A320 flight crew reported not documenting an aircraft equipment problem in the maintenance log.

Attributes
ACN	1617696
Time
Date	201902
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Component
Aircraft Component	Air Conditioning and Pressurization Pack
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 30 Flight Crew Type 296
Person 2
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 108 Flight Crew Type 704
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural MEL Deviation - Procedural Published Material / Policy Deviation - Procedural FAR

Narrative:

Pack 2 deferred was inoperative. After number 2 engine start we did a status check and noticed pack 2 inop which was expected. Below this was ap 2 inop. Expectation bias and fatigue caused failure to realize that ap 2 inop was not related to pack 2 inop. Continued normal taxi and takeoff without ap 2 inop maintenance logbook entry. Wrote up entry during cruise. [Maintenance control] communicated that this was an FMGC 2 failure after second engine start. Fatigue was an issue here.

Original NASA ASRS Text

Title: A320 flight crew reported not documenting an aircraft equipment problem in the maintenance log.

Narrative: Pack 2 deferred was inoperative. After number 2 engine start we did a status check and noticed pack 2 inop which was expected. Below this was AP 2 inop. Expectation bias and fatigue caused failure to realize that AP 2 inop was not related to Pack 2 inop. Continued normal taxi and takeoff without AP 2 inop maintenance logbook entry. Wrote up entry during cruise. [Maintenance Control] communicated that this was an FMGC 2 failure after second engine start. Fatigue was an issue here.

Data retrieved from NASA's ASRS site 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.