Maintenance or Manufacture Fail?

http://www.cbc.ca/news/world/philadelphia-plane-emergency-landing-engine-explosion-1.4623216

A Southwest Airlines jet made an emergency landing at Philadelphia’s airport Tuesday April 17th, 2018, with part of the covering from its left engine ripped off and a window damaged. One person died, the chairman of the U.S. National Transportation Safety Board (NTSB) said Tuesday afternoon. Neither the airline nor the Federal Aviation Administration explained what went wrong. An investigation is underway. – CBC news