2003
Mather Field noise studies:
Glide slopes recorded in radar data
Plots below show glide slopes recorded from radar data, as reported in
the December, 2003 update to the August report on test results.
Altitude at crossing points from Folsom through Cameron Park shows much
more variation with the VOR/DME approach than with the ILS approach.
Altitude conversions to MSL (mean sea level) and agl (above ground
level) from data in the charts use field level = 96 feet MSL as the
reference point for ground level. Notes above each chart identify
terrain clearance at the two noise measurement sites in El Dorado
Hills: Site 3 beneath the ILS approach, and site 7 beneath the
VOR/DME approach.
ILS approach, El Dorado Hills
crossing point at site 3
terrain elevation 1,010 feet msl
Crossing altitudes over site 3:
Typical crossing altitude range is about 3,600 to 4,000 feet MSL
Extreme crossing altitude range
is
about 3,100 to 5,100 feet MSL
Approximate crossing altitudes,
agl over terrain at site 3
2,800 feet: median crossing
altitude
2,600 feet: minimum crossing
altitude for almost all arrivals
3,000 feet:
maximum crossing altitude for almost all arrivals
2,100 feet: extreme
minimum crossing altitude (2 flights in one week)
4,100 feet:
extreme maximum crossing altitude
VOR/DME approach, El
Dorado Hills crossing point at site 7
terrain elevation 785 feet MSL
Crossing altitudes over site 7:
Typical crossing altitude range is about 3,600 to 4,000 feet MSL
Extreme crossing altitude range
is
about 3,100 to 5,100 feet MSL
Approximate crossing altitudes,
agl over terrain at site 3
2,600 feet: median crossing
altitude
1,300 feet: minimum crossing
altitude for most arrivals
3,500 feet:
maximum crossing altitude for most arrivals
1,300 feet: extreme
minimum crossing altitude (2 flights in one week)
5,300 feet:
extreme maximum crossing altitude
Because the VOR/DME approach does not have precision
guidance for the glide slope a larger percentage of arrivals descend to
the 2,000 ft. minimum altitude farther from the airport. They
level out until they reach the designated point, 5.4 miles from the
runway threshold, where they can descend below this altitude.
Sections of glide slopes showing horizontal lines represent aircraft
holding a constant altitude. This requires using significantly more
power than when on a glide slope. At the 3-degree glide slope used for
the ILS approach most jets are at a power setting near flight idle.
Information on this page is based on these public documents, from the
Sacramento County Airport System:
Most of the graphics in this
set of web pages
are extracted from these documents, with permission from and thanks to
SCAS. In many cases portions of them have been highlighted to emphasize
portions relating directly to El Dorado Hills.
