Field reports indicate that the AN/APR-39A(V)1 and AN/APR-39A(V)4 Antenna- Detector cables are
having a high rate of failure on the AH-64A/D, OH-58D and UH- 60A/L aircraft. The existing cables are
not as lexible or durable as the new RG-400 cables. The existing cables currently can not be repaired or
fabricated in the ield.
In the interim while the aircraft technical manuals are being updated with the data supplied from
this Technical Bulletin (TB) the units are authorized to fabricate the RG- 400 cables used on the
AN/APR-39(V)1, AN/APR-39(V)2, AN/APR-39A(V)1 and the AN/APR-39A(V)4 Radar Signal Detecting
The purpose of this Technical Bulletin (TB) is to provide the necessary instructions for local fabrication of
the AN/APR-39(V)1, AN/APR-39(V)2, AN/APR- 39A(V)1 and the AN/APR-39A(V)4 Antenna-Detector
cables and allows the cables to be replaced through attrition. It is recommended that if at least one
Antenna-Detector cable requires replacement that all four (4) cable assemblies be replaced at the same
time to prevent any line loss.
5. End Items to be Inspected. N/A.
6. Assembly Components to be Inspected.. N/A
7. Parts to be removed/installed. N/A
9. Correction Procedures. The following procedures and tables are to be used to locally fabricate the AN/APR-
39(V)1, AN/APR-39(V)2, AN/APR-39A(V)1 and the AN/APR-39A(V)4 cable assemblies using RG-400 cable mate-
New Part Number
Old Part Number
SD18573 45 degree
SD18575 90 degree
SD18573, 45 degree connectors can be used to prevent chafing of the cables in all Iocations.