Do Planes with Two Engines Need Both to Work for Takeoff and Landing?

Many people wonder if both engines are necessary for a plane to take off and land safely. While it might seem logical that a bird-in-the-hand approach is required, it turns out that in certain scenarios, a plane can indeed manage with just one engine. Read to find out why and how this works!

Single-Engine Aircraft

Some military aircraft have been operating with single engines for decades, such as the F-16 and F-35. These aircraft are designed to be highly efficient and capable of performing specific missions, sometimes even using a single engine for extended periods. However, their design allows them to operate with a single engine because of their nature and performance requirements.

Engine Failures and Takeoff Safety

Regulations uphold that twin-engine aircraft (or those with more than two engines) must have both engines running from the start of the takeoff up to the speed of V1, after which an engine failure does not prevent the takeoff. If an engine fails before V1, the plane must abort the takeoff due to insufficient runway to stop safely. After V1, the plane can still continue, but the performance and safety profiles change, often requiring measures such as reducing fuel weight to ensure a single-engine landing at the nearest suitable runway.

Single-Engine Performance

Most twin-engine aircraft, including helicopters, can indeed sustain flight and landing with just one engine. Many can maintain altitude, and most airliners are equipped with such powerful engines that they can perform a "go-around" if one engine is lost during takeoff. However, not all aircraft are created equal in terms of single-engine performance.

Training Aircraft with Poor Single-Engine Performance

Some training aircraft, such as the Piper Apache (also known as the Half-AZZtec) and the Piper Seminole (known as the Semi-Hole), have been designed to prioritize learning single-engine procedures rather than achieve high single-engine performance. These aircraft are equipped with 'unfeathering accumulators,' meaning the engines can be restarted even if the props are feathered, reducing the risk of the engine shaking off its mounts.

Light Twin Aircraft

More typical light twins, powered by high-performance turbocharged piston or turbine engines, can climb at rates of about 500 feet per minute. Such aircraft can manage enough altitude to safely return to land if there's an engine failure at takeoff. En route, a single engine can still allow a slower descent while maintaining a safe enough altitude to reach the nearest airport.

Engine Failures in Multi-Engine Aircraft

Surprisingly, there are generally more engine failures in multi-engine aircraft compared to single-engine aircraft. However, these failures often do not result in major incidents or crashes, and safe landings do not always make headlines. This is why it seems common that dual-engine planes are involved in engine failures.

Understanding these nuances can provide a clearer picture of how modern aircraft operate. Diving into the specifics of engine performance, regulations, and aircraft design can help dispel myths and highlight the sophisticated balance of safety and efficiency in aviation.