Rj85

[GeorgeinBrussels]

Hello. I fairly regularly fly with SN Brussels Airlines (for obvious reasons) and almost always on RJ85s or similar. I have noticed that about two minutes after take-off and a similar time before landing, the aircraft lets out this rather alarming groaning sounds that last perhaps five seconds and I have often wondered what that is.

I have travelled on loads of different Airbuses, Boeings etc., but never one that consistently makes the noise that the RJ85/BAe146 makes.

What love to know what causes this.

Many thanks,

George

[Wycombe]

As far as I know (I'm sure someone who operates the type will correct me if I'm wrong), the noise is caused during flap deployment/ retraction. At a certain point in process, the "howl" is caused by a gap between the inboard flaps and the fuselage.

[rekop]

That is correct. The flap settings are 0, 18, 24, 30, 33. The last apr 5degrees of retraction from flap 18 to flap 0 give this charictaristic sound. The same for the first apr 5degrees when the flaps are selected from flap 0 to flap 18.

[GeorgeinBrussels]

Thanks a lot - I had always wondered.

[WHBM]

All discussed here

http://www.pprune.org/forums/showthread.php?threadid=138702&highlight=flap+noise+146