B767 flight crew reported deviating from ILS course and altitude on approach to spim because of an a...

Attributes
ACN	1219051
Time
Date	201411
Place
Locale Reference	SPIM.Airport
State Reference	FO
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Component
Aircraft Component	Autopilot
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 31500 Flight Crew Type 2000
Person 2
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 250 Flight Crew Total 16000 Flight Crew Type 6000
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types Flight Deck / Cabin / Aircraft Event Passenger Electronic Device

Narrative:

Approximately 3 miles outside final approach fix; aircraft descending in flch to 2000 MSL; passing 3300-3200 MSL aircraft had localizer engaged and captured; aircraft started a 10-15 degree bank right away from the localizer course. Both pilots verbalized the deviation and as the pfd showed a localizer flag I disconnected the autopilot and transitioned to the standby adis which displayed normal course path displays and considered a missed approach nearing 2100 MSL when the first officer confirmed visual sighting of the runway. I confirmed visual with standby ADI guidance; continued the approach manually meeting the 1000 and 500 foot stabilized approach criteria to an uneventful landing. No airport surface traffic was present to affect the localizer signal and arrival congestion prevented further discussion with the tower. I questioned the purser and he stated many people were on their cellphones even after making multiple announcements. This incident was identical to one I had years ago in a 737 on a simultaneous ILS landing iah runway 26L. Can't prove cellphones do this of course; and can't prove they do not. Heads up warning.

Original NASA ASRS Text

Title: B767 flight crew reported deviating from ILS course and altitude on approach to SPIM because of an autopilot error; possibly caused by passenger cell phone use.

Narrative: Approximately 3 miles outside final approach fix; aircraft descending in FLCH to 2000 MSL; passing 3300-3200 MSL aircraft had LOC engaged and captured; aircraft started a 10-15 degree bank right away from the LOC course. Both pilots verbalized the deviation and as the PFD showed a LOC flag I disconnected the autopilot and transitioned to the standby ADIs which displayed normal course path displays and considered a missed approach nearing 2100 MSL when the First Officer confirmed visual sighting of the runway. I confirmed visual with standby ADI guidance; continued the approach manually meeting the 1000 and 500 foot stabilized approach criteria to an uneventful landing. No airport surface traffic was present to affect the LOC signal and arrival congestion prevented further discussion with the tower. I questioned the purser and he stated many people were on their cellphones even after making multiple announcements. This incident was identical to one I had years ago in a 737 on a simultaneous ILS landing IAH Runway 26L. Can't prove cellphones do this of course; and can't prove they do not. Heads Up Warning.

Data retrieved from NASA's ASRS site 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.

B767 flight crew reported deviating from ILS course and altitude on approach to spim because of an autopilot error; possibly caused by passenger cell phone use.