UFC 3-260-03
15 Apr 01
planning purposes and included in the evaluation report along with maintenance requirements for day-to-
day traffic. Design requirements for Army airfields are contained in TI 825-01/AFM 32-1124(I)/NAVFAC
DM 21.10. A more thorough investigation should be completed for the selection of final overlay design
thicknesses.
9. EVALUATION OF AIR FORCE AIRFIELDS. Evaluations indicating the allowable pass/load rela-
tionship will be made for each aircraft group index (table 2-1). The allowable load for Air Force airfields
will be determined for four pass intensity levels based upon the aircraft group index as shown in table 2-4.
Pass intensity levels are for normal conditions and frost melting periods.
Table 2-4
Pass Levels for Air Force Evaluation and Frost or Nonfrost Conditions
Number of Passes for Aircraft Group Index
Pass Intensity Levels
1-3
4-11
12-14
I
300,000
50,000
15,000
II
50,000
15,000
3,000
III
15,000
3,000
500
IV
3,000
500
100
10. EVALUATION OF NAVY AND MARINE CORPS AIRFIELDS.
a. Navy and Marine Corps Air Stations are evaluated for 10-year life expectancy. The projected
aircraft traffic for the next 10 years is first determined. Using aircraft equivalencies (e.g., from ICAO
Aerodrome Design Manual) a design critical aircraft can be found for each feature, together with its critical
passes. The design critical aircraft at this level of passes is equivalent to the whole traffic mix. Following
the FAA definition (FAA AC 150/5320-6D and ICAO section 4.4.11), the design critical aircraft "...should
be selected on the basis of the one requiring the greatest pavement thickness". For evaluation, the Navy
has selected aircraft using the evaluation loads shown in Table 5-2.
b. In the Navy procedure, the whole traffic is converted to passes to fully loaded F-14 (single tricycle
category), then to passes of fully loaded P-3 (dual tricycle category), and so on for all the existing
categories at the airfield (typically five or less). In each case a tentative PCN can be calculated. These
tentative PCNs can be used to impose weight restrictions on each separate category to ensure that the
pavements will last 10 years. The design critical PCN coincides with the tentative PCN of the aircraft
which would require the greatest pavement thickness - this is used for determining the color structural
condition map and overlays. The FLIP chart PCN is also one on these tentative PCNs, but may or may
not coincide with the design critical PCN - the FLIP chart PCN is used for limiting airfield access to
excessively damaging aircraft, as explained below.
c. It is necessary to prevent the use of the pavement by excessively large aircraft that would
generate unacceptable amounts of damage, while avoiding as much as possible restricting day-to-day
operations. This is done via the FLIP chart PCN and ICAOs ACN/PCN method. If the design critical
aircraft PCN defined earlier is chosen for the FLIP (Flight Information Publication) this will restrict day-to-
day operations of the large aircraft. Alternatively, the highest tentative PCN from each of the aircraft
categories regularly using the base can be chosen as the FLIP PCN. This ensures both control over the
most damaging aircraft and little interference with operations.
2-9
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