When Airplanes Reverse by Themselves, or Powerback

It’s common knowledge that a variety of vehicles, from cars to boats, even trains, can shift into reverse and move in the opposite direction. However, it might surprise you to know that airplanes can also do this! Some airplanes have the capability to move backward under their own propulsion, although this practice is now forbidden. This particular maneuver, known as “powerback,” was only allowed for certain types of airplanes.

The standard procedure to reverse an aircraft involves using a tug to push it back and align it for taxiing. Yet, up until 2005, certain airplanes, such as the McDonnell Douglas MD-80, could reverse or “powerback” using their own engine thrust.

The Powerback

The powerback maneuver refers to a specific technique where an aircraft uses its engine power and thrust reversal capabilities to move backwards on the ground. Interestingly, this process is more commonly utilized by propeller-driven or turboprop aircraft. Meanwhile, jet aircraft are often discouraged from powerbacking, with the notable exception of some models with tail-mounted engines.

The Challenges and Concerns Surrounding Powerbacks

Powerbacks might seem like an efficient means of maneuvering aircraft on the ground, but there are several concerns associated with the practice. Among the most significant is the risk of foreign object damage (FOD), which refers to the potential for airborne debris to damage the aircraft. During a powerback, the force of the engines can kick up small objects from the ground, which can then potentially damage the aircraft, hit ground crew members, or even shatter terminal windows. The danger is even more pronounced with aircraft featuring wing-mounted engines, as their close proximity to the ground can enhance the chances of debris ingestion.

Moreover, performing powerbacks could also lead to the risk of a tailstrike if brakes are applied during the backward motion. A tailstrike happens when the tail of an aircraft contacts the ground, which is not only dangerous but also costly to repair.

An Efficient Approach with Considerable Drawbacks

Despite the inherent challenges, powerbacks were more frequently utilized during the 1980s. Aircraft with rear-mounted engines like the DC-9s, Boeing 727s, and MD-80s often performed powerbacks as it lessened the need for extensive ground personnel involvement. However, as time passed, these practices were gradually phased out due to various reasons.

Fuel conservation was among the major considerations leading to the decreased use of powerbacks. Additionally, increased wear on engines became a significant concern, leading to higher maintenance costs.

Regulations Around Powerbacks

In the realm of aviation, safety is always paramount, and the powerback maneuver is no exception. In the United States, the Federal Aviation Administration (FAA) and local aviation authorities impose several regulations around the use of powerbacks. The permissions for powerback are typically granted at specific gates in selected airports, and these are visibly marked for the pilots and ground crew.

However, airlines themselves often enforce even stricter safety guidelines. These usually include restrictions on performing powerbacks under certain environmental conditions like rain or snow, where visibility and control could be compromised.

While airplanes doing powerback maneuver were an ingenious solution to ground navigation challenges at one point, the potential risks and inefficiencies it carries have led to its decreased usage.