A passenger spoke up about a wrench stuck in the wing moments before take off.

By Jordi Lippe and Jordi Lippe-McGraw
March 17, 2016
UIG via Getty Images

Moments before an easyJet flight was set to take off, a passenger noticed a wrench stuck in the wing. After reporting it to airline personnel, the plane to turned back, preventing a potential disaster.

The 25-year-old Swiss passenger known only as Christophe told French news site 20 minutes, that he “realized straight away that what I was seeing was not normal.” Flight EZS1465, which was already on the runway, returned to the terminal where the tool was removed. The flight took off an hour later.

An aviation expert told the site that the tool could have caused some serious problems if it got knocked off by vibrations and hit another aircraft.

In fact, a similar scenario likely caused the fatal Concorde crash in July 2000, which killed 113 people. In that incident a strip of metal from another plane fell onto the Charles de Gaulle runway and punctured the jet’s tire, causing rubber fragments to hit a fuel tank and sent the plane speeding into a hotel several miles away.

As for this instance, the airline says it “has launched an immediate investigation and informed the Swiss safety authorities in accordance with our procedures.”