Oct. 30, 2015

The taxiway “Q” and “B” intersection at San Francisco International Airport (SFO) will be closed for maintenance Nov. 7 and 8.

At SFO, the Q/B intersection has been prone to ponding for years, and this is accelerating the destruction of the pavement. The San Francisco International Airport Authority (SFIA) is concerned that a sudden, significant pavement failure will occur.

An unplanned closure of this intersection could have a far-reaching impact on operations, including gridlock, should the failure occur during busy traffic. An unplanned outage could also cause extended closure periods, as construction equipment, personnel and plans are coordinated. Accordingly, SFIA plans to grind out, re-grade and re-pave the intersection under controlled conditions to prevent an unexpected closure in the future. This project will also require major electrical work, signage changes and repainting of taxiway markings.

Construction is currently scheduled to occur in one 54-hour closure of the intersection. This closure is currently scheduled to begin at midnight (PST) (0800Z) on Saturday, Nov. 7, and end at 6 a.m. (PST) (1400Z) on Monday, Nov. 9. Should rain be a factor, the closure will be postponed to the next weekend.

Operational Impact

The closure of the Q/B intersection will create a one-in-one-out restriction for aircraft taxiing to and from all gates west of Taxiway Q1. Specifically, this will affect United Airlines, SFOs largest customer, as a majority of its gates are west of Q1. Additionally, the proximity of the closure area to Taxiway B1 will render B1 unusable due to insufficient wing tip and jet blast clearance with the construction area. The loss of Taxiway B1 means that access to the end-around Taxiway Z will be unavailable.

Therefore, all maintenance aircraft and tugs that usually utilize Taxiway Z to and from the maintenance centers will need to cross active runways and be subject to the one-in-one out restriction mentioned above.

The one-in-one-out restriction will require SFO ground control to hold aircraft going in one direction while aircraft going in the opposite direction navigate through the restricted area. This can rapidly cause taxiways to become saturated with traffic, which can affect arrival traffic exiting from Runways 28. Without adequate traffic management initiatives, the likelihood of gridlock, missed departure opportunities and missed approaches will increase proportionate to the amount of traffic.

Should weather require a landing and departing Runways 28 operation, the increased crossing of those runways will further increase complexity and delays.

General Aviation Specific Impacts

  • General aviation aircraft that usually use the west end Taxiway Z to access Runways 01 will now be required to cross active runways, further increasing complexity and congestion.
  • Additionally, general aviation aircraft, as well as maintenance aircraft and tugs that need to cross the runways, will need to be coordinated by ground control with the local controller, increasing the complexity of the operation and exposure to runway incursions.


Airborne: 45 minutes possible / Departure: 45 minutes possible

With a GDP in place as described below, arrival delays could exceed 45 minutes. Departures delays could also exceed 45 minutes due to required holding and probable gatehold due to the one-in-one-out restriction.

FAA Traffic Management Initiatives

A ground delay program for arrivals is expected on Nov. 7 and 8.

SFO will be requesting a ground delay program with an arrival rate of 33 per hour in VFR conditions, 30 for IFR conditions, for the Saturday and Sunday of the closure.

SFO plans to use Runway 28R for all arrivals, and keep Runway 28L open for departures that cannot accept Runways 01, and for staging of aircraft waiting to get through the one-in-one-out restricted area.

Oakland Center will work collaboratively with SFO tower, TRACON, ATC Command Center and stakeholders to minimize delays to the maximum extent possible.