<< >> NASA ASRS Report 514920, June 2001

Military C5 flight crew inadvertently transmitted music over their handheld microphone due to the captain switching from the secondary to primary communication radio for position reporting and heard the music being transmitted from the handheld microphone.

Attributes
ACN	514920
Time
Date	200106
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	intersection : abner
State Reference	CA
Altitude	msl single value : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa.artcc
Operator	other
Make Model Name	Galaxy (C5A)
Operating Under FAR Part	Part 91
Navigation In Use	other
Route In Use	enroute airway : r464.airway
Flight Plan	IFR
Person 1
Affiliation	government : military
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 150 flight time total : 6200 flight time type : 800
ASRS Report	514920
Person 2
Affiliation	government : military
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : atp pilot : instrument pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 180 flight time total : 6500 flight time type : 2500
ASRS Report	514913
Events
Anomaly	non adherence other
Independent Detector	aircraft equipment other aircraft equipment : hot mike other flight crewa
Resolutory Action	flight crew : overcame equipment problem none taken : detected after the fact other
Consequence	Other
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

While flying at FL310 between california and hawaii, on track R463 in the vicinity of abner intersection, using commercial radio for position reporting on the HF radio channel 122.82, we unintentionally caused an open (hot) microphone situation and transmitted music on the primary radio channel. This situation lasted approximately 15-20 mins. The error was discovered when preparing the next position report and the hot microphone was immediately terminated. The cause of this incident was an error in switch selection. The crew was using the intercom to listen to music being played on a portable clearance delivery player by placing the pilot's handheld microphone next to the clearance delivery speaker. Initially, the copilot was in charge of the primary HF radio. When the copilot left the flight deck, for physiological purposes, he briefed the pilot on the primary radio. The pilot then selected the primary radio on his transmit wafer switch, not realizing that this caused the handheld microphone to become hot and transmit on the primary radio frequency.

Related reports:

• C172 pilot inadvertently transmitted on guard frequency 121....

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Original NASA ASRS Text

Title: MIL C5 FLC INADVERTENTLY XMITTED MUSIC OVER THEIR HANDHELD MIKE DUE TO THE CAPT SWITCHING FROM THE SECONDARY TO PRIMARY COM RADIO FOR POS RPTING AND HEARD THE MUSIC BEING XMITTED FROM THE HANDHELD MIKE.

Narrative: WHILE FLYING AT FL310 BTWN CALIFORNIA AND HAWAII, ON TRACK R463 IN THE VICINITY OF ABNER INTXN, USING COMMERCIAL RADIO FOR POS RPTING ON THE HF RADIO CHANNEL 122.82, WE UNINTENTIONALLY CAUSED AN OPEN (HOT) MIKE SIT AND XMITTED MUSIC ON THE PRIMARY RADIO CHANNEL. THIS SIT LASTED APPROX 15-20 MINS. THE ERROR WAS DISCOVERED WHEN PREPARING THE NEXT POS RPT AND THE HOT MIKE WAS IMMEDIATELY TERMINATED. THE CAUSE OF THIS INCIDENT WAS AN ERROR IN SWITCH SELECTION. THE CREW WAS USING THE INTERCOM TO LISTEN TO MUSIC BEING PLAYED ON A PORTABLE CD PLAYER BY PLACING THE PLT'S HANDHELD MIKE NEXT TO THE CD SPEAKER. INITIALLY, THE COPLT WAS IN CHARGE OF THE PRIMARY HF RADIO. WHEN THE COPLT LEFT THE FLT DECK, FOR PHYSIOLOGICAL PURPOSES, HE BRIEFED THE PLT ON THE PRIMARY RADIO. THE PLT THEN SELECTED THE PRIMARY RADIO ON HIS XMIT WAFER SWITCH, NOT REALIZING THAT THIS CAUSED THE HANDHELD MIKE TO BECOME HOT AND XMIT ON THE PRIMARY RADIO FREQ.

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.