Narrative:

The flight was proceeding into dulles airport on the jansen 1 arrival, descending through 13000 ft to an altitude clearance of 11000 ft. The captain was flying the aircraft with the autoplt engaged, dfgc #1 in use, autothrottles engaged, VNAV engaged and LNAV was coupled to both flight directors and autoplt. The FMS was being used for navigation on the arrival, and both VHF navigation receivers were tuned to the armel (113.7 frequency) VOR. Suddenly the captain's ADI presentation disappeared, the 'att fail' displayed in the center of the CRT display, and the flight director pitch and bank steering bars were crossed and centered in the center of the display. The first officer's RDMI displayed all 3 red 'off' warning flags, and the first officer's navigation display had 'heading failure' displayed in the top of the presentation. In addition, on the captain's FMA panel, 'no autoland' was steadily illuminated and 'horizon' and 'heading' abnormal lights were flashing. At the time of this failure, the TCASII was operating with normal presentation on the radar scope. However, the presentation disappeared and the amber cautions of 'attitude' and 'heading' were steadily illuminated on the scope for the remainder of the flight. I was unable to change the desired course displayed on the #1 VHF navigation receiver (the knob turned freely, but no course change on the led's could be accomplished), although the first officer's VHF navigation panel functioned properly. Switching from the #1 to #2 digital flight guidance computer had no effect on any of the abnormal presentations. Aircraft control was transferred to the first officer, who flew the remainder of the arrival and conducted a visual approach and landing to runway 1L at dulles. No messages were illuminated at any time on the overhead annunciator panel, nor were any status lights displayed on the adjacent advisory panel (ie, neither the #1 nor #2 ahrs units had reverted to 'basic' mode). When it became apparent that we were not going to be able to regain the #1 navigation/instrument system, ATC (washington approach) was advised of our operating status, whereupon they informed us of visual approach conditions still existing at dulles. The EFIS command switch was positioned to 'both on 2,' restoring a normal pfd presentation on the captain's side, albeit a copy of the display on the first officer's side. After landing at dulles and shutting down the engines, normal presentations returned to all displays following the automatic accomplishment of the power up test on all automated flight instrument system, and no further problems were experienced during subsequent operations. It is interesting to note that at the time of the initial failure, the flight crew suspected possible electronic interference from an onboard source, and requested the flight attendants to ensure that all passenger discontinue use of personal electronic devices. On the ground at dulles, I was told by lead flight attendant that there were probably about 8 personal laptop computers being used by passenger throughout the cabin -- at the time of my request in the air. I suspect that the erroneous instrument displays, and the absence of warning messages, were due not to any inherent equipment malfunction but rather interference from a source outside the cockpit. Callback conversation with reporter revealed the following information: the reporter said that he was unable to bring his displays 'back up' even after all of the laptops were shut off. The displays did not become functional until after the post- landing self test was (automatically) completed. The reporter does not know which of or if all of the laptops caused the abnormal displays. He also does not know if any other electronic devices were in use at the time.

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Original NASA ASRS Text

Title: ACFT EQUIP PROB -- ELECTRO MAGNETIC INTERFERENCE IS CLAIMED TO HAVE INTERFERED WITH APCH PROCS. CAPTS EFIS DISPLAY LOST.

Narrative: THE FLT WAS PROCEEDING INTO DULLES ARPT ON THE JANSEN 1 ARR, DSNDING THROUGH 13000 FT TO AN ALT CLRNC OF 11000 FT. THE CAPT WAS FLYING THE ACFT WITH THE AUTOPLT ENGAGED, DFGC #1 IN USE, AUTOTHROTTLES ENGAGED, VNAV ENGAGED AND LNAV WAS COUPLED TO BOTH FLT DIRECTORS AND AUTOPLT. THE FMS WAS BEING USED FOR NAV ON THE ARR, AND BOTH VHF NAV RECEIVERS WERE TUNED TO THE ARMEL (113.7 FREQ) VOR. SUDDENLY THE CAPT'S ADI PRESENTATION DISAPPEARED, THE 'ATT FAIL' DISPLAYED IN THE CTR OF THE CRT DISPLAY, AND THE FLT DIRECTOR PITCH AND BANK STEERING BARS WERE CROSSED AND CTRED IN THE CTR OF THE DISPLAY. THE FO'S RDMI DISPLAYED ALL 3 RED 'OFF' WARNING FLAGS, AND THE FO'S NAV DISPLAY HAD 'HDG FAILURE' DISPLAYED IN THE TOP OF THE PRESENTATION. IN ADDITION, ON THE CAPT'S FMA PANEL, 'NO AUTOLAND' WAS STEADILY ILLUMINATED AND 'HORIZON' AND 'HDG' ABNORMAL LIGHTS WERE FLASHING. AT THE TIME OF THIS FAILURE, THE TCASII WAS OPERATING WITH NORMAL PRESENTATION ON THE RADAR SCOPE. HOWEVER, THE PRESENTATION DISAPPEARED AND THE AMBER CAUTIONS OF 'ATTITUDE' AND 'HDG' WERE STEADILY ILLUMINATED ON THE SCOPE FOR THE REMAINDER OF THE FLT. I WAS UNABLE TO CHANGE THE DESIRED COURSE DISPLAYED ON THE #1 VHF NAV RECEIVER (THE KNOB TURNED FREELY, BUT NO COURSE CHANGE ON THE LED'S COULD BE ACCOMPLISHED), ALTHOUGH THE FO'S VHF NAV PANEL FUNCTIONED PROPERLY. SWITCHING FROM THE #1 TO #2 DIGITAL FLT GUIDANCE COMPUTER HAD NO EFFECT ON ANY OF THE ABNORMAL PRESENTATIONS. ACFT CTL WAS TRANSFERRED TO THE FO, WHO FLEW THE REMAINDER OF THE ARR AND CONDUCTED A VISUAL APCH AND LNDG TO RWY 1L AT DULLES. NO MESSAGES WERE ILLUMINATED AT ANY TIME ON THE OVERHEAD ANNUNCIATOR PANEL, NOR WERE ANY STATUS LIGHTS DISPLAYED ON THE ADJACENT ADVISORY PANEL (IE, NEITHER THE #1 NOR #2 AHRS UNITS HAD REVERTED TO 'BASIC' MODE). WHEN IT BECAME APPARENT THAT WE WERE NOT GOING TO BE ABLE TO REGAIN THE #1 NAV/INST SYS, ATC (WASHINGTON APCH) WAS ADVISED OF OUR OPERATING STATUS, WHEREUPON THEY INFORMED US OF VISUAL APCH CONDITIONS STILL EXISTING AT DULLES. THE EFIS COMMAND SWITCH WAS POSITIONED TO 'BOTH ON 2,' RESTORING A NORMAL PFD PRESENTATION ON THE CAPT'S SIDE, ALBEIT A COPY OF THE DISPLAY ON THE FO'S SIDE. AFTER LNDG AT DULLES AND SHUTTING DOWN THE ENGS, NORMAL PRESENTATIONS RETURNED TO ALL DISPLAYS FOLLOWING THE AUTOMATIC ACCOMPLISHMENT OF THE PWR UP TEST ON ALL AUTOMATED FLT INST SYS, AND NO FURTHER PROBS WERE EXPERIENCED DURING SUBSEQUENT OPS. IT IS INTERESTING TO NOTE THAT AT THE TIME OF THE INITIAL FAILURE, THE FLC SUSPECTED POSSIBLE ELECTRONIC INTERFERENCE FROM AN ONBOARD SOURCE, AND REQUESTED THE FLT ATTENDANTS TO ENSURE THAT ALL PAX DISCONTINUE USE OF PERSONAL ELECTRONIC DEVICES. ON THE GND AT DULLES, I WAS TOLD BY LEAD FLT ATTENDANT THAT THERE WERE PROBABLY ABOUT 8 PERSONAL LAPTOP COMPUTERS BEING USED BY PAX THROUGHOUT THE CABIN -- AT THE TIME OF MY REQUEST IN THE AIR. I SUSPECT THAT THE ERRONEOUS INST DISPLAYS, AND THE ABSENCE OF WARNING MESSAGES, WERE DUE NOT TO ANY INHERENT EQUIP MALFUNCTION BUT RATHER INTERFERENCE FROM A SOURCE OUTSIDE THE COCKPIT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR SAID THAT HE WAS UNABLE TO BRING HIS DISPLAYS 'BACK UP' EVEN AFTER ALL OF THE LAPTOPS WERE SHUT OFF. THE DISPLAYS DID NOT BECOME FUNCTIONAL UNTIL AFTER THE POST- LNDG SELF TEST WAS (AUTOMATICALLY) COMPLETED. THE RPTR DOES NOT KNOW WHICH OF OR IF ALL OF THE LAPTOPS CAUSED THE ABNORMAL DISPLAYS. HE ALSO DOES NOT KNOW IF ANY OTHER ELECTRONIC DEVICES WERE IN USE AT THE TIME.

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.