Hybridizing Contemporary Glide Slopes

Vertical guidancc for an instrumcnt approach to landing during conditions of rcduced visibility is a crucial element with respect to safety of flight. It is noteworthy that this vertical component - to be most useful and safe - must desirably provide the pilot with no more than several feet of uncertainty. Unfortunately, with GPS the vertical portion of the position information supplied the pilot by GPS signals is thc least prccise because of gcometries involvcd. Augmentation for enhancement of accuracy is quite important and the assertion is that it is necessary for totally safe vertical guidance. Evidence from approximately 60 years of cxpcrience with electronic landing systems serving the public is that there has been no aircraft accident due to a defective vertical guidance signal. Visibilities as low as 600 feet horizontally can exist at certain airports and