Avro RJ100s are to be banned from operating from London City after 31 March, because of noise levels fractionally above those permitted under the stringent Category A designation (94.5 PNdB). Although this technical breach has been reduced from 0.6 dB in 2013 to 0.1 dB above Category A in 2015 — a level imperceptible to the human ear — a ban on RJ100 operations was a condition of the new Planning Permission granted by the Department of Transportation for the airport’s expansion. Currently, only Swiss operates the RJ100 at London City, on three daily round-trips from Genève (LX442/443, LX434/435, and LX446/447) and, in combination with Helvetic ERJ 190s, on four of its five roundtrips from Zürich (LX450/451, LX456/457, LX464/465, and LX455/456).
The supposed ban has clearly not been effectively implemented as G-JOTS (see http://smiliner.com/2017/06/jota-avro-rj100-enters-service/ ) has operated several flights to/from LCY for CityFlyer Express, as reported here: http://thebasource.com/jota-aviation-rj100-g-jots-operates-for-ba-cityflyer-2/ Perhaps the ban will come into effect when works specified in that planning application commence.