Control of Attitude
Chapter 3.1
Determining ATTITUDE
What is the horizon?
On a flat landscape, the answer is easy: it is the line where the Earth and the sky meet.
In a mountainous region, the explanation is somewhat more difficult because we have to imagine a horizontal line in the field of sight.
Determining ATTITUDE
Airplane ATTITUDE in the air and the “horizon”
In straight and level flight, ATTITUDE can be determined by comparing to a source of reference.
The reference to which we can refer to is the “horizon”.
Determining ATTITUDE
The horizon and references with the airplane
The horizon is, in most cases, used as a reference for determining one’s attitude in space. With its position and references, the attitude of the airplane is determined in space.
During a flight in visual conditions, the horizon is compared with references to the aircraft.
Altitude and the horizon
The apparent horizon and the real horizon is surely always parallel. However, they are not always at the same altitude. When the flight altitude increases, the real horizon descends below the field of vision of the pilot.
According to the illustration we see that for the observer, with increasing height above the ground (flying at altitude), the real horizon is sinking away from the horizontal plane.
The Horizon is the Reference for Maintaining the Attitude
Apparent Horizon
Representation of the Apparent Horizon in Difficult Conditions
Recognising the apparent horizon is easy in good visibility, flat surfaces or over the sea. On the otherhand it becomes difficult when in poor visibility or in mountains.
During visual flight without using an Al between cloud layers and in the mountains, the apparent horizon becomes misleading and difficulties in maintaining one’s attitude are encountered.
Flights Without a Horizon Are Impossible
While flying in clouds, the horizon is not visible. Without an artificial representation of the horizon, it is impossible to maintain flight attitude.
During a flight without a horizon, an aeroplane will after a short time, at the latest after 170 seconds, find itself in an uncontrollable situation. Such a flight always ends tragically.