Compiled by Wayne Blanchard 10-9-2023 for upload to: https://www.usdeadlyevents.com/

–43 Aviation Safety Network. Accident Description. United Air Lines 521, 29 May 1947.

–43 CAB. Accident Investigation Report. United Air – LaGuardia Field, NY May 29, 1947.

–43 NFPA. “Recent Fires. May 29, New York, N.Y. Aircraft.” Quarterly, 41/1, July 1947, p68.

Narrative Information

Civil Aeronautics Board Accident Investigation Report (SA-144):

“The Accident

“A United Air Lines C-54, NC 30046, Flight 521, crashed while attempting a take-off from LaGuardia Field. New York, at approximately 1905, May 29, 1947. Of the 48 occupants, 43 were killed, four sustained serious injuries, and one, the pilot, received only minor injuries. The aircraft was demolished by impact and partially consumed by fire.

“History of the Flight

“United Air Lines Flight 521 of May 29, 1947, was scheduled to depart from LaGuardia for Cleveland, Ohio, at 1840. Captain Benton Baldwin, the pilot, reported at 1739 in United’s dispatch office, consulted the company meteorologist, and studied route weather data. He found that thunderstorm conditions existed which resulted from a cold front and prefrontal squall line, located at the time west of the New York area. The flight plan, based on this weather information and prepared by the Captain and his co-pilot, Robert E. Sands, specified instrument flight at 4,000 feet via Newark and Youngstown to Cleveland with Detroit…Michigan, as an alternate….

“At 1855 the engines were started, and Flight 521 requested taxi instructions from the tower. Clearance was given to Runway 13, the wind being reported by the tower as south, variable to southeast, 20 miles per hour. After taxiing out, the aircraft was parked approximately 50 feet adjacent to Runway 18, and, according to Captain Baldwin, the engine ‘run-up’ and ‘take-off check’ was then accomplished.

“Captain Baldwin held at this point, approximately six to seven minutes. An unexpected difference occurred between him and Airway Traffic Control with reference to his clearance which had to be straightened out before departure. At 1903 the tower delivered the corrected clearance from Airway Traffic Control.

“Meanwhile black thunder clouds and lightning were visible west of LaGuardia. The squall line was breaking then over Hell Gate, some two to three miles west of the field. Air crews hurried to land or take off before being overtaken by the approaching storm….At 1904, United’s Flight 521 advised: ‘Ready for take-off.’ The tower operator asked whether the flight wished to wait out the storm on the ground. Captain Baldwin answered: ‘I’ll take off.’ The tower then advised Captain Baldwin: ‘Cleared for immediate take-off, or hold; traffic on final approach north of Riker’s Island.’ Flight 521 taxied from its parked position, rolled onto Runway 18, and without pause or hesitation accelerated for takeoff. The throttles were advanced. Air speed increased to above 90 miles per hour. Captain Baldwin applied back pressure to the control column, but the ‘feel’ of the controls was ‘heavy,’ and the aircraft did not respond. As the aircraft raced toward the boundary of the field, Captain Baldwin decided to discontinue his take-off. About 1,000 feet from the south end of the runway he applied brakes, ordering the co-pilot at the same time to cut the engines. A ground-loop was attempted by heavy application of left brake. The aircraft, however, proceeded to roll straight ahead. Then, with both brakes locked it continued over the remainder of the runway, crashed through the fence at the airport boundary, and half-bounced, half-flew across the Grand Central Parkway. The aircraft finally came to rest immediately east of the Casey Jones School of Aeronautics, a distance of 800 feet from the end of Runway 18 and 1,700 feet from the point at which brakes were first applied. It was almost immediately enveloped in flames. Only Captain Baldwin was able to escape before emergency fire equipment and rescue arrived. Other survivors, one of them later died, were assisted out of the wreckage within a period of 2 to 3 minutes after the crash.

“Investigation….

“The aircraft, NC 30046, a C-54B-DC, was completely destroyed. The fuselage was crushed by impact, and partially consumed by fire. All seats, with the exception of the hostesses’ seats, were found detached from the floor. Fire extinguishers were found not discharged and in the proper racks….

“Discussion….

“…it may be surmised that the plane was overloaded and hence failed to take off. It is true that the plane was overloaded according to the correct calculations for this runway derivable from the approved operating manual for this type of plane with due reference to gradients and obstacles present on Runway 18. But, if the engineers and other experts are to be believed, an airplane loaded to this weight, whatever the legal requirements might be, should have taken off without difficulty from this runway provided that the airplane was functioning normally. And there is not the slightest proof, except one matter later to be mentioned, that the airplane was not functioning in a normal fashion. Nevertheless, the airplane should not have been loaded to this weight for this runway. The fact that it was can be attributed to the miscalculations of United, the lack of any exercise of supervision over the filed weights by the Civil Aeronautics Administration, and the failure of Captain Baldwin even to glance at his chart of operating weights prior to take-off on this runway.

“Two possibilities remain. The first is simply poor pilot technique by Captain Baldwin. He may, for reasons unknown, have become extremely agitated by the sudden approach of the end of the runway – a suddenness that would not be too surprising in the light of the fact that he had never taken off a DC-4 on this runway before. In the light of that realization he may have decided wrongly to cut power instead of pushing his control forward and grasping for the reserve power that would have made for clearance. But this is only surmise.

“A more probable hypothesis is that the gust lock had not been released. Several factors incline towards this conclusion. Due to the gusty character of the winds the gust lock was obviously on when the ship was being taxied to its holding point just off Runway 18. Due to the delay, occasioned partly by the difficulty in securing an appropriate clearance from Airways Traffic Control, the gust lock was probably left on after the pre-take-ff check with the intent that it should be immediately released upon starting the take-off roll. That roll, it will be remembered, was hurried.

“As further evidence of this theory the attitude of the airplane during the take-off roll is to be noted. It was some 2500 feet down the runway before the power was out at the order of Captain Baldwin. At that point, even if no wind conditions prevailed, the airplane would have had a speed of 112 miles per hour. At such a speed it could easily have been pulled aloft; certainly its now-wheel should have left the ground. But the nose-wheel did not leave the ground, according to the testimony of all the observers including that of Captain Baldwin….

“…Thousands of people daily attempt to start their automobiles with the emergency brake on. Emergency brakes and gust locks are necessities. They cannot and should not be legislated out of existence. Fortunately the consequences of leaving an emergency brake on are not serious; unfortunately leaving a gust lock on is not only serious, it is tragic. It will not suffice for us to say simply that this is a case of ‘pilot error’ and wash our hands of the affair. A better devise than those that now exist of assuring that the gust lock on these airplanes is released prior to the take-off roll is demanded….

“Throughout this series of events that in this case produced disaster, one can sense unfortunately too much insistence on speed of dispatch, too much of a tendency to carry loads up to the full amount that the regulations stretched to a bulging point will allow. No one checked Captain Baldwin in his effort to beat the storm. The twenty minute delay in the dispatch of the airplane with the breaking of the squall line predicted exactly as of the time of dispatch was not even communicated to the dispatcher. No responsibility of any character was assumed by that office. The tower, true to its traditions, assumed no responsibility beyond that of traffic separation. The airplane, loaded for the longest runway in traditional dispatching form, was shifted by the pilot to a shorter runway on the assumption that the and component would be sufficient compensation–an assumption that happened to be true. The need to meet schedules as against a potential delay of an hour or so to wait out a storm determined a take-off under marginal conditions. {pp. 16-17}

“Safety, if it is to be achieved, has elements of cost. The line between unsafe and safe operation–whatever regulations or experts may say–is not delineated with the exactness that characterizes Sienese painting[1] or an Ingres drawing. It is possible as in the case of any cliff, to say just where the precipice is, but it is not possible to say just how near one can come to the edge without falling in. Facts that do not respond to slide rules are sometime controlling. Airplanes, as any machine, have temperament and pilots, because they are human beings, possess the same frailty. Allowance in the tightness of operations, in the tightness of formulas, must be made for these. And no such allowances were made. This method of doing things should appropriately be designated as the basic cause of this accident….” {pp. 17-18}

“Findings….

“6. The airplane accelerated normally for a distance of approximately 2000 feet [down a 3530-foot runway] to an air speed in excess of 90 miles per hour after which the pilot applied brakes and ordered the co-pilot to cut the engines.

“7. After application of brakes the aircraft skidded for a distance of 800 feet to the end of Runway 18, and 1700 feet before coming to rest. It was then almost immediately enveloped in flames….

“Probable Cause

“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.” (p. 19)

Supplemental Data

….

“Corrective Action:

“This accident has not only been of concern to the Civil Aeronautics Board but also to the President’s Special Board of Inquiry on Air Safety. A close liaison between the two as well as the Civil Aeronautics Administration has been maintained. The corrective action that has been taken thus stems from all three bodies as well as the municipal airport authority.

“1. The Civil Aeronautics Board has amended Civil Air Regulation–so as to eliminate the word “appreciable”. The result is that all gradients must be included in calculating allowable weight limitations on all runways.

“2. The Civil Aeronautics Board has promulgated for adoption two regulations (1) a regulation providing for an arbitrary reduction in allowable weight limitations that will take account of temperature as affecting take-off loads; (2) a more permanent but still interim regulation permitting the adjustment of allowable loads to changes in temperature on a more scientific basis.

“3. The Civil Aeronautics Board and the Civil Aeronautics Administration have instructed their respective staff to reconsider the transport category requirements for take-off and landing both with regard to the formulation of a United States position on these matters for the purposes of international standardization under the auspices of the International Civil Aviation Organization and with regard to increased safety in American domestic and international requirements. This will take time. Some five or six years of effort went into the formulation of the present transport category requirements.

“4. The Civil Aeronautics Administration in cooperation with the airlines will work out uniform weight limitations for all runways used by the certificated commercial airlines in the United States on the basis of the revised interim formulas.

“5. The Civil Aeronautics Administration has defined and promulgated the definition of winds that are not too unsteady and too variable so as to limit the use of reasonably steady and constant winds as components in the transport category requirements.

“6. The Civil Aeronautics Administration and the Air Transport Association are taking steps to indoctrinate pilots more thoroughly in the meaning and use of the transport category formulas.

“7. The President’s Special Board has requested the manufacturers of this airplane to redesign several aspects of the gust-lock, so as to provide against its locking during take-off or flight and so as to provide more adequate warning against its being locked at the time of take-off. One design feature has already been completed and is being installed.

“8. The President’s Special Board has recommended the installation of lighted wind socks at the ends of all runways utilized by certificated commercial aircraft. Failure of the municipalities to respond to this suggestion may call for further propulsive action.

“9. The municipal authorities of New York City have closed Runway 18 to all four engine aircraft….” (Civil Aeronautics Board. Accident Investigation Report. United Airlines, Inc., – LaGuardia Field, New York – May 29, 1947.)

National Fire Protection Association:

“One of the worst aircraft accidents in history from the viewpoint of fire deaths occurred when a scheduled United Air Lines DC-4 crashed on take-off at LaGuardia Field, killing 43 persons. Using the shortest runway on the field (3500 ft.), the four-engine transport, loaded in excess of federal standards, was not able to get off the ground as shifting winds worked to the disadvantage of the pilot. Realizing that the plane was not becoming airborne, the pilot made a vain effort to stop the forward motion by ground looping. The heavy ship struck a 15 ft. embankment at the edge of the field, bounced into the air across an express highway, and crashed in a swampy open field with fire developing instantaneously. The crash was anticipated before it occurred by a fireman on duty at the airport crash station (operated by the New York Fire Department). The alarm was given and equipment reached the scene in 50 seconds….Firemen removed nine occupants in the crucial moments, while the pilot escaped unassisted…Five of those rescued died from burns in hospitals….Preliminary reports indicate that all deaths were caused by burns and suffocation, none by impact injuries….” (National Fire Protection Assoc. “Recent Fires. May 29, New York, N.Y. Aircraft.” Quarterly of the National Fire Protection Association, Vol. 41, No. 1, July 1947, p. 68.)

Sources

Aviation Safety Network, Flight Safety Foundation, Database, 1947. United Air Lines 521, New York-La Guardia Airport, NY, 29 May 1947. Accessed 10-9-2023 at:

https://aviation-safety.net/database/record.php?id=19470529-1

Civil Aeronautics Board Safety Bureau. Accident Investigation Report. United Air Lines, Inc., – LaGuardia Field, New York – May 29, 1947. Washington, DC: CAB, SA-144. Accessed 10-9-2023 at: https://rosap.ntl.bts.gov/view/dot/33304

National Fire Protection Association. “Recent Fires. May 29, New York, N.Y. Aircraft.” Quarterly of the National Fire Protection Association, Vol. 41, No. 1, July 1947, p. 68.

[1] “The Sienese School of painting flourished in Siena, Italy, between the 13^th and 15^th centuries.” (Wikipedia.)

1947 — May 29, United Airlines 521 crashes and burns during take-off, La Guardia, NY–43