR.I.B — Weather Information — in Area of Operation I (Preflight Preparation) of FAA-S-ACS-8C. It covers your ability to obtain and interpret weather reports, forecasts, and in-flight advisories, and to make a go/no-go decision based on that information.

Q: How long is a TAF valid?

A TAF (Terminal Aerodrome Forecast) covers a period of 24 to 30 hours and a radius of 5 statute miles around the airport. TAFs are issued four times daily by the National Weather Service. The AIM Chapter 7 identifies TAFs as the primary forecast product for destination and alternate planning.

Q: What is the difference between AIRMET Sierra, Tango, and Zulu?

AIRMET Sierra covers IFR conditions and mountain obscuration. AIRMET Tango covers moderate turbulence, sustained surface winds of 30 knots or more, and low-level wind shear. AIRMET Zulu covers moderate icing and freezing levels. All three types are valid for up to 6 hours per issuance.

Q: How does a SIGMET differ from an AIRMET?

SIGMETs (WS) are issued for conditions hazardous to all aircraft: severe or extreme turbulence, severe icing not associated with thunderstorms, dust or sandstorms lowering visibility below 3 miles, volcanic ash, and tropical cyclones. AIRMETs cover lesser hazards primarily affecting light aircraft. SIGMETs are valid for up to 4 hours, or up to 6 hours for tropical cyclones or volcanic ash.

Q: What is a Convective SIGMET and how long is it valid?

A Convective SIGMET (WST) covers hazardous convective weather: embedded thunderstorms, lines of thunderstorms, areas of thunderstorms covering at least 3/8 of an area, severe thunderstorms, and tornadoes. Convective SIGMETs are issued hourly at H+55 and are valid for 2 hours or until superseded.

Q: What is a PIREP and when is a pilot required to file one?

A PIREP (pilot weather report) is a real-time report from an aircraft crew describing actual meteorological conditions encountered in flight — icing, turbulence, cloud tops, visibility, or wind. Pilots are required to file a PIREP when requested by ATC or an FSS, and are encouraged to file any time conditions encountered differ significantly from the forecast.

Q: Does 14 CFR 91.103 require reviewing weather before an IFR flight?

Yes. Under 14 CFR 91.103(a), each PIC must determine "weather reports and forecasts" before any IFR flight. The regulation requires both current conditions (METAR, PIREP) and forecasts (TAF, prog charts, AIRMET, SIGMET). A METAR alone does not satisfy the regulatory requirement.

Q: What weather makes an IFR flight an automatic no-go?

The ACS tests risk management judgment, not a fixed list. However, operationally: a Convective SIGMET on the route is generally a no-go for GA aircraft. Severe icing (SIGMET) or moderate icing in an aircraft without deicing equipment (AIRMET Zulu) is a no-go. Any forecast showing conditions below approach minimums at the destination with no qualified alternate is a no-go.

Sources

• FAA-S-ACS-8C Change 1: Instrument Rating ACS
• 14 CFR 91.103 — Preflight Action (Cornell LII)
• AIM Chapter 7 — Safety of Flight / Meteorology
• FAA-H-8083-15B: Instrument Flying Handbook
• Aviation Weather Center

This article was researched from FAA primary sources (ACS, FAR/AIM, Instrument Flying Handbook) and citing current 14 CFR Part 91 — drafted by MockDPE. Last updated: May 2026. If you spot an inaccuracy, email corrections@mockdpe.org.