Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Aircraft Equipment Problem Less Severe
General Maintenance Action
Aircraft; Procedure; Human Factors; Company Policy
APU drain mast/hydraulic reservoir vent discovered missing after engine shutdown at gate by ground crew.  Upon further discovery a puncture was found in the access panel which houses the mast.  No antenna was found on runway or taxiway used at ZZZ1 by airport personnel.  Captain accomplished preflight walk around at departure airport.  No significant defects were noted at that time.    No items were noted during preflight walk around in ZZZ.  It had been over 5 months since Captain had accomplished a walk around.Captain will leave walk around inspections to First Officer position in the future unless operational considerations dictate otherwise as Captain doesn't recall seeing any damage to the aforementioned area.
Air carrier First Officer reported an APU drain mast/hydraulic reservoir vent was discovered missing by ground crew after landing.