On This Day:
June 24, 1975, a Boeing 727 — Eastern Airlines Flight 66 (link) — leaving Kennedy International Airport, crashed, killing 115 people on board.
The Eastern Airlines Flight 66 – a Boeing 727 – was brought down by wind shear.
Wind Shear: “In general, wind shear refers to any change in wind speed or direction along a straight line.” — “Intense Downdrafts Of Wind”
That afternoon, there were thunderstorms, heavy winds, rain, and sudden burst of wind which threatened air traffic.
Eastern Air Lines Flight 66 was a regularly scheduled flight from New Orleans to New York City. At 3:52, as the plane was approaching, the pilot was told that the airport was experiencing light rain, haze, and zero visibility. That meant that the pilot would need to perform an instrument landing.
There were two arriving flights that day which reported serious problems in landing on runway 22. Approximately ten minutes prior to the crash of Flight 66, a cargo jet (“Flying Tiger-DC-8) reported that there were strong wind shears on the ground.).
Another DC-8 (An Eastern Air Flight 902) while landing on the same runway almost crashed and abandoned its approach. They were down to 250 wind shear was pushing them down 1,500 feet a minute. They were down to approximately 100 feet as they flew out and around.
After that, two aircraft landed safely on runway 22 prior to Flight 66 crash.
Air traffic control gave instructions to flight 66 for landing, ignoring the warnings of both DC-8s and continued to land planes on that runway.
Flight 66 was asked if they heard Flight 902 and answered affirmatively.
The Captain of Flight 66 was warned about the possibility of wind shear, but decided to proceed with the landing.
As the plane began its final approach, the pilots were given the directional vector for avoiding the menacing thunderstorms and set up for the landing pattern.
At 3:59 — on final approach, the flight control tower warned that there were sever wind shift.
First Officer states — “Gonna keep a pretty healthy margin on this one.”
Captain: “I would suggest you do . . . . . In case he’s right (flight 902).
At approximately 4:02 the plane received clearance to runway 22.
Captain asks for any reports on braking conditions on the runway and told there are no reports of any difficulty on braking.
At approximately 4:05, while descending for its landing, sudden wind shears pushed the airplane down.
Flight 66 is less than two miles out, and cockpit warnings go off — losing altitude — and Captain trying to get plane to climb.
The plane begins hitting the initial approach lights — located 2,400 feet before the actual runway. It banked left, hit more of the approach lights, tore off a portion of the wind, and burst into flames.
Only 9 people survived — 7 passengers and 2 flight attendants.
The final report as to the cause . . . .
“The National Transportation Safety Board determines that the probable cause of this accident was the aircraft’s encounter with adverse winds associated with a very strong thunderstorm located astride the ILS (instrument landing system) localizer course, which resulted in high descent rate into the non-frangible approach light towers.
The flight crew’s delayed recognition and correction of the high descent rate were probably associated with their reliance upon visual cues rather than on flight instrument reference.
However, the adverse winds might have been too severe for a successful approach, and landing even had they relied upon and responded rapidly to the indications of the flight instruments.
The NTSB also concluded that failure of either air traffic controllers or the flight crew to abort the landing, given the severe weather conditions, also contributed to the crash:
Contributing to the accident was the continued use of runway 22L when it should have become evident to both air traffic control personnel and the flight crew that a severe weather hazard existed along the approach path.”
Because of this tragic crash, a low-level wind shear alert system (LLWAS) was developed in 1976 and installed in 150 airports up through 1987.
LLWAS are used to identify wind speeds, gain or loss, of between 20-30 knots (23-35 mph), at 2,000 feet or less above the ground, which is usually the altitude of arriving aircraft during the last six miles before an actual landing.
When a pilot receives such an alert, he can decide to land or conduct a missed approach maneuver.
Key Illustrative Thoughts:
* Sources & For more information