Investigation Summary
On the afternoon of June 14, 1940, Aero Flight 1631 departed Tallinn for the short flight across the Gulf of Finland to Helsinki. The aircraft was carrying seven passengers, including American and French diplomatic couriers transporting over 120 kilograms of diplomatic mail. Approximately ten minutes after takeoff, two Soviet aircraft intercepted the airliner. While generally identified as Ilyushin DB-3T torpedo bombers from the 1st Mine-Torpedo Aviation Regiment, contemporary Soviet naval reports from the submarine Shch-301 initially identified the interceptors as Tupolev SB high-speed bombers. According to later Soviet accounts by Lieutenant General Pyotr Khokhlov, the bombers fired warning shots and attempted to force the aircraft to return to Tallinn, though these claims are disputed by the fact that the Kaleva was a clearly marked civilian airliner on a scheduled flight. The bombers eventually opened fire with machine guns, causing the Junkers to catch fire and plunge into the sea near Keri Island. The Soviet submarine Shch-301, which was patrolling nearby as part of a naval blockade of Estonia, arrived at the scene within 40 minutes. The submariners searched Estonian fishing boats that had witnessed the crash and seized all recovered items, including the diplomatic pouches. A Finnish fighter plane sent to investigate the site was forced to depart after observing the submarine and the debris field. The wreckage remained lost for 84 years until it was identified by diving robots in June 2024 at a depth of approximately 70 to 76 meters.
Final Conclusions
The destruction of the Kaleva was a deliberate act of military aggression against a neutral civilian aircraft. While Soviet reports later claimed the aircraft was engaged in espionage or refused to follow instructions, historians generally view the shootdown as part of the Soviet Union's efforts to enforce a total air and naval blockade of the Baltic states immediately prior to their annexation. The Finnish government's decision to remain silent about the cause until the outbreak of the Continuation War in 1941 was a pragmatic choice to avoid provoking a Soviet invasion of Finland during the Interim Peace.
Video Analysis
No video analysis linked for this case file yet.
Systems & Failure Modes
Ilyushin DB-3
Soviet long-range bombers used to intercept and shoot down the civilian airliner using machine guns.
Shchuka-class submarine
The Soviet submarine Shch-301 acted as a recovery vessel, seizing diplomatic mail and valuables from the water and local witnesses.
Interesting Facts
- 01The aircraft was carrying 227 kilograms (500 lbs) of diplomatic mail, including U.S. military codes being evacuated from Estonia.
- 02The victims included Henry W. Antheil Jr., an American diplomat and one of the first U.S. casualties of the World War II era.
- 03The shootdown occurred during the 'Interim Peace' between Finland and the USSR, following the Winter War.
- 04The wreckage was found in 2024 near Keri Island using underwater robots, confirming the location of the engines and landing gear.
- 05Soviet reports confirmed the seizure of various foreign currencies and two golden medals from the crash site.
Safety Actions & Advisories
Diplomatic Suppression
Following the shootdown, the Finnish government officially suppressed the cause of the crash to avoid provoking a Soviet invasion during the 'Interim Peace'. The true nature of the event was only publicly acknowledged after the outbreak of the Continuation War in 1941.
Wreckage Identification and Memorialization
In June 2024, the wreckage was officially located and identified by Estonian divers using underwater robots, allowing for the formal documentation of the site and closure for the victims' families.
Known Controversies & Unanswered Questions
Soviet Justification for the Attack
Reference ↗Soviet Lieutenant General Pyotr Khokhlov claimed the aircraft lacked identification marks and the crew threatened the bombers with pistols, assertions that contradict the known status of the Kaleva as a clearly marked civilian airliner.