UFC 3-535-01
17 November 2005
Table 3-3. Visual Threshold Crossing Height Groups
Approximate
Visual Threshold
Height Group
Cockpit-to-Wheel Height
Crossing Height
#1. Gen. Aviation,
Small Commuters,
3 M (10 ft) or less
10 M (40 ft)
Corporate Turbojets,
T-37, T-38, C-21, T-1,
C-12, C-20 Fighter Jets
#2. F-28, CV-340/440/50,
4.5 M (15 ft)
12 M (45 ft)
B-737, DC-9, DC-8, C-9,
T43, C130, B-2
#3. B-727/707/720/757,
6 M (20 ft)
15 M (50 ft)
KC-135, C-141, C-17,
B-52
#4. B747/767, L-1011,
DC-10, A300, KC-10,
Over 7.5 M (25 ft)
22 M (75 ft)
C-5, VC-25
Refer to FAA AC 150/5345-28 for Group 4, ILS Glide Slope-PAPI coordination and
other additional information.
3-7.4.2
Without an ILS, determine the position and aiming for the PAPI which will
produce the required TCH and clearance over obstacles in the approach area. Where
there is no runway gradient (zero percent grade) and other conditions are ideal, a TCH
of 15 meters (50 feet) and glide path of 3 degrees yields an RRP at 291 meters (954
feet) from runway threshold. Three degrees is about a 19:1 ratio, hence every additional
1 meter (3 feet) TCH required will increase the distance of the RRP from threshold by
19 meters (62 feet). A downward runway grade or a lower glide path angle will increase
the ideal distance of the RRP from threshold for the same TCH. Similarly, an upward
runway gradient or a larger glide path angle will reduce the ideal distance of the RRP
from threshold for the same TCH. A different TCH, based on cockpit-to-wheel height of
the critical aircraft, will also change the location of the RRP, as will other conditions at
the site. See paragraph 12-3 for more specific detail on siting a PAPI system, and for
other siting dimensions and tolerances.
3-7.4.3
No light unit can be closer than 15 meters (50 feet) to any other runway,
taxiway, or apron. Avoid locations where the system could be obscured by other
installations. Do not place other lights so close to the PAPI as to cause pilot confusion.
Where these conditions cannot readily be satisfied with the system located on the left
side of the runway, the system with waiver approval (paragraph 1-10 or paragraph
1-11), may be sited on the right side of the runway.
3-7.4.4
Establish a PAPI clearance plane referenced to a point 90 meters (300
feet) downwind of the PAPI RRP which clears all obstructions in the approach zone.
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