Status:	Final
Date:	03 NOV 1973
Time:	16:40
Type:	McDonnell Douglas DC-10-10
Operator:	National Airlines
Registration:	N60NA
C/n / msn:	46700/14
First flight:	1971
Total airframe hrs:	5954
Crew:	Fatalities: 0 / Occupants: 12
Passengers:	Fatalities: 1 / Occupants: 116
Total:	Fatalities: 1 / Occupants: 128
Airplane damage:	Substantial
Airplane fate:	Repaired
Location:	near Socorro, NM (United States of America)
Phase:	En route (ENR)
Nature:	Domestic Scheduled Passenger
Departure airport:	Houston-Intercontinental Airport, TX (IAH/KIAH), United States of America
Destination airport:	Las Vegas-McCarran International Airport, NV (LAS/KLAS), United States of America
Flightnumber:	27

Narrative:
National Airlines Flight 27 departed Houston for Las Vegas and climbed to FL390. Suddenly the No. 3 engine fan assembly disintegrated and fragments penetrated the fuselage the Nos. 1 and 2 engine nacelles, and the right wing area. As a result, the cabin depressurized and one cabin window, which was struck by a fragment of the fan assembly, separated from the fuselage. The passenger who was sitting next to that window was forced through the opening and ejected from the aircraft. The flightcrew initiated an emergency descent, and the aircraft landed safely at Albuquerque International Airport 19 minutes after
engine failed.

PROBABLE CAUSE: "The disintegration of the No. 3 engine fan assembly as a result of an interaction between the fan blade tips and the fan case. The fan-tip rub condition was caused by the acceleration of the engine to an abnormally high fan speed which initiated a multiwave, vibratory resonance within the fan section of the engine. The precise reason or reasons for the acceleration and the onset of the destructive vibration could not be determined conclusively."

Sources:
» NTSB-AAR-75-2