Collins Radio Airworthiness Directives

Airworthiness Directives; COLLINS RADIO: Applies to All Models 51R-1 and 51R-2 Radio Receivers

Unsafe Condition: Failures of 90/150 cycle tone localizer filters due to electrodeposition of copper from the coil windings to the laminated iron core.

Why matched: Airworthiness Directives; COLLINS RADIO: Applies to All Models 51R-1 and 51R-2 Radio Receivers

Airworthiness Directives; COLLINS RADIO: Applies to All Model 51R-1 and 51R-2 Receivers Incorporating Allite or Thordarson 90/150 Cycle Filters in Their Tone Localizer Indicator Circuits and to All Model 51R-1 Receivers Which Have Not Been Modified in Accordance With Collins 51R-1 Service Bulletin Number 7a

Unsafe Condition: Failure of the 90/150 cycle tone localizer system due to in-service failure of Allite or Thordarson filters, and loss of automatic gain control action leading to course reversal.

Why matched: Airworthiness Directives; COLLINS RADIO: Applies to All Model 51R-1 and 51R-2 Receivers Incorporating Allite or Thordarson 90/150 Cycle Filters in Their Tone Localizer Indicator Circuits and to All Model 51R-1 Receivers Which Have Not Been Modified in Accordance With Collins 51R-1 Service Bulletin Number 7a