At Angel Aviation, we know that executing a flawless approach means nothing if your pitot system fails and you don’t know how to react. IFR flying demands more than procedural knowledge — it demands system knowledge. Before your DPE has you fly a hold or shoot an ILS, they’ll want to know: Can you manage and troubleshoot the aircraft systems that keep you safe in IMC?

This guide covers Instrument Rating ACS Area VI: Aircraft Systems, highlighting the systems you must understand, how they relate to IFR operations, and what questions your examiner will likely ask.

🎯 What the Examiner Is Looking For

Under ACS Area VI, your examiner is checking to see if you can:

  • Identify and explain aircraft systems relevant to IFR flight

  • Describe failure indications and backup procedures

  • Show how these systems impact your decision-making in IMC

  • Demonstrate systems knowledge that supports safe instrument operations

Let’s break down the systems you’re expected to know — and how to brief them with confidence.

✈️ The Pitot-Static System

📚 Ref: FAA-H-8083-15B (IFH), POH

Your DPE may ask:
 👉 “What instruments rely on the pitot-static system?”
 👉 “What happens if your static port ices over in IMC?”

Instruments Affected:

  • Airspeed Indicator – pitot and static

  • Altimeter – static

  • VSI – static

Failure Clues:

  • Airspeed freezes or reads incorrectly

  • Altimeter becomes unresponsive

  • VSI shows 0 during climbs/descents

💡 Angel Tip: Know how to use the alternate static source and what effect it has on your readings (typically higher indicated altitude and VSI rate).

🧭 Gyroscopic Systems

📚 Ref: FAA-H-8083-25B (PHAK)

Understand whether your aircraft uses:

  • Vacuum-driven attitude indicator and heading indicator

  • Electrically driven turn coordinator

Know This Cold:

  • What happens if the vacuum pump fails?

  • What powers the AI and HI in your aircraft?

  • How do you identify failure in IMC?

💡 Angel Pro Tip: Know how your aircraft alerts you to vacuum or electrical system failures — and how to transition to partial-panel flying.

🔌 Electrical System

📚 Ref: POH, FAA-H-8083-15B

IFR flight is heavily reliant on the electrical system — especially for:

  • Avionics (GPS, NAV/COM, autopilot)

  • Pitot heat / prop heat / lighting

  • Gyros (if electric)

✅ Know how to identify an alternator failure
 ✅ Be able to explain how long your battery can power essentials
 ✅ Be familiar with load-shedding procedures

💡 DPE Scenario: “You lose your alternator in IMC — what’s your course of action?”

📡 Navigation & Communication Systems

IFR = NAV/COM.

You must know how your systems work and fail, especially:

  • VOR/LOC – including reverse sensing

  • GPS – RAIM availability and database validity

  • Autopilot – modes, limitations, failure modes

  • Audio panel – isolating failures

  • Transponder & ADS-B

💡 Angel Tip: Make sure your GPS database is up to date and you’re able to explain how to verify it preflight.

❄️ Ice Protection & Pitot Heat

📚 Ref: §91.213, POH

Even if your plane isn’t certified for known icing, know how to manage:

  • Pitot heat usage and failure indications

  • Windshield defrost and cabin heat

  • Alternate air source

  • Carburetor heat or alternate induction air (if applicable)

👉 “What are your personal minimums regarding potential icing?”
 👉 “How would you detect and respond to carb ice in IMC?”

🚨 Failure Scenarios to Prepare For

The examiner may walk you through system failure situations like:

  • Vacuum failure in IMC

  • Pitot-static blockage

  • Loss of primary NAV or GPS source

  • Autopilot runaway or failure

  • Electrical system degradation

Be ready to explain:

✅ What clues indicate the failure
 ✅ What backup instruments/systems are available
 ✅ What you’d do next

💡 Angel Tip: Practice explaining failure scenarios out loud — this is a high-likelihood oral topic.

🧠 Questions You Might Get Asked

✅ “How do you know your pitot heat is working?”
 ✅ “What powers the heading indicator in this airplane?”
 ✅ “What’s the difference between GPS OBS mode and ENR mode?”
 ✅ “How would you fly an approach if your AI failed mid-flight?”
 ✅ “What happens if your battery dies while on an IFR flight plan?”

📚 Key References to Know

  • POH/AFM – System-specific details

  • §91.213 – Inoperative instruments and equipment

  • IFH & PHAK – System operation theory

  • Advisory Circular 91-75 – Cockpit technology use

  • Instrument Rating ACS – Area VI system knowledge expectations

🧾 Final Thoughts from Angel Aviation

Understanding how your aircraft works is non-negotiable for safe IFR flying. In instrument conditions, you’re relying on those systems to keep you upright, on course, and informed — and your examiner knows it.

This isn’t about memorizing components. It’s about understanding cause and effect, diagnosing problems, and staying ahead of the airplane when your equipment doesn’t cooperate.