Instrument rating · ACS IR.VII.B
One Engine Inoperative by Reference to Instruments
In the clouds, an engine failure is flown on the instruments: attitude and rudder first, then the same flow, then a plan with ATC.
This lesson is written for multi-engine land or multi-engine sea. You picked single-engine land: speeds, altitudes and procedures differ, so follow your POH/AFM and your instructor.
Why this one matters
An engine failure in instrument conditions doubles the workload: no outside horizon, a yawing airplane, and decisions about altitude, weather and approaches. A pilot who flies attitude and rudder first, then works the flow, keeps control.
Can’t miss
- •On instruments, the first sign is yaw: the heading turns and the ball (or slip indicator) moves. Hold the attitude and add rudder.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes; Instrument Flying Handbook (FAA-H-8083-15B))
- •The flow, in order: control and attitude; power forward; drag off; identify ("dead foot, dead engine"); verify; feather; secure by the checklist; then troubleshoot.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes; Instrument Rating ACS (FAA-S-ACS-8C), IR.VII.B.S2, S6)
- •Verify by slowly closing the suspected engine's throttle: no change is the confirmation. Manifold pressure, fuel flow and EGT are supporting evidence only.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
- •Zero sideslip on instruments: bank about 2-3° toward the operating engine on the attitude indicator, with the ball one-third to one-half out toward it, not centered.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes; Instrument Rating ACS (FAA-S-ACS-8C), IR.VII.B.S4)
- •If you can't hold the yaw or roll with full rudder, reduce power on the operating engine and lower the nose until control returns. Blue line is for performance; VMC is the control limit.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
- •Instrument rating standard: altitude ±100 feet (or minimum sink), airspeed ±10 knots, heading ±10°.(Instrument Rating ACS (FAA-S-ACS-8C), IR.VII.B.S8)
- •Decide early: the nearest airport with an approach you can fly on one engine, and tell ATC.(Instrument Rating ACS (FAA-S-ACS-8C), IR.VII.B.S9)
What you should know
Procedures on instruments K1 · R1 · R6
- Yaw shows as a heading change and a displaced ball; roll follows. Hold the wings with aileron and stop the yaw with rudder.(Instrument Flying Handbook (FAA-H-8083-15B))
- Set blue line, then the flow: power forward, drag off, identify (dead foot), verify (close the throttle: no change), feather, secure by the checklist; the engine gauges support, but don't replace, the verify step.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
- Then zero sideslip and trim: about 2-3° of bank toward the operating engine on the attitude indicator, the ball one-third to one-half out toward it.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
- Turns: a failure in a turn is flown the same way, roll toward wings level or the zero-sideslip bank first. Turn in either direction at standard rate or less, keep the zero-sideslip offset through the turn, and lead the rollout.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes; Instrument Flying Handbook (FAA-H-8083-15B))
- Once secured, troubleshoot by the checklist and judge whether a restart is wise; after a fire, a mechanical failure or an unknown cause, keep it secured.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes; Your airplane's POH/AFM)
- If you can't stop the yaw with full rudder, reduce power on the operating engine and lower the nose; then build back to blue line.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
- Configure for least drag: propeller feathered, gear and flaps up unless the approach needs them, cowl flaps as the POH says; every bit of drag costs single-engine performance.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
Performance and fuel R2 · R5
- Losing one engine costs half the power but 80-90% of the climb performance. Many light twins can't climb on one engine, and some can't hold altitude, at gross weight on a hot day or at a high field.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
- Single-engine service ceiling: where the airplane climbs only 50 feet per minute at VYSE. Absolute ceiling: where it can't climb at all. Above the absolute ceiling it drifts down at VYSE and levels off there; between the two it still climbs, just slowly.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
- If you can't hold altitude, fly blue line for the least sink and ask ATC for a lower altitude, at or above the minimum en route or vectoring altitude where you can.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
- Fuel: crossfeed is an emergency procedure, used only as the POH says, never for takeoff or landing, and never toward a side with a fire or a leak. Plan the diversion at single-engine fuel flow.(Your airplane's POH/AFM)
Low altitude and attention R3 · R4
- Hold blue line; don't let the airspeed decay trying to climb. VXSE is used only to clear an obstacle after takeoff, then accelerate to VYSE. The hard floor with asymmetric power is VMC (VSSE for intentional failures); a stall there can roll into a spin.(Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes)
- Tell ATC: declare an emergency when warranted, state that you are on one engine, and ask for the vectors, altitudes and runway you need.(Aeronautical Information Manual (AIM))
- A failure is loud and startling. Fly the airplane first (control, then airspeed), then work the flow and checklists in order, and divide attention between the failure, the flight path and traffic.(Risk Management Handbook (FAA-H-8083-2A))
On the flight
ACS standards
- Recognize, control, set engine controls, reduce drag, identify, verify, simulate feathering; best engine-inoperative airspeed and trim; checklists; troubleshoot; monitor.(Instrument Rating ACS (FAA-S-ACS-8C), IR.VII.B.S1-S7)
- Altitude ±100 feet (or minimum sink), airspeed ±10 knots, heading ±10°; decide on a safe landing and stay within the airplane's limits.(Instrument Rating ACS (FAA-S-ACS-8C), IR.VII.B.S8-S11)
What your instructor is watching for
Your instructor watches for attitude and rudder control on the instruments, the flow in order, a correct verify step, blue line and zero sideslip in straight flight and turns, a clear decision about where to land, and good use of ATC.
Scenarios
Decide what you would do first, then see the worked answer.
The heading swings left and the ball moves right.
Which engine failed? See the worked answer
The left: the airplane yaws toward the dead engine; you'll need right rudder ("dead foot" is the left).
Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes
The minimum en route altitude is 7,000; your single-engine absolute ceiling is 5,500 and you're at 9,000.
What do you do? See the worked answer
You'll drift down toward 5,500, below the MEA: tell ATC now, ask for vectors toward lower terrain or the nearest suitable airport, and declare an emergency.
Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes
In a standard-rate turn the right engine fails.
What do you do first? See the worked answer
Hold the attitude, roll toward the good engine and stop the yaw with rudder, then blue line and the flow; resume the turn with zero sideslip once secured.
Airplane Flying Handbook (FAA-H-8083-3C), Transition to Multiengine Airplanes
Common mistakes
Chasing heading with aileron alone.
Uncoordinated, losing performance.
Instead: Rudder for yaw, small bank toward the good engine.
Verifying on the gauges.
They can mislead; the throttle test doesn't.
Instead: Close the suspected throttle: no change confirms it.
Not telling ATC.
You may need lower altitudes and priority.
Instead: Declare and state your needs.
Now train it
Say it out loud, hear it asked, and take the quick check in this lesson’s practice pack. It tracks your shaky spots.
Got it?
When it feels solid, practice one engine inoperative by reference to instruments out loud with our examiner.
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Go to the source (free)
Teaching this? The instructor lesson plan →
Sources
- Airplane Flying Handbook (FAA-H-8083-3C): Transition to Multiengine Airplanes
- Instrument Flying Handbook (FAA-H-8083-15B)
- Risk Management Handbook (FAA-H-8083-2A)
- Instrument Rating ACS (FAA-S-ACS-8C): Area VII (multiengine)
- Your airplane's POH/AFM: Emergency Procedures; Performance
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-13.