Simplify the following text for a Grade 10 native English-speaking person.
Original: The passengers of the Boeing 737 were freed in an assault carried out by German GSG 9 special forces in the early hours of 18 October 1977 which saw the death of three of the militants .
Simplified: After several weeks that were called the German Autumn , the passengers of the aeroplane were freed in an assault carried out by German GSG 9 special forces in the early hours of 18 October 1977 .