Quite a few times I've sat at the end of D concoure at LGA watching planes go by and I've noticed on the Dash 8's that there is a small pipe sticking out of the rear the engine housing which a white smoke or steam seems to be coming out of during taxi (unfortunately you can't see it at all in this picture). I just was wondering if someone could shed some light on what it's coming from and what is causing it.
Scootertrash From United States of America, joined Aug 2001, 569 posts, RR: 9
Reply 4, posted (11 years 11 months 3 days 15 hours ago) and read 2106 times:
Seems we have some disagreement here. In training (which I admit was a while ago) we were told that was a fuel vent... Then again it was a pilot doing the talking, so ya never know.
Next time I preflight an -8 (it'll be a few weeks until I get my medical back) I will look harder at the aft end of the nacels. If memory serves me correctly, there are two tubes back there, one small and narrow and one wide and unpainted. The wide one is where the smoke comes from.
Yikes! From Canada, joined Oct 2001, 284 posts, RR: 1
Reply 5, posted (11 years 11 months 3 days 14 hours ago) and read 2094 times:
The wide one (about an inch and a half in diameter) is an oil breather tube. Peculiar to the deHavilland series of aircraft and a source of perennial oil staining of the aft nacelles of Twin Otters, Dash 7's & 8's.
Any fuel that is purged during engine shutdown goes into a collection cannister which vents elsewhere during flight.
The little tube is at 90 degrees to the airflow and is a pneumatic trigger mechanism once sufficient airspeed is reached to dump that purged fuel from a dedicated cannister in the nacelle. That fuel goes out a separate line well away from the engine exhaust.
Viflyer From US Virgin Islands, joined May 1999, 502 posts, RR: 0
Reply 9, posted (11 years 10 months 4 weeks 1 day 15 hours ago) and read 1914 times:
Thanks all for the replys, I use to be LGA based and I couldn't get a straight answer from any of the crews I worked with (mainly because all of them mostly flew Metros, J32s, Saabs, and ATR's).