Citation 525, D-ITAN and Boeing 777 300ER, TC-JJA
The crew of D-ITAN were cleared to depart London City Airport on a DVR 4T SID, which required them to climb initially to 3,000 ft amsl. They read back their cleared altitude as 4,000 ft, an error that was not noticed by the Tower controller. At about the same time, TC-JJA was cleared to descend to an altitude of 4,000 ft while turning onto a southerly heading prior to intercepting the ILS for Runway 27R at Heathrow Airport. D-ITAN climbed through 3,000 ft while turning right and passed TC-JJA on a nearly reciprocal heading approximately 0.5 nm away and 100 to 200 ft below. TC-JJA generated three TCAS RAs in short succession but the aircraft did not follow the commands. D-ITAN was unable to generate RAs. The crew of D-ITAN saw TC-JJA in time to take effective avoiding action. Five Safety Recommendations are made.