Task X.C
One Engine Inoperative (Simulated) (solely by Reference to Instruments) During Straight-and-Level Flight and Turns
To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with flight solely by reference to instruments with one engine inoperative.
Note: See Appendix 2: Safety of Flight and Appendix 3: Aircraft, Equipment, and Operational Requirements & Limitations for information related to this Task.
References: FAA-H-8083-2, FAA-H-8083-3, FAA-H-8083-15, FAA-H-8083-25; FAA-P-8740-66; POH/AFM
Study Notes
AMEL/AMES task. Same engine-out flow as visual flight — while holding altitude, heading, and a scan under the hood.
Control first: stop the yaw with rudder, keep the wings near level on the attitude indicator, and hold heading. Then the standard flow — engine controls set, drag reduced, identify (dead foot), verify (retard throttle), simulate feather (evaluator sets zero thrust) — followed by best engine-inoperative airspeed, zero-sideslip trim, and the securing checklist (AFH ch 13, IFH).
Same as visual: the yaw tells me — dead foot, dead engine. On instruments the heading indicator and turn coordinator show the yaw immediately, and engine gauges (fuel flow, EGT, MP) support the diagnosis. Verification by retarding the suspect throttle is non-negotiable before feathering anything (AFH ch 13, ACS X.C R1).
Hand-flying an untrimmed, slipping twin while scanning gauges is a workload trap. Setting 2–5° bank into the good engine, half-ball, and trimming the rudder pressure off frees attention for the scan and the checklist — and the performance gained may be what lets me hold altitude at all (AFH ch 13).
Accept the drift-down: hold VYSE for minimum sink rather than dragging the nose up and decaying toward VMC. Then make the performance-based decision the ACS asks for — divert to the nearest suitable airport, tell ATC, and plan the descent so it ends at a runway.
Tolerances:
- Altitude: ±100 ft (or minimum sink if applicable)
- Airspeed: ±10 kt
- Heading: ±10° (ACS X.C S8–S9)
The operating engine is now doing all the work at high power — fuel burn on that side is high, and I may have usable fuel trapped on the dead-engine side. Know the POH crossfeed procedure and plan reserves accordingly; fuel starvation of the good engine is an unforgivable second emergency (ACS X.C R5, POH).
Declare the emergency and use ATC: vectors to the nearest suitable approach, terrain and weather info, priority handling. Use the autopilot if appropriate to shed workload, brief passengers, and keep the operating engine's gauges in the scan. Single-pilot resource management is a graded element here (ACS X.C S11, PHAK ch 2).
Official ACS elementsreference
Knowledge1 element
The applicant demonstrates understanding of:
PA.X.C.K1Procedures used if engine failure occurs during straight-and-level flight and turns while on instruments.
Risk Management5 elements
The applicant is able to identify, assess, and mitigate risk associated with:
PA.X.C.R1Identification of the inoperative engine.PA.X.C.R2Inability to climb or maintain altitude with an inoperative engine.PA.X.C.R3Low altitude maneuvering, including stall, spin, or controlled flight into terrain (CFIT).PA.X.C.R4Distractions, task prioritization, loss of situational awareness, or disorientation.PA.X.C.R5Fuel management during single-engine operation.
Skills11 elements
The applicant exhibits the skill to:
PA.X.C.S1Promptly recognize an engine failure and maintain positive aircraft control.PA.X.C.S2Set the engine controls, reduce drag, identify and verify the inoperative engine, and simulate feathering of the propeller on the inoperative engine (evaluator should then establish zero thrust on the inoperative engine).PA.X.C.S3Establish the best engine-inoperative airspeed and trim the airplane.PA.X.C.S4Use flight controls in the proper combination as recommended by the manufacturer, or as required to maintain best performance, and trim as required.PA.X.C.S5Verify the prescribed checklist procedures used for securing the inoperative engine.PA.X.C.S6Attempt to determine and resolve the reason for the engine failure.PA.X.C.S7Monitor engine functions and make necessary adjustments.PA.X.C.S8Maintain the specified altitude ±100 feet or minimum sink rate if applicable, airspeed ±10 knots, and the specified heading ±10°.PA.X.C.S9Assess the aircraft’s performance capability and decide an appropriate action to ensure a safe landing.PA.X.C.S10Avoid loss of airplane control or attempted flight contrary to the engine-inoperative operating limitations of the airplane.PA.X.C.S11Use single-pilot resource management (SRM) or crew resource management (CRM), as appropriate.