Narrative:

The problem occurred in oct/99 at XX25Z on the 325 degree radial 34 DME off of lapaz, mexico VOR. Mazatlan center frequency had been continuously blocked by a stuck microphone between loreto (lto) and lapaz (lap) YY15Z. Aircraft X unable to contact center for descent clearance. In accordance with 10-7 pages of our commercial chart manual and aim procedures, we followed lost communication procedures and contacted next expected controller (lapaz control 120.6). Lapaz approach issued descent clearance. Aircraft X began descent and called out of FL330. Lapaz control confirmed our descent and said to report passing 16000 ft. Lapaz approach soon thereafter had us recontact mazatlan center on 128.0 (the frequency with the stuck microphone). After we reinitiated contact with mazatlan center, we were questioned on our descent clearance. We advised mazatlan center we were cleared the descent by lapaz approach. Mazatlan said stand by and continue your descent. We suggested a leveloff but mazatlan center issued a descent to FL200. We were then switched back to lapaz approach control and the flight to sjd continued normally. No potential conflict was noted on TCASII, visually, or by lapaz approach. Upon arrival at sjd, the captain inquired by telecon with lapaz approach if there were any questions or problems with the descent clearance north of lapaz. Lapaz said there were no problems. Caused by: lost communication failure of lapaz approach controller to properly coordinate with mazatlan center prior to issuing descent clearance. Submitted to prevent similar occurrence. Needs better coordination between lapaz approach and mazatlan center.

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Original NASA ASRS Text

Title: AN MD83 FLC RECEIVED A DSCNT CLRNC FROM LAP TRACON WHILE MMZT ARTCC HAD A BLOCKED FREQ NEAR LAP, FO.

Narrative: THE PROB OCCURRED IN OCT/99 AT XX25Z ON THE 325 DEG RADIAL 34 DME OFF OF LAPAZ, MEXICO VOR. MAZATLAN CTR FREQ HAD BEEN CONTINUOUSLY BLOCKED BY A STUCK MIKE BTWN LORETO (LTO) AND LAPAZ (LAP) YY15Z. ACFT X UNABLE TO CONTACT CTR FOR DSCNT CLRNC. IN ACCORDANCE WITH 10-7 PAGES OF OUR COMMERCIAL CHART MANUAL AND AIM PROCS, WE FOLLOWED LOST COM PROCS AND CONTACTED NEXT EXPECTED CTLR (LAPAZ CTL 120.6). LAPAZ APCH ISSUED DSCNT CLRNC. ACFT X BEGAN DSCNT AND CALLED OUT OF FL330. LAPAZ CTL CONFIRMED OUR DSCNT AND SAID TO RPT PASSING 16000 FT. LAPAZ APCH SOON THEREAFTER HAD US RECONTACT MAZATLAN CTR ON 128.0 (THE FREQ WITH THE STUCK MIKE). AFTER WE REINITIATED CONTACT WITH MAZATLAN CTR, WE WERE QUESTIONED ON OUR DSCNT CLRNC. WE ADVISED MAZATLAN CTR WE WERE CLRED THE DSCNT BY LAPAZ APCH. MAZATLAN SAID STAND BY AND CONTINUE YOUR DSCNT. WE SUGGESTED A LEVELOFF BUT MAZATLAN CTR ISSUED A DSCNT TO FL200. WE WERE THEN SWITCHED BACK TO LAPAZ APCH CTL AND THE FLT TO SJD CONTINUED NORMALLY. NO POTENTIAL CONFLICT WAS NOTED ON TCASII, VISUALLY, OR BY LAPAZ APCH. UPON ARR AT SJD, THE CAPT INQUIRED BY TELECON WITH LAPAZ APCH IF THERE WERE ANY QUESTIONS OR PROBS WITH THE DSCNT CLRNC N OF LAPAZ. LAPAZ SAID THERE WERE NO PROBS. CAUSED BY: LOST COM FAILURE OF LAPAZ APCH CTLR TO PROPERLY COORDINATE WITH MAZATLAN CTR PRIOR TO ISSUING DSCNT CLRNC. SUBMITTED TO PREVENT SIMILAR OCCURRENCE. NEEDS BETTER COORD BTWN LAPAZ APCH AND MAZATLAN CTR.

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.