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An MD90 crew, during cruise at FL310, experienced a loud squeal between communication xmissions to ARTCC.
| Attributes | |
| ACN | 550807 |
| Time | |
| Date | 200206 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : sjn.vortac |
| State Reference | AZ |
| Altitude | msl single value : 31000 |
| Aircraft 1 | |
| Controlling Facilities | artcc : zab.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | MD-90 Series (DC-9-90) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 550807 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Events | |
| Anomaly | aircraft equipment problem : less severe inflight encounter other other anomaly other |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | none taken : anomaly accepted |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | ATC Facility Aircraft |
| Primary Problem | ATC Facility |
| Situations | |
| ATC Facility | communication equipment : zab.artcc |
Narrative:
While flying in the vicinity of sjn VOR and talking to ZAB sector 50 on 127.67, there was a very loud squeal on the frequency that is a hazard both to ATC communication and pilot's hearing. The squeal only occurs between xmissions. During xmissions from either ground or aircraft, it went away and the xmissions were loud and clear. Even though the xmissions are clear, it is still a hazard because it is so loud that air crews have to turn the radio volume way down to protect their hearing. The interference is apparently intermittent and when it is occurring does not affect all aircraft on the frequency. I believe it is a ZAB radio problem though because the controller stated that it had been an ongoing problem for about 2 yrs. Callback conversation with a ZAB ARTCC operations manager revealed the following information: such a communications problem would have been reported and logged for a maintenance check. He was very candid and admitted certain problems do arise from time-to-time, but none have involved the area or frequency mentioned.
Original NASA ASRS Text
Title: AN MD90 CREW, DURING CRUISE AT FL310, EXPERIENCED A LOUD SQUEAL BTWN COM XMISSIONS TO ARTCC.
Narrative: WHILE FLYING IN THE VICINITY OF SJN VOR AND TALKING TO ZAB SECTOR 50 ON 127.67, THERE WAS A VERY LOUD SQUEAL ON THE FREQ THAT IS A HAZARD BOTH TO ATC COM AND PLT'S HEARING. THE SQUEAL ONLY OCCURS BTWN XMISSIONS. DURING XMISSIONS FROM EITHER GND OR ACFT, IT WENT AWAY AND THE XMISSIONS WERE LOUD AND CLR. EVEN THOUGH THE XMISSIONS ARE CLR, IT IS STILL A HAZARD BECAUSE IT IS SO LOUD THAT AIR CREWS HAVE TO TURN THE RADIO VOLUME WAY DOWN TO PROTECT THEIR HEARING. THE INTERFERENCE IS APPARENTLY INTERMITTENT AND WHEN IT IS OCCURRING DOES NOT AFFECT ALL ACFT ON THE FREQ. I BELIEVE IT IS A ZAB RADIO PROB THOUGH BECAUSE THE CTLR STATED THAT IT HAD BEEN AN ONGOING PROB FOR ABOUT 2 YRS. CALLBACK CONVERSATION WITH A ZAB ARTCC OPS MGR REVEALED THE FOLLOWING INFO: SUCH A COMS PROB WOULD HAVE BEEN RPTED AND LOGGED FOR A MAINT CHK. HE WAS VERY CANDID AND ADMITTED CERTAIN PROBS DO ARISE FROM TIME-TO-TIME, BUT NONE HAVE INVOLVED THE AREA OR FREQ MENTIONED.
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.