Passenger use of cellular phone causes heading track position deviation.

Attributes
ACN	265160
Time
Date	199402
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : lga
State Reference	NY
Altitude	msl bound lower : 17000 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny tower : isp
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 5000
ASRS Report	265160
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	flight crew : overcame equipment problem other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

On climb out from lga we were receiving erratic navigation signals from several vors. Also were noting dr lights intermittently on our omega. ATC gave us a couple of vectors towards fixes which were up to 20 degrees off our course even though we showed centered on both HSI's and our ONS. We did 2 precision updates on the ONS and still were getting dr lights. Asked the flight attendants to walk through the cabin and check for cellular phones, radios, etc. Upon inspection, 1 cellular phone had been used and was still on and 1 portable radio was still being used. Once these items were shut off all indications were normal. Callback conversation with reporter revealed the following: reporter revealed that this passenger had been told before this to not use the phone, but that was in the pretkof briefing and referred to 10000 ft and below. This had occurred from 17000 ft to FL280 so the ban is incorrect in the assumption that 10000 ft is the altitude limit on these occurrences. Passenger denied using the phone at this point but it was then revealed that the phone was not transmitting but was in T he 'on' position, taking incoming pages if need be, in a standby position. Reporter had no idea that aircraft was off course until ATC called.

Original NASA ASRS Text

Title: PAX USE OF CELLULAR PHONE CAUSES HDG TRACK POS DEV.

Narrative: ON CLBOUT FROM LGA WE WERE RECEIVING ERRATIC NAV SIGNALS FROM SEVERAL VORS. ALSO WERE NOTING DR LIGHTS INTERMITTENTLY ON OUR OMEGA. ATC GAVE US A COUPLE OF VECTORS TOWARDS FIXES WHICH WERE UP TO 20 DEGS OFF OUR COURSE EVEN THOUGH WE SHOWED CTRED ON BOTH HSI'S AND OUR ONS. WE DID 2 PRECISION UPDATES ON THE ONS AND STILL WERE GETTING DR LIGHTS. ASKED THE FLT ATTENDANTS TO WALK THROUGH THE CABIN AND CHK FOR CELLULAR PHONES, RADIOS, ETC. UPON INSPECTION, 1 CELLULAR PHONE HAD BEEN USED AND WAS STILL ON AND 1 PORTABLE RADIO WAS STILL BEING USED. ONCE THESE ITEMS WERE SHUT OFF ALL INDICATIONS WERE NORMAL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR REVEALED THAT THIS PAX HAD BEEN TOLD BEFORE THIS TO NOT USE THE PHONE, BUT THAT WAS IN THE PRETKOF BRIEFING AND REFERRED TO 10000 FT AND BELOW. THIS HAD OCCURRED FROM 17000 FT TO FL280 SO THE BAN IS INCORRECT IN THE ASSUMPTION THAT 10000 FT IS THE ALT LIMIT ON THESE OCCURRENCES. PAX DENIED USING THE PHONE AT THIS POINT BUT IT WAS THEN REVEALED THAT THE PHONE WAS NOT XMITTING BUT WAS IN T HE 'ON' POS, TAKING INCOMING PAGES IF NEED BE, IN A STANDBY POS. RPTR HAD NO IDEA THAT ACFT WAS OFF COURSE UNTIL ATC CALLED.

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.