At 3 AM recently I happened to be up and about and I
heard a whining-whirring sound that turned out to be the
police helicopter circling over the public housing
project up the street. But...when that chopper comes
around in the daytime and evenings, it's much louder --
the well-known bupbupbup that lowers the quality of life
in this part of town. So how did they fly relatively
quietly at 3 AM and why don't they use that mode more
often?

--
Charles Packer
http://cpacker.org/whatnews
mailboxATcpacker.org