| CPC G01M 99/002 (2013.01) [B64D 45/00 (2013.01); F15B 19/00 (2013.01); G01M 99/007 (2013.01); B64D 2045/0085 (2013.01)] | 20 Claims |
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1. A diagnostic system comprising:
a hydraulic system onboard an aircraft, the hydraulic system comprising a pump configured to pump hydraulic fluid on the aircraft, the pump including an inlet, a discharge outlet, and a case drain outlet, wherein the inlet is fluidly connected to a reservoir and receives an incoming flow stream of the hydraulic fluid from the reservoir, the discharge outlet emits a high pressure flow stream of the hydraulic fluid configured to be conveyed to a hydraulic load to perform work, and the case drain outlet emits a cooling flow stream of the hydraulic fluid that is discrete from the high pressure flow stream, wherein the cooling flow stream has a lower pressure than the high pressure flow stream;
a first temperature sensor configured to measure a first temperature of the incoming flow stream upstream of the inlet of the pump;
a second temperature sensor configured to measure a second temperature of the cooling flow stream downstream of the case drain outlet of the pump; and
a controller including one or more processors and configured to:
determine a value of a temperature rise of the hydraulic fluid across the pump as a difference between the first temperature and the second temperature;
obtain an expected range for the temperature rise of the hydraulic fluid across the pump based on a speed of the pump; and
in response to the value of the temperature rise being outside of the expected range, generate a maintenance message for communication to one or more devices that are off-board the aircraft, wherein the maintenance message indicates that the pump is operating in a degraded state.
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