Watch your jetblast
A Lufthansa Boeing 747-800, registration D-ABYJ performing flight LH-403 from Newark,NJ (USA) to Frankfurt/Main (Germany), had safely landed on Frankfurt's runway 25L and was taxiing to its gate C15 via taxiway N. While turning left off taxiway N onto gate C15 the engine exhaust gasses hit two airport busses serving another aircraft at parking position V129 and caused a number of bus windows to shatter. Flying splinters of glass injured one of the 70 passengers on one of the busses.
On Dec 4th 2015 Germany's BFU reported in their August bulletin that according to the flight data recorder the aircraft's speed reduced from 5 to 1 knot while turning left into the gate, the #4 engine accelerated to 50% N1 with engine #1 remaining at 40%, engine #2 at 0% and engine #3 at 43% N1. The aircraft's speed increased to 7 knots afterwards.
The first bus received a shattered window on the right hand side between front and middle door, the left hand engine cover at the rear of the bus was torn away. The second bus received two shattered windows at the left hand rear of the bus, the splinters exited the bus through the opened right hand aft door and were distributed all over stand V129. The flying splinter caused a minor facial injury to one of the 70 passengers aboard that second bus.
The BFU reported that the airline stated in their operations manual: "[…] Idle thrust is adequate for taxiing under most conditions. A slightly higher thrust setting is required to begin taxiing. […] Breakaway power should be limited to 40% N1!" In another section of the operations manual it is written: "One or two engine(s) should be shutdown for environmental reasons and fuel saving, taking into account condition of taxiways and ramps (i.e. upslope, icing etc.). […] Two engines out taxi-in permitted if all conditions are favorable (e.g. weight, taxi route, weather)."
On Jul 4th 2016 the BFU concluded their investigation with their factual report without conclusions or analysis.