United Flight 328 Boeing 777 Engine Failure After Departure from Denver

On February 20, 2021, United Airlines Flight 328 experienced a catastrophic engine failure shortly after departing Denver International Airport on a scheduled flight to Honolulu, Hawaii. The aircraft, a Boeing 777-200 carrying 231 passengers and 10 crewmembers, was forced to return to Denver following the failure of its right engine.

Video recorded by passengers aboard the aircraft showed the damaged engine on fire as the aircraft returned to the airport. Witnesses on the ground reported seeing debris falling from the aircraft during the event. Pieces of the engine cowling and other components fell into residential areas near Denver, including debris that damaged the cab of a pickup truck parked in a neighborhood beneath the flight path.

Accident Summary

What Happened on United Flight 328

Shortly after departing Denver International Airport on February 20, 2021, United Airlines Flight 328 experienced a catastrophic failure of its right Pratt & Whitney PW4000 engine. Passengers and observers on the ground reported seeing flames and debris coming from the engine as the aircraft continued climbing away from the airport.

The flight crew declared an emergency and returned the aircraft to Denver. During the event, portions of the engine nacelle and other components separated from the aircraft and fell into residential areas beneath the flight path. Despite the dramatic engine failure and debris field, the Boeing 777 landed safely at Denver International Airport and no injuries were reported among the 231 passengers and 10 crewmembers on board.

Aircraft and Engine Context

The aircraft involved in the incident was a Boeing 777-200 equipped with Pratt & Whitney PW4000 series turbofan engines. The Boeing 777 is a long-range widebody aircraft used extensively in international commercial airline operations.

Modern turbofan engines are designed with containment structures intended to prevent internal engine failures from damaging the aircraft or endangering persons on the ground. When a catastrophic engine failure occurs, investigators closely examine whether engine components were properly contained within the engine nacelle and whether aircraft systems performed as designed.

Accident Investigation

The National Transportation Safety Board opened an investigation into the engine failure. Investigators typically examine engine components, maintenance history, inspection procedures, and operational data recorded during the flight.

In events involving uncontained or partially contained engine failures, investigators analyze fan blade condition, engine casing integrity, and whether debris exited the engine structure during the failure sequence. Detailed examination of recovered components is often required to determine the origin of the failure.

The investigative process conducted by the National Transportation Safety Board is described in greater detail in our discussion of the NTSB investigation process.

Regulatory and Industry Response

The engine failure prompted immediate action by aviation regulators and airlines operating aircraft equipped with similar engines. United Airlines temporarily grounded certain Boeing 777 aircraft equipped with Pratt & Whitney PW4000 engines while inspections were conducted.

Aviation authorities in other countries, including Japan, also responded by reviewing the continued operation of aircraft equipped with the same engine model. When failures of similar components occur across multiple aircraft, regulators may require inspections, operational limitations, or temporary groundings while the cause of the failures is investigated.

Aviation Accident Litigation

Serious in-flight engine failures can raise complex questions involving aircraft design, engine manufacturing, maintenance practices, and inspection procedures. These issues are frequently examined in subsequent aviation accident litigation.

Examples of aviation accident cases involving aircraft systems failures and product liability issues appear in our summaries of Representative Aviation Matters and Selected Aviation Verdicts and Settlements. Patterns observed in aviation accident litigation are also discussed in our analysis of Aviation Crash Litigation: Common Patterns in Reported Cases.