B747-400 loses radio contact with ATC during approach at nrt, japan. Aircraft had a stuck microphone...

Attributes
ACN	386284
Time
Date	199711
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : yq airport : nrt
State Reference	FO
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : nrt
Operator	common carrier : air carrier
Make Model Name	B747-400
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent : approach descent other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 100 flight time total : 16000 flight time type : 500
ASRS Report	386284
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

We were at 4000 ft, estimated 230 KIAS, heading 340 degrees magnetic. Approximately 10 mi southeast of yokoshiba NDB 'yq' being vectored for an ILS runway 34 approach at narita, japan. We were on approach control frequency and lost VHF communications. We immediately squawked 7600 in the transponder and the first officer switched the #2 radio to narita tower frequency while I stayed on approach control frequency. I was the PF. We were on a vector to yokoshiba NDB at the time of the incident. Almost immediately I could hear narita approach again and attempted unsuccessfully to contact them. The first officer was unable to contact tower so he switched back to approach control and then I was unable to hear approach control again. Both the first officer and I were using minitel mikes. On this B747-400 aircraft, the first officer also has a hand-held microphone which hangs near his flight bag on the right side wall. He determined that his book of approach plates was pressing against the microphone and blocked the frequency selected by him. He unkeyed the microphone and we re-established communications with approach control. We were assigned a new transponder squawk and vectored for another approach and landed uneventfully at narita.

Original NASA ASRS Text

Title: B747-400 LOSES RADIO CONTACT WITH ATC DURING APCH AT NRT, JAPAN. ACFT HAD A STUCK MIKE CAUSED BY ONE OF THE FLC.

Narrative: WE WERE AT 4000 FT, ESTIMATED 230 KIAS, HDG 340 DEGS MAGNETIC. APPROX 10 MI SE OF YOKOSHIBA NDB 'YQ' BEING VECTORED FOR AN ILS RWY 34 APCH AT NARITA, JAPAN. WE WERE ON APCH CTL FREQ AND LOST VHF COMS. WE IMMEDIATELY SQUAWKED 7600 IN THE XPONDER AND THE FO SWITCHED THE #2 RADIO TO NARITA TWR FREQ WHILE I STAYED ON APCH CTL FREQ. I WAS THE PF. WE WERE ON A VECTOR TO YOKOSHIBA NDB AT THE TIME OF THE INCIDENT. ALMOST IMMEDIATELY I COULD HEAR NARITA APCH AGAIN AND ATTEMPTED UNSUCCESSFULLY TO CONTACT THEM. THE FO WAS UNABLE TO CONTACT TWR SO HE SWITCHED BACK TO APCH CTL AND THEN I WAS UNABLE TO HEAR APCH CTL AGAIN. BOTH THE FO AND I WERE USING MINITEL MIKES. ON THIS B747-400 ACFT, THE FO ALSO HAS A HAND-HELD MIKE WHICH HANGS NEAR HIS FLT BAG ON THE R SIDE WALL. HE DETERMINED THAT HIS BOOK OF APCH PLATES WAS PRESSING AGAINST THE MIKE AND BLOCKED THE FREQ SELECTED BY HIM. HE UNKEYED THE MIKE AND WE RE-ESTABLISHED COMS WITH APCH CTL. WE WERE ASSIGNED A NEW XPONDER SQUAWK AND VECTORED FOR ANOTHER APCH AND LANDED UNEVENTFULLY AT NARITA.

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.

B747-400 loses radio contact with ATC during approach at nrt, japan. Aircraft had a stuck microphone caused by one of the flight crew.