Flight crew of an large transport air carrier aircraft had stuck microphone resulting in less than s...

Attributes
ACN	245685
Time
Date	199307
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ord
State Reference	IL
Altitude	msl bound lower : 4000 msl bound upper : 7000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other 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 : 180 flight time total : 10000 flight time type : 2000
ASRS Report	245685
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 6100 flight time type : 1200
ASRS Report	245670
Events
Anomaly	aircraft equipment problem : critical conflict : airborne less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Miss Distance	horizontal : 3000 vertical : 0
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

This was a scheduled air carrier flight from btv to ord. First officer was pilot at controls and departure was normal. Upon captain's first radio call to departure, there was a loud squeal and the air carrier headset I was using became unusable. First officer made radio calls while I plugged in spare hand microphone and headset (we used a boom microphone). This arrangement worked well en route and we sent company a maintenance message regarding defective headset. Ord was landing runway 22L, runway 22R with gusty winds out of south. Were vectored for ILS runway 22R approach with WX of 35 scattered, 7 mi visibility in haze. At about 19 mi final we were 'cleared for runway 22R ILS call tower at ridge OM.' I acknowledged clearance and we got busy configuring for approach and briefing special procedures for wind. About 2 mi prior to the OM we received a TCASII TA. We observed an aircraft approximately 1/2 mi off our left, same altitude and diverging. At that point I realized that it had been very quiet on the previously busy approach frequency. I called with a radio check and was advised we had a stuck microphone the last 10 mi and just had a near miss. Visibility was fairly good and traffic was in sight and we were on localizer and GS runway 22R and took no evasive action. There was no TCASII RA. The chain of events started on departure from btv when the headset that we always use failed. This put me in a different situation (hand microphone and uncomfortable head phones) than we usually use. This was not significant but gave just enough of a different perspective to perhaps prevent me from recognizing the stuck microphone earlier. The situation also was compounded by the windy conditions at ord making the crew preoccupied with the approach so as not to recognize the stuck microphone. Although this was not a close 'near miss' it could have been. TCASII was doing its job although in the busy terminal areas such as ord, it is often turned off due to nuisance advisories on parallel approachs. Ord approach frequency is often congested and this demonstrates what can happen when it gets blocked.

Original NASA ASRS Text

Title: FLC OF AN LGT ACR ACFT HAD STUCK MIKE RESULTING IN LTSS FROM ANOTHER ACFT ON APCH.

Narrative: THIS WAS A SCHEDULED ACR FLT FROM BTV TO ORD. FO WAS PLT AT CTLS AND DEP WAS NORMAL. UPON CAPT'S FIRST RADIO CALL TO DEP, THERE WAS A LOUD SQUEAL AND THE ACR HEADSET I WAS USING BECAME UNUSABLE. FO MADE RADIO CALLS WHILE I PLUGGED IN SPARE HAND MIKE AND HEADSET (WE USED A BOOM MIKE). THIS ARRANGEMENT WORKED WELL ENRTE AND WE SENT COMPANY A MAINT MESSAGE REGARDING DEFECTIVE HEADSET. ORD WAS LNDG RWY 22L, RWY 22R WITH GUSTY WINDS OUT OF S. WERE VECTORED FOR ILS RWY 22R APCH WITH WX OF 35 SCATTERED, 7 MI VISIBILITY IN HAZE. AT ABOUT 19 MI FINAL WE WERE 'CLRED FOR RWY 22R ILS CALL TWR AT RIDGE OM.' I ACKNOWLEDGED CLRNC AND WE GOT BUSY CONFIGURING FOR APCH AND BRIEFING SPECIAL PROCS FOR WIND. ABOUT 2 MI PRIOR TO THE OM WE RECEIVED A TCASII TA. WE OBSERVED AN ACFT APPROX 1/2 MI OFF OUR L, SAME ALT AND DIVERGING. AT THAT POINT I REALIZED THAT IT HAD BEEN VERY QUIET ON THE PREVIOUSLY BUSY APCH FREQ. I CALLED WITH A RADIO CHK AND WAS ADVISED WE HAD A STUCK MIKE THE LAST 10 MI AND JUST HAD A NEAR MISS. VISIBILITY WAS FAIRLY GOOD AND TFC WAS IN SIGHT AND WE WERE ON LOC AND GS RWY 22R AND TOOK NO EVASIVE ACTION. THERE WAS NO TCASII RA. THE CHAIN OF EVENTS STARTED ON DEP FROM BTV WHEN THE HEADSET THAT WE ALWAYS USE FAILED. THIS PUT ME IN A DIFFERENT SIT (HAND MIKE AND UNCOMFORTABLE HEAD PHONES) THAN WE USUALLY USE. THIS WAS NOT SIGNIFICANT BUT GAVE JUST ENOUGH OF A DIFFERENT PERSPECTIVE TO PERHAPS PREVENT ME FROM RECOGNIZING THE STUCK MIKE EARLIER. THE SIT ALSO WAS COMPOUNDED BY THE WINDY CONDITIONS AT ORD MAKING THE CREW PREOCCUPIED WITH THE APCH SO AS NOT TO RECOGNIZE THE STUCK MIKE. ALTHOUGH THIS WAS NOT A CLOSE 'NEAR MISS' IT COULD HAVE BEEN. TCASII WAS DOING ITS JOB ALTHOUGH IN THE BUSY TERMINAL AREAS SUCH AS ORD, IT IS OFTEN TURNED OFF DUE TO NUISANCE ADVISORIES ON PARALLEL APCHS. ORD APCH FREQ IS OFTEN CONGESTED AND THIS DEMONSTRATES WHAT CAN HAPPEN WHEN IT GETS BLOCKED.

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.

Flight crew of an large transport air carrier aircraft had stuck microphone resulting in less than standard separation from another aircraft on approach.