CL65 crew had erratic localizer and GS possibly caused by passenger cell phone use.

Attributes
ACN	524699
Time
Date	200109
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : kenil
State Reference	IL
Altitude	msl single value : 2500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : c90.tracon tracon : phl.tracon
Operator	common carrier : air carrier
Make Model Name	Regional Jet CL65, Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 22l other
Flight Phase	descent : approach
Route In Use	approach : instrument precision arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 131 flight time total : 6000 flight time type : 3500
ASRS Report	524699
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical cabin event : passenger electronic device cabin event : passenger misconduct non adherence : far non adherence : published procedure non adherence : company policies
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : executed go around flight crew : took precautionary avoidance action
Supplementary
Problem Areas	Aircraft FAA Passenger Human Performance
Primary Problem	Passenger Human Performance

Narrative:

We were in the clouds and on a vector from chicago approach controller to join the localizer for runway 22L at ord. Both navigation radios had been tuned to 110.1 and the identifier (ilqq) had been received. As we were flying toward the course, both the captain's and first officer's CDI's began to waver between full scale and 'fly right' and full scale 'fly left' indications. Our displays also showed intermittent localizer and GS red flags. We wanted to query ATC about the integrity of the 22L localizer, but the controller was talking non-stop and we could not get his attention. I was considering executing a missed approach when the controller called and asked us if we were receiving the localizer. We answered that our CDI's were wavering. The controller broke us off the approach and gave us vectors around for a second approach. The second approach to runway 22L was uneventful and all indications were normal. After deplaning the passenger at the gate, we discussed what had happened with the flight attendant. The flight attendant stated that, during her final walk through the cabin before landing, she had to ask a passenger to turn off a cell phone that he was using. By my estimation, the time that the flight attendant said she saw the passenger using his cell phone correlates approximately to the time we were receiving the faulty localizer course indications during the first approach.

Original NASA ASRS Text

Title: CL65 CREW HAD ERRATIC LOC AND GS POSSIBLY CAUSED BY PAX CELL PHONE USE.

Narrative: WE WERE IN THE CLOUDS AND ON A VECTOR FROM CHICAGO APCH CTLR TO JOIN THE LOCALIZER FOR RWY 22L AT ORD. BOTH NAV RADIOS HAD BEEN TUNED TO 110.1 AND THE IDENTIFIER (ILQQ) HAD BEEN RECEIVED. AS WE WERE FLYING TOWARD THE COURSE, BOTH THE CAPT'S AND FO'S CDI'S BEGAN TO WAVER BETWEEN FULL SCALE AND 'FLY RIGHT' AND FULL SCALE 'FLY LEFT' INDICATIONS. OUR DISPLAYS ALSO SHOWED INTERMITTENT LOC AND GS RED FLAGS. WE WANTED TO QUERY ATC ABOUT THE INTEGRITY OF THE 22L LOC, BUT THE CTLR WAS TALKING NON-STOP AND WE COULD NOT GET HIS ATTENTION. I WAS CONSIDERING EXECUTING A MISSED APCH WHEN THE CTLR CALLED AND ASKED US IF WE WERE RECEIVING THE LOCALIZER. WE ANSWERED THAT OUR CDI'S WERE WAVERING. THE CTLR BROKE US OFF THE APCH AND GAVE US VECTORS AROUND FOR A SECOND APCH. THE SECOND APCH TO RWY 22L WAS UNEVENTFUL AND ALL INDICATIONS WERE NORMAL. AFTER DEPLANING THE PAX AT THE GATE, WE DISCUSSED WHAT HAD HAPPENED WITH THE FLT ATTENDANT. THE FLT ATTENDANT STATED THAT, DURING HER FINAL WALK THROUGH THE CABIN BEFORE LANDING, SHE HAD TO ASK A PAX TO TURN OFF A CELL PHONE THAT HE WAS USING. BY MY ESTIMATION, THE TIME THAT THE FLT ATTENDANT SAID SHE SAW THE PAX USING HIS CELL PHONE CORRELATES APPROX TO THE TIME WE WERE RECEIVING THE FAULTY LOCALIZER COURSE INDICATIONS DURING THE FIRST APCH.

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.