dynamics

Thank you kindly for your detailed explanation. I would be most grateful if you could forward me a scanned copy of the manual.

According to troubleshooting section of AMM If the fuel quantity indicator displays zero kilograms and presents Error Code 2, this signifies the presence of a short circuit within the compensator unit(HI-Z to COMP LO-Z). An Error Code 4 indicates either an open circuit or a short circuit within the TANK LO-Z line.Should Error Code 5 be displayed, it denotes a short circuit in tank unit (HI-Z to TANK LO-Z).Finally, the appearance of Error Code 10 implies the existence of either an open circuit or a short circuit within the HI-Z line itself.
Could you please clarify the technical meaning of the terms 'HI-Z to COMP LO-Z', 'TANK LO-Z line', 'HI-Z to TANK LO-Z', and 'HI-Z line' within the context of the fuel quantity measurement system?

Are you familiar with potential factors or system anomalies that might lead to a loss of fuel quantity indication in the left-hand main fuel tank of the aircraft?

To the best of my understanding, based on the attached document and the link provided below, the TTR-920 TCAS model does not appear to be eligible for an upgrade to TCAS Change 7.1. Please do correct me if I am 
mistaken:

aeroscanservice.com/en/TCAS_Version_7.1

Are you suggesting that there are additional components, beyond the TCAS computer, which are not included in the catalogue?

Do you know why the TCAS computer is not included in the red-highlighted section of the table of contents in the parts catalogue, as shown in the attached file?