B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 151
Communication Breakdown
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Human Factors
As we approached the end of runway; FO told Tower we were ready for takeoff. We both heard 'no delay; cleared for takeoff'. At the time we did not see any other aircraft at the end of the runway. As I started to take the runway I saw movement on the other side and stopped well short of the runway but not before crossing the hold line. We then queried ATC who informed us the clearance was for another aircraft. They subsequently cleared us for takeoff.First I broke my number 1 rule: If not 100 percent sure stop and verify! I will redouble my efforts to slow it down and be 100 percent sure of any and all clearances!
Upon reaching the end of Taxiway X; I called Tower and informed them we were ready to depart. We did not see a small general aviation aircraft on the other side of the runway also waiting to depart. I then heard Tower clear us to depart (what I thought). I read back the instructions as we rounded the corner from Taxiway X. Upon crossing the hold short line I heard Tower clear another aircraft to depart. We immediately came to a stop and saw the general aviation aircraft on the opposite taxiway. He also had crossed his hold short line. Tower inquired if we had already crossed the line and I acknowledged that we had. We were then cleared for an immediate departure. The small general aviation aircraft was asked to make a 180 back across his hold short line. He complied. When in question VERIFY! I did not do this. Verify your call sign in ANY ATC radio transmission. I assumed the takeoff clearance was for us and due to partially blocked radio call; missed the fact that it was not for us.
B737 flight crew reported they thought a clearance from the Tower to depart was for them; but was actually a clearance for an aircraft entering from the other side. The error was not detected prior to crossing the hold line.