Capital Airlines Flight 75
Encyclopedia
Capital Airlines Flight 75 was a domestic scheduled Capital Airlines
flight
operating between La Guardia Airport and Atlanta Airport
. A Vickers Viscount
flying the route crashed in Chase, Maryland
, on May 12, 1959, with the loss of all onboard. The crash was the second of three involving a Capital Airlines Vickers Viscount in as many years; the other two were Capital Airlines Flight 20
and Capital Airlines Flight 67
.
The flight left the terminal at La Guardia at 3:20 in the afternoon, 20 minutes after it was scheduled to begin, and took off at 3:29. It then climbed to 14,000 feet before coming onto the assigned airway
, Victor 3. By 4:02 the crew contacted the Washington Center, reporting over Westchester and estimating Westminster at fifteen minutes away. In the same message they noted that there were thunderstorm
s along the assigned course, and requested permission to stay in the clear a little south of Westminster. The air traffic controller
acknowledged the message and gave the go-ahead. At 4:10 the flight called again, the pilots noting that they had slowed somewhat to account for turbulence
. This was the last message sent by the flight crew; three minutes later, the plane entered an area of severe turbulence, lost control, and entered a steep descent.
It is believed that the craft reached an airspeed
of 335 knots, fully 15 percent more than the Viscount's never-exceed speed, and about 5 percent in excess of the maximum speed demonstrated when the plane was certified. Consequently, at about 5000 feet both of the horizontal stabilizers failed at once, separating downard. The separation caused the plane to pitch violently downard; the gyroscopic loads combined with inertia
to cause all four engine
nacelles to break upward. Both wings were then subjected to extreme downloads. Under the pressure the right wing separated, and the integrity of the left was completely destroyed.
With so much of the aircraft's superstructure gone, the left wing induced drag on the fuselage
, yawing it violently to the left. More forces from that direction tore off the vertical fin, which came away with portions of the fuselage, already weakened from losing the left stabilizer, still attached. Further gyrations caused the left wing to disintegrate, opening its fuel cell
s and leading to a flash fire
. What was left of the fuselage crumbled, and the craft plunged to the ground in rural Maryland
.
The cause of the accident was determined to be a loss of control of the plane in turbulence, resulting in an involuntary steep descent which created aerodynamic loads in excess of those for which the craft had been designed.
Capital Airlines
Capital Airlines was an airline serving the eastern United States that merged into United Airlines in 1961. Its primary hubs were National Airport near Washington, DC, and Allegheny County Airport near Pittsburgh. In the 1950s it was the largest US domestic carrier after the Big Four . Its...
flight
Flight
Flight is the process by which an object moves either through an atmosphere or beyond it by generating lift or propulsive thrust, or aerostatically using buoyancy, or by simple ballistic movement....
operating between La Guardia Airport and Atlanta Airport
Hartsfield-Jackson Atlanta International Airport
Hartsfield–Jackson Atlanta International Airport , known locally as Atlanta Airport, Hartsfield Airport, and Hartsfield–Jackson, is located seven miles south of the central business district of Atlanta, Georgia, United States...
. A Vickers Viscount
Vickers Viscount
The Vickers Viscount was a British medium-range turboprop airliner first flown in 1948 by Vickers-Armstrongs, making it the first such aircraft to enter service in the world...
flying the route crashed in Chase, Maryland
Chase, Maryland
Chase is an unincorporated community in eastern Baltimore County, Maryland, United States.-Geography:Chase is located at . Chase is located on the waterfront of the Gunpowder River, Middle River, Dundee Creek, Saltpeter Creek, and Chesapeake Bay...
, on May 12, 1959, with the loss of all onboard. The crash was the second of three involving a Capital Airlines Vickers Viscount in as many years; the other two were Capital Airlines Flight 20
Capital Airlines Flight 20
Capital Airlines Flight 20 was a U.S. domestic scheduled passenger flight between Washington, D.C., and Norfolk, Virginia, run by Capital Airlines. A Vickers Viscount flying the route crashed into a farm in Charles City County, Virginia, on January 18, 1960. The flight originated at National...
and Capital Airlines Flight 67
Capital Airlines Flight 67
Capital Airlines Flight 67 was domestic scheduled passenger flight operated by Capital Airlines that crashed on final approach to Freeland, Michigan, USA, during a severe snowstorm on April 6, 1958...
.
The flight left the terminal at La Guardia at 3:20 in the afternoon, 20 minutes after it was scheduled to begin, and took off at 3:29. It then climbed to 14,000 feet before coming onto the assigned airway
Airway (aviation)
In aviation, an airway is a designated route in the air. Airways are laid out between navigational aids such as VORs, NDBs and Intersections ....
, Victor 3. By 4:02 the crew contacted the Washington Center, reporting over Westchester and estimating Westminster at fifteen minutes away. In the same message they noted that there were thunderstorm
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...
s along the assigned course, and requested permission to stay in the clear a little south of Westminster. The air traffic controller
Air traffic controller
Air traffic controllers are the people who expedite and maintain a safe and orderly flow of air traffic in the global air traffic control system. The position of the air traffic controller is one that requires highly specialized skills...
acknowledged the message and gave the go-ahead. At 4:10 the flight called again, the pilots noting that they had slowed somewhat to account for turbulence
Turbulence
In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time...
. This was the last message sent by the flight crew; three minutes later, the plane entered an area of severe turbulence, lost control, and entered a steep descent.
It is believed that the craft reached an airspeed
Airspeed
Airspeed is the speed of an aircraft relative to the air. Among the common conventions for qualifying airspeed are: indicated airspeed , calibrated airspeed , true airspeed , equivalent airspeed and density airspeed....
of 335 knots, fully 15 percent more than the Viscount's never-exceed speed, and about 5 percent in excess of the maximum speed demonstrated when the plane was certified. Consequently, at about 5000 feet both of the horizontal stabilizers failed at once, separating downard. The separation caused the plane to pitch violently downard; the gyroscopic loads combined with inertia
Inertia
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...
to cause all four engine
Engine
An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...
nacelles to break upward. Both wings were then subjected to extreme downloads. Under the pressure the right wing separated, and the integrity of the left was completely destroyed.
With so much of the aircraft's superstructure gone, the left wing induced drag on the fuselage
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...
, yawing it violently to the left. More forces from that direction tore off the vertical fin, which came away with portions of the fuselage, already weakened from losing the left stabilizer, still attached. Further gyrations caused the left wing to disintegrate, opening its fuel cell
Fuel cell
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
s and leading to a flash fire
Flash fire
A flash fire is a sudden, intense fire caused by ignition of a mixture of air and a dispersed flammable substance such as a solid , flammable or combustible liquid , or a flammable gas...
. What was left of the fuselage crumbled, and the craft plunged to the ground in rural Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
.
The cause of the accident was determined to be a loss of control of the plane in turbulence, resulting in an involuntary steep descent which created aerodynamic loads in excess of those for which the craft had been designed.