What are these two tail elements of the Avro RJ100? What are these two tail-side elements of British Aerospace Avro RJ100 and what is their function:



Photo source: Eric Verplanken, jetphotos.net.
The one behind is an aerobrake. The tail opens up to increase drag. It is much better seen in this Wiki image:



The one in front looks instead like the APU exhaust.