Piper PA-28-161 Warrior — Instrument Checkride Guide

What IFR-relevant systems does the Piper PA-28-161 Warrior have?

The PA-28-161 Warrior is a four-seat, low-wing, fixed-gear aircraft with a normally aspirated, carbureted Lycoming O-320. Its analog instrument panel uses a combination of vacuum-powered and electrically-powered gyroscopic instruments — and its low-wing fuel architecture differs fundamentally from the Cessna 172 high-wing gravity-feed system that many instrument students trained on first. Understanding these distinctions is not optional for the checkride oral: the DPE will ask.

Fuel system. The Warrior carries fuel in two independent wing tanks. Because the aircraft is low-wing, fuel cannot gravity-feed to the engine as it does in a Cessna 172. The engine-driven fuel pump is the primary source; an electric boost pump is used during engine start, takeoff, landing, and whenever the engine-driven pump fails or fuel pressure drops below normal. The fuel selector positions available on the PA-28-161 allow selection of individual tanks — know your specific aircraft's selector positions and the manufacturer's guidance on switching tanks, which is in the POH.

Vacuum system. The engine-driven vacuum pump drives both the attitude indicator (AI) and the directional gyro (DG). A vacuum pump failure in IMC eliminates your two primary attitude and heading references simultaneously — the classic partial-panel emergency. Per the Instrument Flying Handbook (FAA-H-8083-15B) , PIC must be able to identify a vacuum failure, control the aircraft using remaining instruments, and request assistance. Expect a partial-panel scenario on your checkride.

Electrical system. The Warrior uses a standard 28-volt, single-alternator, single-battery electrical system. An alternator failure during IFR begins draining the battery immediately. Know your load-shedding priority order and, from your specific aircraft's POH, the approximate battery-only endurance on the avionics load you carry.

How does the low-wing fuel system work and why does the DPE focus on it?

The fuel system distinction between high-wing and low-wing aircraft is one of the most reliable DPE oral topics for Warrior applicants. The Instrument Flying Handbook identifies fuel system knowledge as a required element of preflight planning and systems understanding. Here is what you must be able to explain:

• Low-wing design: fuel sits below the engine and cannot gravity-feed — engine-driven pump is mandatory for fuel delivery under normal operations
• Engine-driven pump: primary fuel delivery device; failure causes fuel pressure to drop, which can cause engine roughness or stoppage
• Electric boost pump: backs up the engine-driven pump; required ON for engine start, takeoff, and landing per the PA-28-161 checklist — confirm with your aircraft's POH
• Fuel selector: allows selection of individual tanks; the DPE will ask you to explain tank selection discipline and when you switch
• Contrast with Cessna 172: the 172's high-wing design allows gravity feed to both the engine-driven pump and, in the BOTH position, direct gravity flow — no electric boost pump is required for routine operations in the same way
• Fuel pressure gauge: the primary indication that the engine-driven pump is working; monitor for normal indication after start and during flight

The DPE is not looking for a verbatim checklist recitation. They want to hear that you understand the architecture — why each component exists and what happens when it fails.

What are the vacuum and electrical instrument systems in the analog Warrior?

The analog PA-28-161 uses a split power architecture for its gyroscopic instruments. This architecture determines what survives a partial failure — and the DPE will test you on it directly. Per FAA-H-8083-15B Chapter 5 , knowing the power source of each flight instrument is a foundational IFR skill.

The turn coordinator's electrical power source is the key fact. In a vacuum failure, the turn coordinator remains operational and becomes your primary gyroscopic attitude reference for partial-panel flight. The magnetic compass, though subject to errors during turns and accelerations, is your backup heading reference when the DG flags. Know how to use both.

The vacuum gauge in the cockpit is your early warning system. A low or zero vacuum reading while the AI and DG still appear to function normally indicates a vacuum pump failure in progress — the gyros will continue to spin on momentum for several minutes before tumbling.

What avionics suites are common in training Warriors?

Avionics configurations vary significantly across the PA-28-161 fleet because individual operators have upgraded aircraft over time. The following represent configurations commonly found in instrument training aircraft. Always verify your specific airplane before the checkride.

• Nav/comm: Bendix/King KX-155 or KX-165 — analog nav/comm with VOR/ILS and, on the KX-165, built-in glideslope receiver; verify which nav head is in your aircraft and whether it has a built-in glideslope
• GPS: Garmin GNS 430 or GNS 530 (WAAS or non-WAAS depending on aircraft) — if present, supports RNAV approaches; WAAS-capable units support LPV minimums
• Transponder: Bendix/King KT-76C or equivalent Mode C transponder; must be inspected per 14 CFR 91.413 within the preceding 24 calendar months
• Autopilot: Bendix/King KAP 100 or KAP 140 two-axis autopilot in some aircraft — many training Warriors are hand-fly only; confirm before the checkride
• ADF: some aircraft carry an ADF receiver for NDB approaches; verify whether your aircraft is ADF-equipped if the planned checkride airport has an NDB approach
• DME: occasionally installed; verify if your scenario includes DME-required procedures

If your Warrior is equipped with a GNS 430W or GNS 530W, the DPE will expect you to know the database currency requirements under the applicable AFM supplement — the same 28-day AIRAC cycle that applies to any IFR-certified GPS navigator. An expired GPS database means you cannot legally fly GPS approaches regardless of whether the procedure appears unchanged on the chart.

What are the most common DPE oral questions for the Warrior?

DPEs examining instrument applicants in the PA-28-161 consistently focus on the fuel system, vacuum failure recognition, partial-panel procedures, and the differences between the Warrior and common high-wing trainers. These questions are grounded in ACS task areas II and VI .

1. 1
   Walk me through the fuel system. Why is the boost pump required for takeoff and landing, and what does it back up? (Tests low-wing fuel architecture — the top oral topic for all PA-28 checkrides)
2. 2
   What happens to your attitude indicator and heading indicator if the vacuum pump fails? What do you do? (Tests vacuum system failure recognition and partial-panel procedure)
3. 3
   Which of your gyroscopic instruments survives a vacuum pump failure and why? (Tests knowledge of power sources — turn coordinator is electric; AI and DG are vacuum)
4. 4
   How do you recognize a vacuum failure before the gyros tumble? (Tests vacuum gauge monitoring — the correct answer is declining suction gauge, not a tumbled horizon)
5. 5
   Your student trained in a Cessna 172. Explain to them how the Warrior's fuel system differs and what checklist items are different. (Common DPE framing — tests applied comparison knowledge)
6. 6
   When and why do you apply carburetor heat in the Warrior? (Tests O-320 carburetor ice awareness — applies during power reductions and in conditions conducive to icing)
7. 7
   Where in the aircraft maintenance records do you verify the altimeter, static system, and transponder inspection currency? (Tests 14 CFR 91.411 and 91.413 logbook knowledge)
8. 8
   Your VOR check was performed 35 days ago. Can you depart IFR? (Tests 14 CFR 91.171 — the answer is no; the check must be within 30 days)

How does the Warrior differ from the Piper Archer for the instrument checkride?

The PA-28-161 Warrior and the PA-28-181 Archer share the same PA-28 airframe lineage and low-wing fuel architecture — so the fuel system oral questions are nearly identical. The primary differences relevant to the checkride:

• Engine: the Warrior uses a Lycoming O-320 (approximately 160 hp); the Archer uses a Lycoming O-360 (approximately 180 hp). Both are normally aspirated and carbureted on analog variants
• Avionics: vary by aircraft, not by model — a Warrior and Archer of similar vintage may have identical panel configurations
• Fuel system architecture: identical low-wing design with engine-driven primary pump and electric boost pump — the same DPE questions apply
• Vacuum system: same split power architecture (vacuum AI and DG; electric turn coordinator) on analog variants of both models
• For G1000-equipped Archers, the vacuum system is entirely absent — solid-state AHRS replaces it; see the Archer G1000 guide for that failure architecture

If you have trained in the Archer and are flying the Warrior for your checkride (or vice versa), the system knowledge transfers almost entirely. Verify the specific aircraft's POH for any checklist differences.