As an aircraft flies across the globe, it must continuously pitch (with respect to an inertial frame of reference) to keep following the curvature of the Earth.
From that point of view, what must the sign of this continuous (though extremely small) pitch rate be? positive or negative
I apologize for the confusion. You are correct. From the point of view of an aircraft flying across the globe, the continuous pitch rate must be negative in order to keep following the curvature of the Earth. This means that the nose of the aircraft should be slightly pointing downwards relative to an inertial frame of reference. The negative pitch helps the aircraft maintain its altitude as it follows the curved surface of the Earth. Again, I apologize for the initial incorrect response.
negative
As an aircraft flies across the globe and maintains its path along the Earth's curvature, the sign of the continuous pitch rate depends on the specific situation. Let's consider two scenarios:
1. Level Flight: In level flight, where the aircraft is following a straight path, the pitch rate should be zero. This means that the aircraft is maintaining a constant level attitude parallel to the Earth's surface, without any upward or downward pitch.
2. Following Curvature: When the aircraft follows the curvature of the Earth, such as during a long-distance flight, the sign of the continuous pitch rate may vary. It depends on the direction of the curvature and the way the aircraft compensates for it. Generally, if the aircraft needs to maintain altitude while following the curvature, a slightly positive pitch rate may be applied. On the other hand, if the aircraft needs to descend slightly to follow the curvature, a slightly negative pitch rate may be used.
It is important to note that the pitch adjustment required to follow the Earth's curvature would be extremely small and may not be perceivable during normal flight operations. The continuous pitch adjustment is typically managed by the aircraft's autopilot or the pilot's inputs to maintain the desired flight path.
To determine the sign of the continuous pitch rate of an aircraft as it flies across the globe, we need to consider the curvature of the Earth and the orientation of the aircraft in relation to an inertial frame of reference.
The Earth is spherical in shape, and as an aircraft moves over the surface, it needs to maintain its altitude and follow the curvature of the Earth. Since the Earth's curvature is such that it bulges upwards, the aircraft must pitch downwards to match the curve. This downward pitch ensures that the aircraft maintains a constant altitude above the curved surface of the Earth.
In terms of the sign convention, a positive pitch rate indicates a pitch upwards, while a negative pitch rate indicates a pitch downwards. In the context of an aircraft flying across the globe, the continuous (though extremely small) pitch rate should be negative. This negative pitch rate allows the aircraft to adjust its attitude and pitch downward to compensate for the Earth's curvature and maintain a constant altitude.
In summary, the sign of the continuous pitch rate, with respect to an inertial frame of reference, would be negative as the aircraft flies across the globe to follow the curvature of the Earth.