DC9 experiences navigation equipment interference from ped in ZMP airspace.

Attributes
ACN	415547
Time
Date	199809
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dsm
State Reference	IA
Altitude	msl bound lower : 35000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp
Operator	common carrier : air carrier
Make Model Name	DC-9 30
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : flight engineer
Experience	flight time last 90 days : 250 flight time total : 16000 flight time type : 5000
ASRS Report	415547
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

While at cruise at FL350, the captain's radar altimeter flag began flapping, and TCASII occasionally annunciating 'TCASII fail.' RA and TCASII tests were normal, so I asked the lead flight attendant to do a ped walk, and the end result was a pronet pager in use. The gentleman switched the unit off and removed the batteries and the indications ceased.

Original NASA ASRS Text

Title: DC9 EXPERIENCES NAV EQUIP INTERFERENCE FROM PED IN ZMP AIRSPACE.

Narrative: WHILE AT CRUISE AT FL350, THE CAPT'S RADAR ALTIMETER FLAG BEGAN FLAPPING, AND TCASII OCCASIONALLY ANNUNCIATING 'TCASII FAIL.' RA AND TCASII TESTS WERE NORMAL, SO I ASKED THE LEAD FLT ATTENDANT TO DO A PED WALK, AND THE END RESULT WAS A PRONET PAGER IN USE. THE GENTLEMAN SWITCHED THE UNIT OFF AND REMOVED THE BATTERIES AND THE INDICATIONS CEASED.

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.