Boeing has advised the three operators of MD-11 aircraft to ground their planes following a recent crash of a UPS cargo plane shortly after takeoff from Louisville Muhammad Ali International Airport in Kentucky. The company's Safety Review Board determined that further engineering analysis is necessary for the aircraft.

"This recommendation was made in an abundance of caution, and we will continue coordinating with the FAA on this matter," Boeing stated. Approximately 70 MD-11s are currently in service, operated by FedEx, UPS, and Western Global.

In response to the crash, UPS announced it is temporarily grounding part of its fleet. FedEx confirmed it is immediately grounding its 28 MD-11 planes while conducting a safety review. Western Global has not yet commented on the situation. UPS stated that it is grounding its fleet of McDonnell Douglas MD-11 planes, which represent about 9% of its total fleet, "out of an abundance of caution and in the interest of safety."

The cause of the crash remains under investigation. The National Transportation Safety Board (NTSB) provided additional details about the incident, revealing that the crew attempted to control the aircraft for about 25 seconds before it crashed. NTSB official Todd Inman noted that the crew had completed their standard checklist and briefing, and the takeoff roll was uneventful.

"About 37 seconds after the crew called for takeoff thrust, a repeating bell was heard on the cockpit voice recorder," Inman said during a press briefing. The bell continued until the recording ended 25 seconds later, coinciding with the crash. Inman suggested that the bell might have indicated a fire, as seen in footage of the incident, but he refrained from speculation.

The NTSB plans to produce a written transcript of the cockpit voice recorder audio, which will be made public in several months.

UPS Flight 2976 crashed around 5:15 p.m. local time on Tuesday while en route to Daniel K. Inouye International Airport in Honolulu. The left engine detached after a "large plume of fire" erupted from the left wing, according to the NTSB. Inman reported that the bulk of the left engine pylon remained attached to the engine when it separated from the wing. Both components are currently being examined in a secure facility.

Investigators found additional pieces of the engine attachment in the grass near the runway and planned to conduct another search with a metal detector. As crews sifted through a half-mile of charred debris, a victim was located at the crash site on Friday, raising the confirmed death toll to 14, including the three pilots on board.

Louisville Mayor Craig Greenberg expressed condolences, stating, "We pray for each of the victims' families, and pray that no additional victims are lost as our first responders continue to search and seek answers that we all are looking for." As of Thursday, nine individuals believed to have been near the crash site were still missing.

FedEx has stated that it will continue to monitor the situation closely as investigations proceed.