Paved areas 139.305 and safety areas 139.309 Flashcards
What are the two purposes airport pavements are designed and constructed?
to support the critical loads imposed on them, and to produce a smooth, skid-resistant, and safe-riding surface
Flexible Pavement
tends to compress under load. Reflects the deformation of subgrade and the subsequent layers to the surface. grass, dirt, gravel, and asphalt
Ridged Pavement
Resists compression under load. loads are distributed over a wide area of subgrade soil. normally uses Portland cement concrete
the two major elements most contributing to pavement deterioration are?
effects of weathering, Loads imposed by aircraft
PCN
Pavement classification number: the strength of pavement, in terms of the load-carrying capacity
ACN
Airplane Classification Number: the effect of an individual airplane on different pavements using this number
LCN
Load Classification Number: for pavements with lower bearing strengths, the naming convention uses the following codes for gear designation purposes
S-Single
D-Dual
T-Trippel
Q-Quadruple
Flexible Pavement Distresses
Cracking, Disintegration, Distortion, Loss of skid resistance
Ridged Pavement distresses
Cracking, Joint seal damage, Disintegration, Distortion, Loss of Skid resistance
Hot-mix asphalt (HMA)
a blend of asphalt binder and well graded, high quality aggregates. they are mixed and placed while hot. used in construction of new airfield pavement and patching and overlay of pavements
tack coat
a light application of emulsified asphalt applied to an exiting pavement to provide a bond with an overlaying course like HMA. its used on the sides of an existing pavement that has been cut vertically before application.
crack filler material
hot-applied, for asphalt concrete an Portland cement concrete pavements
Concrete
it is a blend of Portland cement, fine and coarse aggregate, and water, with or without additives. used to repair a distressed Portland cement concrete pavement so it may be used at its original designed capacity
Skid resistance
the ability of a pavement to provide a surface with the desired friction characteristics under all weather conditions. it is affected by the polishing action of aircraft traffic and ground vehicles, contaminants on the pavement, fuel or other fluid spillage, rubber deposits, pavement texture, paint markings, and pavement abnormalities
Dynamic Hydroplaning
Occurs on any surface. A wave of water builds up in front of the rolling tire, which allows the tire to ride on a cushion of water and lose contact with the runway surface
Viscous Hydroplaning
occurs form the lubricating effect that results when a thin film of oil, grease, dirt, rubber particles or a smooth runway combine with water or other liquid, resulting in slippery pavement. it prevents a tire from making positive contact with the pavement, and it results in skidding. it can occur at lower speeds
Rubber reversion hydroplaning
caused by the rubber heat buildup beneath a tire footprint due to friction. the heat causes the tire to revert to its uncured state and form a seal that traps high pressure superheated steam. primarily occurs during landing, and prevents a spin-up of the tire on touchdown
how to treat surfaces to decrease hydroplaning
pavement grooving, a porous friction course, wire combing
Ways to remove rubber
high-pressure water spray, chemical solvents, high-velocity abrasive impact techniques, mechanical grinding
4 ways friction evaluations may be conducted
Decelerometers (DEC): spot check instead of a continuous graphic record. a minimum of 3 break tests per part of the runway
Electronic: automatically computing a nd reporting friction averages for each one-third of the runway. also provide a printed record. taken at 20mph
Mechanical: considered as only a backup to the first two. they require longer runway down time and don’t give a printed copy
Continuous Friction Measuring Equipment (CFME): Recommended for pavement surfaces covered with contaminants, as they provide a continuous graphic record of the pavement surface friction characteristics. may be self-contained or towed, taken at 40 mph
Decelerometers (DEC):
spot check instead of a continuous graphic record. a minimum of 3 break tests per part of the runway
Electronic friction evaluation
automatically computing a nd reporting friction averages for each one-third of the runway. also provide a printed record. taken at 20mph
Mechanical friction evaluation
considered as only a backup to the first two. they require longer runway down time and don’t give a printed copy
Continuous Friction Measuring Equipment (CFME)
Recommended for pavement surfaces covered with contaminants, as they provide a continuous graphic record of the pavement surface friction characteristics. may be self-contained or towed, taken at 40 mph
A formal FOD management program addresses the following
- Prevention: awareness, training and education, maintenance
- Detection: operations, equipment
- Removal: equipment, operations
- Evaluation: data collection and analysis, continuous improvement
FOD Equipment
Mechanical: power sweepers, vacuum systems, jet air blowers
non-mechanical: friction mat sweepers, magnetic bars, rumble strips
distinction between moment and non-movement areas at airports is based on two factors
operation control, and FAA design standards
When may a displaced threshold be required
When an object obstructs the airspace needed for landing, when there are environmental considerations such as noise abatement, and when runway safety area dimensions or obstacle-free area lengths are needed
what is a major goal of taxiways
to maintain a smooth flow with a minimum number of points requiring a change in the airplane’s taxiing speed
what is a major goal of aprons
the ready accommodation of either a changing or static mix of aircraft
the main reasons for the use of artificial turf at airports are to…?
mitigate soil erosion, minimize maintenance and management of turf, enhance visual aesthetics
