Editor’s notice: This story initially ran in 2019.
Flight delays at San Francisco Worldwide Airport recurrently exceed two hours when it is wet, windy or foggy, whereas airports in San Jose and Oakland report few if any delays. The issue is exacerbated right now of 12 months by a gradual stream of winter storms blowing in off the Pacific.
As most frequent vacationers know, delays mount at SFO virtually each time a storm blows in off the Pacific. Simply have a look at these soggy numbers from the U.S. Bureau of Transportation Statistics: SFO ranked twenty eighth out of 30 main airports in on-time arrivals in 2018 (you’ll be able to see the most recent stats right here.)
Why does SFO appear to endure so many extra weather-related delays than different airports within the Bay Space? In fact, the reply is difficult, however for essentially the most half, the principle purpose is capability. SFO’s runways are too shut collectively to permit simultaneous operations throughout moist climate. As a result of environmental considerations (examine that right here), there aren’t any present plans to additional separate the runways, which might require growth into the Bay.
SFO runways are designed to deal with as much as 60 plane arrivals per hour in dry climate. That is as a result of the airport operates two units of parallel runways – one set for takeoffs, the opposite for landings. These pairs of parallel runways intersect at their midpoint forming a large “X.” (See determine right here or in slideshow up prime.) Throughout dry climate, two streams of planes can land and take off from these parallel runways.
The issue is that planes are solely allowed to take off and land concurrently on these parallel runways throughout clear, dry climate.
When storms blow in, air site visitors management modifications up the formation by which planes land, from the dry climate “West Plan” (with plane arriving on runways 28L or 28R and departing on runways 01L or 01R) to the stormy climate “Southeast Plan” (when plane arrive on 19L & 19R and depart on 10L & 10R).
When air site visitors controllers change to the Southeast plan (see map), simultaneous operations on parallel runways was forbidden, which cuts the airport’s capability (about 60 landings per hour) in half throughout storms. In 2013, Carefully-Spaced Parallel Runway (CSPR) procedures started at SFO, permitting staggered approaches to parallel runways. Previous to this, unhealthy climate days lowered the arrival charge to as low at 25-27 landings per hour, however these enhancements now permit as many as 36 per hour in unhealthy climate. That is nonetheless fairly gradual.
In the event you stay in San Francisco, you’ll be able to inform when planes change to the Southeast Plan as a result of some arriving plane whistle and moan as they descend by the clouds over town as they method SFO. (To me, that is all the time an indication that the winter storm door has opened.)
The primary purpose that airports in Oakland and San Jose do not face such on-time efficiency points– even when it is raining— is as a result of their quantity is low. They hardly ever exceed their capability for arrivals in good or unhealthy climate. (For instance, neither airport is included within the BTS’s prime 30 airports cited right here.) You possibly can test the FAA’s delay map and notifications right here.
The airport is relying on a technological repair to the issue. “Additional enhancements will proceed to enhance this charge,” stated SFO’s spokesperson Doug Yakel. “We’re funding the set up of a Floor-Based mostly Augmentation System, which broadcasts a hyper-accurate GPS sign that may help way more refined approaches than presently potential. This might permit plane to make use of a landing level additional down the runway, curved approaches, approaches additional offshore, or at increased altitudes. Any of those would permit extra environment friendly use of our parallel runways.”
So till these enhancements come into play, and we nonetheless face 3-plus hour delays on stormy days at SFO, what can vacationers do to keep away from this? Fly early throughout storm season. Earlier than 9 a.m., arrival quantity at SFO is beneath 30 per hour. However after 9 a.m., simply over 30 plane are scheduled to land. The arrivals charge peaks between 12 midday and a pair of p.m. when 40+ plane per hour are scheduled to land at SFO. The state of affairs often doesn’t enhance till later within the afternoon when arrival quantity falls beneath 30 per hour.
