Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all BAE Systems (Operations) Limited Model Avro 146-RJ series airplanes. This proposed AD would require an inspection of the Thales Avionics distance bearing indicator (DBI) to determine part number (P/N) and serial number (S/N), and replacement of the affected DBI with a new or modified DBI. This proposed AD is prompted by a report of defective electrical insulators in DBIs. We are proposing this AD to prevent a short circuit in the DBI due to defective electrical insulation, which could potentially cause a loss of primary navigation instruments (such as airspeed indicator, altimeter, and global positioning system (GPS) information).