曝光臺 注意防騙 網曝天貓店富美金盛家居專營店坑蒙拐騙欺詐消費者

Tire Pressure
?? psi
21
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
21
• Official ACN values are provided by the Aircraft
Manufacturer
Airplane Characteristics for Airport Planning
ACN/PCN System – Official ACN
• Airplane Characteristics
manual report official
center of gravity and
max gross load for ACN
calculation.
• Tire pressure (used in ACN
calculation) is also reported
for standard configuration
ACN/PCN System
23
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
23
FAA Guidance on ACN-PCN
AC 150/5335-5A STANDARDIZED METHOD OF
REPORTING AIRPORT PAVEMENT STRENGTH – PCN
• AC introduces the COMFAA program.
• COMFAA can be used to calculate ACN values for any
airplanes.
• Manufacturer’s have provided CG and max load data for
ACN determination.
COMFAA 2.0 Program
COMFAA 2.0 Program
Select desired aircraft group
Select desired airplane
26
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
26
COMFAA 2.0 Program
The internal aircraft library in
COMFAA contains the
manufacturers data for ACN
determination.
Coverages is set to 10,000
per ICAO procedure.
27
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
27
COMFAA 2.0 Program
In ACN Computation mode, ACN values are calculated for 4
standard subgrade conditions using the identified airplane data
Flexible Rigid
28
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
28
ACN-PCN SYSTEM – PCN Values
• PCN values are reported in a coded format using 5
parts separated by “/”
Sample 39/R/B/W/T
• Information includes
• Numerical PCN Value
• Pavement Type
• Subgrade Category
• Allowable Tire pressure
• Method used to determine the PCN value
29
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
29
ACN-PCN SYSTEM
• PCN Numerical value is a relative indication of the load carrying
capacity of a pavement in terms of a standard single wheel load 181
psi (1.25 MPa)
• PCN value derived from the ACN value of the most demanding
airplane.
• PCN values can be determined in two ways
• Using Aircraft
• Technical Evaluation
39/R/B/W/T
PCN Numerical value
30
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
30
ACN-PCN SYSTEM
• Pavement may be either Rigid (R) or Flexible (F)
• Rigid – Single Stiff Layer to support and distribute load
• Flexible – Multiple flexible layers to distribute load
• Composite pavements (overlays etc.) are reported as the type which
most accurately reflects the structural action
39/R/B/W/T
Pavement Type
31
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
31
ACN-PCN SYSTEM
39/R/B/W/T
Subgrade Category
Subgrade
Strength Category CODE
RIGID
k-Value* pci (MN/m3)
FLEXIBLE
CBR-Value
High A 552.6 (150) 15
Medium B 294.7 (80) 10
Low C 147.4 (40) 6
Ultra Low D 73.7 (20) 3
*Effective k-value
32
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
32
ACN-PCN SYSTEM
39/R/B/W/T
Allowable Tire Pressure
Category Code Tire Pressure Range
High W No pressure limit
Medium X Pressure limited to 218 psi (1.5 MPa)
Low Y Pressure limited to 145 psi (1.00 MPa)
Very Low Z Pressure limited to 73 psi (0.50 MPa)
Recent request to ICAO have proposed modifying this table to increase
allowable tire pressures
33
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
33
ACN-PCN SYSTEM
PCN values can be determined in two ways
• U =Using Aircraft
• Simply select highest ACN from all airplanes using facility
• T = Technical Evaluation
• PCN based on technical study of pavement structure and traffic
data.
39/R/B/W/T
Method used to determine PCN
34
Transportation Systems Workshop
April 23, 2008
Federal Aviation
Administration
34
　
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：航空資料37(4)