Why don't airplanes use reverse thrust to reverse?


Why don't planes use reverse thrust to reverse?

During landing, aircraft engines can be switched to reverse thrust. This helps to slow down the speed by directing the energy of the jet engines against the forward motion. Air is “sucked in” into the engines, but instead of being ejected back, it is directed to the side holes on the side of the engines, which provide braking.

Some aircraft, such as the Douglas DC-8, can theoretically use this function at any time. However, for modern aircraft, the use of reverse thrust in flight is prohibited.

The use of reverse thrust in the air ended in disaster in 1991. Scheduled flight 004 of Lauda Air operated as scheduled from Bangkok-Don Mueang International Airport (DMK) to Vienna-Schwechat International Airport (VIE) in the Austrian capital. On May 26, 1991, a Boeing 767 took off from Bangkok at 23:02 local time for a ten-hour flight.

Five minutes after takeoff, a warning light came on, indicating that a possible failure could trigger the thrust reverser on the number one engine. A few minutes after the reverse of this engine actually worked, sending the aircraft into a steep left dive, killing all 233 passengers and crew on board.

Reverse thrust can only be used to help slow the aircraft down the runway after landing. But can this mechanism be used to bring the aircraft out of a stationary position? And if so, why do airlines use a tractor to pull away from a boarding bridge? The tug requires an operator, time to connect to the aircraft, and is another element that can fail. It also makes parking more expensive.

Why don't planes use reverse thrust to move in reverse?

In the 1970s and 80s, some aircraft were allowed to perform reverse maneuvers with the help of engines. This practice continued even into the 21st century by Air Tran, American, Northwest.

There are several reasons why using reverse thrust in the immediate vicinity of the terminal building and nearby other equipment is impractical and even dangerous. While it is technically possible for aircraft, there are many things that can go wrong.

For example, the sudden whirlwinds of air around an aircraft can pick up not only dust from the concrete, but also larger objects that can cause damage to the fuselage. They may affect the air bridge itself, other ground vehicles and aircraft, or personnel near the aircraft. The ground crew will need to clear the area before turning on the engines, and this is unlikely to save time compared to using a tug.

There is a possibility that objects will be drawn into the engine. As the turbine spins with increasing power, it creates a vortex. This can cause items such as tools, rags, gloves, etc. to get into expensive engines.

Reversing thrust consumes a lot of fuel and makes the engines very noisy. Today, noise pollution is becoming an increasingly important factor in the operation of airports. Therefore, it is understandable that everyone would like to avoid unnecessary noise.

Finally, pilots in an airplane cannot see behind them, since airplanes do not have rear-view mirrors like cars do. That is, they will need a spotter on the ground anyway. This defeats the purpose of starting without any assistance.

In general, it is too risky for the airport, ground crew and aircraft to use reverse thrust so close to the terminal building. The upside is saving a few minutes and dollars, but the downside can be millions of dollars in damage and a broken airliner.

Thus, small but powerful tractors will continue to tow aircraft.

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