The crash of a UPS plane shortly after its left engine flew off of its wing and sparked a massive fire during takeoff could spell the end of the 109 remaining MD-11 airliners that exclusively have been hauling cargo for more than a decade.

The fate of the planes won’t be determined until after UPS, FedEx and Western Global see how expensive the repairs the Federal Aviation Administration orders will be and learn whether there is a fatal flaw in their design. The package delivery companies already may have been thinking about retiring their MD-11s — which average more than 30 years old — over the next few years and replacing them with newer planes that are safer and more efficient. The FAA grounded all MD-11s and the 10 remaining related DC-10s after the crash.

Fourteen people — including the plane’s crew of three — died after the aircraft crashed into several businesses near Muhammad Ali International Airport in Louisville, Ky., on Nov. 4. The plane got only 30 feet into the air.

The National Transportation Safety Board said its investigators discovered cracks in key parts that failed to keep the rear of the engine attached to the UPS plane’s wing. The crash reminded analysts of the 1979 disaster that killed 273 after the left engine of an American Airlines jet catapulted up and over its wing after takeoff in Chicago.

An FAA spokesperson said the agency is working with NTSB and Boeing, which bought the company that made the MD-11s in 1997, to determine what needs to be done.

Both the DC-10 and MD-11 have some of the highest accident rates of any commercial planes, according to statistics published annually by Boeing. Twice in the 1970s, a DC-10 lost its rear cargo door in flight. The second time in 1974 caused a crash outside Paris that killed 346 people. Yet airlines loved the DC-10 for years, and the Air Force maintained a fleet of dozens of tankers based on the DC-10 that it flew for decades before retiring them last year.

Formerly independent aircraft company McDonnell Douglas announced the MD-11 in 1984. The three-engine plane appeared promising with its larger capacity and longer range than the DC-10, but its performance never fully lived up to expectations, and newer planes from Boeing and Airbus eclipsed it. Schiavo said the MD-11 was “practically obsolete” when it came out compared to two-engine planes, which are cheaper to operate. Only 200 MD-11s were built between 1988 and 2000.

Most MD-11s started out carrying passengers, but eventually airlines decided to retire the model in favor of other planes. The last MD-11 passenger flight by KLM Royal Dutch Airlines took place in 2014.

MD-11 aircraft made up about 9 percent of the UPS fleet and 4 percent of the FedEx fleet, the companies have said. Western Global only owns 16 MD-11 planes.