Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/17/84; site bcsaic.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!mtuxo!mtunh!mtung!mtunf!ariel!vax135!cornell!uw-beaver!ssc-vax!bcsaic!ted From: ted@bcsaic.UUCP (ted jardine) Newsgroups: net.aviation Subject: Re: Sinus troubles Message-ID: <189@bcsaic.UUCP> Date: Sat, 13-Jul-85 21:40:15 EDT Article-I.D.: bcsaic.189 Posted: Sat Jul 13 21:40:15 1985 Date-Received: Thu, 18-Jul-85 04:48:29 EDT References: <830@rayssd.UUCP> <103500001@uiucuxc> Reply-To: ted@bcsaic.UUCP (ted jardine) Organization: Boeing Computer Services AI Center, Seattle Lines: 27 Though it may seem trivially obvious, sinus and ear problems on descent are caused by the rate of change of 'cabin' pressure being greater than the rate at which the sinus or ear can adapt to the change. The problem is more frequently encountered on high performance aircraft, especially airline aircraft, because of pressurization and their high rate of descent. A rate of descent of more than 3000 fpm is not uncommon until reaching the initial approach fix. I'm no expert on pressurization systems, but I know that they are designed to maintain a 10,000 foot cabin pressure above that altitude and then ambient pressure (perhaps at a lower rate of change) below 10 thousand. The rate of change in a smaller airplane is not nearly as great, perhaps 500-1,000 fpm. Using an antihistamine and an inhaler is appropriate for anyone with unusual sinus difficulties, as it keeps the passages into the sinus cavities and the ear as clear as possible. Also useful is a procedure called the Valsalva (sp?) method, in which you close your mouth, pinch your nose shut and forcefully exhale. Using this several times during descent will clear up almost all ear problems and many sinus problems will at least be reduced, if not disappear. In the good old days, long before deregulation, the flight attendants used to have antihistamine inhalers, but that practice has been abandoned. For small children, giving them something to suck on before and during the descent is often very helpful. One of the side effects of a baby crying is to open up the Eustachian tube which alleviates the pain. Just 'tricks' I've learned bouncing around up there. TJ (with Amazing Grace) The Piper (aka Ted Jardine) Boeing Artificial Intelligence Center ...uw-beaver!uw-june!bcsaic!ted