Here you will find:
Partially. The power and serial sections are similar across the LTN-9x series, but the calibration constants and fault codes are unique to the LTN-92. For example, the LTN-90 uses a different gyro dither frequency. ltn-92 manual
A degraded mode used if navigation memory is lost or if the system cannot maintain navigation accuracy. It provides pitch and roll information (acting as a backup attitude gyro) but does not provide valid position or heading data. Here you will find: Partially