Narrative:

Mlt X issued clearance to cross puttz intersection at FL270. Did not acknowledge. Reissued clearance and mistakenly gave cross puttz at FL240. Aircraft acknowledged. The data block showed aircraft descending to FL270 with air carrier Y just in front, level at FL240. Both aircraft changed to next controller after handoff. Mlt X checked on out of FL290 descending to FL240. Mistake was not caught and shortly thereafter loss of separation occurred. Supplemental information from acn 238114: military X cleared to cross the puttz intersection on the finks 5 arrival into washington, dc, at FL240. Clearance was received at approximately 60 DME bkw. (Puttz is the 072/95.) upon acknowledging the center clearance, the crew set and confirmed the altitude in the alerter and began the descent. Frequency change was given to dulles approach. The crew checked in '...descending to FL240' at which time we were asked to maintain FL250, we were already through FL250 and in fact slowing our vvi to approximately 200-300 FPM and actually at FL247, we leveled at FL244 and climbed back to FL250. We spotted an air carrier Y at our 1-2 O'clock position converging. The controller immediately gave air carrier Y a clearance to descend. We were asked to contact dulles for possible action. Contact was made with dulles and we were told no further information was required of the crew that 'controller error' was noted.

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Original NASA ASRS Text

Title: MIL X ERRONEOUS DSCNT TO OCCUPIED ALT HAD LTSS FROM ACR Y. SYS ERROR.

Narrative: MLT X ISSUED CLRNC TO CROSS PUTTZ INTXN AT FL270. DID NOT ACKNOWLEDGE. REISSUED CLRNC AND MISTAKENLY GAVE CROSS PUTTZ AT FL240. ACFT ACKNOWLEDGED. THE DATA BLOCK SHOWED ACFT DSNDING TO FL270 WITH ACR Y JUST IN FRONT, LEVEL AT FL240. BOTH ACFT CHANGED TO NEXT CTLR AFTER HDOF. MLT X CHKED ON OUT OF FL290 DSNDING TO FL240. MISTAKE WAS NOT CAUGHT AND SHORTLY THEREAFTER LOSS OF SEPARATION OCCURRED. SUPPLEMENTAL INFO FROM ACN 238114: MIL X CLRED TO CROSS THE PUTTZ INTXN ON THE FINKS 5 ARR INTO WASHINGTON, DC, AT FL240. CLRNC WAS RECEIVED AT APPROX 60 DME BKW. (PUTTZ IS THE 072/95.) UPON ACKNOWLEDGING THE CTR CLRNC, THE CREW SET AND CONFIRMED THE ALT IN THE ALERTER AND BEGAN THE DSCNT. FREQ CHANGE WAS GIVEN TO DULLES APCH. THE CREW CHKED IN '...DSNDING TO FL240' AT WHICH TIME WE WERE ASKED TO MAINTAIN FL250, WE WERE ALREADY THROUGH FL250 AND IN FACT SLOWING OUR VVI TO APPROX 200-300 FPM AND ACTUALLY AT FL247, WE LEVELED AT FL244 AND CLBED BACK TO FL250. WE SPOTTED AN ACR Y AT OUR 1-2 O'CLOCK POS CONVERGING. THE CTLR IMMEDIATELY GAVE ACR Y A CLRNC TO DSND. WE WERE ASKED TO CONTACT DULLES FOR POSSIBLE ACTION. CONTACT WAS MADE WITH DULLES AND WE WERE TOLD NO FURTHER INFO WAS REQUIRED OF THE CREW THAT 'CTLR ERROR' WAS NOTED.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.