Narrative:

After boarding the aircraft it was apparent that it would be unacceptable for safe flight when it was discovered to be completely covered in a dense layer of condensation. Every passenger seat had a small puddle of water. Every switch; panel and instrument in the cockpit was drenched in condensation. Beads of water formed and dripped from the overhead panels. It was brought to the attention of the agent; dispatch and maintenance control. A decision was made by the captain and I; final authority of safety of flight; to call contract maintenance and have a safety inspection performed in the east and east compartment. Concurrence was given by both maintenance control and dispatch. I was reluctant to add electrical demand on the ground power; so all checks and procedures were delayed to when deemed safe by maintenance. The APU was started and used in high temp mode to evaporate the liquid. This worked well and by the time (approximately 45 minutes) contract maintenance came; much had dissipated. Aircraft was inspected and found to be safe. I was told the ground air was on all night and blows very cold air into the cabin. High humidity and cold soaked components leads to condensation. All systems checked and set for a normal flight. The duty pilot on arrival in ZZZ was very accusatory as to the reason for the delay. I will differ to ground operations pilot experience when they can match and surpass my nearly 25 year experience flying the 737. I would accomplish the exact same steps to ensure that the flight could be accomplished safely. I had the full support from both the first officer and flight attendants.

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Original NASA ASRS Text

Title: B737-700 Captain described the aircraft's condition after cold ground air conditioning operated all night condensing humid air. The flight station; passenger seats; and equipment were dripping liquid which was evaporated with warm APU air conditioning.

Narrative: After boarding the aircraft it was apparent that it would be unacceptable for SAFE flight when it was discovered to be completely covered in a dense layer of condensation. Every Passenger seat had a small puddle of water. Every switch; panel and instrument in the cockpit was drenched in condensation. Beads of water formed and dripped from the overhead panels. It was brought to the attention of the Agent; Dispatch and Maintenance Control. A decision was made by the Captain and I; final AUTHORITY of SAFETY of flight; to call Contract Maintenance and have a safety inspection performed in the E and E compartment. Concurrence was given by both Maintenance Control and Dispatch. I was reluctant to add electrical demand on the ground power; so all checks and procedures were delayed to when deemed safe by Maintenance. The APU was started and used in high temp mode to evaporate the liquid. This worked well and by the time (approximately 45 minutes) Contract Maintenance came; much had dissipated. Aircraft was inspected and found to be safe. I was told the ground air was on all night and blows very cold air into the cabin. High humidity and cold soaked components leads to condensation. All systems checked and set for a normal flight. The Duty Pilot on arrival in ZZZ was very accusatory as to the reason for the delay. I will differ to Ground Operations Pilot experience when they can match and surpass my nearly 25 year experience flying the 737. I would accomplish the exact same steps to ensure that the flight could be accomplished SAFELY. I had the full support from both the FO and Flight Attendants.

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.