Both heads flushed normal during the survey. Keep in mind our new boat (91 model year) spent most of her time at the dock with little to no use for several years. Patti and I had been cleaning below decks to get Belle-Vie ship shape. We cleaned and checked the forward head and it worked normal, except for a loud thunp below her feet, while sitting in the starboard setee. Did the same with the aft head. The first time it flushed fine, then it would not discharge. I borrowed a plunger from my neighbor, thinking the line was plugged, but to no avail. So, I pulled the discharge line from the head, and after releasing a considerable amount of compressed air, went about attaching a city water hose to the line to clear it. The first time it seemed to clean it out after some rumbling. Again, it released compressed air when I disconnected the city water line. I tried it one more time just to make sure. I remembered reading a forum article about plugged holding tank vents, so I pulled the sole board covering the holding tank and disconnected the vent line from the tank. I then connected the city water line to the vent hose and looked to see if anything was coming out of the scupper. Nothing! Nada! Zip! I took a small screw driver, and hanging over the side, inserted it into the scupper and gently poked at the opening. First I got a hiss, then a whoosh of water as the pressure blew out some little critter's nest that had plugged the opening. After reconnecting the vent and discharge lines, I checked the heads again and both worked like a charm. As a closing note, thanks to those who have contributed articles to this forum, and especially to Ms. Peggy Hall. They have been very helpful to me in solving Belle-Vie's mostly minor problems. Terry