Multiengine Instructor (MEI) Oral Exam

• Hold a commercial or ATP certificate with an airplane category and multiengine class rating.
• Hold an instrument rating, or ATP instrument privileges. This is required for the multiengine instructor rating itself, not only if you plan to teach instruments.
• You do not need an existing CFI. The multiengine rating can be your initial flight instructor certificate. The spin training endorsement still applies, and it has to be done in an airplane certificated for spins, which no twin is.
• Log at least 15 hours of PIC time in multiengine airplanes.
• Pass a practical test in a multiengine airplane, demonstrating and simultaneously explaining the multiengine maneuvers to instructor standards. It is normally flown from the right seat, since that is where you will be instructing from.
• Adding the rating to a CFI you already hold skips the fundamentals of instructing knowledge test, but every other eligibility requirement still applies.

Not for certificate or rating training. You need at least 5 flight hours of PIC time in the specific make and model first.

• The requirement is per make and model, not per class. Hours in a Seminole do not qualify you to instruct in a Baron.
• It applies to multiengine airplanes, helicopters, and powered-lifts alike.
• The scope is training for a certificate or rating. A flight review or a routine checkout falls outside this paragraph, though you still need the category and class ratings on both your instructor and pilot certificates.
• Your MEI permits you to instruct in any multiengine airplane class (land or sea) for which you are rated on your commercial or ATP certificate. The instructor certificate carries "Airplane Multiengine" with no land or sea distinction.

Only if you demonstrated instrument proficiency in a multiengine airplane on the checkride.

• The instrument rating itself is issued for the category (airplane), not the class, so nothing about the rating stops you.
• But per the ACS: if you hold both a single- and multiengine rating and have not demonstrated instrument proficiency in a multiengine airplane, your certificate must bear a limitation that multiengine flight is permitted in VFR conditions only.
• That's what ACS Tasks X.C and X.D exist for. They aren't required if you already demonstrated instrument proficiency in a multi, or if you don't hold an instrument airplane rating at all.
• Removing the limitation later requires testing those Tasks in an airplane with a manufacturer's published V_MC.
• Currency is a separate question from privileges. Instrument currency under § 61.57(c) is by category, so approaches flown in a single count toward currency for the multi and vice versa. That does not lift a VFR-only limitation - if your certificate carries one, being instrument current does not authorize you to fly the twin IFR.

• You receive it when you complete the AMEL practical test in a multiengine airplane that does not have a manufacturer's published V_MC - for example a Cessna 337, whose engines are in line with the fuselage and produce no asymmetric thrust.
• The published V_MC appears on the type certificate data sheet (TCDS) or in the AFM. That's the actual test, not simply where the engines are mounted.
• It restricts you to multiengine airplanes that don't produce asymmetric thrust.
• To remove it, take a practical test on the multiengine Tasks in a multiengine airplane that does have a published V_MC.

Exactly what it says: you fly the maneuver and teach it out loud, at the same time, to the standard expected of an instructor.

• Every Task in the ACS's Multiengine Operations area uses that phrasing, and the evaluator must assess all of them.
• Flying a maneuver correctly in silence does not satisfy the skill element. Neither does a good briefing followed by a quiet demonstration.
• The explanation has to track what the airplane is doing as it happens, which is why it is harder than either half alone.

On the AMEL practical test you had to fly it. Here you fly it while narrating the control inputs, the reasons for them, and the errors you are watching for.

The ACS's Multiengine Operations area has three Tasks and the note is unambiguous: the evaluator must assess all of them.

• Maneuvering with One Engine Inoperative
• V_MC Demonstration
• Demonstration of Effects of Various Airspeeds and Configurations during Engine Inoperative Performance

Beyond that area:

• In Technical Subject Areas, the evaluator must select One Engine Inoperative Performance for a multiengine applicant, on top of the Tasks required of everyone.
• In Emergency Operations the rule is a selection, not all Tasks. The evaluator must take:
  • Task E or Task F - engine failure during takeoff before V_MC, or engine failure after liftoff
  • Task G - approach and landing with an inoperative engine, which is not optional
  • at least one other Task
• In a propeller-driven airplane that does not require a type rating, at least one landing must be demonstrated and explained with a simulated feathered propeller at zero thrust.

So Multiengine Operations is tested in full, while Emergency Operations is a selection with Task G fixed.

• Takeoff ground roll: the mixture. Introduce the failure at a speed no greater than 50% of V_MC. If the student does not promptly retard both throttles, you still have the other mixture to pull.
• In flight: a smooth throttle reduction. Below 3,000 ft AGL the FAA recommends throttle for every in-flight simulated failure, because the engine keeps running and stays available for instant use.
• Above 3,000 ft AGL no FAA source names a method. The mixture is sanctioned for the ground roll only, so an in-flight mixture cut rests on your judgment and the AFM/POH rather than on published guidance.
• Smoothly, every time. Engines with dynamic crankshaft counterweights are damaged by abrupt throttle movement.
• Never below V_SSE. If no V_SSE is published, use V_YSE. Simulating a failure below that speed is a very high and unnecessary training risk.

Only in the right context, and only with prior agreement.

• Brief simulated failures in advance. The student should know how a failure will be introduced and what response is expected of them.
• Unannounced failures are suitable only in testing and checking scenarios, and only when both pilots have agreed to that before the flight.
• A pre-flight brief along the lines of "at some point today I will fail an engine with no further warning" satisfies that. Quietly deciding mid-lesson to catch someone out does not.

Surprise is a checking tool rather than a teaching one. During instruction the student is building a procedure, and nobody practices a procedure well while being startled by it. Save it for the stage check, and brief it even then.

If the engines have dynamic counterweights, abrupt throttle reductions can damage them, and repeated abuse eventually leads to engine failure.

• High rpm with low manifold pressure, over-boosting, and propeller feathering can cause the same damage.
• Not every engine has them. The handbook points to larger, more complex engines, but the manufacturer's list is what settles it. Check your exact model.

The exposure is yours more than the student's. You are the one pulling throttles several times a flight, several flights a week.

1. Reduce the throttle smoothly on the engine you are failing.
2. The student runs the memory items and retards the propeller control toward feather.
3. Before it reaches feather, move the propeller control forward and set the manifold pressure and rpm that produce zero thrust in your airplane.
4. Say what you did, out loud. Words to the effect of: "I have the right engine; you have the left. I have set zero thrust and the right engine is simulated feathered."

Zero thrust puts the engine where a feathered propeller's drag would be, so the student sees representative single-engine performance without an actual shutdown, and the propeller never has to be unfeathered in flight.

Step 4 is not a courtesy. Any ambiguity about who is operating which systems or controls increases the likelihood of an unintended outcome, and that ambiguity is what puts two people's hands on the same quadrant.

You are. The instructor cares for the "failed" engine exactly as the student cares for the operative one.

• At a zero-thrust setting, the cowl flap is normally closed and the mixture leaned.
• Clear the engine occasionally so the plugs do not foul at a prolonged low power setting.
• Where you can, avoid a high power application immediately after a prolonged cool-down at zero thrust.

The reason is that a simulation quietly becomes an emergency if the engine is shock-cooled or loaded up and then does not respond when you need it. The whole premise of simulating with the throttle is that the engine remains available, and that is only true if somebody is tending it.

It also models what you want the student doing later: an engine that is secured still gets managed, not forgotten.

Because the windmilling propeller lies to the pilot, and the lie is expensive.

• A windmilling propeller has often given the improperly trained multiengine pilot the mistaken perception that the engine is still developing useful thrust.
• That produces a psychological reluctance to feather, since feathering stops the propeller turning and feels like giving something up.
• The reluctance costs exactly the performance the airplane needed.

So demonstrate both, back to back, at altitude: the same airplane at the same speed and weight, windmilling and then at zero thrust. The rate of climb difference makes the argument better than any briefing.

On the practical test, the ACS sets three gates.

• Engine failure after liftoff: not simulated until at least 400 ft AGL and at least V_SSE, V_XSE, or V_YSE.
• Single-engine demonstration tasks: the evaluator picks an entry altitude that lets them finish no lower than 3,000 ft AGL, or the manufacturer's recommended altitude, whichever is higher. That is a floor for the maneuver, not the 3,000 ft threshold that decides which method you use.
• Anything requiring feathering or shutdown: only at a position and altitude from which a safe landing at an established airport is possible if the propeller will not unfeather or the engine will not restart.
• If it will not unfeather or restart in flight, treat it as an emergency, not as a training exercise that went long.

In training the FAA's light-twin guidance adds caution rather than a limit. Approach simulated failures below 400 ft AGL with extreme caution, and reserve anything below 200 ft AGL for a simulator or training device. The two 400 ft figures are not the same rule: one is a test limit, this is a caution.

The designed defense is procedural, and the handbook names one concrete backup.

• The verify step is the guard. Retarding the throttle of the engine believed to have failed is a reversible test before an irreversible action, and teaching the student to never skip it does more than any physical intervention.
• On the takeoff roll, if the student does not promptly retard both throttles, the instructor can always pull the other mixture.
• Brief the division of controls before the flight, and restate it in the air. Two people reaching for the same quadrant is the outcome you are preventing.

Beyond that, instructors commonly shadow the quadrant with a hand and stay ready to block a pedal before a wrong input loads up. That is accepted practice rather than published procedure, so treat it as technique and brief it, not as something the student should be surprised by.

Because feathering the operating engine is unrecoverable at low altitude, and misidentification under stress is common.

To verify: slowly retard the throttle of the engine you believe has failed.

• If nothing changes - no change in yaw, sound, or performance - your identification was correct.
• If the airplane's behavior worsens, you had the wrong engine. Restore that throttle immediately.

Do it slowly and deliberately. The whole point is a reversible test before an irreversible action.

The step is skipped only where the AFM says so, and never as a time-saver.

Dead foot, dead engine.

• The airplane yaws toward the failed engine, so you push the rudder on the operating side to stop it. The foot that is doing nothing is on the side of the dead engine.
• This works because it keys off a control input you are already making, not off an instrument you have to find and interpret.

Why not just read the gauges? On a sudden failure, engine instruments can be ambiguous or slow - a partial power loss may show near-normal indications, and manifold pressure can read high on a failed engine. The rudder never lies about which way the airplane is yawing.

Confirm with instruments once the airplane is under control, but identify with your feet first.

Yes, in a few cases:

• Below the AFM's minimum altitude or airspeed for the procedure, where the manufacturer specifies flying the airplane first.
• When you are about to land anyway - Very low, with the runway made, securing the engine is less important than flying the landing.
• During training, where instructors commonly simulate a failure with zero thrust rather than actually feathering, to keep a restart from being necessary.
• When you have not verified which engine failed. Feathering the wrong one is worse than the drag of a windmilling propeller.

Also relevant: the ACS requires that Tasks involving actual feathering or shutdown be done only at a position and altitude where a safe landing on an established airport is possible if the propeller won't unfeather or the engine won't restart.

It depends on altitude, workload, and whether you have any idea what happened.

• Secure it if you are low, busy, close to an airport, or the cause is obvious and serious - fire, severe vibration, oil loss, mechanical noise. Never restart an engine that may be damaged or burning.
• Consider a restart only with plenty of altitude, the airplane stabilized and cleaned up, and a plausible cause you can address: fuel selector on an empty tank, a switched-off boost pump, carburetor ice, a magneto problem.

Order of operations matters. Fly the airplane, clean up the drag, get to a stable single-engine condition and on the way to an airport first. Troubleshoot only with whatever attention is genuinely left over, and always with the checklist.

The engine whose failure would most adversely affect the performance or handling qualities of the airplane.

• In a conventional twin with both propellers turning clockwise as seen from the cockpit, the critical engine is the left one.
• "Critical" is about the remaining engine's ability to yaw the airplane. Losing the left engine leaves the right engine producing the larger yawing moment, so more rudder is needed and V_MC is higher.
• If the airplane has counter-rotating propellers, there is no critical engine.

PAST is the usual mnemonic, not FAA language.

• P-factor - At a positive angle of attack the descending blade produces more thrust. On a conventional twin, both propellers turn clockwise, so that blade is on the right of each disc and both thrust lines shift right. On the left engine that shift is inboard, toward the fuselage; on the right engine it is outboard. The right engine ends up with the longer arm and produces a stronger yawing moment.
• Accelerated slipstream - Each propeller's high-velocity air adds lift on the wing behind it, centered on that same displaced thrust line. So it too sits farther out on the right engine, giving a longer rolling arm.
• Spiraling slipstream - The corkscrew off the left propeller wraps around the fuselage and strikes the left side of the vertical stabilizer, countering the yaw when the right engine fails. The right propeller's corkscrew passes outboard of the tail, so there is no matching help to lose.
• Torque - Due to Newton's third law, in a conventional twin with both propellers rotating clockwise, the aircraft rolls in the opposite direction (counter-clockwise), which produces a left roll. When you lose any engine, asymmetric thrust creates a rolling and yawing motion towards the dead engine. With the left engine out, torque adds to the existing roll toward the dead engine created by asymmetric thrust, and with the right engine out, torque opposes it.

All four point the same way: losing the left engine on a conventional twin with clockwise-rotating props is worse.

Think of it as thrust arms about the center of gravity.

• Because of P-factor, each engine's effective thrust line sits slightly to the right of its physical centerline.
• If the right engine fails, the operating left engine's thrust line has been shifted toward the fuselage - a shorter arm - so it produces a smaller yawing moment. Easier to control, lower V_MC.
• If the left engine fails, the operating right engine's thrust line has been shifted away from the fuselage - a longer arm - so it produces a larger yawing moment. Harder to control, higher V_MC.

Since losing the left engine leaves you fighting the bigger moment, the left engine is critical. Spiraling slipstream, accelerated slipstream, and torque all reinforce the same conclusion.

• The propellers turn in opposite directions, with the descending blade of each on the inboard side. That pulls each engine's thrust line toward the fuselage and makes the two moment arms equal.
• Both engines then produce the same yawing moment when the other fails, so there is no critical engine. A Seminole, a Duchess, and a Seneca are common examples.
• With both engines running, torque and spiraling slipstream effects also cancel between them.

Two things not to over-claim: it does not mean the airplane has no V_MC, and it does not mean an engine failure is benign. You still get a large yawing moment, still need rudder and bank, and still fly the full engine-failure flow. Nor do torque, P-factor, and slipstream disappear once an engine quits - the operating engine still produces all three. Counter-rotation equalizes the two failure cases; it doesn't remove the effects. It just means it doesn't matter which one quits.

V_MC is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is still possible to maintain control of the airplane with that engine inoperative and then maintain straight flight at the same speed with a bank angle of not more than 5°.

Two things students routinely miss:

• It's about directional control, not performance. Being above V_MC says nothing about whether the airplane will climb.
• The red line is one number determined under one specific set of certification conditions. Actual V_MC on any given day is usually lower, but under the wrong conditions it can be higher than the mark on the dial.

Legacy § 23.149 set the conditions, deliberately the most unfavorable realistic combination. What the rule itself says:

• Bank angle of not more than 5° toward the operating engine, holding straight flight at the same speed after the critical engine is suddenly made inoperative - (a).
• V_MC for takeoff may not exceed 1.2 V_S1, with V_S1 at maximum takeoff weight - (b).
• Most unfavorable weight and center of gravity, airborne with ground effect negligible - (b). For a light twin the most unfavorable CG is the aft limit, because it shortens the rudder arm.
• Maximum available takeoff power initially on each engine - (b)(1).
• Trimmed for takeoff - (b)(2).
• Flaps in the takeoff position - (b)(3).
• Landing gear retracted - (b)(4).
• All propeller controls in the recommended takeoff position throughout - (b)(5).
• Rudder pedal force not exceeding 150 lb, and no need to reduce power on the operating engine - (e).
• No dangerous attitude, and it must be possible to prevent a heading change of more than 20° - (e).

Two conditions people recite that the rule doesn't name explicitly. Both still come from it:

• Windmilling propeller - (b)(5) keeps the propeller controls in the recommended takeoff position, and on a twin without autofeather that leaves the failed propeller windmilling. An airplane certified with autofeather is a different case - know which one you fly.
• Cowl flaps set for takeoff - the AFH reads the (b)(3) takeoff flap condition as covering wing flaps and cowl flaps.

Paragraph (c) adds the landing configuration, but exempts reciprocating airplanes of 6,000 lb or less, which is every piston trainer.

No. The red line is one number determined under one specific set of certification conditions, and your actual V_MC moves with conditions.

• Most of the time your actual V_MC is lower than red line, because you are rarely at the most unfavorable weight, CG, and configuration all at once.
• But it can be higher than red line when you are outside what certification assumed. The big one is failing to bank into the operating engine - wings level, the real loss of control can come almost 20 kt above the published number.
• Other ways to get there: operating outside the approved envelope (aft of the CG limit), flying clean when certification used the takeoff flap setting, or a propeller that fails to feather when certification assumed an automatic feathering device.
• A related trap that isn't the same thing: certification allowed up to 150 lb of rudder force. Don't apply what's available and you lose control above the airplane's V_MC - which doesn't raise the aerodynamic V_MC, only the speed at which you run out of control.
• What does not belong on that list: a tired operating engine. Less power means less asymmetric thrust, so V_MC goes down, not up - a worn engine costs you climb, not directional control.
• Nor an approved aft CG, or a windmilling propeller on a twin whose red line was established with one. Those are the conditions § 23.149(b) already assumes, not departures from them. Know your own airplane, though: where certification assumed automatic feathering, a propeller that windmills instead is a departure.

Treating red line as a hard floor is the mistake. Being 5 kt above the mark is not the same as having control margin.

It is the largest single lever you have, and the only one you control directly in the moment.

• Banking toward the operating engine tilts the lift vector, and its horizontal component helps the rudder oppose the yaw from asymmetric thrust.
• Certification allows a bank of not more than 5°. Flying wings level instead of banked raises V_MC dramatically - the AFH says V_MC may increase more than 3 knots for each degree of bank reduction between 5° and wings level, which is why it also says loss of directional control can come almost 20 knots above the published number with the wings held level.
• Banking beyond about 5° keeps lowering V_MC but degrades climb performance and moves you away from zero sideslip, so it isn't free.

This is why "bank into the good engine" is the reflex being trained, not an optional refinement.

More power raises V_MC. It is the most direct relationship of any factor: the yaw you are fighting comes from thrust on one side, so more thrust means a larger yawing moment and a higher speed needed to generate the rudder force that opposes it.

• Certification uses maximum available takeoff power initially on each engine - § 23.149(b)(1) - because that is the worst case.
• The rule also requires that it not be necessary to reduce power on the operating engine to keep control at V_MC - (e). Throttling back is not an allowed part of the test.
• It follows that reducing power on the good engine removes the yaw at its source - which is why power comes off, not on, in a V_MC recovery.
• This is also the mechanism behind the altitude effect: a normally aspirated engine cannot make takeoff power up high, so the asymmetric thrust weakens and V_MC falls.

The corollary: less power means less asymmetric thrust, so a tired or partially failed operating engine leaves you with a lower V_MC, not a higher one.

An aft CG raises V_MC, which is why certification uses the most unfavorable (aft) CG.

• The rudder generates a yawing moment equal to force times arm, and that arm is the distance from the CG to the rudder.
• Moving the CG aft shortens the arm, so the same rudder deflection produces less corrective yawing moment.
• With less authority available to oppose the asymmetric thrust, you need more airflow over the rudder to do the job - a higher speed.

A forward CG has the opposite effect and lowers V_MC. It's one of the few cases where loading the airplane forward is a controllability benefit, not just a stability one.

Heavier is lower. This one is counterintuitive and gets asked constantly.

• When you bank into the operating engine, the horizontal component of lift is what helps the rudder fight the yaw.
• At a given bank angle, a heavier airplane is producing more total lift, so that horizontal component is larger and does more of the work.
• More help from the lift vector means you need less help from airflow over the rudder, so V_MC goes down.

That's why certification specifies the most unfavorable weight. Be careful not to confuse this with performance: the heavier airplane has a lower V_MC but worse single-engine climb.

V_MC decreases with altitude in a normally aspirated twin.

• The operating engine loses power as density altitude rises, so the asymmetric thrust producing the yaw gets weaker.
• Less yaw to oppose means less rudder authority required, which means a lower speed will do.

Two important qualifiers:

• Indicated stall speed does not change with altitude, so the gap between the two closes and eventually reverses.
• A turbocharged twin holds full rated power up to its critical altitude, so its V_MC may stay high well into the climb - and can remain above the stall speed where a normally aspirated twin's would not.

Extending the landing gear lowers V_MC. The gear adds keel area and drag, increasing directional stability - the fuselage resists being yawed out of line, so less rudder is needed to balance the asymmetric thrust. Certification uses gear retracted because that's the more unfavorable case.

Extending flaps also lowers V_MC, slightly, for two reasons:

• Lower angle of attack. Flaps let the wing make the same lift at a lower AoA, and the asymmetry you're fighting is largely P-factor, which grows with angle of attack. Less AoA means a smaller yawing moment to balance, so less rudder, so a lower V_MC.
• Flap drag in the slipstream. The flap section behind the operating engine sits in that engine's accelerated slipstream and makes more drag than the same section on the dead side. That small asymmetry pulls the nose back toward the operating engine, opposing the yaw.

The flap effect is small and airplane-specific, which is why certification uses the takeoff position rather than clean. Note the AFH lists takeoff flaps as a condition without explaining the mechanism - the reasoning above is aerodynamic, not a quotable handbook passage.

Don't turn any of this into a technique. Lowering the gear to reduce V_MC trades a control benefit for a large drag penalty and destroys whatever single-engine climb you had - a good exam answer about aerodynamics, and a bad plan in the airplane.

• A windmilling propeller produces a large amount of drag well out on the wing, adding to the yawing moment the rudder must oppose. That raises V_MC.
• A feathered propeller has its blades edge-on to the airflow, producing minimal drag, which lowers V_MC and substantially improves climb.

Certification assumes the propeller is in the position it automatically assumes when the engine fails - for most training twins, windmilling. That's the conservative case, and it's why feathering promptly is worth so much: it improves both controllability and performance at the same time.

• In a normally aspirated twin, V_MC falls with density altitude as the operating engine loses power, while indicated stall speed stays essentially constant. A turbocharged twin holds full asymmetric thrust to critical altitude, so its V_MC need not fall this way.
• Low down, V_MC may be above the stall speed - so a slowing airplane loses directional control first.
• High up, V_MC drops below the stall speed - so the airplane stalls before it reaches V_MC. Both the ACS and the AFH say so for normally aspirated engines: at some altitude the two speeds are the same.

This matters in two directions:

• It's why the ACS has you recover a V_MC demonstration at the first indication of loss of directional control, stall warning, or buffet. At altitude, the stall arrives first, and a stall with asymmetric thrust can rapidly develop into a spin.
• It's why a demonstration at a safe altitude can never show you the low-altitude case, which is the one that actually kills people.

SMACFUM is the list of conditions your airplane's published V_MC was measured under. Every letter but U is set to make V_MC as high as possible - which is why the red line is a worst case rather than a number you will see in normal flight.

• Because every row but U is set against you, your actual V_MC is usually lower than the red line.
• It can sit above the red line too. Giving up the bank is the big one. So is anything outside what certification assumed - an aft CG beyond the approved envelope, or a propeller that windmills where the airplane was certified with autofeather.
• Density altitude assumes a normally aspirated engine. A turbocharged twin holds rated power to its critical altitude, so its V_MC stays high well into the climb - above that altitude it falls off like any other.
• This is a mnemonic for the factors that move V_MC - not the certification standards. § 23.149 also fixes trim and out of ground effect, and sets criteria the airplane had to meet: a 150 lb rudder pedal force limit, no more than 20° of heading change, and V_MC no greater than 1.2 V_S1. Those are pass/fail standards rather than things that move the speed.

The combination of bank and rudder that makes the airplane fly straight through the air with the fuselage aligned to the relative wind, producing the least possible drag with one engine inoperative.

• With asymmetric thrust, you need rudder to stop the yaw. Rudder alone leaves the airplane flying slightly sideways through the air, which is drag you cannot afford.
• Adding a small bank toward the operating engine lets the horizontal component of lift do part of the work, so less rudder is needed and the fuselage lines up with the airflow.
• It is the configuration in which published single-engine climb performance was actually measured. Fly it any other way and you will not see book numbers.

• Bank approximately 2° toward the operating engine. The precise angle varies by model from 1.5° to 2.5° - the 5° certification limit is not a zero-sideslip figure and does not establish it.
• Hold enough rudder toward the operating engine to stop the yaw.
• The inclinometer ball ends up one-third to one-half of a ball width displaced toward the operating engine - not centered.

So the picture is: slight bank into the good engine, ball split toward the good engine, heading steady. A yaw string will show you directly whether the fuselage is aligned with the airflow - the AFH recommends one for exactly this - but it won't hand you the bank-and-rudder combination or your airplane's performance optimum. The ball alone certainly won't; the combination is what matters.

Raise the dead: the dead engine's wing comes up.

Although it feels correct, it worsens your climb rate.

• With wings level and the ball centered, the rudder is doing all the work of opposing the yaw, and the airplane ends up slipping through the air toward the inoperative engine.
• The fuselage is presented at an angle to the relative wind, which adds substantial parasite drag at exactly the moment you have no surplus power.
• Zero sideslip is what produces the best rate of climb - or the least rate of descent. In a light twin that margin is thin enough that giving up part of it can be the entire difference between climbing and not.
• It also raises V_MC, because you have given up the help of the lift vector's horizontal component.

Wings level is the single most common way trained pilots quietly throw away their single-engine performance.

• Holding heading on ailerons alone takes 8-10° of bank toward the operating engine (AFH Fig 13-16).
• With no rudder input, the ball is displaced well toward the operating engine - far more than the third to half a ball of zero sideslip.
• The airplane is left in a large sideslip toward the operating engine, and climb performance is greatly reduced.
• The risk of losing directional control is high enough that instructors should not normally demonstrate it.

Wings level and excessive bank bracket zero sideslip from either side: one slips toward the dead engine, the other toward the good one. Wings level is the moderate error; excessive bank is the severe one.

Why bank and rudder together produce zero sideslip

• Left engine out: the right engine's thrust yaws the nose toward the dead engine. Right rudder stops the yaw.
• But the rudder is a lifting surface. The side force it produces on the tail acts toward the dead engine, and with the wings level nothing opposes it - so the airplane slips through the air, fuselage skewed to the relative wind.
• Bank ~2° toward the operating engine. The lift vector tilts, and its horizontal component acts toward the good engine, opposing the rudder's side force.
• With the two in balance, the airplane no longer has to slip to make up the difference. The fuselage aligns with the relative wind: zero sideslip.

Why that leaves the ball off center

• The horizontal component of lift is what normally turns an airplane. Here it is fully committed to opposing the rudder, so the net sideways force is zero - the flight path stays straight and the heading holds.
• In a normal coordinated turn the ball centers because the bank produces a turn, and the turn's inertia pushes the ball outboard by exactly as much as gravity pulls it toward the low wing.
• In zero sideslip there is no turn, so nothing offsets gravity. The ball responds to gravity alone and settles toward the low wing - one-third to one-half a ball width toward the operating engine. Its displacement is really just reading your bank angle.

Why this contradicts the single

• In a single, a slip (ball toward the low wing) and a skid (ball toward the high wing) are the same thing in opposite directions - both are sideslip, and both show on the ball.
• What a single doesn't have is a standing sideways force. The rudder can certainly make one - a forward slip is exactly that - but it is a force you are choosing to hold, and releasing it removes the force and the sideslip together. Centering the ball and zeroing the sideslip normally coincide, which is why "step on the ball" works in either direction.
• With an engine out, the rudder you hold is opposing a yawing moment from thrust, not from the relative wind. It stays there whether or not the fuselage is aligned, and the ball - which only sees the sum of the forces - cannot tell the two sources apart.
• So "balanced" now has two solutions: let the air balance the rudder, which takes a sideslip, or let the horizontal component of lift balance it, which does not. Only the second is zero sideslip.

In a single, a centered ball means no sideslip. In a twin with an engine inoperative, it means no bank - and with rudder held in, no bank means you are slipping. Chasing the ball back to center from a correct 2° of bank takes still more rudder, restores the sideslip, and turns you instead of holding heading.

• Apply rudder immediately and firmly. The initial input is large - stopping the yaw is the first priority, before anything else.
• Once the airplane is stabilized in zero sideslip, trim the rudder to relieve the pressure. Holding a heavy leg load for a long single-engine approach is how mistakes creep in.
• Retrim as airspeed and power change, since the required rudder varies with both.
• Be ready to remove that trim during recovery or a change in configuration; rudder trim held into a power reduction can produce yaw in the opposite direction.

The workload argument matters: an untrimmed leg gets tired, and a tired leg relaxes at exactly the wrong moment on short final.

They are separate questions, and confusing them is dangerous.

• Controllability - Can you keep the airplane pointed where you want? This is the V_MC question. Its answer is airspeed, bank, and rudder.
• Performance - Can you climb, hold altitude, or only slow the descent? This is the single-engine climb question. Its answer is weight, density altitude, configuration, and drag.

Being above V_MC tells you only that you can steer. Many light twins are perfectly controllable while descending steadily into terrain.

The practical consequence: after the failure you solve control first (pitch for V_YSE, bank into the good engine, stop the yaw), then solve performance (clean up the drag, feather), then decide where the airplane can actually go.

To let you recognize the onset of loss of directional control with an engine inoperative, and to practice recovering from it promptly.

• It is a demonstration of a flight characteristic, not a maneuver you would ever perform operationally.
• It teaches the cues - the rudder running out of travel, the airplane starting to yaw despite full rudder, the buffet or stall warning.
• It also shows, concretely, that V_MC is not a fixed number: the speed at which you lose control in the demo will usually be well below red line, and at altitude the stall may arrive first.

It's Task X.B in both the Private and Commercial ACS.

Set up to approximate the certification conditions, which is what makes the demonstration meaningful:

• Landing gear up
• Flaps in the takeoff position
• Cowl flaps as required
• Trimmed for takeoff
• Both engines set to a safe starting power, then the critical engine reduced to idle (or simulated) and maximum power on the operating engine
• Propeller of the simulated failed engine windmilling (not feathered)
• Bank up to 5° toward the operating engine

Do it at an altitude that allows recovery no lower than 3,000 ft AGL, and clear the area thoroughly first.

• Enter high enough to complete the recovery no lower than 3,000 ft AGL.
• The reason is the realistic failure mode. If the demonstration goes wrong, it goes wrong as a stall with asymmetric thrust, which can rapidly develop into a spin - and a light twin has no approved spin recovery and can lose a great deal of altitude.

There's a second, subtler reason worth understanding: because V_MC decreases with density altitude while stall speed doesn't, a demonstration at altitude is inherently more likely to produce a stall than a genuine loss of directional control. The altitude that makes the maneuver safe is the same thing that makes it show you the stall case rather than the V_MC case.

• Clear the area and set up so the whole maneuver happens at least 3,000 ft AGL.
• Configure per the manufacturer; absent that, the ACS spells it out: gear up, flaps takeoff, cowl flaps takeoff, trim takeoff, props high rpm.
• Critical engine to idle with its propeller windmilling - not the zero-thrust setting used for the engine-failure Tasks - and the operating engine to takeoff power.
• Establish a climb attitude about 10 kt above V_SSE and a bank of up to 5° toward the operating engine.
• Increase pitch slowly to decelerate at about 1 knot per second, adding rudder as needed to hold heading.
• Continue to the first indication of loss of directional control, stall warning, or buffet.
• Recover immediately: reduce power on the operating engine enough to stop the yaw, lower the angle of attack, add no power on the failed engine, and recover within 20° of entry heading.

The deceleration rate is part of the standard. Going faster takes a steeper pitch attitude, which drives the angle of attack up and can carry you past the first cue before you recognize it - and a V_MC demo that degrades into a stall with high asymmetric thrust "may result in an unrecoverable loss of control and a fatal accident."

The first indication of any of three things:

• Loss of directional control - Full rudder is in and the airplane still begins to yaw
• Stall warning - Horn or light
• Aerodynamic buffet

Whichever comes first is your cue. You are not trying to find the "real" V_MC, and you never continue past the first indication to see what happens.

At altitude in a normally aspirated twin, the stall warning or buffet very often arrives before the loss of directional control, because V_MC has fallen below the stall speed. Recognizing that is part of the lesson.

Simultaneously:

• Reduce power sufficiently on the operating engine - This removes the asymmetric thrust causing the yaw
• Decrease the angle of attack as necessary to regain airspeed and directional control
• Do not add power on the simulated failed engine

Then recover to V_SSE/V_YSE as appropriate and advance power smoothly.

ACS standards:

• Recover within 20° of the entry heading
• Maintain V_SSE/V_YSE during recovery within ±5 kt (commercial) or +10/-5 kt (private)

The instinct to fix a yaw with more power on the good engine is exactly backwards here - it makes the yaw worse. Power comes off.

The stall. The student is focused on directional control, often to the extent that impending stall indications go unnoticed.

• Spin awareness should be at its greatest during V_MC demonstrations, stall practice, slow flight, and any condition of high asymmetric power.
• In a multiengine airplane the yawing moment that turns a stall into a spin is already there, supplied by asymmetric thrust.
• A forward CG gives better stall and spin avoidance characteristics but does not eliminate the hazard.
• Very few twins have ever been spin-tested, and none are required to be.

So your attention is split differently from the student's: they own the rudder and the heading, you own the stall margin. If the stall warning or buffet arrives first, that is the recovery cue, and recognizing it is part of the lesson rather than a failed demonstration.

Because a stall with asymmetric thrust can rapidly develop into a spin, and light twins are not certified for spins or required to demonstrate spin recovery.

The ACS is explicit on the related hazard: do not perform this maneuver by increasing pitch attitude to a high angle with both engines operating and then reducing power on the critical engine. That technique is hazardous and may result in loss of airplane control - it sets up a yaw at high angle of attack, which is precisely how a spin starts.

The correct method establishes the asymmetric condition first, at a safe speed, then decelerates slowly toward it. And you stop at the first indication, every time.

Do not pitch up to a high attitude with both engines operating and then reduce power on the critical engine. The ACS says the technique is hazardous and may result in loss of airplane control. The handbook separately warns that demonstrating V_MC with an engine cut from high power creates a high likelihood of loss of control.

• It stacks the two ingredients of a spin at once: a high angle of attack and a sudden asymmetric yawing moment.
• It also arrives at the condition faster than the student, or you, can evaluate it.

The sanctioned entry runs the other way round: establish the single-engine condition first, then decelerate at 1 knot per second, no faster. That rate is part of the standard, and rushing it is what produces the steep pitch attitude the prohibition is aimed at.

By artificially limiting rudder travel to simulate maximum available rudder, a technique the handbook sanctions for exactly this case.

The pedals are interconnected, so one going forward pulls the other aft toward the pilot. You block the pedal coming aft, which is the opposite side from the rudder you are limiting:

• Simulated left engine failure needs right rudder, so block the left pedal from traveling aft.

• Simulated right engine failure needs left rudder, so block the right pedal from traveling aft.

• Limiting travel means "full rudder" arrives sooner, so the airplane departs directionally at a higher airspeed, above the stall, where you can show the real cue.

• Use a speed approximately 20 knots above V_S when limiting rudder travel.

• It avoids the hazard of spinning from a stall with high asymmetric power, and it still demonstrates loss of directional control.

The alternative is not "demonstrate it anyway." At some density altitudes, or in an airplane whose V_MC is at or below V_S, the real demonstration is not possible, and riding one down to a stall with the good engine at takeoff power is how it becomes a spin.

• No. Normal-category multiengine airplanes are not approved for spins and have no published spin recovery procedure, because no spin recovery testing is required for certification.
• The dangerous combination is asymmetric thrust plus a stall. Yaw at the stall is exactly what starts a spin, and a twin gives you a powerful yawing moment for free the moment an engine fails.
• Recovery in a twin is often unreliable, and altitude loss can be extreme.

The defense is procedural, not a recovery technique: never let the airplane get slow with asymmetric power. That is the reason you recover a V_MC demonstration at the first indication rather than riding it to the stall.

Roughly 80% of your climb performance, not 50%.

• You lose half your power, but climb performance depends on excess power - what's left over after overcoming drag. Most of the remaining engine's output is consumed just holding level flight.
• On top of that, the dead engine adds drag, and the control inputs needed to stop the yaw add more.
• A typical light twin at gross weight on a warm day may climb only 100-200 fpm on one engine, and some can't climb at all.

The practical conclusion: a light twin's second engine buys you time and options, not guaranteed climb. Treat single-engine climb as something you verify in the charts before takeoff, not something you assume.

• In normal two-engine flight you have a large surplus of thrust over drag, and that surplus is what climbs the airplane. Adding drag just eats into a healthy margin.
• With one engine out, the surplus is nearly gone. Every additional unit of drag comes straight out of climb rate.
• A windmilling propeller, extended gear, extended flaps, or flying with a sideslip can each individually erase what little climb you have.

This is why the OEI flow is fundamentally about drag reduction, and why the cleanup happens before you try to troubleshoot anything.

• Published single-engine climb assumes the best case: critical engine feathered, gear and flaps up, zero sideslip, V_YSE, maximum power on the good engine, and a new airplane flown by a test pilot.
• Real numbers in a light twin at gross on a warm day are commonly 100-200 fpm, and can be zero or negative.
• Every departure from that ideal costs you: a windmilling prop, gear down, flaps out, or a sideslip can each individually consume all of it.

The planning discipline is to look up single-engine climb for today's weight, pressure altitude, and temperature before you take off, and to know your single-engine service ceiling. If the chart says you can't climb, the airplane will not surprise you by climbing.

Roughly in order of magnitude for a typical light twin:

1. Windmilling propeller - The single largest item, and the reason feathering is the highest-value action available to you.
2. Extended landing gear - Large parasite drag, and usually the easiest thing to fix.
3. Extended flaps - Significant beyond the takeoff setting.
4. Sideslip - Flying wings level or with the ball forced center.
5. Open cowl flaps - Small individually, and not a free cleanup: cowl flaps are engine-temperature control, and the operating engine at climb power may need them open. Set them as the AFM directs, not reflexively closed.

The order is why the OEI flow is about drag reduction before it's about troubleshooting. You buy back climb in the order above, then worry about why the engine quit.

Control first, then drag, then diagnosis - the order the AFH says most AFM/POH checklists use. Your airplane's checklist is the authority; some retract the gear before the flaps.

Control

• Pitch for V_YSE (blue line)
• Rudder to stop the yaw, bank ~2° into the operating engine (zero sideslip)

Configure / reduce drag

• Mixtures forward
• Props forward
• Throttles forward
• Flaps up
• Gear up
• Cowl flaps as required

Identify, verify, feather

• Identify - "Dead foot, dead engine," from the control inputs, not the gauges
• Verify - Slowly retard the suspect throttle. No change in performance is the verification
• Feather - Corresponding propeller control fully aft

Then secure the engine, declare as appropriate, and fly the airplane to a landing. Finish with the printed checklist, deliberately - other than closing the failed engine's cowl flap, none of the remaining items affects climb performance.

The flow includes flaps and gear even when they're already up. A memory item either initiates an action or confirms a condition, and the same flow has to work for a failure during a go-around.

Artificially limit the manifold pressure available on the operating engine. Most multiengine training happens in four- to six-seat airplanes at weights well below maximum, where single-engine performance at low density altitude is deceptively good.

The cost: less power on the operating engine also means less asymmetric thrust, so V_MC falls. You are buying performance realism by spending controllability realism. The handbook recommends doing it only occasionally.

• The density altitude at which the airplane, with the critical engine inoperative and its propeller feathered, can still climb at 50 fpm at V_YSE.
• It is far lower than the all-engines service ceiling - often only a few thousand feet, and on a hot day at a high field it can be below the terrain around you.
• This is the number that answers the real question after an engine failure: can I climb, hold altitude, or only slow my descent?
• It's also why a drift-down plan matters - but get the trigger right. Between this altitude and the single-engine absolute ceiling the airplane still climbs, just at less than 50 fpm. Only above the absolute ceiling does a failure mean losing altitude. Plan on the service ceiling anyway: the AFH cautions that engine and propeller wear, turbulence, and pilot technique mean the airplane may not hold altitude even at the published single-engine ceiling.

• It tells you the highest altitude the airplane can still climb at 50 fpm with one engine feathered - in practice, the highest altitude you can count on holding. Above it the airplane still climbs, just at less than 50 fpm, up to the single-engine absolute ceiling where climb is no longer possible. Above that, a failure means a drift down.
• Over terrain, that turns into a screening question: is the single-engine service ceiling above the highest terrain and obstacles along your route, with margin? Treat it as a screen, not a clearance calculation - the real answer comes from the AFM single-engine climb data at the weight, temperature, and altitude you'll actually be flying.
• If it isn't, you need a different route, a lower weight, a cooler time of day, or an honest acceptance that an engine failure means an off-airport landing.
• It also shapes your escape plan - knowing which direction leads to lower terrain matters far more in a twin that can only descend slowly than in one that can climb.

This is the planning item that separates flying a twin from simply having two engines.

It moves both problems in dangerous directions at once:

• Performance gets worse. Single-engine climb drops sharply and the single-engine service ceiling falls, often below the surrounding terrain. You may have no positive single-engine climb at all.
• V_MC gets lower in a normally aspirated twin, which sounds helpful but means V_MC and the stall speed converge - so the failure mode shifts from a controllability problem toward a stall/spin problem.

The result is a takeoff where an engine failure after liftoff may simply not be survivable as a climb-out, and where the correct plan is to treat the twin like a single: land more or less straight ahead.

The mitigations are the ordinary ones - reduce weight, go early in the morning, use the longest runway, and brief a decision point honestly.

Abort. Close both throttles, maintain directional control, brake as required, and stop on the runway.

• Below V_MC you have no assurance of directional control airborne, so continuing is not a real option.
• Directional control on the ground with asymmetric thrust is itself a handful - closing both throttles removes the asymmetry immediately.
• Use maximum braking as needed, and be prepared to steer with rudder and differential braking.

This is the easy case, and it is only easy if you briefed it. The decision has to already be made before the takeoff roll starts.

If there is usable runway ahead, land on it. Reduce power on the operating engine to reduce the yawing moment, lower the nose, and put the airplane back down.

• Below V_YSE with the gear down and a windmilling propeller, a light twin usually cannot climb. Attempting to continue trades a landing you can make for a crash you cannot avoid.
• Retracting the gear to climb commits you before you know whether the airplane will climb at all.
• If you are airborne with no runway remaining and cannot climb, the decision becomes a controlled off-airport landing. Close the throttles first - with the asymmetry gone you can fly the airplane wings level - then land roughly straight ahead in the best area available. Slowing toward minimum speed while still carrying power on one side is how a forced landing turns into a V_MC rollover.

This is precisely why the takeoff briefing exists. The decision is made on the ground, not in three seconds at 50 feet.

• Gear down is a large drag penalty at the moment you have the least surplus power, and it is usually enough by itself to remove any single-engine climb.
• Gear down also signals that you are still in the phase where landing is a realistic option - the airplane is configured for it and you are close to the runway.
• Once the gear is up and you're climbing at V_YSE, you have committed to flying the airplane somewhere, and the problem becomes managing the pattern rather than stopping.

A widely used rule of thumb: if the gear is still down and there is runway ahead, land. It's a reasonable rule precisely because it removes the hesitation that kills people.

• Accelerate-stop distance - The runway required to accelerate to a given speed, lose an engine, recognize it, and bring the airplane to a full stop.
• Accelerate-go distance - The runway (and air distance) required to accelerate to that speed, lose an engine, and continue the takeoff to a specified height, usually 50 ft.

Both are ACS knowledge items, but normal-category light twins don't all publish them - check your AFM, and where the data isn't there, brief from the takeoff and single-engine performance data you do have.

The critical point: unlike a transport-category airplane, a light twin has no requirement that these distances fit the runway, and no guarantee accelerate-go is even achievable. It's routine for accelerate-go to exceed the runway available, or for the chart to simply not extend to today's conditions - which is itself the answer.

How runway length enters the go/no-go decision: compare accelerate-stop against the runway available and accelerate-go against runway plus clearway. Check normal takeoff distance too - it's the easy number most people compute and then stop thinking. Runway in a twin buys you the ability to stop, which is usually your best option when an engine quits early, so a longer runway widens the window in which aborting is viable - exactly the window where a light twin's continue option is weakest.

Compute both before takeoff where the AFM publishes them. They are what turn a vague plan into a briefed decision point.

The point is to make every decision before you need it. A workable structure:

• Runway and performance - Runway length available, accelerate-stop distance if your AFM publishes it, and whether single-engine climb is positive at today's weight, altitude, and temperature.
• Speeds - Rotation speed, V_MC (red line), V_YSE (blue line), V_XSE if obstacles matter.
• The decision point - The specific condition that separates abort from continue. For example: any failure on the runway, abort; after liftoff with runway remaining and gear down, land; after liftoff, clean, and climbing at blue line, continue.
• The plan if you continue - Initial heading, altitude, obstacles or terrain, which airport you'll return to.
• The plan if you can't climb - Where you'll put it.

Say it out loud. The purpose is to convert a three-second reaction into the execution of a decision you already made.

• Pitch for V_YSE immediately - the airplane will decelerate quickly with the yaw and drag.
• Rudder to stop the yaw, bank into the operating engine for zero sideslip.
• Clean up: mixtures, props, throttles forward; flaps up; gear up; cowl flaps as needed.
• Identify, verify, feather the failed engine.
• Secure the engine per the checklist.
• Assess: what climb do you actually have? Level off if that's all the airplane will do.
• Tell ATC, declare an emergency if appropriate, and get vectors to the nearest suitable airport.

The judgment item is honestly evaluating performance. If the airplane is only holding altitude, an approach you have to go around from is not available to you.

Better in every way that matters, which is why it's the phase used for training.

• You have altitude and airspeed, so there is time to work methodically rather than reflexively.
• You are already clean, so the drag reduction step is mostly just feathering.
• You can trade altitude for time while you run the checklist.

The process is the same - control, configure, identify, verify, feather, secure - but done deliberately and backed up with the printed checklist.

The new problem is where to go. Above the single-engine absolute ceiling the airplane slowly loses altitude until it settles there; below it, level flight is available but climb is little or none. Plan on the service ceiling either way, because the AFH warns that wear, turbulence, and pilot technique mean you may not hold altitude even at the published single-engine ceiling. Pick an airport you can reach from a descending profile, consider terrain, and start the diversion early rather than troubleshooting for ten minutes first.

• Let performance drive configuration. If the airplane is performing, the AFH's normal schedule still applies - gear down on downwind, confirmed abeam the intended landing point. If speed decays or the sink rate builds, hold off the remaining flaps until closer in. A partial-flap landing is fine.
• Fly V_YSE until you are certain of the landing, then slow only as required.
• Fly a normal 3° glidepath. Slightly steeper is acceptable; the long, flat, low final is the one the AFH tells you to avoid, because it leaves you leaning on power you don't have.
• Assume you cannot go around. With one engine inoperative and the airplane configured for landing, a go-around may be impossible. Make the first approach the one you land from.
• Brief and fly a stabilized profile, and don't accept a slam-dunk or a short-approach request from ATC.

The mental shift is that the landing becomes committed much earlier than usual.

It combines every adverse factor at once:

• Low airspeed, near or below V_YSE and closer to V_MC
• Full configuration - gear down, flaps out, maximum drag
• Low altitude, with no room to trade for speed
• A sudden power application on one side, producing a large yawing moment exactly when control authority is at its weakest
• Nose-up trim from the approach, encouraging a pitch-up toward the stall

That's a textbook V_MC rollover or a stall/spin entry, and the altitude available makes recovery unlikely.

The mitigation is procedural: with an engine out, treat the approach as committed to land. Configure late, stay at V_YSE until landing is assured, and don't put yourself in a position where a go-around is the only remaining option.

It is essentially a normal approach and landing - same pattern, same altitudes, same key positions. What changes is that there is less power and it's asymmetric, so the operating engine carries a higher-than-normal setting.

• V_YSE is the minimum airspeed all the way around. Hold it until the landing is assured, then slow to 1.3 V_S0 or the AFM speed. Don't add speed of your own; it only lengthens the roll.
• Gear down on downwind if performance allows, confirmed no later than abeam the intended landing point. Flaps typically 10° downwind, 25° on base.
• Let performance delay the flaps, not a rule. If speed decays or the sink rate builds, wait until closer in. A partial-flap landing is fine.
• Fly a normal 3° glidepath. Slightly steeper is acceptable; the long, flat, low approach is the one to avoid.
• Keep zero sideslip until you transition to land, and make power changes smoothly - a large, sudden application at low speed is a V_MC problem.
• Treat it as committed. A single-engine go-around is a risk to manage, not a plan.
• Pattern direction doesn't matter: the AFH calls turns toward the failed engine of no consequence for controllability and performance.

Late in the flare, as power comes off, the asymmetric yaw goes away, so be ready to release the rudder pressure you have been holding or the airplane will yaw the other way.

They meter cooling air through the engine compartment. Open buys cooling and costs drag, so the schedule tracks where cooling demand is high and airspeed is low.

• Ground operations: fully open, unless the AFM/POH directs otherwise.
• Takeoff and climb: open. High power at low airspeed is the worst cooling case there is.
• Level off: closed, once cylinder head and oil temperatures are in their normal ranges. Lean the mixtures after the temperatures stabilize.
• Engine out, failed engine: closed. Of everything on the securing checklist, this is the only item that costs climb performance if you leave it undone.
• Engine out, operating engine: whatever the temperatures require. It is at high power and low airspeed with a long way to go, and cowl flaps are temperature control before they are a cleanup item.

That last pair is the same asymmetry as the rest of single-engine flight: clean up everything on the dead side, and keep the live engine alive even when it costs you drag.

The handbook says the practice has "always been somewhat controversial" and is cautious about it.

• The learning value may be offset by the hazard of reconfiguring the airplane in extremely limited time, plus the loss of the follow-through you get from a full stop.
• They are not recommended during initial aircraft familiarization.
• Solo touch-and-goes in twins are strongly discouraged.
• A full stop with a taxi back is preferable while the student is still new to the airplane.

If you do them, brief the division of labor beforehand and again in the flare:

• The student maintains directional control, left hand on the yoke, right on the throttles.
• The instructor resets flaps and trim.
• The instructor announces when the airplane is reconfigured.

Allow for the runway, too. A multiengine airplane uses considerably more of it for a touch-and-go than a single does.

Because with only an instructor and a student on board and no bags, some twins sit ahead of the forward CG limit.

• The fix is ballast in the aft baggage compartment, secured and accounted for on the weight and balance.
• It is the opposite of the loading problem most pilots are trained to watch for, which is why it gets missed.

A forward CG also gives better stall and spin avoidance, welcome on a flight full of engine failures and V_MC work, and it lengthens the rudder's moment arm. That lowers V_MC, so the airplane you demonstrate in departs later than the aft-CG case certification assumed.

At least one landing that you simultaneously demonstrate and explain with a simulated feathered propeller, the engine set to zero thrust, using the manufacturer's recommended procedures.

• It is a simulated feather at zero thrust, not an actual shutdown, which is what makes it repeatable and recoverable.
• It applies to tests in propeller-driven airplanes that do not require a type rating.
• The airplane you supply must permit feathering in flight, with one exception: an applicant already holding an unrestricted AMEL may add an AMES rating in a seaplane with no feathering capability.
• The explaining is not optional: flying it correctly in silence does not satisfy the skill element.

Plan the approach so that a go-around remains available and so the field is made with the power you actually have. A single-engine approach flown too low or too slow is a worse problem than a long landing, and the evaluator is watching your energy management as much as your narration.