Commercial Fixed Wing
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Distraction; Communication Breakdown; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors
While holding short between the active runways in SEA I observed my CA (Captain) using his cell phone to send text messages.  I also observed him listening to music throughout all four flights we had together.  Music was streamed to his headset from his company issued iPad using a headphone aux cable.I should have said something during the trip.
First Officer reported observing Captain using cell phone to text; and listen to music during four flights together.