Narrative:

Our facility has suffered from chronic radio/frequency/icss problems for at least 6 months. With the passage of hurricane, these have multiplied. The frequencys are not balanced on the speakers or in the head sets. The icss (landlines) are not balanced and approximately 90% of the time are unusable, ie, 135.7 is a whisper and 118.15 is very loud. While conducting training on combined sectors, the developmental had half the frequencys in the headset and the others on the speaker. An ATR inbound to sju from tkpk at 12000 ft, was issued a restr to cross 35 mi from sju at and maintain 11000 ft, as per local SOP. Approximately 45 mi from sju, the aircraft reported leaving 12000 ft and the developmental and I both understood him to say 'leaving 12000 ft for 11000 ft. The non radar controller on the position immediately made a pointout to the sector below us (surface 10000 ft). The aircraft descended through 11000 ft, at which time I issued him a climb back to 11000 ft. The aircraft descended no lower than 10000 ft. The non radar controller had understood the aircraft to say 'descending to 7000 ft.' reviewing the tapes, the aircraft had indeed said 'descending to 7000 ft.' remedies: 1) standard phraseology should have been used, ie, 'one, one thousand.' 2) frequencys should be balanced, ie, volume should be the same.

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Original NASA ASRS Text

Title: ARTCC CERAP RADAR CTLR, PROVIDING OJT, MISSES INCORRECT PLT CLRNC READBACK ALLEGEDLY DUE TO FREQ HEADSET AND VOICE SPEAKER IMBAL. ADJOINING MANUAL CTLR PERCEIVES INCORRECT READBACK AND INITIATES ADJACENT SECTOR COORD TO POINT OUT ACFT DSNDING BELOW ASSIGNED ALT.

Narrative: OUR FACILITY HAS SUFFERED FROM CHRONIC RADIO/FREQ/ICSS PROBS FOR AT LEAST 6 MONTHS. WITH THE PASSAGE OF HURRICANE, THESE HAVE MULTIPLIED. THE FREQS ARE NOT BALANCED ON THE SPEAKERS OR IN THE HEAD SETS. THE ICSS (LANDLINES) ARE NOT BALANCED AND APPROX 90% OF THE TIME ARE UNUSABLE, IE, 135.7 IS A WHISPER AND 118.15 IS VERY LOUD. WHILE CONDUCTING TRAINING ON COMBINED SECTORS, THE DEVELOPMENTAL HAD HALF THE FREQS IN THE HEADSET AND THE OTHERS ON THE SPEAKER. AN ATR INBOUND TO SJU FROM TKPK AT 12000 FT, WAS ISSUED A RESTR TO CROSS 35 MI FROM SJU AT AND MAINTAIN 11000 FT, AS PER LCL SOP. APPROX 45 MI FROM SJU, THE ACFT RPTED LEAVING 12000 FT AND THE DEVELOPMENTAL AND I BOTH UNDERSTOOD HIM TO SAY 'LEAVING 12000 FT FOR 11000 FT. THE NON RADAR CTLR ON THE POS IMMEDIATELY MADE A POINTOUT TO THE SECTOR BELOW US (SURFACE 10000 FT). THE ACFT DSNDED THROUGH 11000 FT, AT WHICH TIME I ISSUED HIM A CLB BACK TO 11000 FT. THE ACFT DSNDED NO LOWER THAN 10000 FT. THE NON RADAR CTLR HAD UNDERSTOOD THE ACFT TO SAY 'DSNDING TO 7000 FT.' REVIEWING THE TAPES, THE ACFT HAD INDEED SAID 'DSNDING TO 7000 FT.' REMEDIES: 1) STANDARD PHRASEOLOGY SHOULD HAVE BEEN USED, IE, 'ONE, ONE THOUSAND.' 2) FREQS SHOULD BE BALANCED, IE, VOLUME SHOULD BE THE SAME.

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.