Fokker 50 vapour
 

Watching a VLM F50 pushing back today, both engines running, I noticed a jet of vapour (steam?) from the rh side level with the leading edge of the stab at about cabin floor height.

I'm guessing it is something to do with the APU but a definitive answer would be welcome.

Ta!

I'm not sure if there is an APU on the F50. If the F50 has the same pnuematic systems as the F27 (??), could it be some moisture venting out from a outflow outlet of a pneumatic system? Or an outflow for the de-ice boots if it was the first flight of the day.

Mr L.

I would say it was discharge from the air conditioning packs which are positioned at the back.
The F50 can come with an APU in the right nacelle, although I believe if fitted, VLM have removed them. Guess it's better to carry an extra 300kg of payload out of LCY

Thanks for that, Imhotep.
Makes sense if the AC packs are in the empennage.:ok:

Similar question - anyone know why the 717 emits smoke around the starboard engine? As far as I can tell, it is NOT APU related.

It probably is APU related. I ´m not sure about the 717 but all DC-9´s and MD-80/90 aircraft have the apu exhaust emerging through the fuselage on the starboard side just above the stubwing (the small wing that the engine is attached to).

Not sure, as the reason I said not APU related is because the smoke seems to eminate from between the exhaust cone and the reverser bucket clams on the bottom side. Just a relatively thin whisp.

Maybe just oil or lubricant burning off, but seems odd to be ALWAYS the starboard side, and always at the bottom of the exhaust cone area. I have seen it pretty close up at some airports.