The distance required to accelerate to lift-off speed and, assuming failure to engine at the instant that lift-off speed is attained, to bring
the airplane to a complete stop. It is CRITICAL to check this distance before every take-off. If you need more runway than you have, it is not
advisable to take off under those conditions - go to a longer runway, reduce fuel or reduce passengers and baggage.
Accelerate-Go Distance:
The distance required to accelerate to lift-off speed, and assuming failure of an engine at the instant lift-off speed is attained, to continue
the take-off on the remaining engine to a height of 50 feet.
Critical Engine:
Critical engine is the engine whose failure would most adversely affect the performance or handling qualities of the airplane. Usually, in almost
all American twins, the critical engine is the left engine on twins with props that rotate in the same direction. Twins, just like single engine
airplanes, have left turning tendencies. These include torque and P-factor. Because the downward bite of the prop has a larger arm from the
center of thrust on the right engine than it does on the left in conventional twins, when you lose the left engine the larger arm on the right
engine causes more turning tendencies than when you lose the left engine the larger arm on the right engine causes more tuning tendencies than
when you lose the right. Put this on top of the left-turning tendencies already existing on the airplane, and you have a severe rolling and
yawing reaction of the airplane. On airplanes with counter-rotating props, the downward bite of the descending prop blades are the same on both
engines. Thrust line is the distance from centerline of fuselage to downward bite of the propeller. Therefore, no matter which engine you lose
it is not the critical engine. You could also consider both engines to be critical since the loss of either on would adversely affect the
performance or handling qualities of the airplane.
Determining which engine has failed:
It may be difficult to determine which engine has failed. Trust your outside visual sights as well as your instruments. The airplane will
roll and yaw in the direction of the dead engine. Your turn coordinator will show the ball on the side of the good engine. You may see an RPM
drop, and your manifold pressure will go to ambient outside air pressure. You will also probably hear a change in the sound of the engines.
Dead foot, Dead engine.
Loss of power when one engine fails:
When you lose one engine, you don't just lose 50% of your horsepower. You will actually lose 80% of your power or more. For example: You have
two engines at 200 hp each. This is a total of 400 hp. When you lose one engine, you automatically lose 200 hp. This leaves you with 200 hp.
It takes around 160 hp to at least maintain straight and level flight. Now, instead of having 240 hp to climb with (400-160), you only have 40
excess hp to gain altitude with. If your density altitude is high, your performance will be even worse, and you may not even have that. At your
single engine absolute ceiling, you will no longer be able to gain any altitude.
Engine Failure Procedures:
Maintain directional control and airspeed control at all times first and foremost.
- Throttles full forward
- Propellers full forward
- Mixtures full rich
- 3rd notch of flaps up
- Gear up
- Rest of the flaps up
- Fuel selectors ON
- Fuel pumps ON
- IDENTIFY - dead foot dead engine
- VERIFY - throttle to idle. There should be no extra yaw or power changes
- FEATHER - prop to feather
- Mixture to idle cut-off
- EVALUATE - can I climb? Do I need to land ahead or what are my options
- Checklist if time permits
- Fuel pumps back off
- Fuel selector off on dead engine
Windmilling Propeller:
Be certain to be efficient as well as thorough when you have an engine failure. A windmilling propeller causes a huge amount of drag because of
the interruption of the airflow over the wing. You want to reduce your drag as quickly as possible. Also, if you roil pressure is dropping and
your RPM's drop below 800 RPM, a pin moved by centrifugal force will drop into place, preventing feather. You will then be "stuck" with a
windmilling propeller, causing a large amount of drag, and be unable to feather.
Engine-out handling:
When your engine fails, the airplane will yaw and roll towards the dead engine. You will need to put in up to 5 degrees bank with your aileron
to combat the rolling tendency, and ruder towards the operating engine to combat the rolling tendency. This will put you from a sideslip situation
to a zero sideslip situation by "straightening" the airplane into the relative wind.
In the event of engine failure during:
Rollout prior to lift-off - close both throttles immediately and bring the airplane to a safe, complete stop.
Immediately after take-off, prior to safe single engine speed - lower your nose to gain airspeed, if can't climb close both throttles and land
straight ahead. If you CAN climb, reduce drag, follow all procedures, and come in for a safe landing.
It is always better to prepare for a safe, controlled emergency landing than to try to force a climb and lose control.
Single-engine Go-Arounds:
Try to avoid single-engine go-arounds. In most twins, a single-engine go-around is almost impossible. More fatal accidents come from attempts
at these than at off-runway landings. However, if you must do one, plan ahead. You will want all the altitude you can muster. Full power
first, then reduce your drag. MAINTAIN YOUR BEST CLIMB SPEED AT ALL TIMES!