Northwest Airlines Flight 5 was a flight from Miami International Airport to Minneapolis−Saint Paul International Airport, which, on January 4, 1990, suffered the loss of the number three (starboard) engine at 35,000 feet (11,000 m) in mid-flight over Madison, Florida.^[2]

Northwest Airlines Flight 5

The aircraft involved in the incident
Incident
Date	January 4, 1990
Summary	In-flight engine failure and subsequent loss of the engine
Site	near Madison, Florida, United States 30°38′N 83°24′W / 30.633°N 83.400°W / 30.633; -83.400
Aircraft
Aircraft type	Boeing 727-251
Operator	Northwest Airlines
Registration	N280US[1]
Flight origin	Miami International Airport
Destination	Minneapolis−Saint Paul International Airport
Occupants	145
Passengers	139
Crew	6
Fatalities	0
Injuries	0
Survivors	145

The Boeing 727-251, operated by Northwest Airlines, took off from Miami at 08:15 EST on the morning of January 4, 1990. About an hour later, at approximately 09:10 EST, the pilots reported hearing a loud bang towards the rear of the aircraft.^[2] The 14-year-old jet continued to fly normally, and the crew, not knowing that an engine had fallen off,^[3] flew for almost 50 minutes before carrying out a safe emergency landing at Tampa International Airport at 09:58 EST.^[4] The engine, a Pratt & Whitney JT8D-15, was found a day later in a field near Madison, Florida.^[4]

After landing, inspection crews found the forward lavatory external seal was missing and had probably been improperly installed, causing a leakage when the plane was pressurized. The missing seal caused frozen chunks of lavatory fluid to be ingested by the number three engine, thus damaging the compressor blades.^[5] Upon failure, the engine separated from the aircraft fuselage, as it had been designed to do.^[2]

The National Transportation Safety Board (NTSB) determined the probable cause of the incident to be "the failure of company service personnel to properly service the airplane forward lavatory."^[5]