Just a quick a/c specific question...

[Bsmiller05]

I have noticed two specific occurrences from my work as a line guy and have wondered about their cause:

- On Challengers, I notice quite a bit of condensation or water vapor when they're on the ground with the APU running (especially occuring in the flight deck). What's the reason behind this as opposed to other aircraft not having such a noticeable vapor "appearance?"

- On two different days, both of which were rainy, I was marshalling a Citation X, and as each engine had stabilized after startup, I could see a tornado-like "cloud" appear for a few seconds and then dissapear. Each time, it would occur right at the intake of the engine on the surface of the wing.

Any info on these topics would be appreciated. Thanks!

 

[Killtron2000]

I don't know about the challenger but the tornado on the citation x is from humid air being sucked into the engine at a high enough velocity that the pressure drop and corresponding temperature drop causes condensation so it becomes visible. Or it could just be sucking water in off the wing if it was wet.

 

[gatorbuc99]

You can see that on any wing mounted engine when the conditions are right

 

[trafficinsight]

Back when I worked the ramp, someone told me the Challenger has a humidifier installed... I can't vouch for the accuracy of that statement, though it would explain the moisture.

 

[falconvalley]

- On Challengers, I notice quite a bit of condensation or water vapor when they're on the ground with the APU running (especially occuring in the flight deck). What's the reason behind this as opposed to other aircraft not having such a noticeable vapor "appearance?"

When you run cold air on a hot and humid day, you might see some condensation, especially with certain environmental systems. They all cause it, but some more noticable then others.

 

[OldTownPilot]

I have noticed two specific occurrences from my work as a line guy and have wondered about their cause:

- On Challengers, I notice quite a bit of condensation or water vapor when they're on the ground with the APU running (especially occuring in the flight deck). What's the reason behind this as opposed to other aircraft not having such a noticeable vapor "appearance?"

Any info on these topics would be appreciated. Thanks!

When you run cold air on a hot and humid day, you might see some condensation, especially with certain environmental systems. They all cause it, but some more noticable then others.

It's the same thing why you get condensation on the outside of a cold beer on a hot day. The air that it touching the plane is cooled below the dew point.

As for the tornado looking cloud, its probably water being sucked up off the wing.

 

[tonyw]

It's the chemgoo dispenser getting fired up.