Light rainfall over the weekend led to significant cracking and crumbling on part of the main runway at Charles M. Schulz Sonoma County Airport, forcing airport officials to temporarily close the airstrip Sunday for a quick patch.
It was the latest case this year of runway deterioration requiring an emergency fix — a pattern that officials have described as routine but which some airport safety employees say should be cause for alarm.
The new repair, completed Sunday afternoon, took about 15 minutes, said Johannes Hoevertsz, director of the county’s public infrastructure department, which oversees the airport. Two of the three main airlines operating out of the airport, Avelo Airlines and Alaska Airlines, said they were notified of the work and it did not impact their flights.
It’s at least the fourth temporary runway fix that airport officials have been forced to make this year. Airport employees responsible for inspecting the runway have been documenting its deteriorating condition since last August, according to a Press Democrat investigation of failing runway conditions that published in April.
Meanwhile, the Federal Aviation Administration is investigating the airport over a June whistleblower allegation that the airport lacks sufficient fire and rescue staff to respond to aircraft emergencies. The Board of Supervisors on Tuesday is set to discuss a related proposal to add two new airport operations specialists.
As with other emergency runway repairs made earlier this year, airport officials Sunday downplayed the seriousness of the latest required patchwork. Hoevertsz said more concerning was a separate incident Sunday morning involving a man who sneaked onto the airfield and tried to steal a private plane.
“It's funny, because at least for us, it's just another day at the airport,” he said. “The maintenance stuff is not a big deal.”
The damaged area measured 3 feet by 3 feet and two-and-a-half inches deep, said Hoevertsz. He insisted it was not a hole.
“There's no pothole,” Hoevertsz said. “We have delamination of the top layer of asphalt.”
The problems developed after less than a quarter-inch of rain fell Saturday into early Sunday at the airport, marking the first notable precipitation in months.
Crews used universal patching material in the most affected area. It was part of a wider stretch of runway with damage called alligator cracking that airport employees had already been monitoring, Hoevertsz said.
It has been about five months since the appearance of sinkholes and voids on the main runway required crews to make three rounds of emergency repairs overnight.
That work was done on the north end of the runway where pavement was breaking down around an 84-year-old culvert, installed at the start of World War II. It had begun buckling on the inside and collapsing in places where it crossed under the runway.
The county described the deteriorating pavement as a “limited section of degraded pavement with some depressions and separations,” and some officials denied there was a hole on the runway. Photos obtained later by The Press Democrat through a public records request clearly showed a large hole on the runway’s surface May 30 — discovered 12 minutes after the last commercial flight of the day landed on the main runway.
The failing culvert was replaced in late June. Crews at that time also had to make repairs on the south end of the runway where a concrete-encased electrical conduit running underneath had caused the surrounding pavement to settle and collect water.
Timeline of failing runway pavement at the Charles M. Schulz-Sonoma County Airport * On Dec. 10, 2022, airport operations specialist notice standing water on the south end of Runway 14/32, caused a by concrete-encased electrical conduit that runs across the runway, according to internal airport emails. * On Jan. 6, 2023, a senior airport operations specialist sends an email to airport officials alerting them that the main runway pavement near the electrical conduit was “starting (to) fail,” and that the area had “gone downhill fast!” * On Aug. 22, 2023, airport staff report that “depressions” have formed on the runway, which were being flagged by general aviation pilots, according to an internal airport email. * In September 2023, airport officials send a robotic camera-equipped crawler through the culvert. The camera is able to pass all the way through the culvert underneath Runway 14/32. * On Dec. 7, 2023, a senior airport operations specialist emails airport officials that the pavement near the culvert is “degrading faster than anticipated … and it really hasn’t started raining yet.” * On Jan. 12, 2024, a safety inspector with the Federal Aviation Administration conducting an annual inspection orders repairs on runway pavement above the culvert, to be completed by June 1. The airport later gets an extension of a few weeks. * On March 15, 2024, the day after The Press Democrat’s interview with Airport Manager Jon Stout and County Infrastructure Director Johannes Hoevertsz regarding runway problems, the county issues a news release announcing planned repairs on the runway. County officials describe the airport’s response to the FAA’s findings as “proactive.” * Sometime in late March or early April, airport officials again deploy a mobile camera through the 84-year-old culvert. Corrosion is detected but officials said they’re able to get the mobile camera through the entire length of the culvert under the runway. * On May 30, a Thursday, the runway is shut down for 16 hours, starting at 10:30 p.m. to 2 p.m. the next day, as airport officials scramble to get construction crews out to repair a basketball-sized sinkhole and uneven pavement on the northern end of the runway above the culvert. Ground penetrating radar is used and other anomalies are detected. * On June 3, between 10:30 and 11 p.m., another sinkhole is detected after airport staff conduct a “deflection test” by driving a truck over the culvert. The runway is shut down and the hole is patched. Plans are made to execute a more extensive repair the following evening. * On June 4, the runway is closed by 10:30 p.m. to allow, construction crews to conduct the most extensive emergency repair on deteriorating runway above the failing culvert. The work, combined with previous repairs, involves filling voids or cavities in the ground with slurry, leaving a patch of concrete more than 100 feet above the culvert. Crews finish work by 2:30 a.m. June 5. * June 24-25: The runway is closed for roughly 20 hours to allow a full replacement of the failing culvert. Uneven pavement on the southern end of the runway also is addressed. The cost of repairs is expected to total $667,115. * Oct. 13: Cracking and “delamination” in an area of the main runway forces temporary patchwork, with plans for more extensive repairs later in the week.
Sunday’s damage was in a new area of the runway, just south of the airport terminal, airport officials said.
The area is a high-impact spot where the rear wheels of planes touch down, according to Hoevertsz.
When the culvert was failing, the airport used ground penetrating radar to asses the integrity of the runway’s deeper infrastructure and during that process identified voids that were not apparent on the runway’s surface.
The airport has not used the radar to assess the ground beneath the new alligator cracking, Hoevertsz said.
“There's no signs of voids under this pavement,” he said, explaining the process for Sunday’s repairs. “We opened it up, cleaned it and we went down to the next pavement section and it showed no cracks,” Hoevertsz said.
The runway was last repaved in 2001. In 2014, a $55 million project added new pavement on the north end of the main runway but only seal-cracked the rest of the strip, making the majority of the runway surface 22 years old.
The standard life span for runways designed to meet federal aviation guidelines is 20 years.
Airport Manager Jon Stout is talking with the FAA about a larger $42 million runway repaving project expected to roll out in 2028.
Until that repaving project is launched, airport officials will continue with temporary fixes. With coordinated monitoring and maintenance, airport officials have estimated they can extend the runway’s life by 10 years, Stout said in an email to The Press Democrat earlier this year.
Airport officials are planning to address the larger alligator-cracked area with a more lasting repair before the winter rain arrives. That work is expected to be carried out by the end of the week and will require one to two-and-a-half hours of work to be completed at night, Stout said.
“The only urgency that we have (is) that we do the work before it rains a lot, but it's not unsafe,” Hoevertsz said.
You can reach Staff Writer Emma Murphy at 707-521-5228 or [email protected]. On Twitter @MurphReports.
You can reach Staff Writer Martin Espinoza at 707-521-5213 or [email protected]. On Twitter @pressreno.
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