Narrative:

We were on approach to runway 4R -- autoplt #1 engaged to localizer. 10 mi outside the OM. Localizer needle #1, ADI and HSI would peg left or right for 2 seconds then return. #2 operated normally checked with tower and other aircraft all indicated no problems with the localizer. The so made a PA to passenger to discontinue use of computers and cellular phones. By this time we were inside marker at 1200 ft AGL. No further problems noted. We were close to a go around decision. No deviation from localizer GS as we switched to #2. We did also get GS. Flag several times on #1 (intermittent). Also disappeared soon after passenger PA was made. I had the same problem approximately 1 yr ago arriving into lax ILS runway 25. As soon as an announcement was made to the passenger to discontinue cellular phone and computer use the problem was solved. No other aircraft or tower reported any problems with localizer GS. Suggestions: we need to outlaw cellular phone on aircraft to publicize to media and public the safety problem. To develop a cockpit detector and alert system for electronic interference. To fine culprits and publicize. Flight attendants see and know passenger are taking their phones into the lavatories to use. Callback conversation with reporter revealed the following information: the reporter was flying an A300-B4 during both of his encounters with electro-magnetic interference and both incidents were caused by cellular phones while flying an ILS. In this case the ILS, the ADI and the HSI showed full case deflections when operating on the #1 system. The #2 system showed no problems, but was not switched on until about the same time as the announcement to discontinue cellular phone and computer use. The yr earlier event at lax was almost identical except the WX was better.

Related reports:

Google
 

Original NASA ASRS Text

Title: INTERFERING XMITTER -- THE FLC ATTEMPTING TO CONDUCT AN IMC ILS ENCOUNTERS ELECTROMAGNETIC INTERFERENCE FROM A CELLULAR PHONE.

Narrative: WE WERE ON APCH TO RWY 4R -- AUTOPLT #1 ENGAGED TO LOC. 10 MI OUTSIDE THE OM. LOC NEEDLE #1, ADI AND HSI WOULD PEG L OR R FOR 2 SECONDS THEN RETURN. #2 OPERATED NORMALLY CHKED WITH TWR AND OTHER ACFT ALL INDICATED NO PROBS WITH THE LOC. THE SO MADE A PA TO PAX TO DISCONTINUE USE OF COMPUTERS AND CELLULAR PHONES. BY THIS TIME WE WERE INSIDE MARKER AT 1200 FT AGL. NO FURTHER PROBS NOTED. WE WERE CLOSE TO A GAR DECISION. NO DEV FROM LOC GS AS WE SWITCHED TO #2. WE DID ALSO GET GS. FLAG SEVERAL TIMES ON #1 (INTERMITTENT). ALSO DISAPPEARED SOON AFTER PAX PA WAS MADE. I HAD THE SAME PROB APPROX 1 YR AGO ARRIVING INTO LAX ILS RWY 25. AS SOON AS AN ANNOUNCEMENT WAS MADE TO THE PAX TO DISCONTINUE CELLULAR PHONE AND COMPUTER USE THE PROB WAS SOLVED. NO OTHER ACFT OR TWR RPTED ANY PROBS WITH LOC GS. SUGGESTIONS: WE NEED TO OUTLAW CELLULAR PHONE ON ACFT TO PUBLICIZE TO MEDIA AND PUBLIC THE SAFETY PROB. TO DEVELOP A COCKPIT DETECTOR AND ALERT SYS FOR ELECTRONIC INTERFERENCE. TO FINE CULPRITS AND PUBLICIZE. FLT ATTENDANTS SEE AND KNOW PAX ARE TAKING THEIR PHONES INTO THE LAVATORIES TO USE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS FLYING AN A300-B4 DURING BOTH OF HIS ENCOUNTERS WITH ELECTRO-MAGNETIC INTERFERENCE AND BOTH INCIDENTS WERE CAUSED BY CELLULAR PHONES WHILE FLYING AN ILS. IN THIS CASE THE ILS, THE ADI AND THE HSI SHOWED FULL CASE DEFLECTIONS WHEN OPERATING ON THE #1 SYS. THE #2 SYS SHOWED NO PROBS, BUT WAS NOT SWITCHED ON UNTIL ABOUT THE SAME TIME AS THE ANNOUNCEMENT TO DISCONTINUE CELLULAR PHONE AND COMPUTER USE. THE YR EARLIER EVENT AT LAX WAS ALMOST IDENTICAL EXCEPT THE WX WAS BETTER.

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.