Maintenance and Preflight
During an en route stop, company maintenance personnel opened the forward overwing emergency exit to access a navigation light for repair. During the subsequent preflight inspection, the flight engineer observed that the emergency exit appeared to be in place but did not physically examine the exits or their latches.
Pressurization Failure and Captain's Decision
During climbout, the flight crew found they were unable to pressurize the airplane. Despite objections from other crew members, the captain decided to continue the flight. The crew donned their oxygen masks and continued the climb to a cruise altitude of FL330.
Captain Incapacitation and Diversion
Shortly after leveling off at FL330, the captain became incapacitated due to decompression sickness. The first officer assumed command and diverted the flight for an emergency landing at Covington, Kentucky.
Post-Flight Findings
After the flight, the emergency exit door was found lying inside the airplane. An inspection revealed that the exit door could not be properly fitted into its frame, and the door latches would not engage the latch plates on the frame, even when the handle was moved to the locked position.