Air carrier loss of radio contact while on radar vector for localizer intercept.

Attributes
ACN	102966
Time
Date	198901
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : sea
State Reference	WA
Altitude	msl bound lower : 3200 msl bound upper : 3200
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : sea
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 14000
ASRS Report	102966
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance other spatial deviation other spatial deviation
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:

We had received a vector from approach which was a 45 degree left turn to ILS, descent clearance to 3200' approximately 15 mi from airport. After passing through ILS course and hearing no further communication we began to wonder why no approach clearance was given. After a call with no response I looked down at the radio to confirm the frequency. It was then I noticed the transfer switch between the dual head communication was in the mid position rather than the proper detent. I moved the switch inadvertently to other head and got the tower. Then realized the problem and repositioned the transfer switch back to approach. By this time we were through localizer still at 3200' heading toward high terrain. Approach immediately turned us left 270 degrees back to ILS course. Approach and landing was uneventful. I wrote a maintenance squawk on the transmitter transfer switch due to fact it was loose and had play in the detent. I may have ticked the switch when I preset the tower frequency or the switch had not seated properly in the detent, thus causing a loss of all communications. Our final analysis: I feel I should have reacted sooner when the localizer came alive. It is common for approach to take aircraft through localizer and back for spacing, but usually you are warned ahead of time. We were not advised of this possibility, making it imperative that a pilot get suspicious when you are not hearing things you should.

Original NASA ASRS Text

Title: ACR LOSS OF RADIO CONTACT WHILE ON RADAR VECTOR FOR LOCALIZER INTERCEPT.

Narrative: WE HAD RECEIVED A VECTOR FROM APCH WHICH WAS A 45 DEG LEFT TURN TO ILS, DSCNT CLRNC TO 3200' APPROX 15 MI FROM ARPT. AFTER PASSING THROUGH ILS COURSE AND HEARING NO FURTHER COM WE BEGAN TO WONDER WHY NO APCH CLRNC WAS GIVEN. AFTER A CALL WITH NO RESPONSE I LOOKED DOWN AT THE RADIO TO CONFIRM THE FREQ. IT WAS THEN I NOTICED THE TRANSFER SWITCH BTWN THE DUAL HEAD COM WAS IN THE MID POS RATHER THAN THE PROPER DETENT. I MOVED THE SWITCH INADVERTENTLY TO OTHER HEAD AND GOT THE TWR. THEN REALIZED THE PROB AND REPOSITIONED THE TRANSFER SWITCH BACK TO APCH. BY THIS TIME WE WERE THROUGH LOC STILL AT 3200' HDG TOWARD HIGH TERRAIN. APCH IMMEDIATELY TURNED US LEFT 270 DEGS BACK TO ILS COURSE. APCH AND LNDG WAS UNEVENTFUL. I WROTE A MAINT SQUAWK ON THE XMITTER TRANSFER SWITCH DUE TO FACT IT WAS LOOSE AND HAD PLAY IN THE DETENT. I MAY HAVE TICKED THE SWITCH WHEN I PRESET THE TWR FREQ OR THE SWITCH HAD NOT SEATED PROPERLY IN THE DETENT, THUS CAUSING A LOSS OF ALL COMS. OUR FINAL ANALYSIS: I FEEL I SHOULD HAVE REACTED SOONER WHEN THE LOC CAME ALIVE. IT IS COMMON FOR APCH TO TAKE ACFT THROUGH LOC AND BACK FOR SPACING, BUT USUALLY YOU ARE WARNED AHEAD OF TIME. WE WERE NOT ADVISED OF THIS POSSIBILITY, MAKING IT IMPERATIVE THAT A PLT GET SUSPICIOUS WHEN YOU ARE NOT HEARING THINGS YOU SHOULD.

Data retrieved from NASA's ASRS site as of August 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.