B737 flight crew reported a taxiway incursion when the captain's ipad went dark at a critical time.

Attributes
ACN	1285584
Time
Date	201508
Local Time Of Day	0001-0600
Place
Locale Reference	ORD.Airport
State Reference	IL
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Component
Aircraft Component	Tablet
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 168 Flight Crew Type 2127
Person 2
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 59 Flight Crew Type 59
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Ground Incursion Taxiway

Narrative:

On taxi out we were planning runway 22L and received runway 28R A9; T; north; B. Hurry up and get in front of the 767 under tow. Just as I was looking at the taxi diagram; ipad went blank in the power save mode. I continued while trying to get the ipad back up and turned on bravo instead going to tango. Co-pilot's head went down to change runway in the box. About the time I noticed we were on the wrong taxiway; so did ground. We went down to A13 and back around to get on tango.

Original NASA ASRS Text

Title: B737 flight crew reported a taxiway incursion when the Captain's iPad went dark at a critical time.

Narrative: On taxi out we were planning Runway 22L and received Runway 28R A9; T; N; B. Hurry up and get in front of the 767 under tow. Just as I was looking at the taxi diagram; iPad went blank in the power save mode. I continued while trying to get the iPad back up and turned on Bravo instead going to Tango. Co-pilot's head went down to change runway in the box. About the time I noticed we were on the wrong taxiway; so did Ground. We went down to A13 and back around to get on Tango.

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.