| 摘要 |
<p>An aircraft gas turbine engine has first and second electrical harnesses formed from respective first and second flexible printed circuit boards which each provides a plurality of spaced conductive tracks. The conductive tracks are arranged to carry signal of types which either (i) provide engine control and can cause hazardous conditions of the engine in the event of their failure, (ii) detect or prevent hazardous conditions of the engine, or (iii) are not of type (i) and/or of type (ii). The first flexible printed circuit board provides all the conductive tracks which carry signals of type (i) or the first flexible printed circuit board provides all the conductive tracks which carry signals of type (ii). The second flexible printed circuit board provides all the remaining conductive tracks. The first electrical harness is fire-resistant such that it has the capability to withstand the application of heat by a flame, for a period of five minutes without any exposure of its conductive tracks and while retaining the ability of those conductive tracks to carry their signals. The flame has the following characteristics: temperature 1100°C ± 80°C, and heat flux density 116 KW/m 2 ± 10 KW/m 2 .</p> |
