Originally Posted by
walkingtall
fflight was boarded with no ac , the cabin was extremely hot , no water served , cabin crew seemed to think was completely acceptable , telling passenger ac will work when engine is turned on
gate staff not being truthful saying that ac was working in the y cabin so y passengers should board first , I guess so they could get someone to board
Sounds like the APU was inoperative and they needed to use the Ground Power Unit. From what I hear/understand, the GPU does not generate sufficient power for both aircraft systems and air conditioning, so it might appear that the AC was rather weak (likely this is why dedicated air conditioning units are used during aircraft static displays at air shows). Once the engines have started and the aircraft has taken off, the AC would then be more effective in cooling the aircraft.