Aircraft

[ivor4781]

I'm a bit of an aircraft enthusiast (not a spotter) seen hundreds land from around 100 ft + away and yesterday for the first time ever one landed with squealy brakes i though to was so funny , sounded like a car that had worn out brake pads,it was an Embraer 195

[ivor4781]

spelling terrible today "i thought it was so funny" it should read

[retrocop]

Are you sure it was the brakes? I have often heard tyre squeal when a pilot does a hot landing!

[ivor4781]

no i do know the difference retro, this was a high pitch steel on steel noise .the type that sets ya teeth on edge

[retrocop]

Steel on Steel?? That sounds expensive and dangerous for an aircraft! Worn pads spring to mind. Never mind there's always reverse thrust. :-(

[retrocop]

and a ruddy great drogue might help.

[Clanad]

Could be one or more of the brake sets… disc, pads or retainers had just been replaced and "wearing-in", which isn't uncommon. Or could have been a warm day and the pilot-in-command (PIC) didn't have the aircraft exactly aligned with the direction of travel and caused the tires (tyros?) to squeal.

A word about reverse thrust… during demonstration of maximum effort landing when the aircraft is achieving a Certificate of Airworthiness (CofA) when newly manufactured, the short field landing, demonstrating how much runway is required for full stop landing and various weight, temperatures, etc., the aircraft is not allowed to deploy reverse thrust, either turbo-jet reverse thrust devices or turbo-prop reversing of the propeller to aide in shortening the landing distance. It has to be brakes only.

To assist in the controllability, most transport category aircraft, such as the EMB-series, are equipped with anti-skid brakes. No matter how much pressure the pilot applies to the toe-activated brakes, the wheels won't skid, thereby protecting the aircraft from a tire blow-out...

[Clanad]

^ should be (tyres) British spelling and all that…

Additionally, there would be no "steel on steel" noise since the multiple brake "pads" are a synthetic material and closely monitored by airworthiness personnel of the particular air carrier...

[ivor4781]

steel on steel was just ref to the actual sound, i know about aircraft braking systems my main interest is aircraft development and construction be doing this for 40 years, re-verse thrust. speed brakes. the lot

[ivor4781]

and yes clanad they do use reverse thrust you can see the cowling move to allow this if watching them land and also can see it if your a passenger as i did last week returning on a embraer195

[ivor4781]

...sorry i see you mean no reverse thrust on brake testing,yes i know that

[ivor4781]

just found this, so its not a one off then they can squeal,just first time in decades ive heard it
"Brake Squeal
can be defined as torsional vibrations of
non-rotating components about the axle in the
frequency range of 100-1000 Hz. The root cause of this
mode is largely unknown, however, the erratic vibration
phenomenon from flight test suggest that this mode is
caused by the friction character
istics of brake material.
it produces very high oscillatory loads on the landing
gear/brake structure and can
sometimes cause failure. "