ATC equipment problem radar ARTS III a mode C altitude jump.

Attributes
ACN	231108
Time
Date	199301
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : tpa
State Reference	FL
Altitude	msl bound lower : 2500 msl bound upper : 11500
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : tpa
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Route In Use	approach : straight in
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller military : 4 controller radar : 11
ASRS Report	231108
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other

Narrative:

Air carrier X was on a 7 mi final to runway 18R at tampa international airport. He was descending out of 2500 ft, and ARTS data block jumped to 11500 ft for 1 sweep then returned to proper altitude.

Original NASA ASRS Text

Title: ATC EQUIP PROB RADAR ARTS III A MODE C ALT JUMP.

Narrative: ACR X WAS ON A 7 MI FINAL TO RWY 18R AT TAMPA INTL ARPT. HE WAS DSNDING OUT OF 2500 FT, AND ARTS DATA BLOCK JUMPED TO 11500 FT FOR 1 SWEEP THEN RETURNED TO PROPER ALT.

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.