EMB145 first officer reports a rejected takeoff due to a red X on the altitude tape at 56 KTS.

Attributes
ACN	1101581
Time
Date	201307
Local Time Of Day	0601-1200
Place
Locale Reference	MKE.Airport
State Reference	WI
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	EMB ERJ 145 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Other Rejected Takeoff
Component
Aircraft Component	Air Data Computer
Person 1
Function	First Officer Pilot Not Flying
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

First officer pfd displayed a red X on the altitude tape at 56 KTS. We aborted takeoff on runway; returned to the gate and called maintenance. Everything was handled per SOP. Air data computer malfunctioned during takeoff roll.

Original NASA ASRS Text

Title: EMB145 First Officer reports a rejected takeoff due to a red X on the altitude tape at 56 KTS.

Narrative: FO PFD Displayed a red X on the ALT tape at 56 KTS. We aborted takeoff on runway; returned to the gate and called Maintenance. Everything was handled per SOP. ADC malfunctioned during takeoff roll.

Data retrieved from NASA's ASRS site as of July 2013 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.