The crew of a ContactAir Fokker 100 on behalf of Lufthansa, registration D-AFKE performing flight C3-288/LH-288 from Berlin Tegel to Stuttgart (Germany) with 73 passengers and 5 crew, received an unsafe gear indication after lowering the gear on appraoch to Stuttgart, aborted the approach and entered a holding to troubleshoot the problem. The main gear could not be lowered despite 90 minutes troubleshooting, so that the crew was forced to land without main gear at 10:49 local (08:49Z). The airplane landed on its belly on runway 07 and was evacuated via slides. One passenger and one flight attendant received minor injuries, five passengers needed treatment for shock at the airport. The damage to the airplane is not yet known. Fokker Services reported on Sep 19th, that the metal piece about the size of a coin originated from a valve that had long been removed from the aircraft. The airplane had undergone a C-Check at Fokker Services in August before it was handed over to ContactAir on Sep 1st 2009. Due to the size of the piece Fokker Services doubt, that the piece would have been discovered in any check. The runway was closed until 18:30 local (16:30Z) - in the meantime takeoffs and landings of small aircraft were possible after authorities granted permission to use the parallel taxiway for such takeoffs and landings. A total of 167 flights had to be cancelled.