What About Extending Runway 12R/30L North? Scenario 11

Could an extra 36 feet in building height in both the downtown and the Diridon Station Areas be gained without changing current One Engine Inoperative procedures Norman Y. Mineta, San Jose International Airport?

By extending runway 12R/30L over De La Cruz Boulevard into the current FAA VOR antenna field, it looks like the runway could begin 1,360 feet to the north of its current start point. At a 37.5:1 (1-foot elevation for every 37.5 feet in the horizontal direction), this would yield the 36 feet gain, across the board with current OEI.

In the documentation provided by the Airport, the only reference to extending the runway was provided in this slide in a May 2018 presentation. There was no explanation of what had been examined in this so-called Scenario.

Scenario 11 from the May 2018 Report
Scenario 11 from the May 2018 Report

Perhaps, the slide that should have been created is below, which depicts a runway and taxiway extending over De La Cruz Avenue to the field where the FAA’s antenna field is. At some point in the not-too-distant future, the FAA plans on decommissioning that obsolete radio facility, freeing up the land for other uses (within bounds of airspace restrictions), such as a runway extension.

Extension Idea

Would extending the runway necessitate an extension beyond the freeway, etc.?

Hopefully not, as the extended part of the runway (on the north side of De La Cruz) would only be used for take-offs. Page 3-13 of the Comprehensive Land Use Plan for Santa Clara County indicates that there must be a runway protection zone.[1]

“At this airport the RPZ [Runway Protection Zone] as adopted by the airport and the FAA, begins 200 feet out from the runway’s displaced landing thresholds (not the pavement ends). It is a trapezoidal area centered on the extended runway centerline. The size is related to the expected aircraft use and the visibility minimums for that particular runway.”

There is no reason that a longer runway would need to change the displaced landing thresholds.

Would the Investment Be Worth It?

The question is how much would it cost to extend the runway and taxiway over De La Cruz? The documentation provided by the airport doesn’t show any analysis of estimated costs to extend the runway, so we don’t know if this idea was dismissed from a cost-benefit or a technical standpoint.

Although it didn’t make the cost-benefit analysis cut in the study, a net gain of 35 feet would provide greater benefit from a downtown height perspective than any of the scenarios, including the Airport’s recommended Scenario 4. Taken by itself, there would be some gain in the Diridon Station Area as well. If combined with a Scenario 10b, it would allow building heights of 69 to 93 feet taller than today in the Diridon Station Area, which starts to approach height increases suggested by Scenario 4.

If combined with Scenarios 10b it’s reasonable to assume gains for a runway extension to be somewhere between the $438M to $747M of Scenario 10b and Scenario 4, respectively. As pointed out here, the net gains for Scenario 4 would be $26 to $203 lower due to negative economic impact to the airport, which wouldn’t occur with a combined runway extension/Scenario 10b.

But there would be a big upfront construction investment. How much would that cost? That’s a good question and something that should have been addressed by the OEI study.

In the absence of data from the 2018 OEI study, Maui’s airport can be a proxy as it faces a similar dilemma in terms of departures and is planning a runway extension:[2]

“The runway extension, projected to cost $96 million and built by 2021, would allow planes such as the Boeing 737-800 and 777-200 to take off at maximum weight for cities such as Chicago, Dallas and Denver, the plan said. Currently, those flights have to take off with reduced fuel that requires a stop in Honolulu to refuel before heading to the Mainland.”

This 1,500-foot runway extension runs into a road and they are looking at building a tunnel for the road, but they don’t provide an estimate for that cost. Using Caltrans estimates of $500/square foot, the cost of a 150’x1,500’ underpass would be approximately $112.5M.[3] Assuming costs similar to the Maui example of $96M for extending the runway 1,500’, the total cost would be $208M ($112M+96M).

Rounding up to 250M for engineering costs, etc. and applying a cost of financing of 6% over 30 years, would result in a payment of $1.8M per month.[4] Assuming the Airport bore all this cost (no FAA Grants, no value capture from increased heights downtown) and assuming a continued growth to 21.8M passengers (approximate passenger projection by 2038), then the cost per passenger would be approximately $1, which, when added to existing costs, would still be less than SFO and continue to be competitive with OAK’s rates.

Although the above back-of-the-envelope financial analysis assumes that SJC shoulders all the costs, it doesn’t include the gains from being able to continue to market SJC as the international airport in the heart of Silicon Valley.

[1] See https://www.sccgov.org/sites/dpd/DocsForms/Documents/ALUC_SJC_CLUP.pdf and Appendix A for a map showing the runway protection zones.

[2] See http://www.mauinews.com/news/local-news/2017/02/a-longer-main-runway-is-part-of-master-plan-for-kahului-airport/

[3] Costs of Caltrans bridge http://www.dot.ca.gov/hq/esc/estimates/COMP_BR_COSTS_2016-eng.pdf Here is the cost of a couple of different underpasses in southern California http://media.metro.net/projects_studies/regionalrail/PS2415-3420_AlternativesDevelopmentReport_2016-0126.pdf

[4] This website used for calculations http://www.municapital.com/payment-calculator.html

Appendix A – SJC Runway Protection Zones

Runway Protection Zone

Appendix B – Examples of Airports With Runways Over Roads

Nashville

Atlanta

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