Air taxi flight crew reported departing from a taxiway rather than the runway.

Attributes
ACN	1512127
Time
Date	201801
Local Time Of Day	0601-1200
Place
Locale Reference	PIT.Airport
State Reference	PA
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Make Model Name	Small Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 135
Flight Phase	Takeoff
Route In Use	SID KPIT 2
Flight Plan	IFR
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 16050 Flight Crew Type 25
Person 2
Function	Check Pilot
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 198 Flight Crew Total 12200 Flight Crew Type 1156
Events
Anomaly	Deviation - Procedural Clearance Deviation - Procedural FAR Deviation - Procedural Published Material / Policy Ground Incursion Taxiway

Narrative:

Taxiway east takeoff from pit. Arrived at pit and realized I left my identification at home. One hour later [I] arrived at pit [for a] second time feeling bad and rushed. [It was] my second day as new initial operating experience captain; rushed to aircraft boarded started routine. Taxi from concourse to runway 10C. I said to check pilot we should have airport diagram out; he indicated he would direct me. Taxi was routine to taxiway east at or near west. If we had a line-up and wait; I missed that call. The check pilot acknowledged a takeoff clearance. Not sure of our position thinking maybe; we were aft of threshold; I asked check pilot - you want to takeoff here? He said yes; let's go. I thought I was very badly confused and he must be right. I pushed throttles up. I looked out in lights assuring myself; we had pavement enough for takeoff; it looked wrong but tower and check pilot seemed fine; I thought I was wrong; somehow. Take off and flight routine; on handoff we were given phone number; and advised possible pilot deviation. Flight routine; passengers unaware and happy.

Original NASA ASRS Text

Title: Air taxi flight crew reported departing from a taxiway rather than the runway.

Narrative: Taxiway E takeoff from PIT. Arrived at PIT and realized I left my ID at home. One hour later [I] arrived at PIT [for a] second time feeling bad and rushed. [It was] my second day as new Initial Operating Experience Captain; rushed to aircraft boarded started routine. Taxi from concourse to runway 10C. I said to check pilot we should have airport diagram out; he indicated he would direct me. Taxi was routine to taxiway E at or near W. If we had a line-up and wait; I missed that call. The check pilot acknowledged a takeoff clearance. Not sure of our position thinking maybe; we were aft of threshold; I asked Check pilot - you want to takeoff here? He said yes; let's go. I thought I was very badly confused and he must be right. I pushed throttles up. I looked out in lights assuring myself; we had pavement enough for takeoff; it looked wrong but tower and check pilot seemed fine; I thought I was wrong; somehow. Take off and flight routine; on handoff we were given phone number; and advised possible pilot deviation. Flight routine; passengers unaware and happy.

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.