Red Panda
Topic Author
Posts: 1433
Joined: Wed Jun 14, 2000 12:58 pm

What Is The Black Smoke Coming Down From The Gears

Thu Aug 21, 2003 2:18 pm


View Large View Medium
Click here for bigger photo!

Photo © Serge Bailleul



It is normal to have smoke coming out from the rubbers on landing, but what is that smoke falling down from the gear on takeoff?



r panda
 
AJ
Posts: 2295
Joined: Wed Nov 03, 1999 3:54 pm

RE: What Is The Black Smoke Coming Down From The Gears

Thu Aug 21, 2003 2:22 pm

During the retraction cycle of the undercarriage the rotation of the wheels is stopped to prevent gyroscopic rotational forces. When the brakes are applied it can cause any excess grease/dirt etc. to burn off as the brakes are absorbing quite a bit of energy, iplus the heat absorbed during taxi.

You can imagine the stress the brakes would be under in a rejected takeoff!
 
JBirdAV8r
Posts: 3454
Joined: Sun Jun 24, 2001 4:44 am

RE: What Is The Black Smoke Coming Down From The Gears

Thu Aug 21, 2003 2:34 pm

It also stands to point out that the tires aren't smoking, but the brakes  Smile/happy/getting dizzy

As AJ already mentioned, I'd guess this particular airplane had a recent RTO or, perhaps, an extended taxi.
I got my head checked--by a jumbo jet
 
AA737-823
Posts: 4988
Joined: Wed Mar 01, 2000 11:10 am

RE: What Is The Black Smoke Coming Down From The Gears

Thu Aug 21, 2003 2:38 pm

Actually, my understanding is that, while both of the above explanations are correct, the actual stuff you see is carbon- because they're carbon brakes, not steel anymore. When the system 'steps' on the brake pedal during retraction, the wheels stop pretty quickly, producing a puff of black carbon powder from the braking surfaces.

R
 
AJ
Posts: 2295
Joined: Wed Nov 03, 1999 3:54 pm

RE: What Is The Black Smoke Coming Down From The Gears

Fri Aug 22, 2003 12:46 pm

Another example:

View Large View Medium
Click here for bigger photo!

Photo © TTT

 
Bronko
Posts: 795
Joined: Tue Jul 03, 2001 3:28 am

RE: What Is The Black Smoke Coming Down From The Gears

Fri Aug 22, 2003 1:18 pm

So why is this not seen on a regular basis? Does this only happen on a visible level when the breaks are new?
Jet City Aviation Photography
 
jwenting
Posts: 9973
Joined: Mon Apr 23, 2001 10:12 pm

RE: What Is The Black Smoke Coming Down From The Gears

Fri Aug 22, 2003 1:35 pm

It only happens when a lot of brake power is used during taxi or when putting on the brakes before gear retraction.
It might also have to do with environmental conditions (if there's a lot of wind the stuff would probably disperse quickly so you don't see it for example).

Personally I've never really noticed it.
I wish I were flying
 
flyingbronco05
Posts: 3484
Joined: Fri May 10, 2002 11:43 am

RE: What Is The Black Smoke Coming Down From The Gears

Fri Aug 22, 2003 1:57 pm

This has been discussed multiple times in the tech/ops forum.

Do a search Smile

fb05
Never Trust Your Fuel Gauge
 
DC10GUY
Posts: 2590
Joined: Fri Feb 18, 2000 5:52 am

RE: What Is The Black Smoke Coming Down From The Gears

Fri Aug 22, 2003 2:19 pm

You will see this on aircraft with "carbon brakes" .
Next time try the old "dirty Sanchez" She'll love it !!!
 
bio15
Posts: 1048
Joined: Fri Mar 23, 2001 8:10 am

RE: What Is The Black Smoke Coming Down From The Gears

Sat Aug 23, 2003 12:47 am

AJ: I'm probably not very familiar with the subject, but I always thought that the stopping of the rotating wheels was to prevent further damage given a tire blowout during retraction inside the bay. Is that correct?


-Alfredo

Who is online

Users browsing this forum: No registered users and 1 guest

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos