Back in January, just as the Bundeswehr (German army) mission against Isis was getting started, the six Tornado jets were making headlines for the wrong reasons.
The Defence Ministry revealed at the time that the jets couldn’t fly at night because pilots were being blinded by a cockpit light that was far too bright.
On Thursday, the Bundeswehr had to admit that the fleet had been grounded again. According to DPA, the problem is a loose screw on the monitor in the cockpit.
The Bundeswehr has a total of 85 Tornados, and 39 of them have been affected by the defect, including all six involved in the Isis mission.
A spokesperson for the military said on Friday it was not possible to tell how quickly the problem could be solved.
The defect was discovered at by the producer in Germany on Wednesday. The planes were then grounded “in order to rule out any kind of danger to personnel and material,” the Bundeswehr announced.
The six aircraft are fitted with surveillance technology, and have been touted as being capable of taking high-resolution photos and infrared images, even at night and in bad weather. It is unclear whether bombing missions carried out by other countries can continue without the surveillance images gathered by the Tornados.
Based in the NATO base of Incirlik in Turkey, the Tornados form the backbone of Germany’s commitment to the international coalition against Isis. The Bundeswehr has also provided a refueling jet to support bombing missions and a frigate to protect French fighter jets stationed in the Mediterranean.
Earlier in the week, German MPs visited the military base for the first time since Turkey blocked official visits in retribution for the Bundestag (German parliament) voting to recognize the First World War-era Armenian genocide in June.
Germany's military has faced criticism in recent years over the state of its weaponry.
Its G36 assault rifle - which is being phased out by the army - became the butt of jokes after reports that it had trouble firing straight at high temperatures.
Der Spiegel magazine has also reported that only four of the military's 39 NH90 helicopters were usable.
The army also admitted in 2015 that the external fuel tank of one of its Eurofighter combat planes fell off as it was preparing for takeoff.