Dear Mayor and Council Members,
On behalf of City Manager Ed Shikada, please see the staff responses below for questions received for the Monday, December 1 Council Meeting.
Item 12. Approval of Seven Items to Support the Automated Weather Observation System Project, AP-19000, at Palo Alto Airport.
Question from Mayor Lauing:
1. One question I got from a resident concerned with increasing PA aircraft from the new weather gear is whether we can, in the future, turn off the evening hours of weather data if we DO get a huge influx of planes adding noise to the sky at night. It is a good question. I presume we track landings, and if there is no increase then everyone is happy NOW because there is a future “shut off valve” if their worries turn out to be true. And that possibility is unlikely.
Staff Response: The Airport has a entered into a contract with 1200.Aero to track flights that use the airport and would be able to provide data for nighttime operations in the future. However, the AWOS is funded through FAA grants and categorized as an air navigation facility. It must be operated and made available on a nondiscriminatory basis, consistent with the FAA’s grant assurances. The AWOS is capable of operating 24/7. Were the City to selectively limit its operation to certain hours, such as shutting it off at night, such an action could be interpreted as restricting access to weather information for certain pilots or types of operations, which would conflict with the requirement that federally funded facilities be equally available to all users of the National Airspace System. If the purpose of disabling the AWOS during certain hours is to limit nighttime operations, then such an action would be subject to FAA approval under the Airport Noise and Capacity Act of 1990. The City cannot disable facilities for the purpose of restricting flights without FAA approval, and staff believes FAA will not provide such approval in this instance.
These questions were sent to the Council by community members with an interest in the Airport. Given the depth and breadth of the questions and to expedite their handling, staff is treating them as Councilmember consent questions and distributing the answers to the Council and publicly:
1. 5 ft Tower Increase (25ft to 30ft)
At the November 13 meeting, staff stated that the airport tower height would increase by 5 feet. Since this change was not identified in the Council packet, please explain the reason for the height increase given that the project was presented as a replacement rather than a modification, which elements this is associated with e.g. FAA-required PAPI and REIL, what are the associated costs, and identify any other changes to the tower beyond height, including what specific functions these changes are intended to support.
Staff Response: This project involves updating existing facilities at the airport. The existing system is beyond its serviceable life and is being replaced with equipment that meets current FAA design and installation standards. FAA guidance specifies that the nominal height for a wind sensor is 30 feet above ground level, which accounts for the 5-foot increase in tower height. This change reflects compliance with FAA siting and performance standards and not an enhancement of capabilities.
2. Dark-Sky Ordinance Alignment and Lighting Flexibility
Given that the FAA requires the replacement of PAPI and REIL lighting systems, the airport must conform to the FAA standards and specifications. However, FAA guidance allows some flexibility in how PAPI and REIL lighting is implemented.
• Please explain what flexibility PAO has in terms of PAPI and REIL lights configuration, hours of operation, and nighttime lighting intensity. FAA guidance allows options such as reduced nighttime brightness or limiting the hours these systems operate under defined FAA conditions. • Please explain what considerations, if any, were given to the City’s emerging dark-sky goals, which emphasize reducing unnecessary brightness, glare, and nighttime spillover.2. Lighting Ordinance Update / Lighting Considerations
Staff Response: The project is replacing existing PAPIs and REILs that currently operate 24/7 and are designed to meet FAA requirements. The PAPIs will be equipped
with photoelectric control that dims the lights at night, and the REILs will have intensity settings to ensure that they are not too dim during the day and not too bright during the night.
With respect to the City’s Lighting Ordinance update goals scheduled for City Council hearing on December 8, 2025, staff considered the intent of the ordinance during the design process, and the same principles informed staff input during preparation of the draft lighting ordinance to be considered by Council on December 8. The project does not introduce new lighting where none previously existed, and the lighting associated with the PAPI and REIL systems is required for aviation safety. As such, the project does not conflict with existing or future municipal lighting policies and does not introduce unnecessary brightness, glare, or nighttime illumination beyond established FAA standards.
3. Replacement Framing Versus Introduction of New Capabilities
The overall project has been presented as a replacement of existing equipment that will enhance safety and efficiency. However, the construction bid structure shows a Base Bid that combines shared infrastructure for all the elements and a separate bid line for AWOS, in contrast to the PAPI and REIL replacements, which are the only FAA-required components. The existence of a discrete AWOS bid line reinforces that AWOS is not a like-for-like replacement of existing equipment, but rather the introduction of a new capability.
While the report clearly describes that AWOS will provide 24-hour automated weather reporting that does not exist today, it does not explain how this expanded capability fits within the project’s framing as “replacement” under NEPA and CEQA. Nor does it substantiate with data the claim that introducing a 24x7 automated weather information system will not increase the number of operations overall including during nighttime and early morning.
To clarify how AWOS fits within the project classification and its operational implications, please address the following:
• How is the introduction of new 24-hour AWOS capability consistent with the project being described as a replacement under NEPA and CEQA? • Given that the project was positioned as increasing safety, please state whether any safety analysis or supporting documentation exists that identifies the incremental safety benefits of the proposed AWOS-III PT relative to its associated costs.
Staff Response: The project replaces aging airfield facilities with modern technology that provides more accurate and reliable operational information. FAA guidance and national aviation standards support AWOS as the current industry baseline for weather dissemination and airport reporting. Because AWOS is a proven, standard technology deployed widely at general aviation airports, no PAO-specific analytical study was prepared beyond FAA standard criteria. The objective is to provide pilots with accurate real-time weather information to support safe decision-making at the Palo Alto Airport, rather than introduce new operational capacity.
4. Project Cost Transparency and Allocation of Discretionary AWOS versus FAA Required Elements
The report presents the total project cost and funding sources as a combined amount for the AWOS, PAPI, and REIL elements. It also provides separate construction bid amounts for the PAPI equipment, the REILs, and the AWOS.
However, the Base Bid is described as including shared infrastructure for all three elements, such as trenching, conduit, electrical upgrades, and related work, and the report does not indicate how those shared costs are allocated among AWOS, PAPIs, and REILs. The same is true for consultant, engineering, environmental, and administrative costs, which are presented only as aggregate projectwide amounts with no breakdown by element. Furthermore, the packet does not provide any information about the ongoing maintenance costs for each of the AWOS, PAPIs, or REILs, nor does it identify the source of funding for those maintenance obligations.
The report states that PAPI and REIL are required by FAA, but it does not indicate whether AWOS is required or discretionary. It is our understanding that the AWOS element is discretionary. For transparency and to understand the necessity and scale of the discretionary AWOS element, please provide separate cost allocations for AWOS, PAPIs, and REILs including how the shared construction costs in the Base Bid are divided among the three elements, how consultant, engineering, environmental, and administrative costs are allocated across these components, and what the ongoing maintenance costs are for each element and the source of funding for those maintenance costs. In addition, please clarify whether AWOS is FAA required, discretionary, or partially discretionary.
Staff Response: The project has always been considered a single integrated safety project. For this reason, design, electrical distribution, trenching, conduit, and environmental review apply to the project as a whole and cannot be cleanly separated by subsystem. The FAA advised that the project be bid in discrete segments because
federal funding availability may vary by component and fiscal year. Based on preliminary engineering estimates:
• Burns & McDonnell estimated Construction Administration at $55,000 for PAPI/REIL and $30,000 for AWOS.
• C&S Engineers estimated Construction Management at approximately $232,000 for each portion.
Their increased cost on the AWOS portion reflected additional FAA coordination requirements.
Maintenance is funded through the Airport Enterprise Fund — already used to maintain PAPI and REIL systems. Because existing PAPIs and REILs are failing and require frequent service, maintenance costs are expected to decrease with the modernized systems. AWOS maintenance will similarly be funded by Airport enterprise revenues, not the City’s General Fund.
5. Were Alternatives to AWOS level III PT Considered
The AWOS level III PT on a new foundation is proposed in the packet.
What criteria were used to select AWOS III PT (P indicates a sensor to detect the type of precipitation; T indicates a sensor to detect thunderstorm and lightning within a typical range of 30 nautical miles of an airport)?
Why does PAO need to know the type of precipitation (rain vs snow) or detect thunderstorms and lightning miles away given that information is often available on weather apps and AWOS systems available at nearby airports).
Did the airport consider other alternatives such as fix the out-of-service ceilometer in the current weather system, install AWOS level I or AWOS level II or AWOS level III or AWOS level III P, given that the cost varies widely across these alternatives (AWOS implementations can cost range from $20,000 to $500,000).
Please share the alternatives to AWOS level III PT on a new foundation that were considered including the relative costs of the alternatives and the criteria that were used to reject an alternative.
Staff Response: The selection of the AWOS III PT configuration was based on FAA siting guidance, operational needs at PAO, and consultation with FAA technical staff.
AWOS III PT provides the most complete and reliable weather dataset for safe pilot decision-making during varying conditions. While information such as lightning or
precipitation type can be accessed from remote applications, FAA-supported AWOS systems provide standardized, certified weather readings that pilots can safely and legally rely upon during operations. Other system levels were initially reviewed, but FAA consultation determined that AWOS III PT best meets current technical and regulatory expectations for accuracy, data quality, and redundancy. Because the project qualified for a categorical exclusion under NEPA and CEQA, a formal alternatives review process was not required.
6. Claim That PAO Operations Will Not Increase
The community’s concern has consistently focused on the potential for AWOS to increase the number of operations at PAO overall, including during nighttime and early morning hours. The packet, however, cites an example that is framed in terms of overflights, not operations. It states that pilots “noted that overflights of the City could potentially be reduced, because aircraft will not need to fly the approach into San Carlos Airport, but could fly directly to Palo Alto Airport.
If aircraft that would have overflown Palo Alto en route to SQL instead fly directly to PAO and land, this does not reduce operations. It increases them. Any aircraft that lands at PAO instead of SQL adds two PAO operations, one landing and one eventual takeoff. As a result, the example given in the packet reinforces, rather than reduces, the community’s concern about increased operations at PAO.
In addition, the suggestion that AWOS could reduce overflights appears overstated. Only SQL-bound traffic arriving from the south may overfly Palo Alto.
SQL-bound traffic from the north does not need to overfly the City because SQL is located eight miles north of Palo Alto, and east-west routes rarely overfly the City at all. The net effect of 24-hour AWOS on overflights is therefore neutral at best.
Given this, please correct the language in the packet to reflect that the community’s concern pertains to the number of operations at PAO, and that the example provided in the packet would actually increase the number of operations at PAO, not decrease them.
Staff Response: The example in the staff report was intended to illustrate that pilots already fly at night into the Palo Alto Airport. Currently, some aircraft approach Palo Alto using data from other airports and then divert to PAO when visual conditions allow.
Because weather at PAO can differ from Moffett Field or San Carlos, AWOS enables earlier “go/no-go” decision-making. Several pilots have stated that when real-time PAO
weather indicates conditions are unsuitable, they would delay flying rather than attempt an approach. This reinforces that AWOS provides safety and predictability to existing operations rather than enabling additional ones.
7. CATEX Document Discrepancies
Operations Forecast: Please explain why the City marked “No” on the question “Does the forecast of operations exceeding 90,000 annual propeller operations, 700 annual jet operations or 10 daily helicopter operations or a combination of the above?” given that annual operations have greatly exceeded that number since at least 2004. On average, PAO experienced 152,525 operations per year since 2014 when the City took over the airport.
Source: document C1_1925EmbarcaderoRdAPPLY.pdf
Source: PAO Noise Report 2023 (most recent publication of PAO Noise Report)
Light Emissions:
Please explain why the City marked “No” on the question “Will the proposed project produce light emissions impacts” given that replacing PAPI and REIL lights, and possibly adding lights to the apron, will produce light emissions. The question was not about producing additional light emissions. It was about producing light emissions.
Please specify any difference in lights between today’s environment and when the project would be completed:
Clarify whether the old PAPI and REIL lights were incandescent and are being replaced with LED lights. If that is the case, please explain whether there will be more light emissions than previously given that LED lights are typically brighter than incandescent lights.
Explain whether the new PAPI and REIL lights will be exactly at the same location as the old PAPI and REIL lights (we believe that this was mentioned in the November 13 Zoom meeting). If not, please describe the changes in the locations. .
Staff Response: It is important to understand that the purpose of the CatEx checklist is to analyze potential impacts from the project, not the baseline condition. Therefore, all of the questions relate to environmental impacts of the project. Although the environmental consultant could have marked “Yes” for the question regarding projected operations exceeding threshold values and then explained that an analysis is not required, they marked “No” because the installation of AWOS does not increase airport capacity or change permitted operations. The question requires noise analysis if operations are above the specified levels and if the project would result in a change in operations. Because no change in operations is anticipated due to AWOS, no noise analysis was required.
The same analysis applies regarding lighting since the project will not change existing lighting conditions at the Airport:
• The existing REIL and PAPI units are incandescent.
• They are being replaced with FAA-compliant LED units in equivalent locations. • While LED fixtures may appear visually sharper, they are engineered to meet FAA photometric requirements.
• The PAPIs are being relocated to the opposite side of the runway due to FAA visibility criteria — aircraft positioned on the taxiway can obstruct the light path, and relocation ensures proper pilot visibility during approach.
8. AWOS and Grant Assurances
In the December 1, 2025 Council packet, staff stated that “due to federal grant assurances and the AWOS project’s function as a safety facility,” the City would not be able to operate the system on anything other than a 24-hour basis. In FAA documentation, however, AWOS is defined as an air navigation facility (Advisory Circular 150/5220-16E), not a safety facility. After reviewing the grant assurances that were shared with us, we did not see language requiring continuous, 24-hour operation of an AWOS or prohibiting defined operating hours for specific equipment.
FAA Grant Assurances 19 and 22 require the City to operate and maintain federally funded facilities in a safe, serviceable, and nondiscriminatory manner. They do not mandate that an AWOS operate 24 hours per day. As an air navigation and weather reporting facility, AWOS may be operated on defined hours so long as it is properly maintained, accurately published, and available to all users on equal terms. PAO’s FAA-funded control tower also does not operate 24 hours per day, which demonstrates that federally funded aviation facilities are not required to run continuously as long as they are safely maintained and their published hours accurately reflect availability.
Given the differing definitions of AWOS used by the City and the FAA, and because this question involves interpretation of federal grant assurances, we request that the City’s aviation attorney review whether defined hours of AWOS operation would be consistent with the Grant Assurances when AWOS is correctly understood as an air navigation facility. If 24-hour operation of AWOS is believed to be required by FAA regulation or by the grant assurances, please provide the specific FAA citation or grant assurance language that establishes that requirement.
Staff Response: Staff consulted with the City’s aviation attorney to provide additional information on the relationship between grant assurances and hours of operation. An air navigational facility is defined as “any facility that aids in air navigation…having a similar purpose of guiding or controlling flight or the landing or takeoff of aircraft.” This broad definition includes a variety of critical components, such as landing areas, lights,
communication equipment for disseminating weather information, signaling, radio- directional finding, and any other structure for guiding or controlling flight. All air navigation facilities have at least some safety function.
The intrinsic link to safety is that these facilities form the foundational infrastructure of the entire National Airspace System, providing the essential guidance and control that ensures the safe and efficient use of navigable airspace. Traditional systems, such as PAPIs and REILs, provide positional and directional guidance to keep aircraft safely separated and on course. In this manner, these systems provide both safety and navigational benefits.
An AWOS enhances safety in a different and complementary way: rather than telling a pilot where the aircraft is, it tells the pilot whether conditions are safe in a particular location. Continuous, real-time, location-specific weather reporting allows pilots to make safer approach and landing decisions, particularly in rapidly changing conditions.
In areas like the San Francisco Bay Area, weather is not only variable by time but also highly variable by location so precise weather data for the runway is critical for air navigation safety. For instance, instead of relying on weather readings from another airport several miles away—which may not accurately reflect conditions at Palo Alto— pilots will receive precise, on-field measurements of wind speed, visibility, cloud ceiling, and temperature. This enables pilots to assess conditions before committing to an approach, reducing the risk of unexpected weather deterioration, go-arounds, or unstable approaches or other safety compromises. Inaccurate weather information is one of the key causes of aircraft accidents.
Because the AWOS is funded through FAA grants and categorized as an air navigation facility, it must be operated and made available on a nondiscriminatory basis, consistent with the FAA’s grant assurances as pointed out in your letter. The AWOS is capable of operating 24/7. Were the City to selectively limit its operation to certain hours, such as shutting it off at night, such an action could be interpreted as restricting access to weather information for certain pilots or types of operations, which would conflict with the requirement that federally funded facilities be equally available to all users of the National Airspace System. If the purpose of disabling the AWOS during certain hours is to limit nighttime operations, then such an action would be subject to FAA approval under the Airport Noise and Capacity Act of 1990. The City cannot disable facilities for the purpose of restricting flights without FAA approval, and we believe that the FAA will not provide such approval in this instance.
9. Additional Lights on the Apron?
The tower height increase is covered in 1.0 above. At the November 13 meeting some pilots mentioned adding more lights on the apron.
If applicable, please clarify the purpose and benefit of any proposed apron lighting changes, whether they are FAA required or discretionary, and whether they are required to support any of the project elements. If discretionary, please explain the rationale and provide the associated cost allocation.
In addition, please identify any other project elements or modifications that have not been mentioned previously.
Staff Response: No new apron lighting is being installed as part of this project. The scope of work involves only replacement or relocation of existing systems, not expansion of lighting infrastructure or intensification of light coverage.
10. Contract Extension
Please confirm that the current consultant contracts could be extended beyond December 31, 2025, which is the current expiration date. However, the FAA permits contract extensions beyond five years when the original project was included in the Airport Capital Improvement Plan. Staff stated in the packet that this project meets that condition and therefore qualifies for an extension.
Staff Response: Yes, staff has confirmed that the consultant contracts may be extended beyond their original term because the project appears in the approved Airport Capital Improvement Plan. FAA policy allows service extensions when a project was previously included in the ACIP.