Accessing Maintenance Test Mode Data - Honeywell PRIMUS 1000 Pilot's Manual

R
PRIMUS 1000 Integrated Avionics System
The nature of a digital system is either it works or it doesn't. There are
no intermediate stages. An analog system can have many in–between
stages, leading to confusion while troubleshooting. For example, a
digital system's altitude select mode always operates the same if
external sensor data is accurate. As time passes, an analog system
introduces variations to mode performance even if its external sensors
have not yet changed.
A digital system is more likely to have an external sensor problem (such
as the MADC, gyros, accelerometers, NAV/DME) than it is to have a
problem with the integrated avionics computer (IAC). The IAC does
extensive self–testing and continuous monitoring for greater reliability
and maintainability.

ACCESSING MAINTENANCE TEST MODE DATA

NOTE: At no time should maintenance personnel attempt to replace
a Honeywell unit based on event codes alone. The event
codes should be used as a tool along with traditional ground
test methods and other standard maintenance practices.
Troubleshooting
7-2
A28–1146–134
REV 1 Jan/03