An avionics unit assembly for an aircraft can include an avionics unit (e.g., an underwater locator device, “ULD”), and a battery to power the avionics unit. The avionics unit assembly can further include a housing that encases the avionics unit and the battery. The housing includes a vent port for exhausting an emission from the housing during a failure of the avionics unit. The avionics unit assembly can further include one or more of a suppressor that filters the emission, a shield element that is resistant to chemical and/or thermal effects of the emission, and a bracket for mounting the avionics unit to a surface. A method integrating the avionics unit assembly onto a forward aircraft bulkhead at a mount location under an aircraft radome and for manufacturing the avionics unit, and an aircraft including the avionics unit are also described.