1952 — Apr 29, Pan Am 202 structural failure in-flight & crash, central Brazil –19US of 50

–50 Civil Aeronautics Board. AIR. Pan American World Airways, Inc., Near Carolina, Brazil…
–50 Eckert. “Fatal commercial air transport crashes, 1924-1981.” AJFM&P, 3/1, Mar 1982, Table 1.
–50 Gero. Aviation Disasters: The World’s Major Civil Airliner Crashes Since 1950 (2nd Ed.). 1996, 16-17.
41 passengers
9 crew
–50 NYT. “Burned Wreckage of Stratocruiser is Sighted on a Brazilian Hilltop…” 5-2-1952, p1.
–19 Americans.
Narrative Information

Gero:

“Date: 29 April 1952 (c.03:40)
“Location: Central Brazil
“Operator: Pan American World Airways (US)
“Aircraft type: Boeing 377 Stratocruiser (N1039V)

“In the last message received from Flight 202, the airliner was reportedly at an altitude of 14,500 ft (c. 4,400 M0 in visual flight rules (VFR) conditions, with an estimation that it would be abeam of the Carolina check point in 90 min. But there was no further communication with N1039V.

“Two days later the burned wreckage of the Stratocruiser was found scattered for nearly 1 mile (1.5 km) and lying inverted in a tropical forest area in the south-eastern corner of Para state, some 1,000 miles (1,600 km) north-north-west of Rio de Janeiro, where it had last stopped before proceeding on to Port-of-Spain, Trinidad, one segment of a service originating at Buenos Aires, Argentina, with an ultimate destination of New York City. All 50 persons aboard (41 passengers and a crew of nine) perished in the crash.

“It was apparent that the aircraft had disintegrated in flight, while cruising in pre-dawn darkness on an approximate heading of 340 degrees, and that the sequence of events began with the separation of its No. 2 engine/propeller assembly due to highly unbalanced forces. Then, possibly because of severe buffeting, there was a partial failure of the left horizontal stabilizer. Examination of the debris indicated that the outer portion of the stabilizer continued to hang on, oscillating in such a manner as to cause the elevators to snap upward, placing a very high down-load on the tail surfaces. This would in turn have caused a considerable increase in lift on the wings, a sufficient force to break the left one in an upward direction, just beyond the missing inboard power plant. The resulting nosedown pitching motion attributed to the loss of the wing coupled with the existing down-load on the horizontal tail surfaces would likely have caused the empennage to break off in a downward direction which must have been almost simultaneous with the wing failure. Both the left wing and the tail assembly were found a distance from the main wreckage, confirming that these components had separated before the impact with the ground.

“Since it could not be located, there was no way of knowing exactly what happened to the No. 2 engine. However, in other accidents involving the same type of aircraft, such separations were precipitated by the failure of propeller blade, with the resulting imbalance generating destructive forces. As noted in the investigative report, the type of propeller with which the Boeing 377 was equipped had been known to experience fatigue failure after suffering comparatively minor damage.

“Three years later, and following the loss of another Stratocruiser and four lives under similar circumstances, the US Civil Aeronautics Administrat6ion (CAA) issued an advisory that operators of the type replace the hollow steel propeller blades then in use with solid metal ones. Another preventative measure was the development of propeller blade imbalance detectors, the use of which became a CAA requirement, also in 1955.” (Gero, David. Aviation Disasters: The World’s Major Civil Airliner Crashes Since 1950 (Second Edition). London: Patrick Stephens Limited, 1996, pp. 17-18.)

Sources

Civil Aeronautics Board. AIR. Pan American World Airways, Inc., Near Carolina, Brazil, April 29, 1952 (File No. 1-0080). Washington, DC: CAB, released June 26, 1953. Accessed 6-2-2023 at: file:///C:/Users/Wayne/Downloads/dot_33445_DS1.pdf

Eckert, William G. “Fatal commercial air transport crashes, 1924-1981.” American Journal of Forensic Medicine and Pathology, Vol. 3, No. 1, March 1982, Table 1.

Gero, David. Aviation Disasters: The World’s Major Civil Airliner Crashes Since 1950 (Second Edition). London: Patrick Stephens Limited, 1996.

New York Times. “Burned Wreckage of Stratocruiser is Sighted on a Brazilian Hilltop; Search Plane Reports No Sign That Any of the 50 Aboard Survived Crash in Forest. Wrecked Airliner is Found in Brazil.” 5-2-1952, p.1. Accessed 6-2-2023 at: https://www.nytimes.com/1952/05/02/archives/burned-wreckage-of-stratocruiser-is-sighted-on-a-brazilian-hilltop.html