As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MOMENTARY LOSS OF ADC 1 AFTER ROTATION / REMOVED AND REPLACED ADC #1 IAW CRJ 900 AMM 34-13-01-000/400-801-A01-PSA. PERFORMED FUNCTIONAL TEST OF THE #1 ATC ALTTITUDE REPORTING (MODE C) IAW CRJ 900 AMM 34-54-00-720-802. FUCNTIONAL TEST GOOD. IFR 6000 USED FOR TEST."