Someone Somewhere...

SixPapaCharlie

SixPapaCharlie

May the force be with you
Joined
Aug 8, 2013
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First Officer 6PC
Will be flying with their left hand for a few weeks.

Saw this on preflight today. Maybe a new FO that was hazed into believing you have to push on the engine to make sure its not loose.


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Hopefully just a mx greasy handprint.
 
Doesn't that section cool down pretty fast?

My guess is someone with a greasy hand got a nice handprint on the cool metal, the engine heated up and polymerized that thin layer of oil left behind.

You could always high five every other FO you come across and figure out who turns you down. That's your tell...
 
Maybe the plane got pulled over and the cop put his hand on the plane as he was walking up to it?


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Brad Z said:
...My guess is someone with a greasy hand got a nice handprint on the cool metal, the engine heated up and polymerized that thin layer of oil left behind....
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I've seen the same sort of marks, though fingerprints, baked onto fired brass.
 
These airplanes have hundreds of people around them in a given day. It could have been one of them or someone in maintenance, who knows. Really it's a huge nothingburger.
 
Just a public service announcement for anyone thinking about it... infrared thermometers will generally not read the temperature of polished or even smooth metal. They'll read the reflection of the temperature of something else. While it's basic physics, I may or may not have learned that a different way with a piece of 2" copper heating pipe.
 
Albany Tom said:
While it's basic physics, I may or may not have learned that a different way with a piece of 2" copper heating pipe.
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OUCH! I did not know that.

FWIW, I've learned most of my basic physics by watching what a person does right after saying to a friend, "Watch this...hold my beer." :p
 
Albany Tom said:
Just a public service announcement for anyone thinking about it... infrared thermometers will generally not read the temperature of polished or even smooth metal. They'll read the reflection of the temperature of something else. While it's basic physics, I may or may not have learned that a different way with a piece of 2" copper heating pipe.
Click to expand...

Correct. To get accurate temperatures, you need to know the emissivity of the surface. It can be 0 (emits nothing) or 1 (perfect emitter). Emissivity of a highly polished metal is close to zero. Whatever temperature you are measuring it not of the metal itself, but the temperature of some other object that is being reflected by that metal. Emissivity of a dark metal, like anodized aluminum, is about 0.8 or 0.9. Most of the IR thermomemters are assuming a number for emissivity of the surface being measured.
 
That would definitely get my attention on preflight
Probably just a maintenance handprint, but still not the kind of thing you want to see on an engine cowling.
 
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