FMA: THE GUIDANCE AND THRUST CROSSCHECK
A mode tells us how a guidance system is doing its job. The Flight Mode Annunciator, FMA, is the strip across the top of the Primary Flight Display, PFD. Read its five columns from left to right: thrust, vertical guidance, lateral guidance, approach capability, and autopilot/flight-director/autothrust status. That arrangement answers several different questions. What is controlling thrust? What is commanding climb, descent or level flight? What is steering the aircraft along the ground track? Which automatic systems are engaged? We will ask those questions throughout the flight, because a familiar-looking flight path can be produced by quite different modes. [13, PDF pp. 51-64]
The real photograph shows THR CLB, OP CLB and NAV, with ALT armed. THR CLB describes the thrust mode, OP CLB is open climb, and NAV follows the lateral route. Managed climb would show CLB instead of OP CLB; we will explore that difference in the climb chapter. Active means working now; armed means waiting for the conditions that allow a transition. Here, altitude capture is prepared while the climb continues. Mode names are generally green when active and blue when armed, with other conventions for particular states. A starred capture mode identifies acquisition of a target before settled tracking or level flight. [13, PDF pp. 51-64]
The flight director, FD, provides pitch and roll guidance for us to follow when hand-flying; an engaged autopilot can follow the guidance automatically. Autothrust, A/THR, manages thrust in accordance with its active mode. Their status belongs in the same scan as the guidance itself. After a selection, look at the FMA, then confirm the aircraft's response. A button press may have armed the next mode while the present one continues working. In the simulator, pause after an unfamiliar transition and identify those two states. Once the display starts telling a recognisable story, the knobs become much easier to use with confidence. [13, PDF pp. 51-64]
Original Fenix PFD: THR CLB / OP CLB / NAV, with ALT armed. This is open climb, not managed CLB. [1, Source illustration]