811.2360H/10–1546: Telegram
The Acting Secretary of State to the Chargé in Yugoslavia (Hickok)
838. Urtel 1055 Oct 15.17 You should reply to FonOff note Oct 11 substantially as follows:
“US Govt has noted statement in Mins note 11928 Oct 11 refusing payment indemnity for two unarmed Amer transport planes shot [Page 977] down by Yugo fighter aircraft Aug 9 and 19, 1946, respectively, alleging ‘these planes were flying over Yugo territory definitely illegally under perfect weather conditions’.
As pointed out in US Govts previous communications to Yugo Govt aircraft shot down Aug 9 had unexpectedly encountered adverse Aveather, consisting of heavy clouds, icing and high winds. According to testimony of pilot this plane, who had been carefully instructed to avoid flying over Yugo territory, he was on instrument flight at about 15,000 feet and searching for way to emerge from overcast. When he came out of clouds he realized he had drifted off his prescribed course. Before he was able determine his location his plane was attacked by Yugo fighters. His presence over Yugo territory was entirely caused by circumstances beyond his control, and as such can only be considered to have been a result of force majeure.
Testimony of pilot of aircraft shot down Aug 19 cannot be obtained. Nonetheless, meteorological records available to US Govt clearly demonstrate inclemency of weather at time on flight route this ill-fated aircraft. At time of departure this plane from Vienna weather reports then available covering its prescribed route indicated winds 15 miles an hour at 10,000 feet and icing at 12,500 feet—weather conditions which were not sufficiently adverse to cause postponement or cancellation this flight. Pilot this plane, Captain Claeys, accordingly departed at 8:29 AM local time as planned.
Meteorological data prepared shortly after Captain Claeys’ departure and testimony of Major James E. Gordon, pilot of another plane which took off from Vienna for Udine enroute to Pisa at 9:23 AM local time, less than one hour subsequent to Captain Claeys’ departure, reveal that weather conditions encountered by Captain Claeys were in reality much more severe than latter expected. Strataform and cumulus clouds actually extended over much of prescribed flight route. In place of 15 mile an hour wind of which both Captain Claeys and Major Gordon were informed, actual force this wind as estimated by Major Gordon was between 30 and 40 miles per hour at 10,000 feet.
All available evidence thus leads to conclusion that Captain Claeys’ plane encountered materially increased cloud formation and materially increased wind velocity over what he had been led to expect. Conditions such as Captain Claeys actually met require that flight be performed on instruments since it is impossible to maintain visual contact with ground. Captain Claeys’ plane did not have necessary equipment to ascertain wind strength. It must therefore be assumed that pilot was flying on instruments and was not aware of exact extent of increase in wind velocity. He was thus unable make necessary adjustments in his course to avoid being blown over Yugo, a position which in accordance with standing directives he had been carefully instructed to avoid. Hence this plane, like its Aug 9 predecessor, was over Yugo territory only for reasons of force majeure.
It is an established principle of international practice that prior permission for flight through air space of a particular state is not required when flight is occasioned by force majeure. Marshal Tito in his conversation with Amb Patterson Aug 22, 1946 (urtel Aug 22 9 PM18) stated that Yugo will always accept planes forced off course [Page 978] for weather trouble, loss of direction or mechanical difficulties. Consequently, and in view circumstances outlined above, US Govt emphatically rejects contention of Yugo Govt that these two planes were illegally over Yugo territory. US Govt must therefore again request Yugo Govt reconsider its position in regard to compensation for loss of two US aircraft concerned.”