Medium large transport lost all communication for about 30 minutes at cruise.

Attributes
ACN	102835
Time
Date	198901
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : tnp
State Reference	CA
Altitude	msl bound lower : 35000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zab artcc : zla
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise 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 : 20000 flight time type : 2000
ASRS Report	102835
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

While en route from stl to ont we experienced complete VHF communication failure while in ZAB airspace. Flew into ZLA airspace while we attempted to re-establish communications with either center, commerical radio, or company. We were unsuccessful for approximately 25-30 mins. Finally determined that first officer's j-box seemed to jam all frequencys when used, and that #1 VHF communication was inoperative from all stations. Contact finally established with ZLA using #2 VHF communication through captain's j-box and successful descent and approach completed to ont airport. All radios and j-boxes worked normally on ground(?). Could not figure out what the problem was, so next crew was extensively briefed on our problems and company advised to be alert for possible moisture/etc in radio components of this aircraft. No deviation from flight plan route were experienced since VHF navigation radio's were unaffected. However, a rather abrupt descent into ont was necessary due to close proximity of airport when communications finally re-established and center was not too happy with us. One bright note: while trying to re-establish communications a hasty review of communication failure procedure was subsequently accomplished.

Original NASA ASRS Text

Title: MLG LOST ALL COM FOR ABOUT 30 MINUTES AT CRUISE.

Narrative: WHILE ENRTE FROM STL TO ONT WE EXPERIENCED COMPLETE VHF COM FAILURE WHILE IN ZAB AIRSPACE. FLEW INTO ZLA AIRSPACE WHILE WE ATTEMPTED TO RE-ESTABLISH COMS WITH EITHER CENTER, COMMERICAL RADIO, OR COMPANY. WE WERE UNSUCCESSFUL FOR APPROX 25-30 MINS. FINALLY DETERMINED THAT F/O'S J-BOX SEEMED TO JAM ALL FREQS WHEN USED, AND THAT #1 VHF COM WAS INOP FROM ALL STATIONS. CONTACT FINALLY ESTABLISHED WITH ZLA USING #2 VHF COM THROUGH CAPT'S J-BOX AND SUCCESSFUL DSCNT AND APCH COMPLETED TO ONT ARPT. ALL RADIOS AND J-BOXES WORKED NORMALLY ON GND(?). COULD NOT FIGURE OUT WHAT THE PROB WAS, SO NEXT CREW WAS EXTENSIVELY BRIEFED ON OUR PROBS AND COMPANY ADVISED TO BE ALERT FOR POSSIBLE MOISTURE/ETC IN RADIO COMPONENTS OF THIS ACFT. NO DEVIATION FROM FLT PLAN ROUTE WERE EXPERIENCED SINCE VHF NAV RADIO'S WERE UNAFFECTED. HOWEVER, A RATHER ABRUPT DSCNT INTO ONT WAS NECESSARY DUE TO CLOSE PROX OF ARPT WHEN COMS FINALLY RE-ESTABLISHED AND CENTER WAS NOT TOO HAPPY WITH US. ONE BRIGHT NOTE: WHILE TRYING TO RE-ESTABLISH COMS A HASTY REVIEW OF COM FAILURE PROC WAS SUBSEQUENTLY ACCOMPLISHED.

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.