Date: 201508
Local time of day: 0601-1200
Location: SEA.Airport, WA
Flight conditions: VMC
Light: Daylight
Aircraft: Medium Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Tower SEA
Second aircraft: Commercial Fixed Wing
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion
Second reporter function: Captain; Pilot Flying
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Less Severe; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
When detected: Taxi
Contributing factors: Procedure; Human Factors
Primary problem: Human Factors

Narrative: We landed on runway 16R; was told to cross 16C on taxiway N and hold short of 16L.  We were number two behind another aircraft in the wait to cross 16L. [Aircraft Y] was told to line up and wait on 16L and was informed there would be crossing traffic. After the tower controller told a departing aircraft to switch to departure; he told the aircraft in front of us to cross 16L; then told us to cross 16L and to contact ground.  In his radio call he also informed us that traffic was holding.  It seemed like it was taking a few seconds longer for us to get moving when an EICAS message appeared indicating emergency brake malfunction.  The captain recycled the brake and the EICAS message disappeared and we began our taxi roll onto the runway. There had been radio silence on the tower frequency during this time. As we were entering the runway; the taxiway we were on was angled away from the approach end of the runway; restricting my view of the Aircraft Y holding on the runway that we were crossing.  My captain cleared left; reminding me of the aircraft holding; and I verbalized that the right was also cleared. While crossing the runway; I switched frequencies to ground control after instructed to do so by my captain as to coordinate gate holding instructions.  As we had just entered the active runway to cross; Aircraft Y was cleared for takeoff. They aborted the takeoff seconds later.  There seemed to be confusion from the tower after that as to why Aircraft Y decided to abort; and Aircraft Y seemed confused as to why there was an aircraft crossing down the field.  When Aircraft Y asked the tower controller if he was aware of the crossing; tower said he was not; but believed we were cleared to cross.The root cause of this event would be the tower controller not realizing or verifying that our aircraft was clear of the runway before he cleared Aircraft Y for takeoff. Contributing factors would be multiple aircraft being told to cross the runway; Aircraft Y not realizing that the second aircraft told to cross was not clear of the runway; due to the angle of the taxiway that we were crossing on only the captain could see the aircraft holding; that taxiway was more than a mile down the filed from the traffic holding on the runway which made it difficult to see if the aircraft had started his takeoff roll; a slight delay in our taxi across the runway due to a temporary emergency brake issue; and not waiting until completely clear of the runway to switch to ground frequency.Tower should pay better attention to the location status of all aircraft they are controlling and give clearances to. Aircraft should be completely cleared of the runway before a takeoff clearance is given. An aircraft holding on the runway should verify the runway is clear off all aircraft before starting the takeoff roll.  Any delay of movement from an aircraft cleared for movement should be communicated; no matter how short the delay time may seem.  Not switching from tower frequency until completely cleared of the runway.


Second narrative: This morning we received clearance to cross runway 16L; traffic is holding; then go to ground.  I pushed the power up waited a second and we didn't move.  So I pulled the power back cycled the parking brake and continued to cross 16L as instructed.  This action maybe took an extra 5 seconds.  Half way across the runway we swapped over to ground; finished crossing the runway; and taxied into the ramp.  Right after we swapped onto ground; Tower cleared Aircraft Y for takeoff.  Aircraft Y started their Takeoff roll then rejected the takeoff because of an aircraft on the runway.  We had no knowledge of Aircraft Y rolling until ATC gave us a number to call and we listened to our radio transmissions [from a website]. ATC launched an aircraft before we were safely across 16L.To avoid this event; we could taxi more expeditiously and avoid swapping frequencies before we have completely crossed the runway.


Synopsis: Pilots report of being told to cross and having a short delay in doing so. The Tower Controller then clears a departure for takeoff while aircraft is slowly crossing downfield. The departing aircraft aborts takeoff and Tower has crossing traffic call for a possible deviation.