NC16933
1939-AUG-13 · Guanabara Bay, Rio de Janeiro, Brazil

Pan American Airways (Pan Am) — Flight NC16933

A Pan American Airways Sikorsky S-43B flying boat, christened Baby Clipper, crashed into Guanabara Bay while attempting to land at Santos Dumont Airport. During a circling maneuver for a normal approach, the left engine suffered a total loss of power. The aircraft entered a descending left yaw turn that steepened until the seaplane struck a caisson at Ilha das Cobras. The impact destroyed the aircraft, resulting in the deaths of 14 of the 16 people on board. This was the first accident involving a Pan Am aircraft in Brazil.

Aircraft
Sikorsky S-43B
Registration
NC16933
Phase
Cause
Souls on Board
16
Fatalities
14
Origin → Dest
Pan American Field, Miami, Florida → Santos Dumont Airport, Rio de Janeiro, Brazil
Report

Investigation Summary

The aircraft was completing a multi-stop international journey from Miami to Rio de Janeiro, having made 19 scheduled stops across the Caribbean and South America. The full route included stops at Antilla, Port-au-Prince, San Pedro de Macorís, San Juan, Port of Spain, Georgetown, Paramaribo, Cayenne, Bélem, São Luís, Fortaleza, Natal, João Pessoa, Recife, Maceió, Aracaju, Salvador, Caravelas, and Vitória. While Miami was the original point of departure for the entire flight sequence, the final leg of the journey originated from Vitória-Goiabeiras Airport. As the crew prepared for arrival at Santos Dumont Airport, the left Pratt & Whitney Hornet engine failed. The resulting asymmetrical thrust caused the aircraft to yaw and roll into a descending turn. The investigation by the Civil Aeronautics Board (CAB) determined that the loss of power forced the crew into an attempted landing under extremely hazardous conditions. The aircraft struck a caisson, a large watertight chamber used for underwater construction, located approximately one kilometer from the airport.

Final Conclusions

The Civil Aeronautics Board (CAB) concluded that the probable cause was the loss of power from the left engine during the landing approach, which necessitated an attempted landing under extremely hazardous conditions. The aircraft was written off as a total loss.

Video Analysis

No video analysis linked for this case file yet.

Airframe & Maintenance

Airframe Hours
3,650
Engines
Pratt & Whitney R-1690-S1EG Hornet

Systems & Failure Modes

i

Pratt & Whitney R-1690-S1EG Hornet Engine

The aircraft was powered by two radial engines; the failure of the left unit created significant asymmetrical thrust during the low-speed approach phase.

i

Sikorsky S-43B Airframe

A twin-engine amphibious flying boat known as the Baby Clipper, designed for short-haul routes in the Caribbean and Latin America.

Interesting Facts

  • 01The aircraft was a Sikorsky S-43B flying boat, serial number 4324, manufactured in 1936.
  • 02The flight involved 19 intermediate stops between Miami and Rio de Janeiro.
  • 03There were only two survivors among the 16 occupants.
  • 04The crash occurred approximately one kilometer north of the destination airport.
  • 05The aircraft had accumulated 3,650 total airframe hours at the time of the accident.

Safety Actions & Advisories

CAB Investigation and Reporting

Source ↗

The Civil Aeronautics Board (CAB) conducted a full investigation into the engine failure and subsequent loss of control, resulting in a formal report (dot_33012_DS1) detailing the hazards of low-altitude engine failure during circling maneuvers.

Location

Guanabara Bay, Rio de Janeiro, Brazil · -22.8941, -43.1643

Case File History

  1. CorrectionUpdated investigation summary, event timeline and safety actions.
  2. CorrectionUpdated investigation summary.

Related Cases

Case ID · pan-am-guanabara-1939Last updated · Filed

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