Sfo Airport Parallel Landing

[Keri Gamrath]

Triple takeoff/landing capabilities are a necessity for many large airports as it allows many aircraft to arrive and depart in a short amount of time. Each country sets its own standards for the separation between runways required for parallel approaches. In the United States, the Federal Aviation Administration dictates that airports must have at least 3,000 feet (910 m) between runways,[1] though it can grant special permission to conduct parallel approaches with less separation if deemed necessary.

The main objective of implementing simultaneous operations on parallel or near-parallel runways is to increase runway capacity and aerodrome flexibility. The largest increase in overall capacity often includes the use of independent approaches to parallel or near-parallel runways.

The safety of parallel runway operations in controlled airspace is affected by several factors such as the accuracy and use of the associated radar monitoring system, the effectiveness of the process of controller intervention when an aircraft deviates from the correct ILS localiser or RNAV course and the precision with which aircraft can and do fly the approach.

It should be noted that when the spacing between two parallel runways is lower than the specified value determined by wake turbulence considerations, the runways are considered as a single runway with regard to vortex wake separation.

Factors which may have an impact on the maximum capacity or the desirability of operating parallel runways simultaneously are not limited to runway considerations. Taxiway layout and the position of passenger terminals with reference to the runways may make it necessary for traffic to cross active runways, a situation which may not only lead to delays but also to a decrease of the safety level due to the possibility of runway incursions by either arriving or departing aircraft.

Theoretical studies and practical examples indicate that maximum aerodrome capacities can be achieved by using parallel runways in a mixed mode of operation. In many cases, however, other factors such as the land-side/air-side infrastructure, the mix of aircraft types, and environmental considerations result in a lower achievable capacity.

Because of these constraints, maximum runway capacity may, in some cases, only be achieved by adopting a fully segregated mode of operation, i.e. one runway is used exclusively for landings while the other is used exclusively for departures.

Parallel Runway Operation need to be carefully managed in such a manner as to minimise the risk of runway incursion or wrong runway use. Closely-spaced parallel runways may affect the pilots' situational awareness or lead to their distraction or confusion.

Independent operations on closely-spaced parallel runways are significantly safety critical and should be used only after a proper risk assessment has been undertaken. In this process, the issues listed below, which are contained in ICAO Doc 9643 Manual on Simultaneous Operations on Parallel or near parallel Instrument Runways (SOIR), should be considered:

No special procedures have been developed as yet for simultaneous operations to near-parallel runways. Each situation is considered on a case-by-case basis and is dependent on a number of variable conditions.

In order to maximise the capacity there are some concepts such as High Approach Landing System (HALS) that were developed and deployed (for a given period of time only) to allow aircraft to land simultaneously on closely spaced parallel runways at Frankfurt Airport. The concept involved adopting a second, strongly displaced landing threshold for the southern runway to mitigate against wake turbulence by flying above the vortices of the leading aircraft.

Abilene Regional Airport Abu Dhabi International Airport Amsterdam Airport Schiphol Ashgabat Atlanta/Hartsfield-Jackson International Auckland Airport Austin-Bergstrom International Airport Bangkok/Suvarnabhumi International Airport Barcelona/El Prat Airport Billings Logan International Airport Boise Airport Brownsville/South Padre Island International Airport Calgary International Airport Capital Region International Airport Cavern City Air Terminal Charlotte Douglas International Airport Chicago O'Hare International Airport Cincinnati Municipal Airport Clinton National Airport Colorado Springs Airport Columbus Air Force Base Copenhagen Airport, Kastrup Da Nang International Airport Dallas Love Field Dallas-Fort Worth International Airport Dayton International Airport Daytona Beach International Airport DeKalb-Peachtree Delhi/Indira Gandhi International (IGI) Airport Dubai International Airport

I was listening to some RealATC this evening and came to this one about an accident at LaGuardia airport. This question is not about the accident in any way, but I am using this video because it has an example of what I mean and has a labelled diagram as well.

Major commercial airports try to have as many parallel runways as possible, as crossing runways are a hassle. (See DFW, ATL, LAX, many other examples of new or remodelled major airports using almost exclusively parallel runways). But sometimes (for any number of reasons, a main one at LGA being space) parallel runways haven't been built, so they can't be used.

Any time the winds and traffic permit an airport may chose to use intersecting runways. You can read some interesting info on it here and here. In some cases when both runways are in use they may have the aircraft execute Land And Hold Short procedures. The pilot has the final say in a LAHSO situation and you can call no joy if you think you cant complete the maneuver as requested.

Some airports may only have 2 runways set up in an intersecting layout and may not have the luxury of parallel runways. Depending on terminal layout at commercial airports using both runways may aid in traffic flow on the ground as well as getting planes in the air.

Winds permitting generally have to do with the maximum cross wind component of a given airplane. Although generally speaking you will see this done in calm wind situations. The other cause I have seen for this is instrumentation, some airports may have intersecting runways that are not equipped the same or of the same length. As lets say the favorable runway is is 5000ft visual approach only strip and you need 6000ft to land. Luckily the airport has another intersecting runway that is a 7000ft strip (and has an ILS approach not that you need it (its nice out)). They may have you come into the other runway while they sequence small visual traffic on to the short strip (possibly having them land short if need be).

While landing at an airport, have you ever noticed another aircraft landing simultaneously on a parallel runway? While it is common to spot other aircraft taking off or landing on other runways, parallel takeoffs and landings are not very common.

Simultaneous landings or takeoffs, such as those that can be witnessed at San Francisco International Airport (SFO), can be incredibly beautiful, especially for those onboard who witness another aircraft land right alongside them. Despite the fact that these events are rather marvelous to behold, they are surprisingly rare among US airports.

However, the facilities that are required for a simultaneous landing are actually rather common, as all an airport requires are two parallel runways separated by more than 4,300 feet. Furthermore, parallel takeoffs and landings can even be authorized with less than that separation distance under specific circumstances, such as if both aircraft are significantly smaller.

Despite this, simultaneous landings and takeoffs are actually rather rare, and many have only seen them at a few US airports. Therefore, which airports could permit these marvelous landings, and why are they not that common even when the appropriate facilities are available?

There are far more airports with the appropriate facilities for simultaneous parallel landings than one might expect. Examples of these airports include Newark Liberty International Airport (EWR), where United Airlines maintains an operational hub, and Kansas City International Airport (MCI).

In fact, there are actually numerous airports that maintain the facilities for triple parallel landings in the United States. In fact, 23 different US airports can accommodate three aircraft approaching three runways simultaneously, some of which are rather small. Wichita Falls Regional Airport (SPS), a mixed-use facility operating military flights out of nearby Sheppard Air Force Base and scheduled commercial service from American Eagle, has three parallel runways capable of simultaneous landings.

Some airports can theoretically even accommodate more than three aircraft landing or taking off at once, including Denver International Airport (DEN) and Dallas-Fort Worth International Airport (DFW). Chicago-O'Hare International Airport (ORD) can even hypothetically permit six aircraft to land simultaneously, which would truly be a sight to behold.

In most situations, when an airport has two runways, one is used for takeoffs and the other for arriving flights, which is far more efficient than utilizing both for both departing and landing flights. Thus, it's rather uncommon to see simultaneous arrivals even when airports do have multiple runways.

As SKYbrary mentions, even if airports have more than two runways and use multiple runways for landings or takeoffs, aircraft are often guided onto staggered approaches, which require fewer air traffic control precautions to be taken via diagonal instead of horizontal aircraft separation. Only under very specific circumstances are parallel landings utilized.

One time in which simultaneous landings are optimal is when an airport is experiencing significant one-way traffic. For example, if an airport has a large influx of arriving flights and very few departing flights, it may make sense to utilize both runways for simultaneous approaches as is done in San Francisco during certain times of the day.

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