Large transport ahd has false GPWS and radar altimeter indications.

Attributes
ACN	269863
Time
Date	199404
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : mip
State Reference	PA
Altitude	msl bound lower : 37000 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	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 : 300 flight time total : 8000 flight time type : 3000
ASRS Report	269863
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	other
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

While holding at mip VOR at FL370, GPWS sounded 'too low terrain' numerous times. Radar altimeter indicated 9o0 ft AGL. This went on for several mins. Asked flight attendant to check cabin for electronic devices. Youth shut off cassette FM radio and problem ceased. Some computers were also being operated but no cell phones were observed. Passenger began to shut off devices when flight attendant visited cabin to check on EMI problem.

Original NASA ASRS Text

Title: LGT AHD HAS FALSE GPWS AND RADAR ALTIMETER INDICATIONS.

Narrative: WHILE HOLDING AT MIP VOR AT FL370, GPWS SOUNDED 'TOO LOW TERRAIN' NUMEROUS TIMES. RADAR ALTIMETER INDICATED 9O0 FT AGL. THIS WENT ON FOR SEVERAL MINS. ASKED FLT ATTENDANT TO CHK CABIN FOR ELECTRONIC DEVICES. YOUTH SHUT OFF CASSETTE FM RADIO AND PROB CEASED. SOME COMPUTERS WERE ALSO BEING OPERATED BUT NO CELL PHONES WERE OBSERVED. PAX BEGAN TO SHUT OFF DEVICES WHEN FLT ATTENDANT VISITED CABIN TO CHK ON EMI PROB.

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.