AIRCRAFT BLEED AIR SYSTEMS AND METHODS

A method (80) of monitoring bleed air provided from a first engine (10) to a second engine (10) of a multi-engine aircraft (1) includes operating the first engine (10) in a powered mode to provide motive power to the multi-engine aircraft (1); and when the first engine (10) is in the powered mode: actuating an air valve (14') to open an air flow path (A) from a compressor section (9) of the first engine (10) to a plurality of parts of the second engine (10), after the step of actuating the air valve (14'), determining a change in a temperature in a main gas path (AF) of the first engine (10) at a location in the main gas path (AF) at or downstream of a combustor (8) of the first engine (10), and in response to determining that the change is below a threshold, executing an action with respect to the first engine (10), the air valve (14'), and/or the second engine (10).