When on short final, it is customary on the 146's and ARJ's to use the Airbrake, to compensate for this, you need to use more thrust, this effectively puts the Aircraft into a nose down attitude.
Try a few practice landings at London City (EGLC), this has a 5.5° glideslope and you won't be able to land there without the Airbrake being set almost at the top of the glide !!
Regards, ................Adrian W.
P.S. the Airbrake lever should be set to maximum of 80% when on approach.
100% is used ONLY on the ground to deploy the Lift Dump Spoilers, this function is manual on the 146's and should be automatic on the ARJ's.
P.P.S. if you have a look at photos of the 146's on final approach, on one of the many aviation photo sites such as