Engine Failure During Takeoff Before VMC (Simulated) (AMEL, AMES)

Two skills, and nothing else:

• Close the throttles smoothly and promptly when the simulated engine failure occurs (S1)
• Maintain directional control and apply brakes (AMEL) or flight controls (AMES) as necessary (S2)

There is no airspeed or heading tolerance on this task because there is no decision to make. Below VMC, on the ground, the answer is always reject (FAA-S-ACS-7B, Task IX.E).

"If an engine fails below VMC while the airplane is on the ground, the takeoff needs to be rejected. Directional control can only be maintained by promptly closing both throttles and using rudder and brakes as required. If an engine fails below VMC while airborne, directional control is not possible with the remaining engine producing takeoff power" (AFH ch. 13).

That last sentence is the whole task. Getting airborne below VMC with an engine out and takeoff power on the other side means full rudder cannot stop the yaw — the airplane departs controlled flight a few feet off the ground.

Use the manufacturer's recommended VR or VLOF; if no such speeds are published, use a minimum of VMC plus 5 knots for VR. "On takeoffs, the airplane should never be airborne before the airspeed exceeds VMC" (AFH ch. 13).

Be alert on short-field takeoffs with partial flaps: many light twins "have a strong tendency to become airborne prior to VMC plus 5 knots." Do not fight it with forward elevator — that produces wheelbarrowing. Let it fly but keep it a few inches off the runway, and be ready to abort.

Red radial line — VMC. Currently defined in 14 CFR 23.2135(c) as the calibrated airspeed at which, following the sudden critical loss of thrust, it is possible to maintain control of the airplane. The older 23.149 definition — control with the critical engine suddenly inoperative, then straight flight at the same speed with not more than 5° of bank — still applies to airplanes certificated under it.

Blue radial line — VYSE, best single-engine rate of climb.

Critical point for the oral: "There is no requirement under either determination that the airplane be capable of climbing at this airspeed. VMC only addresses directional control" (AFH ch. 13). Red line buys you control, not performance.

VMC is fixed only for the certification conditions. In service it varies (AFH ch. 13, historical 14 CFR 23.149):

• Power — VMC increases with power on the operating engine. Normally aspirated: highest at takeoff power at sea level, decreasing with altitude. Turbocharged: constant up to the engine's critical altitude, then decreasing
• Propeller drag — highest VMC with the critical engine's prop windmilling at low pitch, high rpm; certification uses the takeoff position unless the engine has autofeather
• CG — VMC increases as CG moves aft (shorter rudder moment arm). For a typical light twin, the aft limit is the most unfavorable
• Weight — VMC increases as weight is reduced
• Landing gear — VMC increases when the gear is retracted; extended gear aids directional stability
• Flaps — takeoff position, normally 0° for most twins
• Bank angle — up to 5° toward the operating engine, and this one dominates

Task X.B has the full treatment of how far each factor moves the number, including the bank-angle sensitivity.

Because you are on the ground, or a few feet above it, below VMC — and the one control that most powerfully lowers VMC is unavailable to you.

• Banking up to 5° toward the operating engine is what buys back directional control in the air, and the sensitivity is large (see Task X.B for the numbers)
• On the runway you cannot bank. The gear is on the pavement, and rolling a wing down near the ground risks a propeller or wingtip strike
• So below VMC on takeoff there is no aerodynamic solution at all. The airplane is simply uncontrollable on one engine at that speed

That is the entire reason this Task's answer is close both throttles and stop rather than any attempt to fly. Every VMC-recovery technique you learn elsewhere assumes altitude and bank you do not have here.

Accelerate-stop distance is the runway length required to accelerate to a specified speed (either VR or VLOF, as the manufacturer specifies), experience an engine failure, and bring the airplane to a complete stop (AFH ch. 13).

"The regulations do not specifically require that the runway length be equal to or greater than the accelerate-stop distance. Most AFM/POHs publish accelerate-stop distances only as an advisory. It becomes a limitation only when published in the limitations section of the AFM/POH." Experienced multiengine pilots insist on at least accelerate-stop runway anyway, as a matter of safety and good operating practice.

A useful cross-check the AFH offers: add the takeoff distance to 50 feet and the stopping distance from 50 feet. "If the runway is no longer than the total value, the odds are very good that if anything fails, it will be an off-runway landing at the least."

Promptly close both throttles and maintain directional control with rudder, nosewheel steering, and brakes. Aggressive use of all three may be needed to keep the airplane on the runway, particularly if the failure was not immediately recognized (AFH ch. 13).

The mindset that separates a good abort from a bent airplane: "the primary objective is not necessarily to stop the airplane in the shortest distance, but to maintain control of the airplane as it decelerates. In some situations, it may be preferable to continue into the overrun area under control, rather than risk directional control loss, landing gear collapse, or tire/brake failure in an attempt to stop the airplane in the shortest possible distance."

Configuration decides both the speed at which you become controllable and how the reject goes:

• Flaps. VMC is determined with the flaps in the takeoff position — normally 0° for most light twins (AFH ch. 13). A short-field takeoff flap setting gives many light twins "a strong tendency to become airborne prior to VMC plus 5 knots," which is precisely the state this task exists to prevent. If the runway lets you use a normal-flap takeoff, use one
• Landing gear. VMC increases when the gear is retracted; extended gear aids directional stability (AFH ch. 13). On the ground and during the reject the gear is where you want it — so do not reach for the handle. A premature liftoff followed by a gear retraction removes both the runway and the stabilizing effect at once
• Power. Both throttles closed is the first control input, not a cleanup step. "Directional control can only be maintained by promptly closing both throttles and using rudder and brakes as required" (AFH ch. 13)

The configuration decision is made before the takeoff roll, in the brief. There is no time to reconfigure at 40 knots.

Simulated failures during the takeoff ground roll may be accomplished with the mixture control, and "the simulated failure should be introduced at a speed no greater than 50 percent of VMC." If the pilot does not react promptly by retarding both throttles, the instructor can pull the other mixture (AFH ch. 13).

Your job is the pre-takeoff contract: a pre-takeoff safety brief that "clearly defines all pre-planned emergency actions to all crewmembers" — even flying alone, review it. "Indecision at the moment an emergency occurs degrades reaction time and the ability to make a proper response." Say the abort criteria out loud before you push the throttles up, and the reaction is already made.