United Air Lines Flight 521

1947 aviation accident over the United States

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United Air Lines Flight 521

The wreckage of Flight 521

Accident
Date| May 29, 1947 (1947-05-29)
Summary| Pilot error
Site| LaGuardia Airport, New York City, United States
40°46′06″N 73°53′05″W﻿ / ﻿40.7683°N 73.8847°W﻿ / 40.7683; -73.8847
Aircraft

A United Airlines Douglas DC-4, similar to the accident aircraft
Aircraft type| Douglas DC-4
Aircraft name| Mainliner Lake Tahoe
Operator| United Air Lines
IATA flight No.| UA521
ICAO flight No.| UAL521
Call sign| UNITED 521
Registration| NC30046
Flight origin| LaGuardia Airport, New York, United States
Destination| Cleveland Municipal Airport, Cleveland, Ohio, United States
Occupants| 48
Passengers| 44
Crew| 4
Fatalities| 43
Injuries| 5
Survivors| 5

United Air Lines Flight 521 was a scheduled passenger flight operated by a Douglas DC-4 from LaGuardia Airport, New York City, United States, to Cleveland, Ohio, United States. On May 29, 1947, while attempting to take off on runway 18, the aircraft failed to get airborne, overran the end of the runway, ripped through an airport fence onto traffic on the Grand Central Parkway, and slammed into an embankment, ultimately plunging into a pond and exploding. Ten people escaped the flaming wreckage; only five of them survived.[1]

It was the worst commercial aviation disaster in United States history at the time. Its record stood for less than 24 hours before an Eastern Air Lines DC-4 crashed near Baltimore, Maryland, killing all 53 aboard.[1]

## Investigation

[edit]

The Civil Aeronautics Board concluded the report on the accident by citing pilot error. The report read: "The Board determines that the probable cause of this accident was either the failure of the pilot to release the gust lock before take-off, or his decision to discontinue the take-off because of apprehension resulting from rapid use of a short runway under a possible calm wind condition."

Although the board came to the conclusion that pilot error was likely the cause, the May 31, 1947, edition of The New York Times told a different (albeit preliminary) tale:

"The United Air Lines DC-4 that crashed and burned at La Guardia Field Thursday night never got into the air and the pilot, after using up about two-thirds of the 3,500-foot runway, was trying to halt his giant craft by braking and ground looping. All night, on-the-scene inquiries by both the company and officials of the Civil Aeronautics Board established these facts yesterday. They agreed also that the wind shift, described by a company official as 'of almost unbelievable suddenness', led Capt. Benton R. Baldwin, the pilot, to decide against proceeding with the take-off, but they differed on whether the pilot had been apprised of approaching wind shifts before the take-off."

It seemed, at least early on, the cause may have actually been wind shear (although it is referred to as "wind shift" in the article).

## References

[edit]

1. ^ a b "RUNWAY 18 Air Safety, May-June 1947 Chapter 197". New York Daily News. September 21, 2000. Retrieved March 15, 2025.

## External links

[edit]

* Aviation Safety Network entry on the incident
* Report of the Civil Aeronautics Board \- PDF

* v
* t
* e

Aviation accidents and incidents in 1947 (1947)

Jan 11

Stowting Dakota accident

Jan 25

Croydon Dakota accident

Jan 26

KLM Copenhagen disaster

Feb 15

Avianca Douglas DC-4 crash

Apr 22

Columbus mid-air collision

May 29

United Air Lines Flight 521

May 29

Héðinsfjörður air crash

May 30

Eastern Air Lines Flight 605

Jun 13

Pennsylvania Central Airlines Flight 410

Jun 19

Pan Am Flight 121

Jul 29

Yogyakarta Dakota incident

Aug 2

BSAA Star Dust accident

Aug 28

Kvitbjørn disaster

Oct 24

United Air Lines Flight 608

Oct 26

Pan Am Flight 923

Nov 28

General Leclerc's aviation accident

Dec 27

Korangi Creek crash

1946  ◄ ► 1948

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* Flight 23 (1933)
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Aviation accidents and incidents in the United States and U.S. territories in the 1940s

1940|

* Lovettsville air disaster (August)

1941|

* Eastern Air Lines Flight 21 (February)
* Northwest Airlines Flight 5 (October)

1942|

* TWA Flight 3 (January)
* American Airlines Flight 28 (October)

1943|

* Pan Am Flight V-1104 (January)
* American Airlines Flight 63 (Flagship Ohio) (July)
* American Airlines Flight 63 (Flagship Missouri) (October)
* Tamaqua, PA crash (November)

1944|

* American Airlines Flight 2 (February)
* TWA Flight 277 (June)
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1945|

* American Airlines Flight 6001 (January)
* Eastern Air Lines Flight 45 (July)
* National Airlines Flight 16 (October)

1946|

* Pennsylvania Central Airlines Flight 105 (January)
* Mount Tom B-17 crash (July 9)
* TWA Flight 513 (July 11)

1947|

* Columbus mid-air collision (April 22)
* United Air Lines Flight 521 (May 29)
* Eastern Air Lines Flight 605 (May 30)
* Pennsylvania Central Airlines Flight 410 (June)
* United Air Lines Flight 608 (October 24)
* Pan Am Flight 923 (October 26)*

1948|

* Mantell UFO incident (January 7)
* Los Gatos DC-3 crash (January 28)
* Delta Air Lines Flight 705 (March 10)
* Northwest Orient Airlines Flight 4422 (March 12)
* United Air Lines Flight 624 (June)
* Lake Mead Boeing B-29 crash (July)
* Northwest Orient Airlines Flight 421 (August)
* Georgia USAF Boeing B-29 crash (October)
* Airborne Transport DC-3 disappearance (December)

1949|

* Strato-Freight Curtiss C-46A crash (June)
* Standard Air Lines Flight 897R (July)
* Eastern Air Lines Flight 537 (November 1)
* American Airlines Flight 157 (November 29)

This list is incomplete.
An asterisk (*) denotes an incident that took place in a U.S. territory, including Alaska and Hawaii prior to statehood.
1930–1939 ◄ 1940–1949 ► 1950–1959
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