The loose manhole cover that caused two red flags during second practice at the Las Vegas Grand Prix has been welded in place to avoid a repeat on qualifying day or during Saturday's race.
A marshal alerted the FIA's race control to apparent movement from the manhole cover ahead of Turn 17 during Thursday's second practice session, and a red flag was flown to allow race control to inspect the site.
Track action restarted 15 minutes later but was suspended again when more movement from the manhole cover was observed, with the session eventually timing out under the red flag.
The FIA carried out further inspections overnight and discovered a fault with the cover before opting to take additional precautions by welding it shut along with 14 other manhole assemblies around the circuit.
"The manhole that prompted the red flag in FP2 was disassembled and further inspected," an FIA statement said ahead of the final practice session on Friday. "A specific fault was found with the closure mechanism, and it was possible to address this issue overnight.
"In addition to the work conducted to address the issue identified, the cover of this manhole has been welded to provide further mitigation. All other manhole covers on or close to the racing line were reinspected overnight, and additional welding was applied to a further 14 manhole assemblies."
Thursday's stoppages evoked memories of a similar incident at the inaugural Las Vegas Grand Prix two years ago when a smaller valve cover came loose on The Strip and damaged the underside of Carlos Sainz's Ferrari.
The 2023 incident resulted in the first practice session ending early and second practice being delayed until the early hours of the following day.
Loose drain covers have occurred at a number of street circuits in the past and tend to be caused by the forces generated by the underside of F1 cars, which are designed to generate low pressure and suck the car to the track.
The final practice session for the Las Vegas Grand Prix gets underway at 4:30 p.m. local before qualifying takes place at 8 p.m.