Ahad, 23 Februari 2014

Federal Aviation Administration

Federal Aviation Administration
US-FederalAviationAdmin-Seal.svg
Flag of the United States Federal Aviation Administration.svg
Flag of the Federal Aviation Administration
Agency overview
FormedAugust 23, 1958
Preceding AgencyCivil Aeronautics Administration
JurisdictionUnited States federal government
Headquarters800 Independence Avenue SW Washington DC, 20591
38°53′14.31″N 77°1′19.98″W
Annual budget15.956 billion USD (FY2010)
Agency executiveMichael Huerta, Administrator
Parent agencyU.S. Department of Transportation
Websitewww.FAA.gov
Footnotes
[1][2]
The Federal Aviation Administration (FAA) is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of American civil aviation. The Federal Aviation Act of 1958 created the organization under the name Federal Aviation Agency. The agency adopted its current name in 1966 when it became a part of the U.S.Department of Transportation.

Major functions

The FAA's roles include:
  • Regulating U.S. commercial space transportation
  • Regulating air navigation facilities' geometry and flight inspection standards
  • Encouraging and developing civil aeronautics, including new aviation technology
  • Issuing, suspending, or revoking pilot certificates
  • Regulating civil aviation to promote safety, especially through local offices called Flight Standards District Offices
  • Developing and operating a system of air traffic control and navigation for both civil and military aircraft
  • Researching and developing the National Airspace System and civil aeronautics
  • Developing and carrying out programs to control aircraft noise and other environmental effects of civil aviation

Organizations

The FAA is divided into four "lines of business" (LOB).[3] Each LOB has a specific role within the FAA.
  • Airports (ARP) - plans and develops projects involving airports, overseeing their construction and operations. Ensures compliance with federal regulations. [4]
  • Air Traffic Organization (ATO) - primary duty is to safely and efficiently move air traffic within the National Airspace System. ATO employees manage air traffic facilities including Airport Traffic Control Towers (ATCT) and Terminal Radar Approach Control Facilities (TRACONs). [5] See also Airway Operational Support.
  • Aviation Safety (AVS) - Responsible for aeronautical certification of personnel and aircraft, including pilots, airlines, and mechanics. [6]
  • Commercial Space Transportation (AST) - ensures protection of U.S. assets during the launch or reentry of commercial space vehicles.[7]

Regions and Aeronautical Center Operations

The FAA has its headquarters in Washington, D.C[8] as well as the William J. Hughes Technical Center in Atlantic City, the Mike Monroney Aeronautical Center in Oklahoma City, and nine regional offices:

History


FAA Headquarters, Washington, D.C.
The Air Commerce Act of May 20, 1926, is the cornerstone of the federal government's regulation of civil aviation. This landmark legislation was passed at the urging of the aviation industry, whose leaders believed the airplane could not reach its full commercial potential without federal action to improve and maintain safety standards. The Act charged the Secretary of Commerce with fostering air commerce, issuing and enforcing air traffic rules, licensing pilots, certifying aircraft, establishing airways, and operating and maintaining aids to air navigation. The newly created Aeronautics Branch, operating under the Department of Commerce assumed primary responsibility for aviation oversight.
In fulfilling its civil aviation responsibilities, the Department of Commerce initially concentrated on such functions as safety regulations and the certification of pilots and aircraft. It took over the building and operation of the nation's system of lighted airways, a task that had been begun by the Post Office Department. The Department of Commerce improved aeronautical radio communications and introduced radio beacons as an effective aid to air navigation.
The Aeronautics Branch was renamed the Bureau of Air Commerce in 1934 to reflect its enhanced status within the Department. As commercial flying increased, the Bureau encouraged a group of airlines to establish the first three centers for providing air traffic control (ATC) along the airways. In 1936, the Bureau itself took over the centers and began to expand the ATC system. The pioneer air traffic controllers used maps, blackboards, and mental calculations to ensure the safe separation of aircraft traveling along designated routes between cities.
In 1938, the Civil Aeronautics Act transferred the federal civil aviation responsibilities from the Commerce Department to a new independent agency, the Civil Aeronautics Authority. The legislation also expanded the government's role by giving them the authority and the power to regulate airline fares and to determine the routes that air carriers would serve.
President Franklin D. Roosevelt split the authority into two agencies in 1940, the Civil Aeronautics Administration (CAA) and the Civil Aeronautics Board (CAB). CAA was responsible for ATC, airman and aircraft certification, safety enforcement, and airway development. CAB was entrusted with safety regulation, accident investigation, and economic regulation of the airlines. The CAA was part of the Department of Commerce. The CAB was an independent federal agency.
On the eve of America's entry into World War II, CAA began to extend its ATC responsibilities to takeoff and landing operations at airports. This expanded role eventually became permanent after the war. The application of radar to ATC helped controllers in their drive to keep abreast of the postwar boom in commercial air transportation. In 1946, meanwhile, Congress gave CAA the added task of administering the federal-aid airport program, the first peacetime program of financial assistance aimed exclusively at promoting development of the nation's civil airports.
The approaching era of jet travel, and a series of midair collisions (most notable was the 1956 Grand Canyon mid-air collision), prompted passage of the Federal Aviation Act of 1958. This legislation gave the CAA's functions to a new independent body, the Federal Aviation Agency. The act transferred air safety regulation from the CAB to the new FAA, and also gave the FAA sole responsibility for a common civil-military system of air navigation and air traffic control. The FAA's first administrator, Elwood R. Quesada, was a former Air Force general and adviser to President Eisenhower.
The same year witnessed the birth of the National Aeronautics and Space Administration (NASA), created in the wake of the Soviet launching of the first artificial satellite. NASA assumed NACA's role of aeronautical research while achieving world leadership in space technology and exploration.
In 1967, a new U.S. Department of Transportation (DOT) combined major federal responsibilities for air and surface transport. The Federal Aviation Agency's name changed to the Federal Aviation Administration as it became one of several agencies (e.g., Federal Highway Administration, Federal Railroad Administration, the Coast Guard, and the Saint Lawrence Seaway Commission) within DOT (albeit the largest). The FAA administrator would no longer report directly to the president but would instead report to the Secretary of Transportation. New programs and budget requests would have to be approved by DOT, which would then include these requests in the overall budget and submit it to the president.
At the same time, a new National Transportation Safety Board took over the Civil Aeronautics Board's (CAB) role of investigating and determining the causes of transportation accidents and making recommendations to the secretary of transportation. CAB was merged into DOT with its responsibilities limited to the regulation of commercial airline routes and fares.
The FAA gradually assumed additional functions. The hijacking epidemic of the 1960s had already brought the agency into the field of civil aviation security. In response to the hijackings on September 11, 2001, this responsibility is now primarily taken by the Department of Homeland Security. The FAA became more involved with the environmental aspects of aviation in 1968 when it received the power to set aircraft noise standards. Legislation in 1970 gave the agency management of a new airport aid program and certain added responsibilities for airport safety. During the 1960s and 1970s, the FAA also started to regulate high altitude (over 500 feet) kite and balloon flying.

FAA Joint Surveillance Site radar,Canton, Michigan
By the mid-1970s, the agency had achieved a semi-automated air traffic control system using both radar and computer technology. This system required enhancement to keep pace with air traffic growth, however, especially after the Airline Deregulation Act of 1978 phased out the CAB's economic regulation of the airlines. A nationwide strike by the air traffic controllers union in 1981 forced temporary flight restrictions but failed to shut down the airspace system. During the following year, the agency unveiled a new plan for further automating its air traffic control facilities, but progress proved disappointing. In 1994, the FAA shifted to a more step-by-step approach that has provided controllers with advanced equipment.[9]
In 1979, Congress authorized the FAA to work with major commercial airports to define noise pollution contours and investigate the feasibility of noise mitigation by residential retrofit programs. Throughout the 1980s, these charters were implemented.
In the 1990s, satellite technology received increased emphasis in the FAA's development programs as a means to improvements in communications, navigation, and airspace management. In 1995, the agency assumed responsibility for safety oversight of commercial space transportation, a function begun eleven years before by an office within DOT headquarters. The agency was responsible for the decision to ground flights after the September 11 attacks.
In 2007, two FAA whistleblowers, inspectors Charalambe "Bobby" Boutris and Douglas E. Peters, alleged that Boutris said he attempted to ground Southwest after finding cracks in the fuselage, but was prevented by supervisors he said were friendly with the airline.[10] This was validated by a report by the Department of Transportation which that found FAA managers had allowedSouthwest Airlines to fly 46 airplanes in 2006 and 2007 that were overdue for safety inspections, ignoring concerns raised by inspectors. Audits of other airlines resulted in two airlines grounding hundreds of planes, causing thousands of flight cancellations.[11] The House Transportation and Infrastructure Committee held hearings in April 2008. James Oberstar, former chairman of the committee said its investigation uncovered a pattern of regulatory abuse and widespread regulatory lapses, allowing 117 aircraft to be operated commercially although not in compliance with FAA safety rules.[10] Oberstar said there was a "culture of coziness" between senior FAA officials and the airlines and "a systematic breakdown" in the FAA's culture that resulted in "malfeasance, bordering on corruption."[10] In 2008 the FAA proposed to fine Southwest $10.2 million for failing to inspect older planes for cracks,[12] and in 2009 Southwest and the FAA agreed that Southwest would pay a $7.5 million penalty and would adapt new safety procedures, with the fine doubling if Southwest failed to follow through.[13]

Recent agency activities

In December 2000, an organization within the FAA called the Air Traffic Organization,[14] or ATO, was set up by presidential executive order. This became the Air Navigation Service Provider for the airspace of the United States and for the New York (Atlantic) and Oakland (Pacific) oceanic areas. It is a full member of the Civil Air Navigation Services Organisation.
The FAA issues a number of awards to holders of its licenses. Among these are demonstrated proficiencies as an aviation mechanic, a flight instructor, a 50-year aviator, or as a safe pilot. The latter, the FAA "Wings Program", provides a series of three badges for pilots who have undergone several hours of training since their last award. For more information see "FAA Advisory Circular 61-91H".
On March 18, 2008, the FAA ordered its inspectors to reconfirm that airlines are complying with federal rules after revelations that Southwest Airlines flew dozens of aircraft without certain mandatory inspections.[15] The FAA exercises surprise Red Team drills on national airports annually.
On October 31, 2013, the FAA announced it will allow airlines to expand the passengers use of portable electronic devices during all phases of flight, but cell phone calls will still be prohibited. Implementation will vary among airlines. The FAA expects many carriers to show that their planes allow passengers to safely use their devices in airplane mode, gate-to-gate, by the end of 2013. Devices must be held or put in the seat-back pocket during the actual takeoff and landing. Cell phones must be in airplane mode or with cellular service disabled, with no signal bars displayed, and cannot be used for voice communications due to FCC regulations that prohibit any airborne calls using cell phones. If an air carrier provides Wi-Fi service during flight, passengers may use it. Short-range Bluetooth accessories, like wireless keyboards, can also be used.[16]

Criticism[edit]

The FAA has been cited as an example of regulatory capture, "in which the airline industry openly dictates to its regulators its governing rules, arranging for not only beneficial regulation but placing key people to head these regulators."[17] Retired NASA Office of Inspector General Senior Special Agent Joseph Gutheinz, who formerly was a Special Agent with both the U.S. Department of Transportation Office of Inspector General and FAA Security, is one of the most outspoken critics of FAA. Rather than commend the agency for proposing a 10.2 million dollar fine against Southwest Airlines for its failure to conduct mandatory inspections in 2008, he was quoted as saying the following in an Associated Press story: "Penalties against airlines that violate FAA directives should be stiffer. At $25,000 per violation, (which is how the 10.2 million dollar figure was reached) Gutheinz said, airlines can justify rolling the dice and taking the chance on getting caught. He also said the FAA is often too quick to bend to pressure from airlines and pilots."[12] Other experts have been critical of the constraints and expectations under which the FAA is expected to operate. The dual role of encouraging aerospace travel and regulating aerospace travel are counter intuitive. For example, to levy a heavy penalty upon an airline for violating an FAA regulation which would impact their ability to continue operating would not be considered encouraging aerospace travel.
On July 22, 2008, in the aftermath of the Southwest Airlines inspection scandal, a bill was unanimously approved in the House to tighten regulations concerning airplane maintenance procedures, including the establishment of a whistleblower office and a two-year "cooling off" period that FAA inspectors or supervisors of inspectors must wait before they can work for those they regulated.[11][18] The bill also required rotation of principal maintenance inspectors and stipulated that the word "customer" properly applies to the flying public, not those entities regulated by the FAA.[11] The bill died in a Senate committee that year.[19]
In September 2009, the FAA administrator issued a directive mandating that the agency use the term "customers" only to refer to the flying public.[20]

List of FAA Administrators

FAA process

Designated Engineering Representative (DER)

A Designated Engineering Representative (DER) is an engineer who is appointed to act on behalf of a Company or as an individual Consultant (IC).[23]
  • Company DERs act on behalf of their employer and may only approve, or recommend approval, of technical data to the FAA for this company.
  • Consultant DERs are appointed to act as an independent DER to approve or recommend approval of technical data to the FAA.

Designated Airworthiness Representative (DAR)

A DAR is an individual appointed in accordance with 14 CFR 183.33 who may perform examination, inspection, and testing services necessary to the issuance of certificates. There are two types of DARs, manufacturing and maintenance.[24]
Manufacturing DARs must possess aeronautical knowledge, experience, and meet the qualification requirements of Order 8100.8.
Maintenance DARs must hold: a mechanic's certificate with an airframe and powerplant rating under 14 CFR part 65, Certification: Airmen Other Than Flight Crewmembers, or a repairman certificate and be employed at a repair station certificated under 14 CFR part 145, or an air carrier operating certificate holder with an FAA-approved continuous airworthiness program, and must meet the qualification requirements of Order 8100.8, Chapter 14.
Specialized Experience – Amateur-Built and Light-Sport Aircraft DARs Both Manufacturing DARs and Maintenance DARs may be authorized to perform airworthiness certification of light-sport aircraft. DAR qualification criteria and selection procedures for amateur-built and light-sport aircraft airworthiness functions are provided in Order 8100.8.

See also

Selasa, 18 Februari 2014

Capacity of Runway Systems

Capacity of Runway Systems 

The capacity of a system of runways is determined by the capacity of the individual
runways that area available for simultaneous use. The previous chapter described
methods for computing the theoretic maximum throughput capacity (MTC) for the
individual runways. This chapter describes how the capacity for a system of runways is
determined.

The capacity of multiple runway systems is determined by the number of runways
available for simultaneous use.
(1) wind direction and magnitude 
(2) independence of runways 
(3) Noise and/or environmental constraints 

Wind Direction and Magnitude 

Winds are the primary determinant of the number of runways available for simultaneous 
use. Aircraft can use a runway for takeoff or landing only when the crosswinds are within 
prescribed limits and tailwinds does not exceed 5 – 6 knots (9-11 km/h). The prescribed 
limits for crosswinds are summarized in the table below: 
 
Aircraft Type                                                      Maximum Crosswind Allowed 
Reference field length < 1200m                                    10.5 knots 
1200m > reference field length >1499m                         13 knots 
                                                                                     16 knots 
Reference field length > 1500m                                      20 knots 
 
At airports that experience frequent periods of sustained strong winds from several 
different directions, the number of runways aligned with the wind direction to meet an 
availability of 95% can be high. In contrast, several major airports operate with an 
availability in excess of 95% with single direction runways.

The capacity of a runway system is primarily determined by the number of runways 
available for use at any given time and. This is known as the runway configuration and is 
determined by wind direction and magnitude, the geometry of the runways and 
noise/environmental considerations. 

Independence of Runways 

In addition to the number of active runways, the capacity of the runway system is also 
determined by the independence of the available runways. Independent runways operate 
without restrictions. Dependent runways operate with restrictions determined by the type 
of operations on adjacent runways. 

There are two type of dependence:
 (1) parallel runway dependence, and 
(2) intersection runway dependence. 

Dependence and Independence of Parallel Runways 

Parallel runways are a common geometric configuration used at major airports. By 
duplicating the number of runways in a given direction, the capacity of the runway 
system is increased when prevailing wind require use of these runways. 

Operations on parallel runways can be grouped into three categories: 
(i) dependent close parallel runway operations,
 (ii) dependent medium spaced parallel runway operations, and 
(iii) independent parallel runway operations. 
The degree of dependence for mixed arrival/departure operations for parallel runways in 
summarized in Table 1. 
 
For close parallel runways, when the runways are used exclusively for arrivals or 
exclusively for departures, they must operate as dependent runways and the separation 
rules for single runway operation apply. For example, for arrivals, sequential aircraft 
landing on each runway must have the same separation requirement as if they were 
landing on the same runway. 
 
When close parallel runways are used for departures and arrivals, they must operate as 
dependent runways and the single runway rule applies. The landing aircraft must be at 
least 2nm from the departure runway when the departure begins and may not touchdown 
before the departure has left the runway. One small variant is that a departing aircraft 
does not have to wait until the landing aircraft has cleared the adjacent parallel runway 
before initiating the departure roll. 


When one medium parallel runway is used for arrivals only and the other for departure 
only, the runways can also operate independently. 
When parallel runways are more than 4300 ft apart, the runway can be operated 
independently. In some cases, the FAA has authorized the use of parallel runways spaced 
3400 ft apart to operate as independent runways when the Air Traffic Controllers have 
use of the Precision Runway Monitor (PRM) system. The PRM provides improved 
accuracy radar surveillance data to the controllers to ensure safe separation. 
 
The discussion above is based on the assumption that the parallel runway thresholds are 
aligned. When the runways are staggered such that the runway thresholds are offset, then 
the “effective separation distance” between runway centerlines is adjusted. Foe example, 
when arrivals are to the “near end” runway and departures on the “far end” runway, the 
2500 ft separation requirement is reduced by 100 ft for each 500 ft of threshold offset 
down to a minimum of separation distance of 1200 ft. For example, when a runway offset 
is 1000ft, a separation of 2300 ft between runway centerlines is equivalent to a 2500 ft 
separation distance. When departures are to the near end and arrivals to the far end, the 
separation distance is reduced. 
Intersecting, Converging, or Diverging Runways 
Intersecting runways are constructed to support multiple prevailing wind directions using 
restricted real-estate. Runways are considered to intersect when their tarmac crosses each 
other. Runways converge or diverge when the projections of their centerlines converge or 
diverge. 
The rules that affect capacity vary from airport to airport and from country to country for 
intersecting, converging and diverging runways and are too variable to generalize in this 
text, but some basic principles apply. 

Noise Considerations 

Environmental considerations, especially noise has an important influence in determining 
runway system capacity. Air traffic controllers choose runway configurations to 
minimize noise over populated regions. For example, at Los Angeles airport, shown in 
Figure 2, assuming wind conditions are calm and operations can occur from either end of 
the runway, ATC can choose to operate the runways by landing from the east and 
departing towards the ocean (west). In this way, the population to the east of the airport is 
subject to the idle thrust noise from descending aircraft, and not the Maximum takeoff 
thrust required for departures.

There are three types of noise-related restrictions and configurations are usually due to: 
 Noise mitigation for densely populated areas 
 Short-term and long-term goals for runway utilization. The objective is to 
distribute noise among neighboring communities in a way that is considered fair 
by the parties involved. 
 Minimize continuous exposure of any single community to noise on any 
particular day. For example, in Boston/Logan no runway can be used continually 
for more than 4 h in any single direction and no runway can be used for more than 
24 h in any 72-h period.



Runway designations

Runway designations change over time because the magnetic poles slowly drift on the Earth's surface and the magnetic bearing will change. Depending on the airport location and how much drift takes place, it may be necessary over time to change the runway designation. As runways are designated with headings rounded to the nearest 10 degrees, this will affect some runways more than others. For example, if the magnetic heading of a runway is 233 degrees, it would be designated Runway 23. If the magnetic heading changed downwards by 5 degrees to 228, the Runway would still be Runway 23. If on the other hand the original magnetic heading was 226 (Runway 23), and the heading decreased by only 2 degrees to 224, the runway should become Runway 22. Because the drift itself is quite slow, runway designation changes are uncommon, and not welcomed, as they require an accompanying change in aeronautical charts and descriptive documents. When runway designations do change, especially at major airports, it is often changed at night as taxiway signs need to be changed and the huge numbers at each end of the runway need to be repainted to the new runway designators. In July 2009 for example, London Stansted Airport in the United Kingdom changed its runway designations from 05/23 to 04/22 after dark.



Parallel Runway Designations

Situation

Several New Zealand aerodromes have parallel runways where there is a main sealed runway with a secondary parallel grass runway. The aerodromes include one main international aerodrome (Christchurch), a number of regional certificated aerodromes, and some unattended/non-certified aerodromes (eg Ardmore).

The Issue

ICAO Annex 14 requires that a runway designation marking shall be provided at the threshold of paved runways and recommends the same for unpaved runways. Annex 14 also states that, where provided, the designation marking shall consist of a two-digit number and, for parallel runways, be supplemented with a letter “L”, “R” or “C” (left, right or centre), as appropriate.
In New Zealand, not all parallel runways use the Annex 14 convention mainly due to one runway being sealed and the other grass. It has also become common practice to only mark the sealed runway at the threshold with the grass runway not having a specific runway designator marking. If the grass runway is marked, it does not generally include the supplementary “L”, “R” or “C”.
Airways New Zealand has noted that at several controlled aerodromes there has been inconsistent naming of parallel runways and consequently inconsistent use of radio phraseology when clearing an aircraft to land. At some aerodromes, the term “runway” is used for the sealed runway and “grass” for the parallel grass runway. The problem with this is that the grass strip is itself a “runway”, so it is open to misinterpretation. This is unsatisfactory from a human factors point of view and can lead to an incident. At other aerodromes the terms “seal” and “grass” are used.

The CAA Position

Parallel Runways with the Same Physical Surface

Aerodromes with parallel runways of the same physical surface must use the letter supplement “L”, “R” or “C” as appropriate. The aerodrome operators must ensure the correct runway designation marking including letter supplement is positioned at the threshold of each runway in accordance with Advisory Circular AC139-6 or AC139-7 as appropriate. Radio phraseology including the runway designator and letter supplement must be used by pilots and air traffic control (ATC), if applicable, in accordance with AC91-9.

Parallel Runways with Different Physical Surfaces

Aerodromes with parallel runways that clearly have different physical surfaces do not need to use the “L” or “R” letter supplement. This is dependent on the aerodrome layout, but if no letter supplement is used, then pilots and ATC radio phraseology must include the prefix "seal" or “grass” with the runway designator in accordance with AC91-9. The aerodrome operator should still ensure the correct runway designation marking is positioned at the threshold of each runway in accordance with Advisory Circular AC139-6 or AC139-7 as appropriate, but without the letter supplement. It is recognised that the marking of grass runways is difficult and a proposed change to the aerodrome Advisory Circulars will allow for different marking methods.

Part 172 – Air Traffic Control

To ensure a consistent and unambiguous service at aerodromes with parallel runways with different surfaces, ATC clearances are to include the prefix “seal” (RWY designator), or the prefix “grass” (RWY designator), as appropriate, in accordance with AC91-9. However, at aerodromes with one main sealed instrument runway, and a parallel much shorter grass runway, where the aircraft concerned can only use the sealed runway, the use of the prefix “seal” may be omitted.


The following Advisory Circulars are being updated to reflect the CAA position:
AC139-6 Aerodrome Standards and Requirements: All aeroplanes conducting Air Transport Operations - All Aeroplanes above 5700 kg MCTOW
AC139-7 Aerodrome Standards and Requirements: Aeroplanes at or below 5700 kg MCTOW - Non Air Transport Operations

Types of Runway




Runways are the designated paths where aircrafts takes off, lands and taxies. Runways are laid 
out according to the numbers on a compass where 0 & 360 is north, 90° is East, 180° is South, 
and 270° is West. A runway's compass direction is indicated by a large number painted at the 
end of each runway 
 
Simple runway picture:


Basically there are four types of runways:
1. Single runway
2. Parallel runway
3. Open V-runways
4. Intersection runways

Single Runway
This is a runway optimally positioned for prevailing wind, noise, land use and other determining
factors and should accommodate 42 to 53 operations per hour.

Parallel Runway
Here further four types of runway are possible depending on how closely they are placed next to
each other that should accommodate 64 to 128 operations per hour


Open – V Runways
Two runways that diverge from different directions but do NOT intersect form a shape that looks
like an "open-V" are called open-V runways and are used when there is little to no wind as it
allows for both runways to be used at the same time. When the winds become strong in one
direction, then only one runway will be used.


Intersecting Runways
Two or more runways that cross each other are classified as intersecting runways. This type of
configuration is used when there are relatively strong prevailing winds from more than one
direction during the year. When the winds are strong from one direction, operations will be limited
to only one runway.




http://www.mission10x.com/mission-10x/PublishingImages/resources/pdfs/typesofrunways.pdf



Runway Configuration



Runway Configuration

The combination of runways that are active at any particular time at an airport is known as the “runway configuration” in which the airport operates at that time. The sequence of configurations selected by controllers greatly influences an airport’s capacity to serve demand for arrivals and departures. This paper is concerned with determining a sequence of runway configurations and the assignment of arrivals and departures to the active runways that together minimize the cost incurred at the airport due to delayed aircraft.

The availability of certain configurations at most major airports might be restricted by the weather conditions prevailing at any particular time. For example, a runway cannot be operated in the presence of strong crosswinds (relative to the orientation of that runway); or a runway might not be adequately instrumented for operations under poor visibility conditions. There are also physical limits to the capacity of each configuration, i.e., to the number of arrivals and departures that can be accommodated in a given length of time while operating in a given configuration. In an operational context, capacity typically is measured as the expected number of movements that can take place in the presence of continuous demand. 


This is also known as the maximum throughput capacity and is measured as the number of arrivals and departures per unit of time, typically 10, 15, or 60 minutes. In making their decisions concerning the best runway configuration to use at any given time, controllers take into account the capacity of each available configuration, as well as the scheduled demand for arrivals and departures, and the weather forecast, which influences the future availability of the different runway configurations.



The active runway is the runway at an airport that is in use for takeoffs and landings. Since takeoffs and landings are usually done as close to "into the wind" (see headwind) as possible, wind direction generally determines the active runway.
Selection of the active runway, however, depends on a number of factors. At a non-towered airport, pilots usually select the runway most nearly aligned with the wind, but they are not obliged to use that particular runway. For example, a pilot arriving from the east may elect to land straight into an east-west runway despite a minor tailwind or significant crosswind, in order to expedite his arrival, although it is recommended to always fly a regular traffic pattern to more safely merge with other aircraft.
At controlled airports, the active is usually determined by a tower supervisor. However, there may be constraints, such as policy from the airport manager (calm wind runway selection, for example, or noise abatement guidelines) that dictate an active runway selection that is not the one most nearly aligned with the wind.
At major airports with multiple runways, the active could be any of a number of runways. For example, when Chicago O'Hare International Airport is landing on 27L and 32L, departures use 28 and 32R, thus making four active runways. When they are landing on 14R and 22R, departures use 22L and 9R, and occasionally a third arrival runway, 14L, will be employed, bringing the active runway count to five.
At major airports, the active runway is based on weather conditions (visibility and ceiling, as well as wind, and runway conditions such as wet/dry or snow covered), efficiency (O'Hare International Airport can land more aircraft on 14R/32L than on 9R/27L), traffic demand (when a heavy departure rush is scheduled, a runway configuration that optimizes departures vs. arrivals may be desirable), and time of day (O'Hare is obliged to use runway 9R/27L during the hours of roughly midnight to 6 a.m. due to noise abatement).
London Heathrow Airport in the United Kingdom has two parallel runways, designated 09L/27R and 09R/27L. They are most often used in segregated alternate mode, which means one runway is used only for arrivals and the other is only used for departures although at busy periods 'mixed mode' is used in which both runways are used for both takeoff and landing. The segregated mode provides for one runway to be used by landing aircraft from 06:00 until 15:00 and then arrivals will switch to the other runway from 15:00 until after the last departure, after which a separate night alternation scheme operates, involving either the northern or southern runway being used in an easterly or westerly direction on a 4-week cycle. The runways used by landing aircraft before and after 15:00 also alternate on a weekly basis. This only applies to westerly operations as landing aircraft almost always use runway 09L during easterly operations.