LH526 From Germany, joined Aug 2000, 2298 posts, RR: 15 Reply 9, posted (7 years 4 months 2 weeks 1 day 3 hours ago) and read 9851 times:
AIRLINERS.NET CREW FORUM MODERATOR
As covered, it's brake dust!
It's safer to have the wheels retracted after they have come to a complete stiop, hence some seconds before retracting the gear the wheels (wich still run at take off speed rotation) will be slowed down by the brakes to prevent rotatation in the wheel well.
Trittst im Morgenrot daher, seh ich dich im Strahlenmeer ...
Lufthansi From Germany, joined May 2002, 454 posts, RR: 2 Reply 10, posted (7 years 4 months 2 weeks 1 day 3 hours ago) and read 9804 times:
Try to take a bicyles wheel and hold in in your hand while it is turning. Now do the movement of the retracting landing gear. The gyro forces would put the whole aircraft in rotation/sideward movement. Gyro forces always react against the force you put in when "retracting" your bicycle wheel. Actio=reactio
This experiment is even more impressive when you sit on a moveable office chair with wheels. It will start to turn during your experiment as a reaction of your input force.
This is how the old standby horizons for i.e. A gyro remains it's axis' direction in a room. So the aircraft is turning around the stby. horizon. No imagine the aircraft to rotate around the landing gear...
Maybe someone finds a good physical site in English...
HAWK21M From India, joined Jan 2001, 31457 posts, RR: 57 Reply 11, posted (7 years 4 months 2 weeks 1 day 1 hour ago) and read 9665 times:
Quoting LH526 (Reply 9): It's safer to have the wheels retracted after they have come to a complete stiop, hence some seconds before retracting the gear the wheels (wich still run at take off speed rotation) will be slowed down by the brakes to prevent rotatation in the wheel well.
Auto Retract Braking serves the Purpose.
PipoA380 From Switzerland, joined May 2005, 1592 posts, RR: 51 Reply 13, posted (7 years 4 months 2 weeks 17 hours ago) and read 6610 times:
I got a mail from someone working at ATC in Amsterdam, here's the mail:
"Probably hot brakes...it is a long way to the runway. He was flying a long time with his gear down , when I asked him if he had any problems....he anwered ..."just hot brakes, keeping the gear down for cooling" That happened somewhere near the date this picture was made."
Excellent coincidence if it really was the same day!
It's not about AIRBUS. it's not about BOEING. It's all about the beauty of FLYING.
I seriously doubt that since it appears as if (judging by the nose gear doors) the gear is beginning the retraction sequence. If it is retracting, the braking that occurs automatically during retraction is the cause, as explained above by a couple of people.
On the planes I work, you can see it each and every time you watch one take off - just after the gear unlocks and begins moving the brakes auto-actuate and there's a puff of black smoke as the dust comes off.