| Accident summary | |
|---|---|
| Date | November 3, 1973 |
| Type | Uncontained failure |
| Site | New Mexico, United States |
| Passengers | 116 |
| Crew | 12 |
| Injuries | 24 |
| Fatalities | 1 |
| Survivors | 127 |
| Aircraft type | Douglas DC-10-10 |
| Aircraft name | Barbara[1], [2] |
| Operator | National Airlines |
| Tail number | N60NA |
| Flight origin | Miami Miami International Airport |
| Destination | San Francisco |
On November 3, 1973, a National Airlines (NA) DC-10-10 aircraft (N60NA) was operating as a scheduled passenger flight between Miami and San Francisco with intermediate stops at New Orleans, Houston, and Las Vegas (NA Flight 27).
At about 4:40 p.m., while the aircraft was cruising at 39,000 feet (12,000 m) 65 miles southwest of Albuquerque, the No. 3 engine fan assembly disintegrated (uncontained failure) and its fragments penetrated the fuselage, the Nos. 1 and 2 engine nacelles (which contain those engines), and the right wing area. The resultant damage caused decompression of the aircraft cabin and the loss of certain electrical and hydraulic systems.[3]
The flight crew initiated an emergency descent, and the aircraft was landed safely at Albuquerque International Airport 19 minutes after the engine failed. The 115 passengers and 12 crewmembers exited the aircraft by using the evacuation slides. As a result of the accident, one passenger died and 24 persons were treated for smoke inhalation, ear problems, and minor abrasions. The plane was repaired and was later flown by Pan Am (as Clipper Meteor)
One passenger, G.F. Gardner of Beaumont, Texas,[4] was partially sucked into an opening left when a cabin window failed, after it too was struck by engine fragments. He was temporarily retained in that position by his seatbelt. "Efforts to pull the passenger back into the airplane by another passenger were unsuccessful, and the occupant of seat 17H was forced entirely through the cabin window."[5] The New Mexico State Police and local organizations searched extensively for the missing passenger. A computer analysis was made of the possible falling trajectories, which narrowed the search pattern. However, the search effort was unsuccessful, and the body of the passenger was not recovered until two years later, when a crew constructing tracks for the Very Large Array radio telescope came upon his skeletal remains.[6]
The National Transportation Safety Board determined the probable cause of this accident was 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.
According to the NTSB, "The precise reason or reasons for the acceleration and the onset of the destructive vibration could not be determined conclusively," but enough was learned to prevent the occurrence of similar events. The speed of the engine at the time of the accident caused a resonance wave to occur in the fan assembly when the fan blades began to make contact with the fan shroud. The existing engines had a rearward blade retaining capability of 18,000 pounds to prevent the blades from "walking" towards the front of the aircraft and part with the fan disk. That was not enough. As a result of this accident, GE re-designed the engine so that the blade retaining capability was increased to 60,000 pounds, and that change was incorporated into all engines already in service.[3]
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