Investigation Summary
The investigation into Flight 607-E was severely hampered by the depth of the Atlantic Ocean, which prevented the recovery of the main wreckage. The 'E' in the flight number designated an 'Extra' economy service to accommodate high seasonal demand. The flight had successfully completed its first leg from Amsterdam and refueled at Shannon. Approximately 35 minutes after departure from Shannon, the aircraft disappeared. The search and rescue operation found only floating debris and a portion of the occupants. The investigation focused on the Wright R-3350 engines, which were known for their complexity. A specific theory emerged regarding the supercharger gear shifting mechanism: if a gear was damaged during acceleration, metal particles could enter the oil system and obstruct the propeller regulator valves. This would lead to an uncontrollable overspeed and a decrease in propeller pitch that could not be corrected by feathering, potentially causing the propeller to shear off or creating uncontrollable aerodynamic drag.
Final Conclusions
The Dutch and Irish investigating boards determined that the most likely cause was a malfunctioning outboard propeller. They hypothesized that metal particles, generated by a damaged supercharger gear, obstructed the oil feed line regulator valves. This led to an overspeeding condition where the propeller pitch decreased and could not be feathered. Such a malfunction would occur rapidly, likely leaving the crew with insufficient time to recognize the nature of the failure and restore controlled flight. The board explicitly stated there was no evidence of maintenance neglect, crew error, or a bomb explosion.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Systems & Failure Modes
Wright R-3350 Engine
The aircraft's powerplants, specifically the supercharger gear system, were suspected of generating metal debris.
Propeller Pitch Regulator
Valves that control the angle of the propeller blades; suspected to have been jammed by metal particles, causing an unrecoverable overspeed.
Interesting Facts
- 01The crash was the deadliest civil aviation disaster involving a single aircraft at the time of the occurrence.
- 02Six members of the Egyptian national fencing team were among the 91 passengers killed.
- 03The aircraft had only 886 total airframe hours at the time of the accident.
- 04Only 34 of the 99 people on board were recovered from the ocean.
- 05The aircraft was named Hugo de Groot after the Dutch jurist and philosopher.
Safety Actions & Advisories
Propeller Overspeed Awareness
The investigation highlighted the extreme rapidity of propeller overspeed malfunctions on the Super Constellation, leading to increased emphasis on rapid recognition and emergency feathering procedures.
Known Controversies & Unanswered Questions
Bomb Explosion Hypothesis
Reference ↗Early press reports suggested a bomb might have caused the crash. The investigation board officially addressed these claims, stating they were based on misunderstandings and that no conclusive evidence of an explosion was found.