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Comm volume on medium large transport aircraft are lever type that are easily inadvertently shut off and or easily snagged by microphone cord and shut off, effectively severing communications.
| Attributes | |
| ACN | 149902 |
| Time | |
| Date | 199007 |
| Day | Mon |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : xxx |
| State Reference | US |
| Aircraft 1 | |
| Controlling Facilities | tower : jfk |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 15000 flight time type : 200 |
| ASRS Report | 149902 |
| Events | |
| Anomaly | aircraft equipment problem : less severe |
| Independent Detector | other flight crewa |
| Resolutory Action | none taken : anomaly accepted |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Subject is the poor design of the volume levers on the audio selector boxes. These communication boxes have a lever actuated volume control which is very easily moved. I have shut my volume off several times during flight and been unaware I was out of contact with ATC until the other crew members answers a call from ATC. On the medium large transport a and B captain and first officer side two items very easily shut off the volume. The auxiliary light for the flight bag is located directly aft of the communication box; the coiled cord to this light very easily catches the levers on the communication box when the light is used to check windshield wiper ice at night or checking charts. On many medium large transport aircraft (not all), the captain and first officers microphone jack is located right next to the communication box and the coiled cord may be dragging across the volume levers whenever the microphone is used. For safety reasons I believe these audio boxes should be removed and replaced with a safer item at all locations.
Original NASA ASRS Text
Title: COMM VOLUME ON MLG ACFT ARE LEVER TYPE THAT ARE EASILY INADVERTENTLY SHUT OFF AND OR EASILY SNAGGED BY MIC CORD AND SHUT OFF, EFFECTIVELY SEVERING COMS.
Narrative: SUBJECT IS THE POOR DESIGN OF THE VOLUME LEVERS ON THE AUDIO SELECTOR BOXES. THESE COM BOXES HAVE A LEVER ACTUATED VOLUME CTL WHICH IS VERY EASILY MOVED. I HAVE SHUT MY VOLUME OFF SEVERAL TIMES DURING FLT AND BEEN UNAWARE I WAS OUT OF CONTACT WITH ATC UNTIL THE OTHER CREW MEMBERS ANSWERS A CALL FROM ATC. ON THE MLG A AND B CAPT AND F/O SIDE TWO ITEMS VERY EASILY SHUT OFF THE VOLUME. THE AUX LIGHT FOR THE FLT BAG IS LOCATED DIRECTLY AFT OF THE COM BOX; THE COILED CORD TO THIS LIGHT VERY EASILY CATCHES THE LEVERS ON THE COM BOX WHEN THE LIGHT IS USED TO CHK WINDSHIELD WIPER ICE AT NIGHT OR CHKING CHARTS. ON MANY MLG ACFT (NOT ALL), THE CAPT AND F/OS MIC JACK IS LOCATED RIGHT NEXT TO THE COM BOX AND THE COILED CORD MAY BE DRAGGING ACROSS THE VOLUME LEVERS WHENEVER THE MIC IS USED. FOR SAFETY REASONS I BELIEVE THESE AUDIO BOXES SHOULD BE REMOVED AND REPLACED WITH A SAFER ITEM AT ALL LOCATIONS.
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.