Thursday, May 28, 2015

How Does Human Waste Fall From Airplanes?

Joe Cambray was out playing horseshoes at his step-daughter's sweet sixteen birthday party when all of a sudden brown feces started raining down on the party, splattering everywhere. Kristy Rogy, who was at the party, quickly checked her phone and saw that there were five airplanes flying over the area. The event quickly became a big news story with headlines such as "Girl's Sweet 16 party ruined by piles of feces falling from passing airplane." Was the substance that fell on the party human waste from an airplane as the family thought or was it from some other source?  

How Airplane Waste Systems Work  
     Airplanes have two types of waste systems: the newer vacuum waste systems and the older closed waste systems. The closed waste system works just like a regular toilet as the waste gets flushed into an onboard sewage tank. The newer vacuum waste systems, which most airplanes now have, uses the difference between the cabin pressure and the pressure outside the aircraft to suck the waste into a sewage tank, thus creating the loud sound during flushingWhen the aircraft arrives at an airport, the sewage is drained from the tank through a hatch located on the outside of the planeOne of the biggest myths surrounding human waste disposal in commercial aviation is that the pilots can press a button in the cockpit that dumps the sewage onboard on to an unsuspecting location below. While airlines in the old days used to dump human waste produced onboard, now it isn't even possible to open the sewage hatch from inside the plane.  

Blue Ice 
Waste systems on airplanes are susceptible to leaks, usually in the form of blue ice. Most waste systems use a disinfectant during flushing which is usually the color blue. When the sewage tank leaks, the mix of blue chemicals and human waste seeps out of the sewage hatch and onto the airplane's metal skin, immediately freezing. When the airplane descends for landing, the ice melts and slides off the aircraft and down to the ground. There have been many reports of blue ice over the years. In Armstrong County Pennsylvania, located near Pittsburgh, a home was splattered with blue ice. Thankfully, US Airways workers (this was back in 2002 when Pittsburgh was a major hub for US Airways) came over and cleaned up the mess, although US Airways didn't admit responsibility. Just recently, a house in the UK was pelted by blue ice. (side note: Water leaks from aircraft can produce giant ice boulders which can fall to the ground. In Colorado, an ice boulder crashed through the roof of a house, thankfully no one was injured. In the UK a man was hit by a medium sized ice pellet while sitting out in his yard). However, sewage leaks are very rare on commercial aircraft and even more rare are reports of blue ice.    

While the  five aircraft overhead the sweet sixteen party in Levittown, Pennsylvania did not dump the sewage onboard purposefully, a leak could have been possible. During the fall season, the FAA says on their website that they receive a heightened amount of reports of falling waste due to flocks of migratory birds. Joe Cambray told Fox Philadelphia that the mess in the backyard "looked like a hundred birds flew over and went to the bathroom simultaneously." He was probably right.    


No comments:

Post a Comment