Speedbrakes ON BAE146

[HEALY]

Have noticed the deployment of the 'speedbrakes' on the empennage (spelling???) a few times prior to landing on the BAE 146 acft. Are they independant too the spoilers on the wings and what are their intended purposes in flight?

Curiosity has gotten the better of me.

[Capt Claret]

Healy,

SOP on the 146 is to deploy the Airbrake just prior to touchdown to minimise landing roll. The airbrake is independant of the lift spoilers, though both are controlled by the same lever.

The Airbrake lever is on the left side of the centre pedestal. Moving the lever aft causes hydraulic pressure from the Green system to open the Airbrake. It is infinitely controlable between fully closed and fully open, and there is no speed restriction on its use, though as with most drag devices, that faster one is the more effective it is.

When the Airbrake lever is in the fully open position, usually resting against a "gate", once wheels are on the ground further aft movement of only a few centimetres will deploy the lift spoilers.

The lift spoilers are inturn controlled by squat switches to prevent them from deploying in the air, so it would be feasable to select lift spoilers in the air and have them automatically deploy on touchdown, though this is contrary to the AFM and company SOP.

The Airbrake control lever is often fondly referred to at the PCL. The Pilot Correction Lever, it's a wonderful device for correcting botched descent profiles, or, allowing 250 KIAS to inside 10nm from touchdown then slowdown reconfigure and land.

[False Capture]

Just out of interest, the Avro RJ is capable of Cat 3B autolands whilst the BAe 146 is not. The airbrake is deployed by 500' AAL on an autoland approach as opposed to 100'AAL on a normal approach. If you're watching an Avro RJ on approach and the airbrake has been out for a while before landing then there's a good chance an automatic landing is being carried-out.

[HEALY]

Thankyou both for the very informative answers, much appreciated.

[WHBM]

Looking at 146s making the steep (5.5 degree) approach to London City airport, they all seem to have the airbrake deployed throughout finals - possibly it's what enables them to make such an approach in the first place.

[False Capture]

Spot-on WHBM. Before glideslope capture the landing gear and landing flap (33 degrees - maximum available on the 146/RJ) are down. The airbrake is then deployed once the glideslope is captured. If the airbrake is not selected when the a/c starts this steep descent then the speed increases and a go-around is on the cards.

[square leg]

False Capture is correct.

The BAe Avro is CAT3A approved with 150m RVR (special approval).

On Low Vis approaches (CATII & CATIII) the Airbrake is deployed at 600 ft RA according to SOPs (possibly company specific 500 vs. 600)

Oh yes, some call the airbrake a "bird-catcher":D