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B757 flight crew has stuck microphone at cruise. Recognizes lack of communication and keys microphone.
| Attributes | |
| ACN | 332458 |
| Time | |
| Date | 199604 |
| Day | Sun |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : mke |
| State Reference | WI |
| Altitude | msl bound lower : 41000 msl bound upper : 41000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zau artcc : segu |
| Operator | common carrier : air carrier |
| Make Model Name | B757 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 85 flight time total : 19000 flight time type : 1700 |
| ASRS Report | 332458 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | aircraft equipment problem : less severe other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | none taken : detected after the fact |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Flight was from sea to pit. After about 2 1/2 to 3 hours cruise, somehow a microphone in cockpit became hot. After a period of time 5-10 mins not hearing any ATC conversation, I keyed mikes and ATC advised we had an open microphone for about 100 mi and gave us frequency change. We later found frayed headset (boom) cord, but I'm unsure if that caused problem, or a transmit switch stuck. Headset was replaced in pit. At first the silence didn't seem unusual as high altitude flight across northern united states there are sometimes not many aircraft on an individual sector. The problem could have been prevented or detected earlier by a transmit light on radio similar to those on VHF marine radios.
Original NASA ASRS Text
Title: B757 FLC HAS STUCK MIKE AT CRUISE. RECOGNIZES LACK OF COM AND KEYS MIKE.
Narrative: FLT WAS FROM SEA TO PIT. AFTER ABOUT 2 1/2 TO 3 HRS CRUISE, SOMEHOW A MIKE IN COCKPIT BECAME HOT. AFTER A PERIOD OF TIME 5-10 MINS NOT HEARING ANY ATC CONVERSATION, I KEYED MIKES AND ATC ADVISED WE HAD AN OPEN MIKE FOR ABOUT 100 MI AND GAVE US FREQ CHANGE. WE LATER FOUND FRAYED HEADSET (BOOM) CORD, BUT I'M UNSURE IF THAT CAUSED PROB, OR A XMIT SWITCH STUCK. HEADSET WAS REPLACED IN PIT. AT FIRST THE SILENCE DIDN'T SEEM UNUSUAL AS HIGH ALT FLT ACROSS NORTHERN UNITED STATES THERE ARE SOMETIMES NOT MANY ACFT ON AN INDIVIDUAL SECTOR. THE PROB COULD HAVE BEEN PREVENTED OR DETECTED EARLIER BY A XMIT LIGHT ON RADIO SIMILAR TO THOSE ON VHF MARINE RADIOS.
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.