Appendix A — Example flight trajectory

ED Decision 2021/008/R

This Appendix defines an example flight trajectory applicable to a subsonic aeroplane to verify that the system that is defined in CS ACNS.E.LAD.010 meets the position accuracy objectives of CS ACNS.E.LAD.410 (based on the assumptions about the performance of the communication infrastructure, which are defined in paragraph (a) of CS ACNS.E.LAD.320). This Appendix is applicable to a system that transmits activation signals before or without deploying equipment.

(a) Verification condition

(1) The system should be in the least favourable configuration (e.g. if a power supply transition may reset the system, the system is reset; or if a GNSS receiver may be in a cold or warm start-up condition, the cold start-up condition is used).

(2) If a satellite constellation is used, the verification should be based on the number and distribution of satellites that are available for 95 % of the time (e.g. no use of spare satellites).

(3) Location and time of the test or simulation are the least favourable ones. This could be demonstrated by performing a location and time sensitivity analysis.

(4) The verification should include tests that allow confirmation of the radio frequency link performance.

(5) The applicant should document the verification results, including:

(i) assumptions about the system and the communication infrastructure;

(ii) substantiated deviations from the example flight trajectory and its sequence that are described in point (b) of this Appendix;

(iii) the tested flight trajectories;

(iv) for each point of a tested flight trajectory:

(A) position, attitude, speed, and acceleration;

(B) the number of communication infrastructure sensors that are actively used;

(C) the communication link performance (link budget); and

(D) the exchanged data; and

(v) for each tested flight trajectory, the location of the point of end of flight, which is determined based on the activation signals that are transmitted along the tested flight trajectory.

(b) Example flight trajectory

The example flight trajectory and the status of the system should be as described below:

(1) change the system to the armed state and maintain a static position for 15 seconds (s) at an altitude between 0 and 500 metres (m); the attitude angles are:

(i) pitch attitude angle: 0°,

(ii) bank angle: 0°, and

(iii) heading: north;

(2) accelerate in a straight line in north direction, while climbing to reach a 5 000-m altitude after 60 seconds; the horizontal acceleration should be 5.55 m/s2 throughout this phase so that a horizontal speed of 333 m/s is reached at a 5 000-m altitude;

(3) maintain a horizontal speed of 333 m/s for 60 s, while climbing to 10 000 m;

(4) level out, set the pitch attitude angle, roll attitude angle, and heading to 0, activate the system, and while maintaining a horizontal speed of 333 m/s, apply the following during 30 s:

(i) roll:

(A) bank right with a constant roll rate of +30°/s until reaching +30°, then bank left with a constant roll rate of –30°/s until reaching –30°; and

(B) continue this sequence until the end of the 30-s sequence; and

(ii) keep the heading, pitch attitude angle, and altitude unchanged;

(5) while maintaining the same altitude at a constant horizontal speed of 333 m/s, apply the following during 2 s:

(i) pitch attitude: pitch down at a constant pitch rate of –10°/s until reaching –20°;

(ii) roll attitude: bank left at a constant roll rate of –30°/s until reaching –60°; and

(iii) keep the heading and altitude unchanged;

(6) from this point and until altitude is 0 m (corresponding to the point of end of flight), maintain a horizontal speed of 333 m/s, a pitch attitude angle of –20°, and a vertical speed of –80 m/s, while applying the following sequence:

(i) during 17.5 s:

(A) maintain the roll attitude angle at –60°; and

(B) decrease the heading at a constant yaw rate of –10°/s;

(ii) during 4 s:

(A) increase the roll attitude angle at a roll rate of 30°/s to reach +60°; and

(B) decrease the yaw rate at a yaw acceleration of 5°/s² to reach +10°/s;

(iii) during 17.5 s:

(A) maintain the roll attitude angle at +60°; and

(B) increase the heading at a constant yaw rate of +10°/s; and

(iv) during 4 s:

(A) decrease the roll attitude angle at a constant roll rate of –30°/s to reach
-60°; and

(B) decrease the yaw rate at a yaw acceleration of -5°/s² to reach –10°/s; and

(7) after reaching the point of end of flight (altitude is 0 m), maintain stationary position for 60 s.

(c) Pass criteria

The last two-dimensional position that is determined through the activation signals that were transmitted before reaching the point of end of flight is within 6 nautical miles (NM) of the position of that point.

[Issue: CS-ACNS/3]