Kenya’s presidential jet recently caught the attention of curious Kenyans who observed a peculiar angle of attack sensor marked with a red circle

President William Ruto recently used the official presidential Fokker 70 jet for his two-day trip to Rwanda on April 4.

Photos of the head of state arriving in the Kenya Airforce-operated jet were shared on social media, with some hawk-eyed Kenyans spotting a strange-looking instrument on the fuselage of the plane just below the pilots windows.

Water Bottlers Association of Kenya Chairman Henry Kabogo posed a question to Kenyans on Twitter, many whom tried to identify and describe the use of the piece of equipment.

According to an aviation expert who spoke with this writer, the instrument in question can identified as an Angle of Attack (AoA) vane or sensor.

“Simply put, it helps Pilots know the angle at which an aircraft can stall and avoid having the plane in such an angle that would cause the stall.

“A stall is when an aircraft has a breakdown of airflow over the wing thus reducing lift significantly. Mostly it’s due to the angle of attack exceeding the critical point. So the sensor helps the pilots instruments to know what the critical angle of attack is,” the aviator said.

To be able to understand what its it is, one needs to understand what is an angle of attack.

Presidedent William Ruto disembarking from the official presidential jet

Angle of attack

An angle of attack is a term used in aviation that refers to the angle between an aircraft’s wing and the incoming airflow.

In simpler terms, it’s the angle at which the wing is tilted upwards in relation to the direction in which the plane is moving.

The angle of attack is important because it directly affects how much lift the wing can generate to keep the aircraft in the air.

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If the angle of attack is too high, the airflow over the wing can become turbulent, causing the wing to stall and lose lift.

On the other hand, if the angle of attack is too low, the wing won’t generate enough lift, and the plane won’t be able to stay in the air.

A collage of Kenya’s presidential Fokker 70 and a similar KLM plane

Angle of attack vane

Pilots use various instruments to monitor the angle of attack and ensure that it stays within a safe range during flight.

One such instrument is the angle of attack vane, which is a small wing-like device that’s mounted on the outside of the aircraft.

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As the plane moves through the air, the angle of attack vane senses the direction of the incoming airflow and the angle of the wing, sending that information to the cockpit instruments for the pilots to monitor.

A simple diagram explaining the Angle of Attack

Overall, the angle of attack is a critical concept in aviation, as it directly affects the safety and efficiency of flight.

Pilots need to be aware of the angle of attack at all times and adjust the pitch of the aircraft (the angle it’s pointing) to maintain the correct angle of attack for the desired altitude and speed.