WSR-88D Operational Support Facility May 9, 2000

MEMORANDUM FOR:	Operations And Maintenance Focal Points At All USAF and NWS WSR-88D RDA Sites
FROM:	W/OSO41- Tim Crum Chief, Operations Branch
SUBJECT:	Shut Down TPS Model 201-N (IMMEDIATE ACTION REQUIRED)

The Transition Power Maintenance System (TPMS) contractor has requested that the government turn off all model 201-N Transition Power System (TPS) units. The DOC General Counsel for Contract Law and TPMS Contract Officer have agreed with this recommendation. As a result, the National Weather Service (NWS) and Air Force Weather Agency NEXRAD Program Managers direct all NWS and USAF WSR-88D sites with a model 201-N Transition Power System (TPS) to turn the unit off immediately and leave it turned off until further notice. Please confirm completion of TPS shut down by calling the WSR-88D Hotline

Turn off the TPS unit and place it in maintenance bypass IAW AF TO 31P1-4-108-101/ EHB 6-550, page 3-215, para. 3-5.4.62, "Removing TPS from Service." The retransfer switch on the Automatic Transfer Panel in the generator shelter should be left in the "manual" position. Sites should also change RDA Adaptation data for Tower parameter #41 to "False," to prevent "TPS is Off" tower alarm from appearing on the MMI and UCP.

Sites turning off their TPS model 201-N should review their power transition/engine generator use procedures. Pre-TPMS procedures should be used for transfer of power to engine generator in advance of severe weather or occasions when utility power might be interrupted.

The decision to shut down the 201-N units was recently made after the government and the TPMS contractor met to review the status of the TPMS Program and corrective actions for the catastrophic failures many 201-N units have experienced. The TPS units will remain shut down while the government explores and evaluates options for fixes to performance and reliability deficiencies.

The operation of the TPS units (model 35-60) at Altus AFB, OK and Jackson, KY are not affected by this shut down order. However, we recommend that the maintenance staff at these sites make visual and audible checks of the TPS unit for any of the following conditions when they are at the RDA site.

1. Higher-than-normal vibration which may result in higher-than-normal noise,
2. High-pitched squealing noises from the TPS bearing area, or
3. Strong burning smells.

If you detect a problem listed above, please contact the WSR-88D Hotline immediately.

This memo supersedes my earlier memos on the TPMS Program. If you have technical questions on shutting the TPS down, please call the WSR-88D Hotline. If you have programmatic questions or comments, please contact Roger Hall, TPMS Contract Officer Technical Representative or me. We will send all NWS and USAF RDA sites an update on the TPMS Program when additional information becomes available.