Climbing is one of the most important phases of flight. As you may know, it involves an airplane ascending or “climbing” to a higher altitude.
The U.S. Federal Aviation Administration (FAA) typically requires airplanes to fly at least 1,000 feet above congested areas, but most commercial airliners fly above 30,000 feet. After taking off, airplanes will begin climbing. Some airplanes, however, perform step climbs.
Overview of a Step Climb
A step climb is an incremental series of ascents. It’s commonly performed by pilots during long-haul flights. Rather than immediately ascending to cruising altitude after takeoff, pilots will perform a step climb. They will ascend to a particular altitude, followed by ascending to a higher altitude and so on.
The Purpose of Step Climbs
You might be wondering why pilots perform step climbs. After all, wouldn’t it make more sense to immediately ascend to cruising altitude after takeoff? The reason pilots perform step climbs is to maximize the airplane’s fuel efficiency.
Airplanes hold a lot of fuel — especially those designs for long-haul flights. A typical Airbus A380 can carry 82,000 gallons or 250 tons of fuel. All of this fuel adds significant weight to the airplane. Over the course of an airplane’s flight path, though, it will burn this fuel while becoming lighter in the process.
By performing a step climb, pilots can match the airplane’s weight to the ideal altitude. As the airplane burns more fuel and becomes lighter, for instance, they will ascend to a higher altitude. The thinner air will make the airplane more fuel efficient, which translates into cost savings for commercial airlines.
Higher altitudes can also provide smoother air. There may be pockets of rough air and turbulence at lower altitudes. Step climbs allow pilots to ascend above these unfavorable conditions so that passengers have a more enjoyable flying experience.
The Step Climb Process
The process for a step climb is relatively straightforward. It’s known as a “step climb” because it involves a series of ascents. Each ascent represents a step.
Airplanes are heaviest when they initially take off. Fuel, in fact, accounts for more than one-third of a typical airplane’s total weight at takeoff. As the airplane flies, its engines will burn fuel, resulting in a lighter weight. With a step climb, the pilot will ascend to a higher altitude where the air is thinner and there’s less drag. The pilot may perform several incremental ascents throughout the flight before reaching the final cruising altitude.
