16662391
1979-MAR-26 · St. Thomas, U.S. Virgin Islands

Inter-Island Air — Flight 16662391

A Beechcraft B18S operated by Inter-Island Air crashed shortly after takeoff from Cyril E. King Airport in St. Thomas, U.S. Virgin Islands, on March 26, 1979. The aircraft was reportedly on a flight to St. Croix when it encountered difficulties during the initial climb phase.

Aircraft
Beechcraft B18S
Registration
N500V
Phase
Cause
Souls on Board
4
Fatalities
4
Origin → Dest
Cyril E. King Airport, St. Thomas → Alexander Hamilton Airport, St. Croix
Report

Investigation Summary

The aircraft was operating a scheduled cargo flight between the U.S. Virgin Islands. Shortly after lifting off from Runway 09, the left engine suffered a mechanical failure. The pilot reported the emergency to the tower and attempted to return to the airport. However, the aircraft was loaded near its maximum capacity, and the drag from the failed engine, combined with the low altitude of the initial climb, made it impossible to maintain level flight. The aircraft entered a left-hand turn, lost airspeed, and stalled before crashing into the Caribbean Sea approximately 1.5 miles from the runway end. All four occupants, including the pilot and three passengers who were not authorized to be on the cargo flight, were killed.

Final Conclusions

The NTSB determined the probable cause of the accident was the pilot's failure to feather the propeller of the malfunctioning left engine, which resulted in excessive drag. This drag, compounded by the aircraft being loaded near its maximum gross weight with three unauthorized passengers, prevented the aircraft from maintaining level flight or climbing on a single engine. The investigation highlighted that the aircraft's performance margins were insufficient to overcome the aerodynamic penalties of the unfeathered propeller at the low altitude and airspeed following takeoff.

Video Analysis

No video analysis linked for this case file yet.

Airframe & Maintenance

Engines
Pratt & Whitney R-985

Systems & Failure Modes

i

Pratt & Whitney R-985 Engine

The radial engines powering the Beechcraft 18; the left unit suffered an internal mechanical failure shortly after takeoff.

i

Propeller Feathering System

A system designed to turn propeller blades parallel to the airflow to reduce drag after an engine failure; it was not successfully utilized in this event.

Interesting Facts

  • 01The flight was officially designated as a cargo-only operation.
  • 02Three unauthorized passengers were on board the aircraft at the time of the crash.
  • 03The left engine propeller was not found in the feathered position.
  • 04The aircraft was destroyed by impact forces and subsequent immersion in salt water.

Safety Actions & Advisories

Cargo Flight Passenger Enforcement

The FAA increased surveillance of Part 135 cargo operators in the Caribbean region to ensure compliance with passenger carriage restrictions.

Location

St. Thomas, U.S. Virgin Islands · 18.3300, -64.9250

APPROXIMATE POSITION · AIRPORT LEVEL · Coordinates are the estimate published in the official investigation report. The ring shows the accuracy the record supports, not the point of impact.

Case File History

  1. New evidenceUpdated sources.
  2. Final reportUpdated final conclusions.

Related Cases

Case ID · inter-island-air-1979Last updated · Filed

© 2026 TechBridge Software Co., Ltd. — BlackBoxWiki is an open aviation reference. Not affiliated with any aviation authority.