Engineering report finds fault with zip line plans

Full findings by independent engineers released 

Staff Writer
Hawaii Tribune-Herald

The zip line tower collapse that claimed the life of construction worker Ted Callaway on Sept. 21 was “immediate and catastrophic,” according to a report by an independent engineering firm. And, it appears it may have been preventable. 

The Oct. 10 report prepared by Hawaii Engineering Group Inc. was provided to the Tribune-Herald on Monday through an open records request. It was one of many documents included in the now-closed Hawaii Police Department investigation into the fatal accident. 

In the engineering report, company President Ather R. Dar and Senior Engineer Jose Mandawe Jr. detail a site visit they performed at KaphoKine Adventures LLC’s Honolii Mountain Outpost course in Paukaa. 

Among their observations, the engineers noted “several atypical things” having to do with the hand-drawn construction plans stamped by Hawaii-licensed architect William Foulk. 

“The drawings have … no general notes, no construction notes, no civil or structural notes, no material specifications, no notes referencing any environmental Best Management Practices (BMPs) for construction, no notes directing the contractor how to proceed in the event of the discovery of architectural or archaeologically significant artifacts during construction, and no notes directing the contractor on the recommended sequencing of the structural work involved,” the report reads. “There are no notes referencing any site-specific geotechnical conditions, no notes summarizing the design data (e.g., code-prescribed wind and/or seismic parameters) and design criteria …” 

The report also says that while the drawings showed guy wires, which are used to stabilize the zip line platforms, the plans contained no information regarding tensioning, no ground anchor locations, no required anchorage method and no criteria for testing the guy wire anchors. The report adds that “The drawings have approval stamps from the Hawaii Fire Department, the State of Hawaii Department of Health, and the County of Hawaii Planning Department.” 

The engineers conclude that “the mode of failure appears to be failure of the guy wire ground anchors at the rear of the platform that were installed to resist the pulling forces due to the zip line cables at the front of the platform.” They added that “interestingly, these failed cable anchors — and the guy wire cables themselves — are not shown or mentioned on the approved construction drawings. Yet it is our understanding that they are installed on every single platform at all eight platform locations.” 

Hawaii Engineering Group’s assessment lends even more support to the idea that the collapse was caused by a perfect storm of bad weather causing muddy soil conditions, compounded by errors in the planning or construction of the platform. 

Hawaii County Police lead investigator Detective Wendall Carter, incomplete excerpts of whose report were received by the Tribune-Herald in late February, zeroed in on inconsistencies between how the platform was built and how it had been planned while visiting the site shortly after the accident. Among his observations, he discovered that the zip line platform’s support poles had apparently been sunk 5 feet in the ground, instead of the 7.5 feet detailed in the plans. 

“This was evident due to the fact that the dirt line on the utility pole stopped at approximately 5 feet,” he wrote. 

Additionally, he said, cinder appeared to have been used to fill in the tops of the holes around the base of the poles, instead of “compacted base course material,” as called for in the plans. He noted that “the area appeared very muddy and the anchors in the ground could not support the force of the tension of the cable affixed to the tower,” according to a search warrant request approved by Third Circuit District Court Judge Harry P. Freitas. 

In a later visit to the site, Carter was joined by County Department of Public Works Director Warren Lee, who also concluded that the anchors giving way were the cause for the collapse of the 30-foot tower after seeing “two 12-foot long auger anchors” that had been pulled out of the ground, Carter reported. 

While the police have closed their investigation into the accident, the Hawaii Occupational Safety and Health Division has decided to extend its own investigation into the accident, according to Bill Kunstman, a spokesman for the Department of Labor and Industrial Relations. Kunstman had said in early March that the investigation would be complete no later than March 21. 

“Obviously we’ve gone past March 21,” he wrote Saturday in an emailed response to questions about whether any citations would be issued as a result of the incident. “Retired Administrator has counseled to go past the suggested deadline in order to make investigation more complete. As of yesterday, they still were not able to give me a timetable on issuance of the citations.” 

Click here for a PDF of the original newspaper pages.

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