A United Airlines Holdings Inc. (UAL  ) flight reportedly returned to Bradley International Airport in Connecticut after losing part of an engine liner, adding to a series of mishaps this year that have placed the airline under regulatory scrutiny.

The Airbus SE (EADSY  ) A320 aircraft, en route to Denver International Airport, experienced abnormal noise shortly after departure, according to a Federal Aviation Administration (FAA) statement, reported Bloomberg.

United confirmed that a piece of a sound-dampening outer liner was found on the runway post-landing. No injuries were reported, and the FAA is investigating the cause, per the report.

United Airlines' safety procedures have been under review by the FAA following several incidents, including parts of the fuselage coming loose in flight and a wheel detaching during takeoff.

The entire U.S. aviation industry has faced increased scrutiny since January, when an Alaska Air Group Inc (ALK  ) flight experienced a similar issue.

The affected Airbus A320, which is 22 years old, shed several pieces of sheet metal during takeoff. Additional debris was found after the aircraft landed. A nearby JetBlue Airways Corp. (JBLU  ) plane initially reported the debris, leading to some runway diversions.

The United pilot declared an emergency after noticing the engine's exhaust gas temperatures slightly exceeded normal levels, suspecting either a bird strike or a blown tire.

Despite this, the flight, carrying 124 passengers and five crew members, landed safely and taxied to the gate without further issues.

The FAA's examination has temporarily limited United's certification activities, impacting its growth. However, United CEO Scott Kirby has expressed support for the FAA review, viewing it as an opportunity to enhance safety measures.

United Airlines stock has lost over 7% in the last 12 months. Investors can gain access to the stock via U.S. Global Jets ETF (JETS  ) and IShares U.S. Transportation ETF (IYT  ).

Price Action: UAL shares are trading lower by 0.12% at $48.84 in premarket at last check Friday.