Air carrier has communication problem on descent, corrects intercom switches.

Attributes
ACN	247639
Time
Date	199307
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sjc
State Reference	CA
Altitude	msl bound lower : 6000 msl bound upper : 6000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa tracon : oak
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 180 flight time total : 15000 flight time type : 5000
ASRS Report	247639
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While communicating with san francisco center on descent into san jose (captain on the radios and first officer flying) I received a loud squeal that totally negated my ability to communicate. Apparently the first officer was given instructions to continue descent to 6000 ft and a heading by center and was handed off to bay approach. I heard none of this communication, but trusted the first officer. Finally I determined the problem with my intercom panel. I had inadvertently left the button down on the ADF for san jose. I did not realize we had changed frequencys to bay approach and while trying to find out what was causing the loud squeal I turned the radios back to the center frequency. The first officer was unaware of this. After being level at 6000 ft and on a 300 degree heading, we were situated for a perfect downwind to runway 12 at san jose. I got quiet and I queried center about a handoff to approach control. They then told me to contact bay approach. The problem was solved. No conflicts caused and a normal landing was made. Solution: be careful using aircraft intercom with push buttons. While looking directly down at the panel it is difficult to determine whether the buttons are depressed.

Original NASA ASRS Text

Title: ACR HAS COM PROB ON DSCNT, CORRECTS INTERCOM SWITCHES.

Narrative: WHILE COMMUNICATING WITH SAN FRANCISCO CTR ON DSCNT INTO SAN JOSE (CAPT ON THE RADIOS AND FO FLYING) I RECEIVED A LOUD SQUEAL THAT TOTALLY NEGATED MY ABILITY TO COMMUNICATE. APPARENTLY THE FO WAS GIVEN INSTRUCTIONS TO CONTINUE DSCNT TO 6000 FT AND A HDG BY CTR AND WAS HANDED OFF TO BAY APCH. I HEARD NONE OF THIS COM, BUT TRUSTED THE FO. FINALLY I DETERMINED THE PROB WITH MY INTERCOM PANEL. I HAD INADVERTENTLY LEFT THE BUTTON DOWN ON THE ADF FOR SAN JOSE. I DID NOT REALIZE WE HAD CHANGED FREQS TO BAY APCH AND WHILE TRYING TO FIND OUT WHAT WAS CAUSING THE LOUD SQUEAL I TURNED THE RADIOS BACK TO THE CTR FREQ. THE FO WAS UNAWARE OF THIS. AFTER BEING LEVEL AT 6000 FT AND ON A 300 DEG HDG, WE WERE SITUATED FOR A PERFECT DOWNWIND TO RWY 12 AT SAN JOSE. I GOT QUIET AND I QUERIED CTR ABOUT A HDOF TO APCH CTL. THEY THEN TOLD ME TO CONTACT BAY APCH. THE PROB WAS SOLVED. NO CONFLICTS CAUSED AND A NORMAL LNDG WAS MADE. SOLUTION: BE CAREFUL USING ACFT INTERCOM WITH PUSH BUTTONS. WHILE LOOKING DIRECTLY DOWN AT THE PANEL IT IS DIFFICULT TO DETERMINE WHETHER THE BUTTONS ARE DEPRESSED.

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.