Passengers recount midair terror before emergency landing: 'We're

An American Airlines jet bound for Philadelphia never made it out of Missouri airspace on Oct. 17, turning back to St. Louis Lambert International Airport after travelers reported an unsettling odor and violent motion in the cabin. The unscheduled return has drawn attention from aviation specialists, who say contaminated air supplies are a known — if uncommon — culprit behind such incidents.

Expert Points to Engine Oil as Possible Cause

Gary Leff, a Texas-based aviation analyst who runs the blog "View from the Wing," told Fox News Digital that oil from an engine seeping into an aircraft's ventilation system might account for the smell. He stressed, however, that investigators have not established what happened. "When that happens, you can get smoke, you can get vibration, you can get loud noises. It can also wind up making people ill," Leff said. Tracking data from FlightAware reviewed by Fox News Digital indicated the aircraft remained airborne for 34 minutes before touching down again in St. Louis. American Airlines told Fox News Digital in a statement that the flight came back to the airport soon after departure because of a reported odor on board. According to the carrier, the plane landed without incident and was pulled from service so its maintenance crew could examine it.

Passengers Describe Noise, Jolt Before Return

The trouble began even before takeoff. A couple on board — Tessa and Mark Springer of Waterloo, Illinois, who were flying to Pennsylvania for work — told local outlet First Alert 4 that they heard an alarming sound from the rear of the aircraft. The flight had already been held up roughly two hours because of a reported engine problem, according to the couple. "We heard just this really horrible noise coming from the back of the plane. It was like ... real loud buzzing, kind of [a] grinding sound," Mark Springer said. He recalled that the pilot then informed passengers of a mechanical problem. "The pilot comes back on and says, ‘Uh, there’s a problem with the engine on the airplane,’" the passenger added. "'We can’t get it started.'" Once the plane finally left the ground, the ordeal worsened. Roughly 15 minutes into the trip, those aboard felt a sharp lurch that pitched them forward, Mark Springer said. "All of a sudden, the plane just felt like it hit a ... like in a car, when you slam on your brakes. ... Everybody kind of lunges forward like this," he said. "I was like, We’re going to die." Moments later, the situation escalated further. "And then, maybe a minute later, the plane just kind of goes boom and drops. … All of the oxygen masks fall. And we just kind of looked at each other like, is this serious? Is this real?" added Mark Springer. As the aircraft banked back toward the airport, Tessa Springer told First Alert 4 she feared she would not survive.