NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Long-range airplane navigation
From: Glendon
Date: 2004 Nov 28, 12:51 +1100
From: Glendon
Date: 2004 Nov 28, 12:51 +1100
----- Original Message ----- From: "Gennaro Sammarco"To: Sent: Saturday, November 27, 2004 4:37 AM Subject: Re: Long-range airplane navigation > Hi everybody, I fly for Alitalia on B767, long haul flights only, and we > don't use sextants and celnav anymore (unluckily). Navigation is taken care > of by 3 IRS (inertial navigation system based on laser gyro) and 2 GPS when > avilable, because it must not be the only device for navigation but needs a > reliable back up system. > With twin jets, anyway, it is still required to plot the route on a special > nav chart and cross check the position 10 minutes after every meridian on > the track. > Some more specific navigation knowledge, celnav included, was required as > professional licence to upgrade to long haul flights till 1992, when its > necessity by law was cancelled. > Every night crossing, anyway, I have a star finder and a handy program on my > palm (planetarium), and try to spot all the useful stars that I can, > training for celnav on my sailboat. > > Gennaro Sammarco Hi Gennaro Thanks for your note, which I found quite interesting. You mention 3 IRS . Are these run simultaneously and averaged in any way, or are the multiple sets of IRS's, and GPS's for backup in case of failure? I presume the GPS feeds back into the IRS system periodically to re- callibrate it, or whatever the correct expression is. Is radio direction also a component of navigation? I guess celestial has become more and more impractical , and other methods embraced as soon as possible, as aircraft speeds have risen. Hence the relatively early (to my mind) abandonment of celestial in 1992. Lee Martin